Urban Meteorology

Meeting Weather Needs in the Urban Community

Office of the Federal Coordinator for

Meteorological Services and Supporting Research

FCM-R22-2004

January 2004
THE FEDERAL COMMITTEE FOR 

METEOROLOGICAL SERVICES AND SUPPORTING RESEARCH 

VADM CONRAD C. LAUTENBACHER, JR., USN (RET.) 

Chairman, Department of Commerce 

VACANT 

Office of Science and Technology Policy 

DR. RAYMOND MOTHA 

Department of Agriculture 

BRIG. GEN. DAVID L. JOHNSON, USAF (RET.) 

Department of Commerce 

MR. ALAN SHAFFER 

Department of Defense 

DR. ARISTIDES PATRINOS 

Department of Energy 

DR. ROBERT M. HIRSCH 

Department of the Interior 

MR. RALPH BRAIBANTI 

Department of State 

MR. RANDOLPH LYON 

Office of Management and Budget 

 MR. JAMES H. WASHINGTON 

Department of Transportation 

MR. ANTHONY LOWE 

Federal Emergency Management Agency 

Department of Homeland Security 

DR. GHASSEM R. ASRAR 

National Aeronautics and Space 

 Administration 

DR. MARGARET S. LEINEN 

National Science Foundation 

MR. PAUL MISENCIK 

National Transportation Safety Board 

MR. JACK R. STROSNIDER 

Nuclear Regulatory Commission 

MR. HENRY L. LONGEST (Acting) 

Environmental Protection Agency 

MR. SAMUEL P. WILLIAMSON 

Federal Coordinator 

 

 MR. JAMES B. HARRISON, Executive Secretary 

 Office of the Federal Coordinator for 

 Meteorological Services and Supporting Research 

THE INTERDEPARTMENTAL COMMITTEE FOR 

METEOROLOGICAL SERVICES AND SUPPORTING RESEARCH 

MR. SAMUEL P. WILLIAMSON, Chairman 

Federal Coordinator 

MR. THOMAS PUTERBAUGH 

Department of Agriculture 

MR. JOHN E. JONES, JR. 

Department of Commerce 

RADM STEVEN J. TOMASZESKI, USN 

United States Navy 

Department of Defense 

BRIG. GEN. THOMAS E. STICKFORD, USAF 

United States Air Force 

Department of Defense 

MR. RICKEY PETTY 

Department of Energy 

MR. LEWIS T. MOORE 

Department of the Interior 

MR. JEFFREY MACLURE 

Department of State 

VACANT 

Federal Aviation Administration 

Department of Transportation 

 DR. JONATHAN M. BERKSON 

U. S. Coast Guard 

Department of Homeland Security 

DR. S. T. RAO 

Environmental Protection Agency 

MR. JOHN GAMBEL 

Federal Emergency Management Agency 

Department of Homeland Security 

DR. RAMESH KAKAR 

National Aeronautics and Space 

 Administration 

DR. JARVIS MOYERS 

National Science Foundation 

MR. DONALD E. EICK 

National Transportation Safety Board 

MS. LETA A. BROWN 

Nuclear Regulatory Commission 

MS. ERIN WUCHTE 

Office of Management and Budget 

MR. JAMES B. HARRISON, Executive Secretary 

 Office of the Federal Coordinator for 

 Meteorological Services and Supporting Research

Cover Photos (clockwise): 

Top: Hurricane Isabel storm surge, Baltimore Inner Harbor, Top right: Transformer fire after lightning strikes (AP Wide World Photos) 

Lower Right: F2 tornado, Ft. Worth (Ft. Worth Star-Telegram photo, Carolyn Bauman), Lower left: Toxic fumes (AP Wide World 

Photos), Top Left: Los Angeles smog (California Air Resources Board), Center: Atmospheric dispersion model graphic (DTRA) 
OFFICE OF THE FEDERAL COORDINATOR 

FOR 

METEOROLOGICAL SERVICES AND SUPPORTING RESEARCH 

8455 Colesville Road, Suite 1500 

Silver Spring, Maryland 20910 

Urban Meteorology 

Meeting Weather Needs in the Urban Community 

FCM-R22-2004 

Washington, DC 

January 2004 
 iii 

Foreword 

Urban meteorology has come to require much more than observing and forecasting the 

weather of our cities and metropolitan areas. Scientific and technological advances of the 

past several decades enable us to predict a wider set of environmental parameters at finer 

spatial scales, for times ranging from the next hour (in nowcasting) to the next several 

months (for seasonal and climate predictions). As these capabilities have improved, the 

range of potential uses for the information has increased. Even more important, the 

potential value of this information has risen dramatically—provided we can deliver 

reliable information, in formats useful to those who can use it, within the time constraints 

of their decision processes. So understanding who needs the data, what data are truly 

useful and important to these users, and when they need it are tasks just as important to 

urban meteorology as producing the data from observations and predictive tools. 

The diversity and potential value of the applications means that the mission areas of 

many Federal agencies may become involved somewhere along the branching paths from 

observations to applications. Joining them are State and local entities, which are often 

key decision makers and users of the information, as well as stewards for the ultimate 

stakeholders: the residents and businesses of our urban communities. The business sector 

includes partners essential to the production, interpretation, and delivery of 

meteorological information, as well as users of that information. Partners in the academic 

community provide expertise in research, public outreach and education, and the 

innovation and evaluation of products at each step in the process of information creation, 

delivery, and application. To reap the full potential of urban meteorology for our urban 

communities and the nation as a whole, all these partners must participate. 

The discussion framework that follows presents the concept of urban meteorology, the 

principal application areas on which we should focus first, and the roles of the principal 

partners. My intent is not to have the final word on this complex, still evolving field but 

to initiate and foster a broad dialogue among all interested parties. From that dialogue 

will come the agreements, the shared values and objectives, and the recognition of 

common problems through which our combined efforts to improve urban meteorology 

can be coordinated and made more productive. 

