# Presentation: 781529

## Applications of Aircraft Weather Data

- American Meteorological Society Short Course
- San Antonio, Texas January 14, 2007

- Rich Mamrosh – NOAA NWS Green Bay, Wisconsin

- Applications in Field Forecast Offices

## Applications in Field Forecast Offices

**National Weather Service**
- Warning and Forecast Offices
- Center Weather Service Units
- Storm Prediction Center

**Notes:**
Now that we’ve seen how AMDAR data are used in the models, lets take a look at how meteorologists may use the data directly in airline, military, andr government forecast offices. As the data move into the public domain, such forecast applications will be possible elsewhere.

## NWS Forecast Office Applications

- Data Comparison (Radiosonde, Radar, Profilers)
- Marine (Wind and Wave Forecasts)
- Fire Weather (Haines Index, Mixing Heights)
- High Wind Events (Santa Ana, Front Range, Synoptic)
- Aviation  (Ceiling, Visibility, LLWS)
- Winter (Precipitation Type, Lake Effect Snow)
- Convective Storms (Watch and Warning Decisions)

**Notes:**
We will divide this part of the presentation into the seven different phenomenon based groups above.  

## Data Comparison

- Wind Profilers

- Commercial aircraft

- GOES and POES Satellites

- Wind Estimates from Doppler Radar

- Radiosondes

- Numerical models

**Notes:**
AMDAR provide yet another means of comparing data from different upper air systems. AMDAR is frequently used by meteorologists  to verify the initialization and performance of the numerical weather prediction models. It has also been used to flag erroneous radiosonde, profiler, and WSR-88D VAD winds, and to verify GOES and POES satellite soundings.

## Data Comparison

- The NWS in La Crosse, Wisconsin used TAMDAR to verify what looked to be erroneous radiosonde data.
- The dewpoint from the Minneapolis, Minnesota radiosonde seemed way too low.
- TAMDAR data showed that the radiosonde information was indeed correct. This was very important in determining what precipitation type was likely later that day.

- Radiosondes

**Notes:**
Here is an example of how AMDAR data were used to validate what looked to be erroneous radiosonde data. In this example, meteorologists at the La Crosse NWS office thought that the -36C dewpoint around 850mb looked much too low. A TAMDAR equipped aircraft flying in the vicinity reported a dewpoint of -32C, supporting the radiosonde data. This was important, as the dryness of the atmosphere would permit considerable evaporative cooling when precipitation began later that day.

## Data Comparison 

- AREA FORECAST DISCUSSIONNWS LA CROSSE WIAFDARX 401 AM CST MON NOV 1 2004
- .SHORT TERM... THE NOVEMBER 1ST 00Z 850 MB DEW POINT OF -36C AT CHANHASSEN LOOKED INITIALLY SUSPICIOUS WHEN LOOKING AT TRAJECTORIES. **HOWEVER...A MESABA AIRCRAFT WITH THE NEW TAMDAR SENSOR AT 04Z HAD A DEW POINT OF -32C IN THE CHANHASSEN AREA. THE ACCURACY OF THIS DEW POINT IS RATHER CRITICAL BECAUSE IT AFFECTS THE INITIAL ONSET OF PRECIPITATION...**

- Radiosondes

**Notes:**
Here is the Area Forecast Discussion from the La Crosse NWS that discusses the two data sources and forecast rationale.

## Data Comparison

- Model Forecasts

## Data Comparison

- Model Forecasts

- Senior duty meteorologists at NCEP often use AMDAR flight level data to determine the validity of radiosonde winds and temperatures. Meteorologists in WFOs and CWSUs compare AMDAR to model initial analyses and forecasts.
- The Lousiville, Kentucky NWS used AMDAR on May 17, 2005 to validate their suspicions that the NAM model dewpoints in the low levels were erroneous.
- The boundary layer moisture was important in the fog forecast that night.

