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

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2004 Regional Climate HighlightsByGerald
BellClimate Prediction CenterNOAA/NWS/NCEP
Contributors Vernon Kousky, Craig Long,
Rich Tinker, Wasilla Thiaw, Song Yang
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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

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Temperature and Precipitation Anomalies
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Regional Temperature Anomalies during 2004
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Jan.-Sep. 2004 Temperature Rankings
1 is the coldest since 1950 55 is warmest since
1950
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Regional Anomalies during 2004
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Monsoon Rains

• India
• West Africa
• Southern Africa

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June-August India Monsoon Rainfall
Total 2004 rainfall 13 below average
Above average
Figure Courtesy Song Yang See Yang and
Yoo Poster 1.26
Below average
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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
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Anomalous 200-hPa VPOT andDivergent Wind Vectors
Enhanced West African monsoon system and
suppressed rainfall over Central America/ Amazon
Basin predominant since 1995.
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Anomalous 200-hPa STRM andRotational Wind
Vectors
Anticyclonic

• 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)

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Atlantic and East Pacific Hurricane Seasons
See poster Chelliah, Bell and Mo, P. 1.24
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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
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2004 Atlantic Tropical Cyclone Tracks
MDR
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 (9oN-21.5oN).
Figure Courtesy Unisys Weather.com
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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
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Since 1995, 8 of 10 Atlantic hurricane seasons
were above normal. On average 2-3 hurricanes hit
the U.S. in above-normal seasons.
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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
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Standardized SST Departures in Main Development
Region
Above normal 2004 Atlantic hurricane season
associated with ongoing anomalous warmth across
tropical Atlantic that began in 1995reflects
warm phase of Atlantic multi-decadal mode
(Goldenberg et al. 2001)
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Recent Decade of Favorable ConditionsAnomalies
are relative to Inactive 1979-1994 Period
Vertical Wind Shear 200-850 hPa
Bell et al., BAMS, May 2004
700-hPa Zonal Wind
Averaging Regions
700-hPa Relative Vorticity
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Evolution to Early Stages of El Niño
See poster Kousky, P. 1.15
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Latest SST Anomalies (oC) 4-10 October 2004
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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

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Strong MJO during 2004 200-hPa Velocity
Potential Anomaliesaveraged 5N-5S
Anomalous Convergence
Anomalous Divergence
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
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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 Niño-3 region
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Extratropics
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Persistent April-July Circulation over North
America

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

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April-July 2004
300-hPa Heights and Temperatures
Precipitation Percentiles
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June-AugustMean Temperature Rankings
1 is the coldest since 1950 55 is warmest since
1950
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June-August Mean Maximum Temperature Anomalies
(C)
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Some Summertime Cold-air Outbreaks
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Stratosphere

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

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Antarctic Ozone Hole (Concentrations lt220
DU)NOAA SBUV/2 Satellite Estimate
Figure Courtesy of Craig Long, poster P 1.23
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January 2004 Stratospheric WarmingDaily
Temperature Departures (C)
Figure Courtesy of Craig Long, poster P 1.22
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Height Anomalies (m) associated with 2004
Stratospheric Warming
Stratospheric warming contributes to strong
negative phase of the Arctic Oscillation
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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
  stratospherewarming event
• Antarctic ozone hole near 1994-2003 mean size