 //Signed// 

 Samuel P. Williamson 

 Federal Coordinator for Meteorological 

 Services and Supporting Research 
v

TABLE OF CONTENTS 

Foreword...................................................................................................................... iii 

Introduction....................................................................................................................1 

Elements of Urban Meteorology....................................................................................2 

Severe Weather ........................................................................................................2 

Homeland Security...................................................................................................6 

Air Quality ...............................................................................................................8 

Water Quality.........................................................................................................10 

Climate...................................................................................................................11 

Crosscutting Urban Weather and Climate Issues/Components ...................................12 

Integrated Global Observations .............................................................................12 

Research and Technology Tools............................................................................12 

Education, Outreach, and Training ........................................................................13 

Risk Management ..................................................................................................13 

Health Effects.........................................................................................................13 

Information Dissemination ....................................................................................14 

Business Continuity Planning................................................................................14 

Regional Ecosystem Planning and Management...................................................14 

Current Capabilities and Limitations in Weather and Climate Services 

and Products ............................................................................................................15 

Federal Agencies....................................................................................................15 

State and Local Governments ................................................................................17 

Industry and the Private Sector..............................................................................17 

Universities ............................................................................................................17 

Why Focus on Urban Meteorology Now? What Next?...............................................18 
 1 

Introduction 

In recent years there has been increased national and international attention focused on 

the need to address urban weather and climate issues. Of the approximately 280 million 

people living in the United States in 2000, nearly two thirds live in urban areas occupying 

less than two percent of the U.S. landmass. Weather extremes in the urban area are 

responsible for thousands of deaths annually, many of which could be avoided by more 

specific or accurate forecasts, advisories and warnings. To deal with weather and climate 

hazards to safety and property, urban leaders and managers are demanding more accurate 

and specific weather and climate information for use in their decision processes. In 

response to this demand, Urban Meteorology, a specialized, interdisciplinary approach to 

studying the natural and social environmental elements associated with urban 

communities, has gained attention and importance in science, technology development, 

and in applications to a wide spectrum of operational activities. 

Weather has special and significant impacts on people living in large urban areas. Heavy 

rains can cause severe flooding, snow and freezing rain can disrupt transportation 

systems, and severe storms with accompanying lightning, hail and high winds can cause 

power failures. High winds can also slow or stop the progress of automobiles, 

recreational vehicles, rail cars, transit vehicles, and trucks. The urban zone is especially 

susceptible to landfalling hurricanes because of the large numbers of people at risk (a 

large percentage of U.S. urban population lives within 50 miles of the Atlantic or Gulf 

coasts), the high density of manmade structures, and the increased risk of flooding and 

contamination of potable water supplies. 

A compelling case can be made for raising the priority for addressing key issues in urban 

meteorology. The opportunity to address urban meteorology is a result of three basic 

factors: (1) technological advances, (2) concern for national security, and (3) concern for 

public health and safety. With respect to technology, advances in remote sensing and 

other observing platforms have made urban observations on the subregional scale 

possible. The evolution of coupled computer models linking the atmosphere, soil, ocean, 

and biospheric processes along with smaller grid scale has contributed to the ability to 

assess and predict more accurately the state of the urban environment. The increasing 

capacity of computer and communications networks facilitates storing and disseminating 

vast quantities of data quickly. Geographic Information System mapping is a mechanism 

for capturing and integrating observations and modeling data seamlessly into userfriendly information. 

Recent national and international events have heightened attention to acts of terrorism 

particularly in urban centers with their large populations. Nuclear, biological, or 

chemical (NBC) releases whether intentional or accidental result in air, water, or soil 

contamination. These types of contaminants can result in instant death or prolonged 

illness due to exposure. NBC exposure can also result in genetic and physiological 

mutations of a vast number of living organisms including humans, plants, and animals. 

NBC exposure, then, can seriously disrupt a functioning society for a protracted period. 
 2 

Public health and safety in the urban areas are primary concerns for individual citizens, 

governments, and businesses. Studies have found a correlation between disease in the 

urban environment and hydrometeorological processes. Whether these diseases are 

chronic (rheumatic, coronary, neurological), seasonal (allergies), or psycho-social 

(violent behavior, slow reaction to stimuli), the large number of people in the urban 

environment who could be affected by these hydrometeorologically-induced conditions 

and the repercussions on business and the healthcare system are all cause for concern. 

Elements of Urban Meteorology 

This discussion framework highlights five primary focus areas within urban meteorology: 

severe weather, homeland security, air quality, water quality, and climate. Each focus 

area with attendant impacts is described below. 

Severe Weather 

Urbanized areas can vastly aggravate the flash flooding associated with hurricanes and 

other types of severe precipitation events. Changes in surface characteristics in urban 

areas, lead to rapid runoff of precipitation and flooding. In vegetated areas much of the 

water is temporarily intercepted by leaves, needles, and trunks. Some of it is evaporated 

by the plants. The forest litter is a particularly effective storage medium. The radical 

change of surface from permeable soils and vegetation to impermeable pavements, 

parking lots, and roofs shortens the time rain or melt-water reaches the water collection 

areas. 

These severe precipitation events impact the built environment as well. Populations in 

low-income housing (be it trailers, tenement apartments, etc.) are very vulnerable to 

extreme weather events, as structures are often flimsy and located on land subject to 

frequent flooding. Hailstorms and winds can also damage property, including the built 

Hurricane Claudette came 

ashore in Texas on July 

15, 2003, peeling off roofs 

of homes such as this one 

in Palacios, Texas, 

knocking out power and 

flooding low lying areas. 

(AP Wide World Photos) 
 3 

environment, automobiles, utilities, and other urban infrastructure such as traffic signs 

and public transportation vehicles. 

The impacts of severe winter weather on energy supply, demand, and price are multifaceted. Weather extremes generally are much more frequent than seasonal extremes. 

For example, in a given winter, it is not uncommon to have several three-day periods of 

extremely cold days, even though the average temperature for that winter may be quite 

near the long-term seasonal average. As a result, the principal impacts on energy demand 

arise from short-term weather extremes that force energy suppliers to look to the “spot 

market,” thereby dramatically raising the price. Variability below a threshold (whose 

value depends on the resiliency of the portion of the energy delivery system in question) 

can be readily handled by existing system operating protocols. Greater variations, 

however, demand extreme operating measures and trigger price volatility. Forecasting of 

Severe Storms 

Preparation Costs versus Cost Avoidance 

Improvements in forecast skill for severe storms, including hurricanes, tornadoes, and major winter storms, 

clearly save lives and lessen the risks of injury. The extent to which improvements in storm prediction have 

also brought economic benefit is harder to assess. For storms that can be forecast with sufficient lead time 

to protect property (as well as lives), such as hurricanes or major winter storms, the economic benefits of 

preparation (cost avoidance) are typically far more difficult to quantify than are the economic costs of 

preparation. 

