[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231137
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST MON FEB 23 2009

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N9W 2N15W CROSSING THE EQUATOR
NEAR 20W EXTENDING TO 1S25W 2S34W INTO NE BRAZIL NEAR 3S43W.
NUMEROUS MODERATE/ISOLATED STRONG CONVECTION IS S OF 1N BETWEEN
30W-42W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYER TROUGH IS PRESENT ACROSS THE GULF OF MEXICO...WITH
AN ASSOCIATED SURFACE COLD FRONT EXTENDING FROM THE SW FLORIDA
PENINSULA NEAR 26N82W TO THE SE GULF NEAR 24N86W TO THE COAST OF
THE YUCATAN PENINSULA NEAR 21N89W. LOW LEVEL CONVERGENCE IS
SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS
FRONT. TO THE N AND W OF THIS FRONT...GENERALLY FAIR WEATHER IS
PRESENT WHERE NORTHWESTERLY FLOW ALOFT IS SUPPORTING ATMOSPHERIC
SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS. THIS SUBSIDENCE IS
ALSO BEING SUPPORTED BY A 1031 MB SURFACE HIGH OVER S TEXAS NEAR
29N98W. NORTHEASTERLY SURFACE WINDS IN THE WAKE OF THE COLD
FRONT ARE USHERING IN A RELATIVELY COOLER AND DRIER AIRMASS
ACROSS THE N AND W GULF. ADDITIONALLY...STRONG N TO NE SURFACE
WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING
IN STORM FORCE WINDS IN THE E PACIFIC REGION.

CARIBBEAN SEA...
AN INCREASED SURFACE PRESSURE GRADIENT IS RESULTING IN STRONG
TRADE WINDS ACROSS THE CARIBBEAN SEA...WITH NE TO E SURFACE
WINDS OF 20 TO 30 KT ACROSS PORTIONS OF THE SW AND E CARIBBEAN.
GENERALLY FAIR WEATHER CONDITIONS ARE OCCURRING ACROSS THE
CARIBBEAN REGION...WHERE AN UPPER LEVEL RIDGE IS PRESENT.
PATCHES OF LOW LEVEL MOISTURE CONTINUE TO BE ADVECTED WESTWARD
ACROSS THE CARIBBEAN BY THE TRADE WINDS...WITH SCATTERED SHOWERS
EMBEDDED WITHIN THESE PATCHES OF LOW LEVEL MOISTURE. THE
GREATEST CONCENTRATION OF THESE SHOWERS IS E OF 66W.

ATLANTIC OCEAN...
A DEEP TROUGH OVER THE W ATLC IS ASSOCIATED WITH A SURFACE COLD
FRONT THAT EXTENDS FROM THE SE FLORIDA PENINSULA NEAR 27N80W TO
29N74W TO 32N87W TO NE OF THE DISCUSSION AREA...AND A SURFACE
COLD FRONT THAT EXTENDS FROM THE CENTRAL BAHAMAS NEAR 25N76W TO
28N70W TO 32N66W TO NE OF THE DISCUSSION AREA. LOW LEVEL
CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER
SIDE OF EACH OF THESE FRONTS. ACROSS LOCATIONS IN THE CENTRAL
AND E ATLC THAT ARE SE OF THESE FRONTS...SUBSIDENCE ASSOCIATED
WITH A SURFACE RIDGE IS SUPPORTING FAIR WEATHER CONDITIONS.
HOWEVER...AN UPPER TROUGH IS PRESENT WITH AN AXIS THAT EXTENDS
FROM 19N35W TO 29N19W TO 32N16W TO NE OF THE DISCUSSION AREA. TO
THE E OF THIS UPPER TROUGH AXIS...UPPER LEVEL DIVERGENCE
ASSOCIATED WITH AN UPPER LEVEL WIND SPEED MAXIMUM IS SUPPORTING
SCATTERED SHOWERS N OF 27N E OF 23W. THIS ACTIVITY IS BEING
ENHANCED BY LOW LEVEL CONVERGENCE IN THE VICINITY OF A SURFACE
TROUGH THAT EXTENDS FROM 23N15W TO E OF THE CANARY ISLANDS NEAR
29N13W TO 32N11W TO NE OF THE DISCUSSION AREA. ACROSS THE
TROPICAL ATLC...STRONG UPPER LEVEL DIFFLUENCE S OF 5N BETWEEN
27W-54W IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.
THIS STRONG UPPER LEVEL DIFFLUENCE IS ALSO SUPPORTING SCATTERED
SHOWERS AND THUNDERSTORMS S OF 5N BETWEEN 45W-52W.

$$
COHEN




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