## Data Comparison

- AREA FORECAST DISCUSSIONNWS LOUISVILLE KYAFDLMK 940 PM EDT TUE MAY 17 2005
- .UPDATE... HAVE NOTED VERY HIGH DEW POINT ERRORS IN THE RECENT RUNS OF THE ETA (NAM) MODEL. LOOKS AS THOUGH THE NAM HAD WAY UNDER-FORECAST THE MAGNITUDE OF THE DRY POCKET WITHIN THE DAYTIME BOUNDARY LAYER STRETCHING FROM THE OHIO VALLEY INTO THE MID-SOUTH THIS EVENING. **AN ACARS DESCENT SOUNDING INTO EVANSVILLE AROUND 1Z SHOWED 950MB DEWPOINTS OF +4C...THE ETA HAD FORECAST +10 WITH THE GFS MUCH CLOSER AT +5C. WITH THAT SAID...OUR DEW POINT FORECAST WAS ON TARGET. **

- Model Forecasts

**Notes:**
The NWS in Louisville used AMDAR (TAMDAR) to determine that perceived dewpoint errors of the NAM model were indeed true. A TAMDAR equipped aircraft flying into Evansville reported a dewpoint of +4C at 950mb while the NAM had +10C and the GFS +5C. AMDAR data are very useful in determining model performance and initialization. 

## Marine Forecasting

**Notes:**
You might not think that observations from aircraft could be important in making forecasts for mariners, but they are! Large bodies of water are generally data sparse regions, and greatly benefit from additional upper air data.

## Marine Forecasting

- A dense network of wind and temperature soundings are important to the production of accurate wind and waves forecasts.
- Temperature profiles are important to determine stability (which affects mixing down of stronger winds aloft).
- Wind profiles are needed to determine directional and vertical shear (which also affect transport of stronger winds aloft).

**Notes:**
The relative lack of surface, water, and upper air observations make marine forecasting a challenge in most places. The radiosonde network is not sufficiently dense to measure the  atmospheric stability and wind field in the vicinity of the most large bodies of water.

## Marine Forecasting

- A dense network of radiosondes is not available near the oceans and Great Lakes.

**Notes:**
Here is a map of the NWS radiosonde network. Notice that There are only 3 radiosonde locations near the entire Pacific Coast of the lower 48 states! Coverage is also sparse in the Great Lakes. 

## Marine Forecasting

- AMDAR observations have provided meteorologists with valuable supplemental data near the oceans and Great Lakes.
- Forecasters have used AMDAR to issue, continue and discontinue Small Craft Advisories, Gale Warnings and Storm Warnings.

**Notes:**
The addition of AMDAR soundings near the oceans and Great Lakes has provided the additional information needed to produce improved marine forecasts and warnings.

## Marine Forecasting

- The NWS in Grand Rapids, Michigan used AMDAR data in deciding to continue a Gale Warning for the nearshore waters of eastern Lake Michigan on November 6, 2005.
- TAMDAR soundings from Kalamazoo, Michigan showed that there still were winds at nearly 50 knots in the lowest 3,000’ of the atmosphere.
-  In addition, the air was unstable, and the winds had little directional shear – both favorable for the transfer of strong winds to the surface.

- Gale Warning

**Notes:**
Meteorologists at the NWS in Grand Rapids, Michigan were considering allowing a Gale Warning to expire during the morning  hours on November 6, 2005. Surface reports near the Lake Michigan shore had seemed to have peaked or slowly diminished, suggesting that perhaps the strongest winds had passed. AMDAR soundings from southwest lower Michigan showed that not only were there gale force winds present in the lowest 200 mb, but that the atmosphere was sufficiently unstable to bring these winds to the water surface. 

## Marine Forecasting

**GALE WARNING:** A warning of sustained surface winds, or frequent gusts, in the range of 34 knots (39 mph) to 47 knots (54 mph) inclusive, either predicted or occurring, and not directly associated with a tropical cyclone.

- Map of NWS Grand Rapids forecast area. Nearshore marine area is in purple.

- Gale Warning

**Notes:**
Here is a map of the Grand Rapids forecast area. The purple shaded area are the nearshore waters that the Grand Rapids office is responsible for. 

## Marine Forecasting

- AMDAR data in Great Lakes region from 1400 to 1659 UTC on November 6, 2005

- Gale Warning

**Notes:**
This is a map of the flight tracks of aircraft reporting AMDAR data between 1400 UTC and 1700 UTC November 6, 2005. Soundings are available from Kalamazoo, Michigan on the east side of the lake, and from Milwaukee, Wisconsin and Chicago, Illinois on the upstream side.