For example, the costs of preparing for Hurricane Isabel, which made landfall just south of Cape Hatteras, 

include the evacuation of 300,000 residents in North Carolina and Virginia. A number often cited for the 

cost of evacuation and other hurricane preparations—although its factual basis is unclear—is $1 million per 

mile of affected coastline. Airlines canceled 7,000 flights on Thursday, September 18, the day Isabel made 

landfall, at a potential loss estimated at $50 million. However, the ABC News story that quoted this figure 

did not include an estimate of the potential costs in aircraft damage or schedule upsets (not to mention 

economic costs of any lives lost or injuries incurred), if those flights had not been canceled. Nor was there 

an estimate of how many of those lost dollars were regained after the storm passed and passengers 

rebooked, filling up otherwise empty seats. 

By contrast, estimates of the value of cost avoidance are difficult to find, except in anecdotal form. Kristen 

Lentz, the director of public utilities for Norfolk, Virginia, decided on September 15, three days before 

Isabel hit the area and took down its electric power grid, to spend public funds to rent generators for the 

water treatment plant that serves Norfolk, Virginia Beach, and the Norfolk naval bases. Afterward, she 

described her expense as “the best $100,000 we’ve spent in a long time.” Similarly, Admiral Robert J. 

Natter, commander of the Norfolk-based Atlantic Fleet, said that sending the Navy’s ships out to sea before 

Isabel struck cost million of dollars, but he added that the expense would have been far greater if the ships 

had been battered by the hurricane while still in port. Although the cost of plywood to protect windows 

from flying debris was cited in many news stories, the economic benefits of three days’ notice to do so were 

never mentioned. 

The difficulties in measuring cost avoidance from preparations for severe weather can lead the unwary to 

ignore these hidden benefits altogether. A reporter for the Baltimore Sun, in a story the day before Isabel 

struck, noted that a person’s chances of surviving a hurricane are much better now than they were 50 years 

ago. But he added, “improvements in weather predictions haven’t helped brick and mortar.” Owners of 

businesses and homes who had time to board up windows, check sump pumps, and clear furnishings and 

goods from lower floors may have a different view. With respect to preparations for severe weather, it 

seems too convenient to ignore the old proverb that “an ounce of prevention is worth a pound of cure.” 
 4 

these extreme events is therefore more important than detailed forecasting of routine 

variability. 

Meteorological extreme events not only create increased energy demand and price 

volatility but can also disrupt energy delivery capability and service to the consumer. In 

some cases, nature imposes an obviously disruptive event. For example, an ice storm can 

down power lines. Moreover, in the current deregulated, low energy-margin 

environment, a simple error of a few degrees in the daily temperature forecast can 

translate into unanticipated energy demands that trigger alerts in the power grid, spot 

price volatility, or rolling brownouts or blackouts. Because the energy demand for 

summer cooling is much more dependent on a single energy source—electricity—than is 

winter heating, severe summer weather often stresses urban energy supply systems more 

than does winter heating. 

Severe weather has a significant impact on transportation (whether it is the transport of 

goods, products, people, etc.). The availability of surface transportation has 

repercussions not only on the transport of goods and services but also on the ability of the 

public to evacuate and the emergency responder to respond. 

Icing, snow depth exceeding a few inches, and drifting snow can make roadways and 

bridges impassable. More than 6,000 roadway deaths per year are attributable to weather. 

High winds accompanied by blowing and drifting snow can slow or stop the progress of 

automobiles, recreational vehicles, trucks and ships. Below-freezing temperatures or the 

presence of ice can adversely impact marine transportation. In the U.S. the impact of ice 

on marine transportation is particularly evident in the Great Lakes and upper Mississippi 

areas. The commerce that takes place on these waterways can be slowed or stopped by 

prolonged or repetitive freezing conditions. Icing conditions can even adversely impact 

After a power blackout 

across the Northeast in 

August 2003, 

pedestrians leaving 

Manhattan flood New 

York’s 59th Street Bridge 

to Queens. A prolonged 

period of summer heat 

and high humidity, 

which increased energy 

demand for air 

conditioning, was one 

factor in the massive 

power grid failure. (AP 

Wide World Photos) 
 5 

the flow of natural gas and oil within pipelines. Extremely cold weather can snap or 

severely damage cables that support suspension bridges. 

Icing and fog reduce visibility and may have an adverse impact on aviation. With 

appropriate hydrometeorological information beforehand, the aviation community can 

take appropriate steps to minimize the adverse impacts of winter storms. For example, 

knowing when and where winter storms will occur could minimize the need to carry 

needless excess fuel. 

The devastation caused by hurricanes, tornadoes, and flooding on the urban environment 

has been chronicled for decades in the media and scientific journals. However, the 

impact of the urban environment on severe weather is not so widely known. For 

example, an urban barrier effect can alter synoptic and mesoscale systems passing over a 

large metropolitan area. In New York, the city has been shown to decelerate (1) air flows 

during non-urban heat island periods, (2) slow moving synoptic cold fronts, and (3) sea 

breeze fronts. These decelerations were linked to a persistent horizontal divergence 

pattern produce by the city, in which prevailing flow split to form two streams that went 

around the city. During urban heat island periods, it has been shown that the urban 

landscape can enhance convection due to either mechanical convection and/or the heat 

emanating from the urban building configuration. 

Urban areas, particularly those with densely aggregated, tall buildings provide wind 

tunneling which can enhance or produce wind speeds that are not observed in less builtup environments. The contrast in the air temperature as cooler air from a rural area or 

marine area advects toward the city can result in a cold front near the outskirts of a city. 

Under certain conditions this type of cold front can impact (mitigate or enhance) a 

mesoscale or synoptic weather pattern. While it remains to be clarified and 

demonstrated, local “hot spots” such as the urban landscape, may play a more significant 

role in convection initiation than previously realized. In essence, the violent weather 

hazards (such as tornadoes and convective thunderstorms with their associated hail, 

lightning, and strong winds) and more frequent milder disruptions are often facilitated by 

conditions that are locally favorable for extreme weather. 

