[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180625
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI JAN 18 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0545 UTC

...THE ITCZ...
FROM 10N14W 5N20W...CROSSING THE EQUATOR AT 32W...STAYING
JUST SOUTH OF THE EQUATOR TO 44W...AND CONTINUING INTO
NORTHEASTERN BRAZIL NEAR 1S49W. ISOLATED MODERATE SHOWERS TO
LOCALLY STRONG THUNDERSTORMS ARE SOUTH OF 6N BETWEEN 14W AND
30W...AND FROM 2N TO 10N BETWEEN 44W AND 54W. SCATTERED MODERATE
SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FROM THE EQUATOR TO
2N BETWEEN 36W AND 46W...AND IN BRAZIL FROM 4S TO 1N BETWEEN 49W
AND 55W.

...DISCUSSION...

THE GULF OF MEXICO...
BROAD MIDDLE TO UPPER LEVEL SOUTHWESTERLY WIND FLOW COVERS
THE AREA. THE FRONTAL BOUNDARY IN THE GULF OF MEXICO LACKS
STRONG SUPPORT IN THE MIDDLE TO UPPER LEVELS OF THE ATMOSPHERE.
A COLD FRONT RUNS ALONG THE FLORIDA WEST COAST FROM THE
NORTHWESTERN CORNER OF FLORIDA TO WEST CENTRAL FLORIDA...
TO THE NORTHERN YUCATAN PENINSULA. THE FRONT BECOMES STATIONARY
AND IT CUTS ACROSS THE YUCATAN PENINSULA INTO THE SOUTHWESTERN
CORNER OF THE AREA...INTO MEXICO TO 24N100W AND FINALLY TO
27N108W. POSSIBLE SHOWERS ARE SOUTH OF 26N EAST OF 89W...
AND WITHIN A 30 NM TO 40 NM RADIUS OF 21.5N96W.

THE CARIBBEAN SEA...
BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE ATLANTIC OCEAN
SOUTH OF 32N WEST OF 55W...INCLUDING IN THE CARIBBEAN SEA.
A MIDDLE LEVEL ANTICYCLONIC CIRCULATION CENTER IS SUPPOSED
TO BE ABOUT 90 NM NORTH OF EASTERN HISPANIOLA ACCORDING TO THE
GFS MODEL. SUCH A CENTER IS NOT EASY TO SEE WITH THE NAKED EYE
ON SATELLITE IMAGERY. MIDDLE TO UPPER LEVEL DRY AIR/SUBSIDENCE
COVERS THE ENTIRE AREA. SURFACE EASTERLY WIND FLOW IS LOOSELY
RELATED TO LARGE SCALE ANTICYCLONIC FLOW. NO ANTICYCLONIC
CIRCULATION CENTER IS ANYWHERE NEAR THE CARIBBEAN SEA. ONE
CENTER IS JUST NORTH OF BERMUDA IN THE ATLANTIC OCEAN.
LARGE-SCALE ANTICYCLONIC FLOW FROM THIS ATLANTIC OCEAN HIGH
PRESSURE CENTER REACHES THE CARIBBEAN SEA. THE ISOBARS ON THE
SURFACE MAP DO NOT APPEAR TO SHOW A STRONG PRESSURE GRADIENT.
THAT DOES NOT MEAN THAT A SLIGHT CHANGE IN THE PRESSURE FIELD IS
NOT ABLE TO GENERATE COMPARATIVELY STRONGER WIND SPEEDS ACROSS
THE OPEN WATERS OF THE CARIBBEAN SEA. AN EXAMPLE OF FAST WINDS
FROM WHAT DOES NOT APPEAR TO BE SUCH A STRONG GRADIENT ACCORDING
TO THE ISOBARIC ANALYSIS IS FROM 11N TO 14N BETWEEN 73W AND 77W
NORTHEAST-TO-EAST WINDS 25 TO 30 KT AND SEAS TO 11 FT.
THE 24 HOUR FORECAST DOES NOT CHANGE MUCH FOR THIS AREA...AND
IT STAYS PRETTY MUCH THE SAME FOR 48 HOURS EXCEPT FOR POSSIBLY
15 FT OF SEAS.

THE ATLANTIC OCEAN...
A WESTERN ATLANTIC COLD FRONT PASSES THROUGH 32N78W TO A 1014 MB
LOW PRESSURE CENTER NEAR 30N83W IN NORTHERN FLORIDA. ISOLATED
MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS ARE ALONG THIS FRONT.
AN ATLANTIC OCEAN COLD FRONT PASSES THROUGH THE EAST CENTRAL
SECTIONS NEAR 32N39W TO 24N50W TO 23N66W. A MIDDLE TO UPPER
LEVEL TROUGH PASSING THROUGH 33N47W 27N50W 24N51W SUPPORTS
THIS COLD FRONT. ISOLATED MODERATE SHOWERS AND POSSIBLE
THUNDERSTORMS ARE WITHIN 90 NM ON EITHER SIDE OF 23N57W
27N44W...AND WITHIN 30 NM ON EITHER SIDE OF 27N43W BEYOND 32N37W.
A 1027 MB HIGH PRESSURE CENTER IS JUST NORTH OF BERMUDA.
THIS HIGH PRESSURE CENTER AND ITS ASSOCIATED FLUCTUATIONS
IN THE PRESSURE GRADIENT ARE PRODUCING 20 KT TO 30 KT WIND
SPEEDS IN THE SOUTH CENTRAL CARIBBEAN SEA...AND IN PARTS OF
THE ATLANTIC OCEAN. PLEASE REFER TO THE MIAHSFAT2 HIGH SEAS
FORECAST FOR SPECIFIC FORECAST INFORMATION. AN ATLANTIC OCEAN
MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH 32N27W TO 23N33W
TO 14N48W TO NORTHERN GUYANA. A SURFACE RIDGE IS EAST OF THE
32N39W 23N66W COLD FRONT ALONG 20N51W 25N36W BEYOND 32N23W.

$$
MT


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