## Marine Forecasting

- TAMDAR
- Sounding
- From
- Kalamazoo
- Showing
- West winds
- At 46 knots
- About
- 2,200’ AGL.

- Gale Warning

**Notes:**
This sounding from Kalamazoo, Michigan at 1638 UTC shows 46 kt winds just 2200’ above the ground, a nearly unidirectional wind field and unstable air below 850 mb. 

## Marine Forecasting

- AREA FORECAST DISCUSSIONNWS GRAND RAPIDS MIAFDGRR 1032 AM EST SUN NOV 6 2005
- 5 MINUTE WIND DATA AT THE GLERL COAST SITES SHOWS THE
- WINDS HAVE PEAKED AT MKG...LWA AND MICHIGAN CITY IN THE
- PAST HOUR NEAR 45 KNOTS. THE TREND IS NOW DOWN SLOWLY
- ON THE WIND SPEED. **TAMDAR** DATA STILL SHOWS WINDS UNDER
- 5000 FT OF JUST UNDER 50 KNOTS OVER THE WESTERN CWA AT
- 10 AM. AS A RESULT OF ALL OF THAT I **PLAN ON LEAVING THE GALE**
**WARNING AND THE WIND ADVISORY AS IS INTO THE MID AFTERNOON**.

- Gale Warning

**Notes:**
They decided to keep the Gale Warning for the nearshore waters and a wind advisory for the land areas through the mid afternoon based on AMDAR soundings. Winds continued to gust between 40 and 50 mph into the afternoon hours, making it a good decision.

## Marine Forecasting

- AMDAR can provide the information to determine the likelihood of lake and sea breeze formation.
- Lake and sea breezes are hindered by an offshore gradient wind, and enhanced by an onshore wind. Stability also plays a role.

- Lake and Sea Breezes

**Notes:**
The formation of lake and sea breezes are largely determined by differential heating, but effected to a large degree by the stability and wind field of the atmosphere.  AMDAR data from airports near lakes and oceans often provide information that help the meteorologist forecast the development and movement of lake and sea breezes.

## Marine Forecasting

- Meteorologists at the NWS in Cleveland used AMDAR data on April 16, 2005 to forecast the formation and inland penetration of a lake breeze from Lake Erie.
- AMDAR soundings showed that there were significant south (offshore) winds that would slow the formation of the lake breeze, and limit it’s inland movement.
- In addition to it’s importance for mariners, this wind forecast also affects the large hub airport at Cleveland.

- Lake and Sea Breezes

**Notes:**
A sunny and mild day was expected in the Cleveland area on April 16, 2005. Land temperatures were expected to approach 70F, with water temperatures in the upper 30s to low 40s. The large temperatures contrast often results in a significant lake breeze. In this case, however, AMDAR soundings showed rather strong gradient winds from the south, that would hinder the inland penetration of the lake breeze. 

## Marine Forecasting – Lake and Sea Breezes

- AMDAR sounding from 1244 UTC in the vicinity of Cleveland

**Notes:**
Here is an AMDAR sounding from the Cleveland area from 1244 UTC showing winds from the south southeast at 27 knots. A gradient wind such as this blowing offshore will often prevent a lake breeze from developing, or prevent it’s inland movement if it does form.  

## Marine Forecasting – Lake and Sea Breeze

- AREA FORECAST DISCUSSIONNWS CLEVELAND OHIO1159 AM EDT SAT APR 16 2005
- .UPDATED...SOUTH WINDS WERE INCREASING AND TEMPERATURES WERE RISING WITH FULL SUNSHINE. HIGHS SHOULD RANGE FROM 65 TO 70 DEGREES. THE LAKE BREEZE, IF IT DOES DEVELOP, SHOULD BE RIGHT ALONG THE LAKESHORE FROM NEAR CLEVELAND THROUGH ERIE. **AMDAR** DATA NEAR CLEVELAND WAS INDCATING THE WINDS FROM SOUTH AROUND 25 KNOTS AT 2,000 FEET.

**Notes:**
Meteorologists in the Cleveland NWS noticed these soundings and forecasted the lake breeze to only affect the immediate lakeshore. This not only affects mariners and those living near the shore, but also the large hub airport in the city.