Local hailstorms and thunderstorms may be a disaster to crop and gardens within the 

urban environment, pounding young plants into the ground, shredding leaves, or 

shattering flowers and seed heads. Hailstorms, thunderstorms, and dust storms, and their 

associated winds can cause severe damage to urban stands of vegetation, just as they do 

to a standing crop in agricultural settings. This damage is mechanical in nature. In dust 

storms, the dust is raised by the wind and can be carried several kilometers away. It 

causes damage to the plants, particularly small plants, by covering them fully with dust, 

resulting in changes to metabolic processes (photosynthesis, for example). Hailstorms 

and thunderstorms cause direct damage to plants. 

Most heart diseases are caused by arteriosclerosis and have an important meteorotropic 

aspect. They can be classified as coronary thrombosis (formation of a blood clot in the 
 6 

heart or coronary artery), myocardial infarction (deficient blood supply in the heart 

muscles), angina pectoris (paroxysmal thoracic pain). Research strongly suggests a 

meteorotropic relationship between the passage of weather fronts and the increased 

occurrence of these diseases. Heart failure has been shown to occur more frequently with 

the passage of active weather fronts, either cold or warm. Heat waves in urban 

environments increase the risk of heatstroke, heart attack, and other heat-related death 

and illness, particularly for susceptible populations (Figure 1). 

A considerable number of studies have been devoted to the possible direct influence of 

weather and climate on mental processes. Studies examined the relationship between 

year-to-year shifts in temperature and violent and property crime rates in the U.S. A 

positive relation between temperature and serious and deadly assault was observed, even 

after poverty and population age effects were statistically controlled. Similarly, other 

aggressive behavior such as spousal abuse and road rage has been examined with similar 

findings. Violence, a decreased stress tolerance, and ambient temperature are 

curvilinearly related. Specifically, ambient temperature was directly associated with the 

frequency of violence through the mid-80s (Fahrenheit). Beyond this point, however, 

further increases in temperature were associated with a decreasing incidence of violence. 

Restlessness of school children is another condition that has been observed as having a 

meteorotropic influence. It was found that children are more restless during warm events 

than during cold events. For example, school children were found to be more restless 

right before a thunderstorm. This unrest was due to the thermal stresses (heat and 

humidity), which affect the inefficient thermoregulatory system of young children. 

Homeland Security 

When a technological hazard occurs, the primary vectors for spreading the hazardous 

materials are air and water. Most pollution releases occur in the atmospheric boundary 

layer (ABL, that portion of the atmosphere where the earth’s surface (land or water) has a 

direct influence). The stronger the wind shear within the ABL, the stronger the resulting 

Figure 1. Heat-related 

deaths (bars), maximum 

temperature (Tmax), and 

heat index (HI) during the 

Chicago heat wave of July 

11–23, 1995. Adapted 

from National Oceanic 

and Atmospheric 

Administration, National 

Disaster Survey Report: 

July 1995 Heat Wave. 

U.S. Department of 

Commerce, December 

1995, Figure 9 (pg. 23). 
 7 

mechanical turbulence. Thermal effects can counterbalance or enhance the effects of 

wind-induced mechanical turbulence. When the surface temperature is greater than the air 

temperature, dynamic turbulence results and the buoyancy forces intensify the turbulence 

due to wind shear. Hazardous gases or aerosols are transported upward, then dispersed 

laterally by the prevailing wind, forming an atmospheric plume (Figure 2). If the ABL is 

relatively stable, less dispersion occurs. The urban canopy plays an important role in 

varying the ABL. The presence of buildings and other structures affects not only flow 

fields but also the intensity of atmospheric turbulence and ultimately the depth of the 

ABL. 

Depletion is the process by which pollutants are removed from the atmosphere. Clouds, 

precipitation, fog, radioactive decay, and soil deposition on the ground are ways in which 

pollutants can be removed and are all major factors in surface (water or land) 

contamination. Knowing the type and timing of precipitation is very important, in 

responding to hazardous emissions into the atmosphere. Dry deposition occurs during 

the interaction of the pollutant with the earth’s land or aquatic surface. Elements within 

the surface capture the pollutant. Knowing the uptake character of the surface to specific 

pollutants, then, is also important. In the case of radioactive hazardous releases, the decay 

of the pollutant is also a depletion factor. Surface contamination whether by means of 

depletion or deposition ultimately impacts the quality of the food we eat and the water we 

drink. 

The timing of atmospheric conditions is also important. Whether hazardous material 

disperses quickly or remains concentrated depends on the movement of weather systems 

and how quickly a change occurs. For example, if a front moves over a source area, wet 

deposition could be a primary influence on the extent of ground and water contamination 

Figure 2. Atmospheric 

dispersion map, 

prepared for the Salt 

Lake City Olympics, 

showing a planning 

scenario for transport 

and dispersion of a 

plume of anthrax spores 

in case of a 

bioterrorism attack. 

Image courtesy DTRA. 
 8 

if there is accompanying frontal precipitation. On the other hand, the deposition scenario 

could be completely different if the hazardous emission occurred after a frontal passage. 

Problems of modeling in complex terrain and coastal areas present challenges because of 

their non-homogeneous nature. Most of the Nation’s population lives at or near coastal 

areas. Many power plants are near the population being served. These plants are 

potential sources for hazardous releases. They are also potential terrorists’ targets. Thus 

it is important to better understand and characterize coastal areas and other densely 

populated areas that are near potential release sites. Accurately determining the 

dispersion of hazardous material in these areas could have a significant impact on a large 

number of people. Modeling the interaction between indoor and outdoor air is yet 

another factor where increased emphasis should be applied. The coupling between 

indoor and outdoor air is important both as a mechanism for reducing indoor 

concentrations after an indoor release and as a factor affecting the “sheltering-in-place” 

strategy (in subways or above ground facilities) after an outdoor release. 

Air Quality 

Ever since cities developed in antiquity, people noticed that urban air was different from 

rural air. The principal atmospheric difference between urban and rural areas is the 

drastically altered load of pollutants. Land use, agricultural spraying, traffic density 

(particularly land and air traffic), distribution of major point sources such as power 

plants, and heavy industry (e.g., oil refineries and industries that burn coal), play a role in 

aerosol creation, emission, and deposition. These aerosols are not necessarily inert. For 

example, iron acts as a catalyst in chemical reactions. Others like lead and vanadium (a 

component of fuel oil) can be serious health hazards. The presence of ozone can 

aggravate emphysema and reduce resistance to colds and pneumonia. In addition, CO 

interferes with the transfer of oxygen from the lungs to body tissues. Pollution also 

affects the weather and vice versa. SO2, in the presence of atmospheric moisture can turn 

into sulfuric acid. Sulfuric acid is hygroscopic. At 60% relative humidity, sulfuric acid 

begins to grow into droplets interfering with visibility. Decreased visibility can impact 

transportation safety. 

