[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212355
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU JAN 21 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 4N08W 5N13W 3N22W 3N32W CROSSING
THE EQUATOR NEAR 45W AND INTO THE NE COAST OF BRAZIL NEAR 1S49W.
NO SIGNIFICANT DEEP ORGANIZED CONVECTION IS ASSOCIATED WITH THE
ITCZ.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0300 UTC...A COLD FRONT ENTERS THE GULF NEAR GULFPORT
MISSISSIPPI AND EXTENDS SW ALONG 29N90W TO 24N97W. THIS FRONT
LACKS ANY SIGNIFICANT DEEP CONVECTION AS MOST OF THE UPPER LEVEL
SUPPORT IS LOCATED ACROSS THE SE CONUS AND CONTINUES TO MOVE OFF
TO THE NE WHERE A VERY DIFFLUENT PATTERN EXISTS ACROSS THE
MID-ATLC STATES THIS EVENING. HOWEVER...THIS UPPER LEVEL
DIFFLUENT AREA EXTENDS FAR ENOUGH SOUTH COVERING A PORTION OF
THE FAR NE GULF...NORTHERN FLORIDA...AND THE W ATLC WATERS. A
PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM THE BIG BEND REGION
OF FLORIDA NEAR 29N83W ALONG 27N86W TO 25N89W. CONVERGENT S-SE
WINDS AND SW WINDS ARE GENERATING SCATTERED SHOWERS AND TSTMS
WITHIN 60 NM EAST OF THE SURFACE TROUGH N OF 25N. THIS ACTIVITY
SPREADS NE ACROSS THE NORTHERN FLORIDA PENINSULA AS MOSAIC
DOPPLER RADAR IMAGERY INDICATES A VERY INTENSE SQUALL LINE OF
TSTMS JUST NORTH OF DAYTONA BEACH WESTWARD TO GAINESVILLE
FLORIDA. ACROSS THE NW GULF WATERS...WEST OF THE COLD FRONT...
THE REMAINDER OF THE BASIN IS EXPERIENCING GENERALLY FAIR
WEATHER UNDER MOSTLY DRY AIR AND SUBSIDENCE ALOFT AS NW FLOW
DOMINATES AND UPPER LEVEL RIDGING BUILDS IN ACROSS THE FAR
WESTERN GULF WATERS. THIS IS EXPECTED TO BE A SHORT-LIVED
REPRIEVE OF ACTIVE WEATHER FOR THE WESTERN GULF AS THE NEXT COLD
FRONT IS FORECAST TO EMERGE OFF THE TEXAS GULF COAST LATE
SATURDAY.

CARIBBEAN SEA...
MOST OF THE CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER
UNDER THE INFLUENCE OF DRY AIR AND SUBSIDENCE ALOFT AS NOTED ON
WATER VAPOR IMAGERY. HOWEVER...THE PRESENCE OF A WEAK UPPER
LEVEL SHORTWAVE TROUGH EXTENDS FROM HISPANIOLA TO NICARAGUA.  A
SURFACE TROUGH IS ANALYZED MAINLY IN THE TROPICAL NORTH ATLC
WATERS FROM 21N64W ACROSS THE NORTHERN LEEWARD ISLANDS TO
17N63W. LOW-LEVEL CONVERGENCE IS GENERATING ISOLATED SHOWERS
FOCUSED WITHIN 90 NM EITHER SIDE OF THE BOUNDARY AND THEY EXTEND
AS FAR SOUTH AS SAINT VINCENT NEAR 13N61W THIS EVENING.
ELSEWHERE...FRESH TO STRONG TRADEWINDS CONTINUE ACROSS MUCH OF
THE BASIN WITH THE STRONGEST WINDS OFF THE COAST OF COLOMBIA
REACHING GALE FORCE FROM 11N-15N BETWEEN 70W-77W. THESE WINDS
ARE FORECAST TO DECREASE AS THE W ATLC SURFACE RIDGE SLIDES
EASTWARD OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
SCATTERED SHOWERS AND TSTMS EXTEND ACROSS THE NORTHERN FLORIDA
PENINSULA AND W ATLC WATERS N OF 28N W OF 73W AS AN AREA OF
UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL TROUGH
AXIS CONTINUES TO MOVE NE ACROSS THE SE CONUS AND MID-ATLC
STATES THIS EVENING. THIS IS ALL FOUND ON THE NW PERIPHERY
OF A SURFACE RIDGE THAT EXTENDS FROM A 1018 MB HIGH CENTERED
NEAR 28N68W ACROSS THE CENTRAL BAHAMAS AND CUBA. FARTHER EAST...
A COLD FRONT ENTERS THE EASTERN ATLC NEAR 32N29W AND EXTENDS SW
ALONG 26N40W WHERE IT BECOMES A DISSIPATING STATIONARY FRONT
ALONG 24N50W TO 22N63W. ISOLATED SHOWERS ARE WITHIN 120 NM
EITHER SIDE OF THE COLD FRONT N OF 28N AND WITHIN 90 NM EITHER
SIDE OF THE REMAINDER OF THE FRONT. NEAR THE TAIL END OF THE
STATIONARY FRONT...A SURFACE TROUGH IS ANALYZED FROM 21N64W
SOUTH ACROSS THE LEEWARD ISLANDS TO 17N63W. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE FROM 18N-22N BETWEEN 58W-65W. THIS ENTIRE
FRONTAL SYSTEM IS SUPPORTED BY A WEAK AND BROAD UPPER LEVEL
SHORTWAVE TROUGH AXIS EXTENDING FROM THE AZORES NEAR 38N27W TO
26N50W. THE REMAINDER OF THE EASTERN ATLC IS EXPERIENCING
GENERALLY FAIR WEATHER. HOWEVER...AN UPPER LEVEL LOW IS CENTERED
NEAR 14N31W WITH AN AREA OF UPPER LEVEL DIFFLUENCE LOCATED EAST
OF THE LOW. THIS IS GENERATING POSSIBLE ISOLATED SHOWERS FROM
8N-16N BETWEEN 18W-28W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE.

$$
HUFFMAN




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