## Fire Weather

**Notes:**
Large wildfires have captured headlines in much of the United States in the past decade, and more and more people are moving to the arid West. This necessitates the production of accurate fire weather forecasts for the protection of life and property. AMDAR from airports in dry areas can help meteorologists better determine the atmospheric wind, moisture and stability in these regions. 

## Fire Weather

- AMDAR data are becoming increasingly utilized by fire weather forecasters, as coverage expands across the U.S.
- Useful fire weather forecasts are dependent on accurate observations and/or model forecasts of mixing layer heights, Haines indices, and surface relative humidity.

**Notes:**
AMDAR data can be used to generate the various fire weather indices routinely used by meteorologists in the NWS and other agencies. These indices are used in the forecast and warning decision process. 

## Fire Weather

- Smoke from prescribed burns and wildfires can cause serious problems for those with respiratory problems. It also can also cause accidents by reducing visibilities on highways.
- The NWS produces a Smoke Dispersion index based mostly on model forecast soundings. These forecasts are used by fire weather agencies to determine  whether prescribed burns should be allowed, and if wildfires might produce hazardous smoke conditions.

- Smoke Dispersion

**Notes:**
One such index is smoke dispersion. This is important in determining whether it is safe to burn in a controlled environment, and to decide who is at risk during wildfire events.

## Fire Weather

- The Miami NWS used AMDAR to update smoke dispersion forecasts on May 2, 2005.
- ACARS soundings showed very light winds (3-10 kts) in the mixed layer, which inhibits smoke dispersion.

- Smoke Dispersion

**Notes:**
NWS Miami staff updated their smoke dispersion forecast on May 2, 2005 based on the very light winds noted on AMDAR soundings in south Florida.

## Fire Weather

- ACARS sounding
- From 1411 UTC
- On May 2, 2005
- In the vicinity of
- Miami, Florida
- Shows very light
- Winds (< 10 kts)
- in the mixed
- Layer.

- Smoke Dispersion

**Notes:**
This sounding from Miami at 1411 UTC on May 2, 2005 shows very light winds in the mixed layer of the atmosphere. 

## Fire Weather

- AREA FORECAST DISCUSSIONNWS MIAMI FL1030 AM EDT MON MAY 2 2005
- .FIRE...WILL AMEND GRIDS AND FWF. WINDS IN MIXED LAYER ARE FAIRLY LIGHT, WHICH IS CONFIRMED BY **ACARS** DATA. THIS WILL RESULT IN ADJUSTMENTS TO TODAY’S DISPERSION INDICES.

- Smoke Dispersion

**Notes:**
Area forecast discussion from NWS Miami mentions that light winds from AMDAR sounding supports an adjustment to their smoke dispersion index. 

## Fire Weather

- The utility of AMDAR in fire weather forecasting  fostered the development of locally driven efforts.
- An experiment called HI-RISE (Hazardous Incident − Rapid In-flight Support Effort) was conducted in the spring of 2005 by the following participants
- National Weather Service
- Texas Forest Service
- USDA  Agricultural Station
- Aventech Research Inc.

- AMDAR inspired systems

**Notes:**
AMDAR has inspired the development of other airborne sensors that can be used to provide meteorological data useful in fire weather forecasts. 

## Fire Weather

- Air Tractor AT-402B aircraft used in HI-RISE

- Data flow in HI-RISE experiment*

- AIMMS-20 instrumentation

- HI-RISE involved the installation of meteorological instruments on a small fire
- surveillance aircraft, and downlinking the data in real time to meteorologists.

- D

- AMDAR inspired systems

**Notes:**
While the instrumentation used in HI –RISE would not be suitable for high speed commercial aircraft due to drag and weight considerations, they are suitable for slower aircraft used in fire fighting endeavors. Notice the communications architecture is nearly identical to that of AIRDAT’s TAMDAR system.

## Fire Weather

- Non-commercial aircraft such as these can fly REALLY close to fires and
- measure meteorological parameters vital in forecasting fire behavior

**Air Tractor AT-402B aircraft flying over Texas Forest Service ground crew during HI-RISE experiment**

- AMDAR inspired systems

**Notes:**
Fire fighting aircraft such as these can report data in close proximity to active fires. 

## Fire Weather

- Example of aircraft sounding from HI-RISE fire weather experiment.
- Notice highly detailed temperature, moisture and wind data.