A plume of nitric 

acid fumes rises 

from an industrial 

accident site. Local 

wind patterns will 

determine how an 

atmospheric release 

of hazardous 

material spreads 

into the urban 

environment. (AP 

Wide World 

Photos) 
 9 

Accidental or intentional release of hazardous materials into the atmosphere and water 

constitutes a major threat to life and safety. Technological hazards can have local, 

regional, national, and international ramifications. The large number of hazardous agents 

complicates preparedness for and response to biological, chemical, and nuclear hazards. 

In the case of biological agents (such as smallpox, botulism, and anthrax), these can be 

genetically re-engineered to resist traditional therapies. These altered pathogens can also 

bypass human and animal immunities obtained through vaccinations. Additionally, there 

can be a long incubation period and consequent delay in the onset of disease. As a result, 

secondary transmissions become very difficult to detect and plan for. 

Urban areas are not only the recipients of air pollution. Cities can create polluted air, 

which is dispersed over other areas. For example, the air pollution (the source of which 

has been attributed to metropolitan Washington, D.C.), which results in acid rain 

deposition over the Shenandoah National Park. The effects of acid rain are killing prized 

young brook trout. In addition, the air over the park violates federal standards for ozone 

and pocks leaves with black spots, thus reducing the biodiversity of the area and making 

the area more susceptible to invasive species which further reduces the area’s 

biodiversity. The polluted air has also reduced visibility within the park. The park’s 

vistas from the scenic, 105-mile Skyline Drive from Front Royal to Waynesboro are now 

more frequently a haze. The result of the park’s declining biodiversity and scenic views 

is that the number of people visiting the park has decreased from 2 million visitors 

annually in 1993 to 1.4 million in 2002. The decline of visitors means less business for 

the surrounding areas. Urban pollution, then, has its economic drawbacks. 

Whether the pollution is natural or anthropogenic, pollution has negative impacts. In 

addition to the impact on human health and consequently the health care system, polluted 

air also harms plants (by stunting plant growth), animals (by interfering with 

physiological processes), building materials (by eroding concrete, rusting metals, etc.), 

and fabrics. Besides transportation, air quality has a direct economic impact on such 

industries as agriculture, automobiles, and clothing. The damage caused by air pollution 

costs the U.S. alone billions of dollars each year. This cost estimate includes money 

spent for health care, increased maintenance of buildings, and agricultural losses. 

When a technological hazard occurs, the primary vectors for spreading the hazardous 

materials are air and water. It becomes critical to have meteorological and hydrological 

data that represent the atmospheric and hydrologic conditions at the incident site. It is 

equally important that models accurately project the pathogen’s transport to other areas. 

Models, therefore, should be equally accurate for diagnostic and prognostic use. 

Weather patterns can influence air quality. The presence of a stationary high pressure 

system or a sustained period of calm air or light winds can mitigate the transport of 

pollutants. This same weather pattern, however, can contribute to increased pollution 

over a specific location. In addition, ambient levels of air pollutants tend to rise in winter 

because of generally increased atmospheric stability, and reduced mixing depths, leading 

to a poorer dispersive capacity of the atmosphere. Other naturally occurring events can 
 10 

also affect air quality and cloud properties. The Mt. Pinatubo eruption (and resulting 

silicate dust) occurring a half a world away forced the closure of Clark Air Force Base 

and thus changed the U.S. strategic posture in the western Pacific. 

Water Quality 

Many urban areas are located near water bodies. Aside from their aesthetic attractions, 

streams, lakes, and rivers are a source of water supply. The running water also seems to 

offer a cheap, planned or unplanned means of sewage disposal. The problem of water 

quality management in cities has become a major problem of modern society. Poor 

practices in land use have led to large economic losses. Designs of drainage systems 

pose major engineering tasks. Poor designs or overtaxed drainage systems can 

deteriorate water quality and present health concerns. 

Urbanized areas can vastly aggravate flooding. Changes in surface characteristics in 

urban areas lead to rapid runoff of precipitation and flooding. In vegetated areas much of 

the water is temporarily intercepted by leaves, needles, and trunks. Some of it is 

evaporated by the plants. The forest litter is a particularly effective storage medium. The 

radical change of surface from permeable soils and vegetation to impermeable 

pavements, parking lots, and roofs shortens the time that rain or melt-water reaches the 

water collection areas. Storm drain systems deliberately designed to carry the water 

away from residential and business districts reduce the lag times even further. Thus the 

benefit derived by rapid drying of roads sometimes leads to the high cost of flooding. In 

addition, heavy water inflow can cause sewer overflow, which also has a negative impact 

on water quality. 

Run-off from rural to urban areas and vice versa presents other challenges, namely 

excessive silting and eutrophication. Eutrophication is usually produced by the discharge 

Water contaminated with 

heavy metals seeps into a 

creek near Miami, 

Oklahoma, from a flooded 

abandoned mine. Even 

seasonal precipitation on 

contaminated soils can 

cause a problem for urban 

water supplies. (AP Wide 

World Photos)
 11 

Changing climate also changes the 

vulnerability of coastal areas to 

flooding. A 1991 report by the 

Federal Emergency Management 

Agency estimated that a one foot 

rise in sea level would increase the 

size of the 100-year floodplain in 

the U.S. from 19,500 square miles in 

1990 to 23,000 square miles, and 

increase flood damages (and hence 

flood insurance rates) by 36-58 

percent. Photo courtesy EPA. 

of biological wastes into lakes and rivers. Eutrophication produces not only nutrients for 

the algae cover but, because of the high oxygen demand of these wastes, robs the lakes’ 

fauna of an essential element for their survival. These lakes and rivers can ultimately be 

a source of drinking water, which is no longer safe to drink. Thus, control of water 

quality at the inflows, especially adequate dissolved oxygen is a challenge. In addition, 

the presence of septic systems, salting of snow-covered roads, landfills, brown fields, and 

the redevelopment of brown fields can adversely impact ground water quality and surface 

water quality, especially during a heavy water run-off event. 

