[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE APR 26 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION
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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1745 UTC.

...THE ITCZ...

FROM THE COAST OF SOUTHERN LIBERIA NEAR 4N8W...CROSSING THE
EQUATOR ALONG 17W...TO 6S25W...3S35W...INTO COASTAL NORTHEASTERN
BRAZIL NEAR 1S47W. A BROAD AREA OF NUMEROUS MODERATE TO HEAVY
SHOWERS AND THUNDERSTORMS IS FROM 12S-4N BETWEEN 14W-40W.
SCATTERED STRONG CONVECTION IS MOVING OFF THE COAST OF AFRICA
BETWEEN 3W-12W.

...DISCUSSION...

GULF OF MEXICO...
FOR THIS EARLY AFTERNOON...MOSTLY DRY WESTERLY FLOW ALOFT IS
NOTED ON WATER VAPOR IMAGERY. THIS PATTERN IS SUPPRESSING ANY
CONVECTIVE ACTIVITY AND MAINTAINING FAIR WEATHER CONDITIONS OVER
THE GULF. HOWEVER...THE BASE OF AN UPPER LEVEL TROUGH MOVING
ACROSS THE CENTRAL CONUS SUPPORTS AN AREA OF WEAK CONVECTION
OVER THE FAR N CENTRAL BASIN. DOPPLER RADAR IMAGERY INDICATED A
LINE OF MODERATE TO HEAVY SHOWERS AND ISOLATED THUNDERSTORMS
MOVING ENE AT ABOUT 12 KT ALONG THE COAST OF LOUISIANA AND
MISSISSIPPI BETWEEN 87W-90W. THIS LINE WILL CONTINUE TO WEAKEN
THIS AFTERNOON. OTHERWISE...SSE WINDS UP TO 20 KT ARE OBSERVED
ACROSS THE AREA. VISIBLE SATELLITE IMAGERY SHOWED AREAS OF LOW
LEVEL STRATUS CLOUDS AND PATCHY FOG LINGERING OVER THE FAR NW
BASIN. MARINE OBSERVATIONS IN THIS REGION INDICATED VISIBILITIES
AS LOW AS 2 SM...ESPECIALLY NEAR THE COAST OF TEXAS. THESE
CLOUDS ARE EXPECTED TO DISSIPATE OVER THE NEXT FEW HOURS. IN 24
HOURS A COLD FRONT IS EXPECTED TO EMERGE OFF THE TEXAS COAST
WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS.

CARIBBEAN SEA...
MOST OF THE CARIBBEAN SEA W OF 63W IS EXPERIENCING FAIR WEATHER
CONDITIONS DUE TO DRY AND STABLE AIR ALOFT MOVING ACROSS THE
AREA. AT SURFACE...SURFACE AND MARINE OBSERVATIONS INDICATE
15-20 KT TRADE WINDS TURNING N WESTWARD W OF 75W N OF 15N. THE
OVERALL FLOW IS PUSHING SOME LOW LEVEL MOISTURE INLAND OVER
WESTERN PANAMA AND COSTA RICA...GENERATING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS NEAR THE COAST BETWEEN 79W-84W. A SURFACE
TROUGH IS MOVING OVER THE LESSER ANTILLES...ANALYZED FROM SAINT
LUCIA TO VENEZUELA NEAR 10N62W. THIS SYSTEM IS GENERATING
SCATTERED SHOWERS AND THUNDERSTORMS S OF DOMINICA E OF 63W. THE
CONVECTION ASSOCIATED TO THIS SYSTEM HAS BECOME E TO W ELONGATED
OVER THE PAST 6 HOURS. THEREFORE...THESE GROUP OF ISLANDS S OF
16N WILL CONTINUE TO EXPERIENCE CONVECTION FOR AT LEAST THE NEXT
24 HOURS AS THE TROUGH MOVES WEST AT ABOUT 15 KT.

ATLANTIC OCEAN...
MOST OF THE DISCUSSION AREA IS DOMINATED BY A STRONG UPPER LEVEL
RIDGE COVERING THE ATLC W OF 33W. THIS UPPER RIDGE IS SUPPORTING
A 1032 MB HIGH WOBBLING AROUND 33N57W. HOWEVER...A WEAKNESS IN
THE RIDGE ASSOCIATED TO A WEAK MID/UPPER LEVEL TROUGH MOVING
ACROSS THE WSW PERIPHERY OF THE RIDGE IS GENERATING AN AREA OF
SCATTERED MODERATE TO HEAVY SHOWERS AND ISOLATED THUNDERSTORMS
WITHIN 70 NM ON EITHER SIDE OF A LINE FROM 19N64W TO 24N70W TO
30N74W. SHORT RANGE COMPUTER MODELS SUGGEST THIS AREA OF
CONVECTION WILL LINGER OVER THE NEXT 24 HOURS. SIMILAR ACTIVITY
CAN BE FOUND OVER THE FAR W ATLC W OF 79W N OF FREEPORT IN THE
BAHAMAS. A WEAK SURFACE TROUGH IS OVER THE TROPICAL ATLC
ANALYZED FROM 13N53W TO 10N54W. THIS TROUGH IS ALSO RELATED TO A
SECOND TROUGH CURRENTLY MOVING OVER THE LESSER ANTILLES. THESE
TWO FEATURES ARE GENERATING SCATTERED SHOWERS AND THUNDERSTORMS
W OF 50W FROM 11N-16N. THESE FEATURES WILL CONTINUE TO MOVE
WESTWARD INTO THE CARIBBEAN BASIN OVER THE NEXT 24 HOURS. A WEAK
LOW PRESSURE SYSTEM IS CAPTURE ON SATELLITE VISIBLE IMAGERY NEAR
30N30W. A WEAK COLD FRONT EXTENDS FROM THE LOW CENTER ALONG
30N27W TO 27N29W WITHOUT PRODUCING ANY SIGNIFICANT CONVECTION.
ONLY A SMALL AREA OF SCATTERED SHOWERS IS NOTED FROM 30N-34N
BETWEEN 24W-29W. THIS SYSTEM WILL CONTINUE TO WEAKEN OVER THE
NEXT 24 HOURS.

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

$$

GARCIA




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