# Presentation: 657491

## 2004 Regional Climate HighlightsByGerald BellClimate Prediction CenterNOAA/NWS/NCEP

- Contributors: Vernon Kousky, Craig Long,
- 	           Rich Tinker, Wasilla Thiaw, Song Yang

## Outline

**Temperature and precipitation anomalies**
**Indian and African monsoon seasons**
**Active Atlantic, suppressed East Pacific hurricane seasons**
**Evolution to early stages of El Niño, MJO influence**
**Anomalous conditions over North America (Apr-Aug)**
**Stratosphere: Antarctic ozone**
**January stratospheric warming**

## Temperature and Precipitation Anomalies

## Regional Temperature Anomalies during 2004

**Regional Temperature Anomalies during 2004**

## Jan.-Sep. 2004 Temperature Rankings

-  1 is the coldest since 1950
-  55 is warmest since 1950

## Regional Anomalies during 2004

**Regional Anomalies during 2004**

## Monsoon Rains

**India**
**West Africa**
**Southern Africa**

## June-August India Monsoon Rainfall 

**Figure Courtesy: **
**Song Yang **
**See Yang and Yoo**
**Poster 1.26**

**Total 2004 rainfall: **
**13% below average**

- Above average

- Below average

## West Africa and Southern Africa Monsoon Rainfall Anomalies (mm)

- Posters:
- Thiaw and Mo, P. 1.2
- Nicholson, P. 1.19
- Thiaw, P. 1.28

- Posters:
- Thiaw, P. 1.28

## Anomalous 200-hPa VPOT andDivergent Wind Vectors

**Enhanced West African monsoon system and suppressed rainfall **
**over Central America/ Amazon Basin predominant since 1995.**

## Anomalous 200-hPa STRM andRotational Wind Vectors 

_**Inter-hemispheric symmetry to anticyclonic streamfunction anomalies**_
**Stronger subtropical ridges reflect enhanced West African monsoon system and suppressed Amazonian rainfall system (Chelliah and Bell 2004),**
**Classic for above-normal Atlantic hurricane seasons (Bell and Chelliah 2005)**

**Anticyclonic**

## Atlantic and East Pacific Hurricane Seasons

**See poster:**
**Chelliah, Bell and Mo, P. 1.24**

## Very Active Atlantic hurricane Season 

**	****	****	**_**2004         Normals**_
**Tropical Storms           15              9-10**
**Hurricanes                      8               5-6**
**Major Hurricanes          6                 2**

**7 landfalling systems in 2004, 18 landfalls during 2002-2004.**
**14  of these systems made landfall along the Gulf Coast **

## Slide 14

## 2004 Atlantic Tropical Cyclone Tracks

**Figure Courtesy Unisys Weather.com**

**Above-normal seasons have large number of  systems forming in **
**Main Development Region (MDR). During 2004, 8 /14 TS,  7/8 H **
**and 5/6 MH formed in MDR (9****o****N-21.5****o****N). **

- MDR

## Aug-Sep 2004: Total Precipitation (mm) during the periods in which the six landfalling tropical systems were producing precipitation in U.S., and % of 2-month total

## Since 1995, 8 of 10 Atlantic hurricane seasons were above normal.

- On average 2-3 hurricanes hit the U.S. in above-normal seasons.

## Primary Conditions associated with  Active 2004 Atlantic Hurricane Season

**Warmer SSTs**

**These conditions have prevailed since 1995-**
**8 of 10 hurricane seasons have been above-normal.**
**Also characterized the active decades of the 1950s-1960s**

**Primary Conditions associated with  ****Active 2004 Atlantic Hurricane Season**

## Standardized SST Departures in Main Development Region

**Above normal 2004 Atlantic hurricane season associated with ongoing anomalous warmth across tropical Atlantic that began in 1995—reflects warm phase of Atlantic multi-decadal mode (Goldenberg et al. 2001)**

## Recent Decade of Favorable ConditionsAnomalies are relative to Inactive 1979-1994 Period

**Recent Decade of Favorable Conditions****Anomalies are relative to Inactive 1979-1994 Period**

**Averaging **
**Regions**

**Vertical Wind Shear: 200-850 hPa **

**700-hPa Zonal Wind**

**700-hPa Relative Vorticity**

**Bell et al.,**
*** ******BAMS*****, May 2004**

## Evolution to Early Stages of El Niño 

**See poster:**
**Kousky, P. 1.15**

## Latest SST Anomalies (oC): 4-10 October 2004

## Evolution of SST Anomalies Averaged 5oN - 5oS

** ****Largest positive SST anomalies were west of date line until July**
** ****Since July, anomalous warmth has persisted and expanded eastward.**
**Negative anomalies in eastern Pac. disappearing**

## Strong MJO during 2004 200-hPa Velocity Potential Anomaliesaveraged 5N-5S

**MJO has produced significant variability in the atmosphere and in Pacific Ocean temperatures. No El Niño signature yet.         See poster: Weickmann and Berry, P. 1.25**

**Anomalous**
**Divergence**

**Anomalous**
**Convergence**

## Area-Averaged SST Anomalies in Niño-4 and Niño 3 Regions

**Intraseasonal SST fluctuations are associated with oceanic Kelvin  waves triggered by MJO**
**In September,  the anomalous warmth expanded eastward  to cover Ni****ño-3 ****region**

## Extratropics

## Persistent April-July Circulation over North America

**Hot and Dry Alaska**
**Cooler Canada, cooler summer in U.S.**
**Below-average Southwest U.S. monsoon**

## April-July 2004

**April-July 2004**

**Precipitation Percentiles**

**300-hPa Heights and Temperatures**

## June-AugustMean Temperature Rankings

-  1 is the coldest since 1950
- 55 is warmest since 1950

## June-August Mean Maximum Temperature Anomalies (C) 

## Some Summertime Cold-air Outbreaks

## Stratosphere

** ****Antarctic Ozone hole**
** ****January N.H. Stratospheric Warming**

## Antarctic Ozone Hole (Concentrations <220 DU)NOAA SBUV/2 Satellite Estimate

**Figure Courtesy of Craig Long, poster P 1.23**

## January 2004 Stratospheric WarmingDaily Temperature Departures (C)

**Figure Courtesy of Craig Long, poster P 1.22**

## Height Anomalies (m) associated with 2004 Stratospheric Warming

**Stratospheric warming contributes to strong negative phase of the Arctic Oscillation**

## Summary

**Many temperature and precipitation anomalies associated with **
**multi-decadal fluctuations: Chelliah and Bell 2004, Goldenberg et al. 2001)**
**	****       **_**Precipitation:**_**	****	****	**_**Temperature**_
**              ****Enhanced West African monsoon****	****               Warm N. Atl**
**	****Drier Amazon Basin **
**	****Active Atl. hurricanes, **
**	****summertime eastern U.S. rainfall,**
**Evolution to early stages of El Niño**
** **
**No single cause of N.A. circulation anoms. during Apr-Aug., hemispheric-scale pattern of anomalies, extended into middle strat.**
**January negative AO also linked to stratosphere—warming event**
**Antarctic ozone hole near 1994-2003 mean size**