- AMDAR inspired systems

**Notes:**
This sounding from a HI – RISE flight has the meteorological data similar to a WVSS-II or TAMDAR aircraft.

## Fire Weather

- This proof of concept experiment provided valuable real time data to fire weather forecasters at controlled burns in central Texas.
- All of the participants agreed that this concept should be developed further for fire weather and other applications, **including HAZMAT support.**

- HI-RISE Team from NWS, USDA, Texas Forest Service and AVENTEC

- AMDAR inspired systems

**Notes:**
Government agencies may consider using aircraft such as these for rapid deployment to man made or natural disasters. Data such as these would improve small scale diffusion models used in disaster support. 

## High Winds

## High Winds

- Non - convective high wind events occur over the entire country.
- Meteorologists largely rely on model forecasts to issue high wind watches, and a combination of observations and model data to issue warnings.
- The lack of real time upper air data can make warning decisions difficult.

## High Winds

- Downslope high wind events occur with some regularity in the Rocky Mountain region.
- Santa Anna winds in California and strong winds along the front range in Colorado are two well known phenomena that are forecast challenges.

## High Winds

- Schematic of Santa Ana winds in southern California

## High Winds

- A Santa Ana wind event occurred the night of December 22-23, 2006 in southern California.
- Meteorologists at the NWS in San Diego monitored AMDAR soundings during the early morning hours, and decided to upgrade a wind advisory to a high wind warning based on AMDAR soundings.

- Santa Ana

## High Winds

- AREA FORECAST DISCUSSIONNWS SAN DIEGO CA1120 PM PST FRI DEC 22 2006
- .DISCUSSION... UPDATE TO UPGRADE THE WIND ADVISORY FOR THE INLAND EMPIRE AND THE SANTA ANA MOUNTAINS AND FOOTHILLS TO A HIGH WIND WARNING THROUGH EARLY AFTERNOON SATURDAY. RECENT **ACARS SOUNDINGS FROM ONTARIO SHOW A VERY IMPRESSIVE SUBSIDENCE INVERSION NEAR 700 MB FAVORABLE FOR MOUNTAIN WAVE DEVELOPMENT AS WELL AS AN OVERALL STRONG WIND FIELD BELOW 700 MB WITH WINDS UP TO 50 KNOTS OR SO.** WINDS IN THE WINDIER LOCATIONS...BELOW THE CAJON PASS AND NEAR FREMONT CANYON HAVE GUSTED TO AROUND 60 MPH IN THE PAST HOUR.

- Santa Ana

## High Winds 

- AMDAR sounding at 0411 UTC December 23, 2006 from Ontario,
- California showing mountain top inversion and strong wind field.

- Santa Ana

## High Winds

- A High Wind event driven by an intense  cyclone occurred in the Northeast  on November 13, 2003.
- The NWS in Upton (Long Island), New York used AMDAR data to monitor winds aloft in real time, and made warning decisions based on these data.
- The upstream data at the New York area airports was especially valuable.

**New York City**

## High Winds

**Surface weather map from November 13, 2003 shows strong cyclone over southern Quebec**** **

**New York City**

## High Winds

- AREA FORECAST DISCUSSION
- NATIONAL WEATHER SERVICE UPTON NY
- 1000 AM EST THU NOV 13 2003 .
- DISCUSSION... .UPDATE...SEVERAL REPORTS OF DOWNED TREES/DAMAGE AND WINDS AS HIGH AS 52 KT AT AMBROSE LIGHT. HIGHEST LAND BASED WIND IS 48 KT AT LGA. **EXAMINATION OF 12Z ACARS WINDS REPORTS SHOWS THAT 09Z RUC WINDS ARE TOO LOW AND THAT EVEN 06Z ETA WINDS ARE FEW KNOTS BELOW OBSERVED.** AS COLD ADVECTION WORKS IN THIS AFTERNOON...HIGHER LEVEL WINDS WILL WORK DOWN TO SURFACE. USING A 90% RULE OF WINDS ALOFT...RESULTS IN PEAK SURFACE OF 60 KT OR 70 MPH. WILL HEADLINE...WIND GUSTS TO NEAR HURRICANE FORCE.

**New York City**

## High Winds

- 12UTC sounding
- From Brookhaven
- New York shows
- 60+ knot winds
- Within 2,000’ AGL.