Climate 

Climate simulations are predicting an overall warming of the atmosphere due to 

greenhouse gases. For example, CO2 allows sunlight to reach the earth and warm its 

surface, but it prevents some surface heat from escaping out of the atmosphere. This 

greenhouse effect can result in higher mean atmospheric temperatures near the Earth’s 

surface. If these predictions are correct, changes in temperature can increase the power 

needed to cool urban building structures (homes, offices, storage facilities, stores, etc.). 

Similarly, the regional and seasonal temperature fluctuations due to climate oscillations 

(El Nino, for example) may also increase the power demand for heating and cooling. A 

warming climate can also affect the available water for drinking, irrigation, and 

generating power, all of which impact the viability and sustainability of the urban 

community. 

As the risk of flooding increases with climate change, so does the importance of the 

major drainage systems. New design approaches, which explicitly design roads to act as 

drains, can radically reduce the duration of flooding. Litter management is critical to the 

management of urban drainage systems. Often the best investment in drainage is better 

handling of solid waste to prevent systems from becoming rapidly blocked with debris. 

Climate change is likely to amplify the challenge of pest control, as new ecological 

niches appear that may sustain exotic pathogens and disease vectors. For example, 

flooding may become more frequent in some geographic locations with climate change 

and can affect health through the spread of water-borne diseases. 
 12 

Climatological conditions are also important for nuclear, biological, and chemical 

releases, and Homeland Security response scenario planning. For example, 

climatological signals such as El Nino, the North Atlantic Oscillation, and the Pacific 

Decadal Oscillation have a profound effect on atmospheric conditions such as stability, 

precipitation, and prevailing winds. Thus knowing the strength and timing of these 

signals is an integral factor in detecting and responding to hazardous material releases. 

Many states struggle with energy shortages and price volatility. Climate conditions could 

exacerbate the challenges, which these states face. For example, during the summer of 

2001, a severe drought gripped the Columbia River basin causing the second worst water 

shortage in that watershed since records have been kept. The resulting reduction in 

hydroelectric sources contributed significantly to California’s energy shortage. 

Simultaneously, heat waves in California drove demands up sharply leading to enormous 

increases in “spot market” electricity prices. 

Successful forecasts of the 1997-1998 El Nino event and its evident effects on energy 

demand patterns was one of several factors prompting the development of specialized 

financial instruments for energy risk management (the weather derivative). As the full 

weather and climate sensitivities of the revenues and profits of energy providers and 

consumers become better understood and are more clearly delineated, demand for new 

products (insurance, catastrophe bonds, etc.) and associated weather services will likely 

grow. 

Climate change can have an impact on water quality. In those areas where there are more 

frequent heat waves, perhaps of longer duration and more intense storms, greater amounts 

of storm water runoff will occur. Conversely, if precipitation declines, as some climate 

scenarios suggest, farmers will increasingly turn to groundwater and wetlands for 

irrigation, threatening urban water supplies, both in terms of quality and quantity. 

Crosscutting Urban Weather and Climate Issues/Components 

The following crosscutting components are common to most if not all of the major 

issues/concerns related to urban weather and climate. Each of the crosscutting issues or 

factors must be addressed in any actions contemplated to improve weather and climate 

products or services for urban areas. 

Integrated Global Observations 

Observations are the lifeblood for developing forecasts, advisories and warnings that 

cover all of the primary urban weather and climate issues presented above. The present 

state of weather and climate measuring stations in cities is at best inadequate. Stations 

are sited in diverse locations over differing surfaces, at various heights and exposure of 

the individual instruments often violates WMO rules of observing practice. 

Research and Technology Tools 

Although a substantial amount of research and technology development is in progress 

more focus needs to be placed on addressing gaps in weather and climate service and 
 13 

support capabilities. In addition, provisions are needed to routinely transfer the results of 

science research and technology into operational venues throughout government and 

commercial applications. 

Education, Outreach, and Training 

Every new or improved product and service for urban weather and climate applications 

requires some level of education and training to ensure that the information is being 

delivered in an understandable and user-friendly manner. Outreach helps to involve users 

in the process from defining requirements or deficiencies to conducting research or 

development and finally, in delivery of the finished product or service. Using this 

process helps the entire range of users to understand and apply weather and climate 

information in a wide spectrum of endeavors: personal, business, and community. 

Risk Management 

Risks must be considered through continuing assessments of science, technology and 

application uncertainties, as well as in the costs and benefits associated with each of the 

urban issues and the proposed actions to mitigate adverse hazards or impacts. Forecast 

uncertainties must be considered in all decision processes. The educated use of 

probabilities and confidence levels helps users quantify and consider mitigation for the 

risks associated with weather and climate forecasts. In addition to the well-accepted 

mitigation approaches of planning in advance and dealing effectively with weather 

consequences, the more controversial approach of weather modification may be ripe for 

careful scientific investigation (see text box). 

Health Effects 

There are varying degrees of public health concerns and impacts in each of the areas of 

concern in urban meteorology. The health problems associated with the extreme forms of 

urban weather and climate are often at the level of survival whereas lesser degrees of 

weather extremes or even benign periods of weather can be insidious or cumulative in 

their affects on overall public health. A recent example of extreme weather is a record 

heat wave that scorched Europe in August 2003, claiming an estimated 35,000 lives. In 

Weather Modification to Mitigate Weather Effects 

At present, risk mitigation activities related to urban weather involve either preparing in advance or 

responding after the fact. Changing the weather to mitigate risks and improve beneficial effects has been 

attempted, but without demonstrable success. Previous assessments of weather modification by study 

committees of the National Research Council (NRC) have concluded that the science underlying attempts to 

modify the weather is too weak to determine whether such attempts actually produce results. A more 

optimistic view is taken in a new study, Critical Issues in Weather Modification Research, from the NRC. 

This study points to the significant advances in observing, computational, and statistical technologies during 

the 30 years since the last NRC study and calls for a coordinated, sustained national program to answer 

fundamental questions about basic atmospheric processes relevant to weather modification efforts. For 

example, the report describes how millimeter-wave cloud radar could be used to reveal the physical 

transformations in regions of clouds seeded with condensation agents such as silver iodide. The publication 

announcement and the report are available on line at the National Academies Press website, www.nap.edu.
 14 

France alone, 14,802 people died from the searing temperatures--more than 19 times the 

death toll from the SARS epidemic worldwide. In the worst heat spell in decades, 

temperatures in France soared to 104 degrees Fahrenheit (40 degrees Celsius) and 

remained unusually high for two weeks. 