**New York City**

## High Winds

- 1243 UTC
- AMDAR sounding
- from JFK airport
- shows 51 knot
- winds around
- 2400’ AGL.

**New York City**

## High Winds

- 1433 UTC
- AMDAR sounding
- from Newark, NJ
- shows 63 knot
- winds around
- 3000’ AGL and
- an almost dry,
- adiabatic lapse
- rate.

**New York City**

## High Winds

- AREA FORECAST DISCUSSIONNWS GRAND FORKS ND340 AM CST SUN DEC 17 2006
- .SHORT TERM (SUN-TUE)...**AMDAR SOUNDINGS AT 05Z FOR DVL/JMS SHOWED THAT MORE COLD ADVECTION HAD OCCURRED AT 850 MB THAN MODELS ANTICIPATED WHILE LOW LEVEL WINDS WERE STRONGER TOO.** THE COLDER CONDITIONS HAVE KEPT THE BOUNDARY LAYER MORE MIXED AND WINDS ARE ABLE TO MIX THROUGH A BIT EASIER. JMS SHOWED 70 KNOTS AT 801 MB (JUST ABOVE THE INVERSION) AND DVL SHOWED 50 AT 911 MB. **THESE WERE 10 TO 25 KNOTS HIGHER THAN MODEL SOUNDINGS. **

**North Dakota**

## High Winds 

- TAMDAR
- sounding from
- 0509 UTC in
- the vicinity of
- Jamestown,
- North Dakota
- on December
- 17, 2006 shows
- 70 knot winds
- at 801 mb.

**North Dakota**

## Aviation Forecasting

**Notes:**
Now lets take a look at some aviation applications of aircraft weather data. AMDAR data are ideal for aviation forecasting, as the observations are perfectly located at the forecast site. A real good example is Chicago O’Hare...the nearest radiosondes are Davenport, Iowa, Green Bay, Wisconsin and Lincoln, Illinois – all more than 100 miles away. With radiosonde data so far away, it is fortunate that we have over 500 soundings per day at O’Hare. 

## Aviation Forecasting

- Meteorologists at the NWS San Diego office are one of the biggest users of AMDAR data in the United States.  The scarcity of upstream data, varied terrain, and a maritime influence make the availability of frequent upper air data very useful.
- The data are especially useful to monitor the depth of the marine layer, upon which the formation and inland penetration of low clouds and fog are dependant upon.

- Ceiling and Visibility

**Notes:**
When responding to an AMDAR survey in the fall of 2005, forecasters at the NWS in San Diego cited AMDAR as the most important observing system they have.

## Aviation Forecasting

- Ceiling and Visibility

**Notes:**
This map shows the varied terrain of southern California, from the coastal plains to interior valleys and mountains. Hills and small mountains separate the interior valley around Ontario from the coastal plains near Los Angeles. A marine layer with a depth of 1,200’ of more is generally sufficient to climb the hills and enter the valley around Ontario. If moist maritime air enters the valley, it often produces dense fog and low ceilings that can close the airport at Ontario. Accurate ceiling and visibility forecasts depend on accurate determination of marine layer depth.

## Aviation Forecasting 

***The San Diego Forecast Office is responsible for the TAFs for Ontario (ONT), John Wayne (SNA), San Diego (SNA), as well as Palm Springs, Thermal, and Carlsbad (Not shown)***

- Ceiling and Visibility

**Notes:**
You can see from this map that the TAF sites in Ontario and the coastal plains are 100 miles away from the radiosondes at San Diego to the south and Vandenburg Air Force Base to the north. Since the radiosonde sites are so distant, AMDAR data are vital to accurate determinations of marine layer depth.

## Aviation Forecasts

- Ceiling and Visibility

- The TAF for Ontario issued at 2325 UTC on April 30, 2001 mentioned that visibilities might fall to 2 miles late at night, and that skies would be clear.  It was thought that the depth of the inversion would be insufficient to climb the range of hills, and reach the inland valley area.

***TAFONT***

***KONT***

*** ******302327Z 010024 26015KT 5SM HZ SCT250***

***     ******FM0400 25005KT 5SM HZ****** ***

***SKC***

*** ***

***     ******FM0600 VRB03KT 5SM BR****** ***

***SKC***

*** ***

***     ******FM1300 VRB03KT 2SM BR HZ****** ***

***SKC***

*** ***

***     ******FM1900 26009KT 4SM HZ****** ***

***SKC***

*** ***

***     ******FM2200 26015KT P6SM ***

***SKC***

***=***

**Notes:**
Meteorologists at the San Diego NWS on the evening shift of April 30, 2001 thought the marine layer depth was insufficient to enter the valley around Ontario, so they issued this TAF stating that skies would remain clear overnight with visibilities only falling to 2 miles near dawn.

## Aviation Forecasts

- ACARS from Long Beach, California at 0232 UTC on May 1, 2001
- shows the base of a temperature inversion around 1,000’

- Ceiling and Visibility

**Notes:**
Later that evening the forecaster looked at AMDAR soundings from the Los Angeles and San Diego areas to see if that forecast still looked reasonable. This sounding from Long Beach shows the base of the inversion around 1,000’, implying a marine layer depth approximately that deep. The wind field, however, shows onshore flow up to 4,000’ from the west. This suggests that the marine layer will likely deepen with time. 

## Aviation Forecasts

- Ceiling and Visibility

- ACARS from San Diego, California at 0233 UTC on May 1, 2001
- shows the base of a temperature inversion around 1,200’.

**Notes:**
A sounding from San Diego to the south has a marine layer of 1,200’ and northwest onshore winds to 4,000’. The meteorologist is now beginning to rethink the forecast.

## Aviation Forecasts

- Ceiling and Visibility

- ACARS WVSS from Ontario, California at 0201 UTC on May 1, 2001
- shows the base of a temperature inversion around 1,900’.

**Notes:**
The meteorologist then sees this AMDAR sounding from an aircraft taking off from Ontario with a water vapor sensor. This sounding shows that the inversion height is 1,900’ with a westerly flow up to 5,000’. The meteorologist is now thinking that low clouds and dense fog are possible as the boundary layer temperature cools to the dewpoint later that night.

## Aviation Forecasts

- Ceiling and Visibility

- TAFONT

- KONT 010525Z 010606 VRB03KT 5SM BR SKC

***     ***FM1200 VRB03KT 2SM BR OVC008

***      ***TEMPO 1215 1SM BR OVC005

***     ***FM1600 VRB03KT 3SM BR HZ SKC

***     ***FM2000 26012KT 5SM HZ SKC

***     ***FM0500 VRB03KT 4SM BR OVC010=

- The meteorologist noticed that soundings from the evening hours showed that the marine layer was about 1,000 to 1,200 feet along the coast, and 1,900 feet MSL at Ontario.  This suggested that the damp, maritime air had already reached the interior valley, and that low clouds and fog were indeed possible.  This information was used to issue the 06UTC TAF, forecasting IFR ceilings of 5 hundred feet and visibilities around one mile were expected overnight.

## Aviation Forecasts

- AREA FORECAST DISCUSSION...UPDATED
- NWS FORT WORTH TX
- 1055 AM CDT TUE MAY 4 2004
- .AVIATION... 604 AM. VFR...**LLWS THRU 14Z THEN NO CONCERNS.**
**SW WINDS AT 1-2 KFT HAVE SET UP A STRONG INVERSION...AND A LLJ OF ARND 23035KT PER ACARS SOUNDINGS/VWP**. WITH LT 10 KTS AT THE SFC...I WILL MENTION LLWS THRU 14Z. WITH QUICKLY WARMING TEMPERATURES UNDER PLENTY OF SUN...ANY LLWS SHLD BE GONE BY MID MORNING WITH GUSTY S/SW WINDS. SLY WINDS 5-15 KTS TO PREVAIL TONIGHT. 30/SS &&

- Low Level Wind Shear

## Winter Weather

## Winter Weather

- Precipitation type remains one of the main challenges of winter weather forecasting.
- Accurate forecasts require a detailed knowledge of the temperature and humidity structure of the atmosphere.

## Winter Weather

- Meteorologists at the NWS offices in Warsaw, Indiana used TAMDAR during the evening of December 25, 2006 to determine that cloud microphysics were not suitable for heavy snowfall.
- TAMDAR soundings into Fort Wayne showed that temperatures were too warm for significant ice crystal growth.
- They updated their forecast, to reduce (in half) the snow accumulation amounts.