Information Dissemination 

Communication of weather information has to be an end-to-end process. All the 

observations and other data that comprise the weather and climate database infrastructure 

must be readily collected, assembled, quality-checked and made accessible to a wide 

spectrum of users in all levels of government, industry partners, and to the general public. 

All subsequent developments such as numerical models, forecasts, advisories, and 

warnings must be made available for applications that include high-priority, lifeprotection and life-sustaining weather and climate information to everyone in the urban 

communities. 

Business Continuity Planning 

This activity is needed to ensure the survival of an organization or industry when it is 

exposed to a wide range of natural hazards and environmental or other forms of 

terrorism. Each of the six primary urban issues must be evaluated in light of survival 

factors and specific priorities of the business activity and entities involved. 

Regional Ecosystem Planning and Management 

Urban environments are not ecologically isolated from agricultural areas or natural 

ecosystems (forests, grasslands, riparian and coastal wetlands, arid lands, etc.). Linkages 

with urban areas often occur through the weather-related environmental interactions 

described above. Air and water pollution from urban areas can affect agriculture and 

natural resources downwind and downstream. Agricultural and urban communities often 

share the same groundwater and surface water resources. Agricultural practices can 

affect urban water and food supplies, as well as the recreational areas used by urban 

dwellers. Urban forests and green spaces slow and reduce stormwater runoff, flooding, 

and erosion. Urban tree foliage naturally 

filters particulates and pollutants from the 

air. 

Wildfires in natural areas can threaten the 

suburban zone around urban centers, just as 

urban populations seeking recreation provide 

both the demand for and multiple ecological 

stresses on natural areas. Regional high 

winds, such as the Santa Ana winds of 

southern California, can make wildfires 

extremely hazardous to urban areas (see text 

box). 

Santa Ana Winds Fan Killer Fires

During October 2003, wildfires exploded 

across a southern California desiccated by 

Santa Ana winds, killing at least 15 people and 

burning more than 500 homes. The two biggest 

blazes, in eastern San Diego and the San 

Bernardino suburbs of Los Angeles, forced 

thousands to flee and closed major highways. 

Aviation nationwide was disrupted when the 

evacuation of an FAA flight facility near San 

Diego limited flights.
 15 

In addition to the cross-cutting issues described above, a review of the five major urban 

issues shows the influence on and from transportation, energy production and use, and 

biometeorology. For example, in transportation, high winds can impede or stop aviation 

activities, transit vehicles, automobiles, recreational vehicles, trucks and marine 

activities. The availability of surface transportation has repercussions not only on the 

transport of goods and services but also on the ability of the public to evacuate urban 

areas and for response personnel to reach emergency sites. Icing and fog reduce visibility 

and (if in sufficient amounts) may close airports or delay flight operations. Extremely 

cold weather can snap or severely damage cables that support suspension bridges. 

Elevated temperatures can buckle roadways and train rails. Lightning has an impact on 

transportation, not only by damage to trees along roadways but also delays due to 

refueling safety practices and impacts on communication systems. Emissions from 

vehicles can affect air and water quality. Concentrations of emissions or accidental 

releases of hazardous materials from vehicles can pose serious health problems and 

modify weather and climate characteristics for large areas downstream. Having advanced 

weather information (type, quantity, and temporal and spatial extent) with lead-times that 

are relevant to the urban areas would provide benefits to urban commerce and in the 

protection of life and property 

Current Capabilities and Limitations in Weather and Climate Services 

and Products 

Capabilities and limitations of current weather/climate services and products to address 

above issues are found across the Federal agencies, State and local governments, industry 

and universities. A brief profile of capabilities and limitations includes: 

Federal Agencies 

U.S. Department of Commerce, National Oceanic and Atmospheric Administration 

The National Oceanic and Atmospheric Administration’s National Weather Service 

provides basic weather and climate observation networks to serve the nation’s needs and 

international obligations. It collects weather and climate data, conducts initial quality 

assurance, assimilates the data into databases for access by users, and incorporates data 

into numerical and other models to develop forecasts, advisories and warnings. Sources 

of observations include traditional weather stations, weather radars, weather satellites, 

rawinsonde facilities, cooperative weather stations, a reference climatological network, 

experimental research equipment, aircraft reports, hydrological networks and more. The 

greatest limitation is the lack of sufficient observations and more accurate (higher 

resolution) forecasts to meet time and space requirements for urban weather and climate 

applications. 

NOAA’s National Environmental Satellite, Data, and Information Service manages 

United States civil operational environmental satellite systems, as well as global 

databases for meteorology, oceanography, solid-earth geophysics, and solar-terrestrial 

sciences. The activities of the Office of Oceanic and Atmospheric Research support 
 16 

various NOAA meteorological, oceanographic, and space missions including tracking 

and forecasting volcanic ash and improving observation and forecasting tools for severe 

weather. The National Ocean Service acquires water levels, currents, winds and other 

oceanographic data to provide a suite of information products required by marine 

transportation in coastal areas and in ports. 

U.S. Department of Transportation, Federal Aviation Administration 

The Federal Aviation Administration administers weather and climate operations and 

research in support of national aviation activities. The Federal Highway Administration 

conducts similar activities for the roadways, and the Federal Railroad Administration and 

Federal Transit Administration support rail and transit systems. More observations and 

increased forecast accuracy are needed to improve products and services for 

transportation applications in urban and other areas. 

U.S. Department of Homeland Security 

The Department of Homeland Security includes the Federal Emergency Management 

Agency and the United States Coast Guard. These organizations require extensive 

weather and climate data for emergency preparedness, mitigation, and response and 

recovery operations related to natural and other disasters, as well as for rescue and 

lifesaving activities. 

U.S. Department of Defense 

The Department of Defense (DoD) has responsibilities for reporting weather and 

producing weather warnings for hazardous weather for their installations, many of which 

are in or adjacent to urban areas. They also provide specialized worldwide weather, 

space environment and oceanographic analysis and prediction services in support of 

military forces. The DoD relies on the databases of the NOAA National Weather Service 

and other agency databases to provide observations and forecast tools for applications to 

many of their sites and training operations. 