- Northern Indiana

## Winter Weather

- AREA FORECAST DISCUSSIONNWS NORTHERN INDIANA935 PM EST MON DEC 25 2006
- .UPDATE... **2355 UTC TAMDAR DESCENT SNDG INTO KFWA CONFIRMS TEMPS THROUGH 700MB TO BE BARELY SUFFICIENT FOR NUCLEATION WITH TEMPS AOA M7C.** OUTSIDE OF RELATIVELY WEAK AND POORLY DEFINED TRANSITORY BANDING THAT BRINGS A MIX TO BRIEF BURST OF 2-3SM -SN CHANGEOVER...THERE CONTINUES TO BE NO ACCUMS GIVEN 2 INCH SOIL TEMP OF 38F AND MAX SUBCLOUD T OF 2-4C AND WET GROUND MELTING SNOW AS SOON AS IT FALLS. **MOST OF CWA PLAGUED WITH SATURATION BENEATH PRIME NUCLEATION HEIGHT AS SUCH HAVE UPDATED AND BASICALLY HALVED ACCUMS OUTSIDE OF FAR W/NW WITH MENTION OF TRACE MIXED EVENT **

- Northern Indiana

## Winter Weather

**TAMDAR**
**sounding from**
**0027 UTC on**
**December 25,**
**2006 shows a**
**deep, moist**
**layer that is**
**generally too**
**warm for ice**
**crystal **
**Formation. **

- Northern Indiana

## Convective Storms

- Supercell thunderstorm near Joplin, Missouri

## Convective Storms

- AMDAR data has been shown to be very effective in the issuance of convective watches and warnings.
- Real time data has been very valuable in determining the presence of capping inversions, wind shear, low level moisture, etc.

## Convective Storms – Warning Decisions

- The NWS in La Crosse, Wisconsin used TAMDAR in deciding NOT to issue a tornado warning – despite a tornado signature on radar.
- This late season event in October, 2006 shows the utility of AMDAR in the proper depiction of the near-storm environment, which is vital to accurate convective warnings.

## Convective Storms – Warning Decisions

- Surface warm front expected to be the focus for surface based convection during the afternoon hours.  Given the high cape and high shear environment the area was in a Moderate Risk for severe weather with a heightened threat for tornadoes.

##  2000 UTC SPC Day 1 Outlook

- Moderate Risk highlighted area of high shear, instability and moisture pooling along a frontal boundary.

## Convective Storms – Warning Decisions

- MCD indicated storms expected to develop in the outlook area with increasing CAPE just north of a warm front.
- Although a capping inversion was in place this was expected to weaken during the afternoon hours.
- Strong deep layer shear expected to promote supercells with possible tornadoes.

**Tornado Watch was issued  at 2035 UTC.**

## Convective Storms – Warning Decisions

- Map of NWS La Crosse, Wisconsin forecast area (shaded)

## Convective Storms – Warning Decisions

- Large Supercell over the Minneapolis forecast area.

- Multiple tornado warnings were issued for the storm as is moves into western Wisconsin.

- Warning decision needs to be made around 0100 UTC for ARX

## Convective Storms – Warning Decisions

**MSP soundings shows a stronger CAP to the south but a strong and persistent cap in all directions.**

**EAU sounding indicated very dry air at the surface and a strong CAP.**

**LSE soundings show a  strengthening CAP and dry air at the surface.**

**A subsequent MSP sounding showed a  stronger CAP and deeper stable layer than the RUC.**

## Convective Storms – Warning Decisions

- Aircraft soundings gave forecasters confidence in issuing Severe Thunderstorm Warnings and holding off on Tornado Warnings.
- The Supercell subsequently weakened as it moved through the La Crosse
- forecast atea.

## Summary

- The use of AMDAR has increased in WFOs, CWSUs, and NCEP centers in the past decade.
- Applications of AMDAR have been found for almost all weather phenomena.
- Need dense coverage of observations that can be provided by regional airlines.
- Need more water vapor soundings.

## Acknowledgements

- Gary Austin - NWS Green Bay MIC
- Pete Browning - NWS Central Region SSD
- Dave Helms - NWS Office of Science and Technology