U.S. Department of Energy 

The Department of Energy has responsibility for weather and climate support for the 

transport of nuclear and other hazardous materials across urban as well as other areas 

across the nation. Very detailed weather information is needed to support their activities. 

U.S. Department of the Interior 

The Department of the Interior (DOI) has primary responsibility for responding to 

wildland fires. Such fires often occur adjacent to urban areas and smoke or other 

airborne particles can affect air and water quality in urban communities. DOI also has 

responsibilities to monitor air quality in national parks, and collects data related to 

managing water resources and water quality nationally. 
 17 

U.S. Environmental Protection Agency 

The Environmental Protection Agency (EPA) is responsible for air quality and the 

regulations and enforcement of air quality standards. Special measuring equipment and 

networks are needed to assess the dispersion of air contaminants. 

National Aeronautics and Space Administration 

National Aeronautics and Space Administration requires specialized weather and climate 

data for space programs and in research programs to improve air safety. Many of their 

activities are conducted in or near urban areas. 

U.S. Department of Agriculture 

The Department of Agriculture requires a wide range of high quality weather and 

climatological data to successfully carry out their missions. Some of the diverse 

applications that require accurate, timely, and comprehensive data include crop 

monitoring and weather impact assessment, agricultural yield and productivity modeling, 

natural resource conservation planning, forest fire potential monitoring, irrigation 

scheduling, water supply information, reinsurance and compliance programs, crop 

disaster assistance and emergency relief programs, integrated pest management, crop 

yield modeling, and agricultural research studies of agricultural applications. Many of 

their activities take place on urban fringes but also occur within urban areas. 

Nuclear Regulatory Commission 

The licensing and operation of nuclear facilities require the identification of 

meteorological and climatological conditions that can affect the safe operation of the 

facility and that provide input to the assessment of the radiological impacts of any 

airborne releases from the facility. Detailed observations and forecasts of the dispersion 

of such releases would be needed to provide advisories and warning to urban or other 

areas in the path of released materials. 

State and Local Governments 

State and local governments arrange for specialized weather observations and support for 

emergency operations in the wake of a storm or technical hazard. These operations 

include transportation and safety activities such as response to wildfires and hazardous 

material spills. 

Industry and the Private Sector 

This sector uses weather and climate information from government or private sources to 

generate value-added decision support information or services to individuals, 

corporations or government activities. 

Universities 

Universities conduct specialized weather observation and forecasting activities in support 

of research, development and technology transfer activities. 
 18 

Why Focus on Urban Meteorology Now? 

What Next?

The needs of urban users and the issues expressed in this discussion framework involve 

measurement, computational and modeling and information delivery systems. It is clear 

that public decision centers and their industrial counterparts need to take full advantage 

of the meteorological measurement systems and model products that have emerged 

during the past several years from activities such as the NWS modernization effort. This 

will involve substantial investment in local staff training, strategy development, and 

information facilities. In addition, urban leaders need to assess and respond to unmet 

community needs pertaining to observational and modeling resources that are available 

within the current state of the art. Scientists and community leaders together need to 

jointly establish key needs not met by existing technologies, and develop a science-based 

strategy to bring such technologies into practice. 

The OFCM plans to assist in this effort by sponsoring a Forum in late Fall, 2004 to 

address urban weather and climate issues. The Forum will provide an opportunity to 

review requirements and current capabilities, determine unmet needs, discuss priorities, 

and coordinate development of an R & D plan to address the deficiencies in weather and 

climate products and services in urban areas. 
Federal Committee for Meteorological Services 

and Supporting Research (FCMSSR)

Interdepartmental Committee for 

Meteorological Services and Supporting 

Research (ICMSSR)

Federal Coordinator for 

Meteorology

Standing 

Committees

Program 

Councils

National 

Space 

Weather 

Program

National 

Aviation 

Weather 

Program

Environmental 

Services, 

Operations, and 

Research Needs

Operational 

Processing 

Centers

Environmental 

Information 

Systems and 

Communications

Integrated 

Observing 

Systems

Climate Analysis, 

Monitoring and 

Services

Cooperative 

Research

Working Grou

for 

Environmenta

Support to 

Homeland 

Security
THE COMMITTEE FOR 

ENVIRONMENTAL SERVICES, OPERATIONS, AND RESEARCH NEEDS 

COL JOHN LANICCI, USAF, Tri-Chairperson MR. ROBERT MCLEOD, Tri-Chairperson 

U.S Air Force National Weather Service 

Department of Defense National Oceanic and Atmospheric Administration 

 Department of Commerce 

CAPT VIC ADDISON, Tri-Chairperson CDR KEN SCHWINGSHAKL 

Office of the Oceanographer of the Navy Naval Meteorology and Oceanography Command 

U.S. Navy U.S. Navy 

Department of Defense Department of Defense 

 

MR. REGINALD B. LAWRENCE MS. CHARLENE M. WILDER 

National Environmental Satellite, Data, Federal Transit Administration 

and Information Service Department of Transportation 

National Oceanic and Atmospheric Administration 

MR. PAUL A. PISANO DR. JONATHAN M. BERKSON 

Federal Highway Administration U.S. Coast Guard 

Department of Transportation Department of Homeland Security 

 

MR. TIM COHN MR. LEWIS T. MOORE 

U.S. Geological Survey Bureau of Reclamation 

Department of Interior Department of Interior 

MR. RICKEY C. PETTY MS. BONNIE WYATT 

Department of Energy Department of Agriculture 

MR. ROBERT STEFANSKI MS. LETA A. BROWN 

Department of Agriculture Nuclear Regulatory Commission 

MR. DONALD E. EICK MS. ASHLEY CHAPPELL 

National Transportation Safety Board National Ocean Service 

 National Oceanic and Atmospheric 

MR. JOHN GAMBEL Administration 

Emergency Preparedness and Response Department of Commerce 

Department of Homeland Security 

 DR. RAMESH KAKAR 

MR. KEVIN BROWNE National Aeronautics and Space Administration 

Federal Aviation Administration 

Department of Transportation 

 

MS. MARY M. CAIRNS, Executive Secretary 

Office of the Federal Coordinator for 

Meteorological Services and Supporting Research