[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAR 24 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
1715 UTC.

...ITCZ...

ITCZ AXIS IS ANALYZED FROM 06N11W TO THE EQUATOR NEAR 23W THEN
TO 03S31W AND INTO NE BRAZIL NEAR 03S39W. ISOLATED MODERATE
CONVECTION IS FROM THE EQUATOR TO 04N BETWEEN 24W-32W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL SHORTWAVE TROUGH IS
MOVING OFF THE MID-ATLC SEABOARD AND EXTENDS A WEAK COLD FRONT
ACROSS SOUTH CAROLINA AND GEORGIA INTO NORTHERN PORTIONS OF THE
GULF FROM PANAMA CITY FLORIDA TO THE NEW ORLEANS LOUISIANA AREA
THEN STATIONARY TO THE TEXAS COAST NEAR GALVESTON BAY. LACK OF
STRONG UPPER LEVEL SUPPORT AND MOISTURE ARE LIMITING IMPACTS
WITH THE FRONT TO A FAIRLY BENIGN WIND SHIFT AND A MORE APPARENT
MOISTURE/DEW POINT CONTRAST ACROSS THE BOUNDARY. RELATIVELY
HIGHER DEWPOINTS IN THE UPPER 60S AND LOWER 70S ARE OBSERVED ON
SHIPS AND BUOYS ACROSS THE GULF WATERS WHILE CONSIDERABLY DRIER
AIR LOCATES NORTH OF THE FRONT OVER THE GULF COASTAL PLAINS WITH
DEWPOINTS REACHING INTO THE LOWER 40S. THE FRONT IS FORECAST TO
GRADUALLY DISSIPATE OVER THE NEXT 24 HOURS. THE REMAINDER OF THE
GULF IS UNDER THE INFLUENCE OF A SURFACE RIDGE WHICH EXTENDS
FROM THE SW NORTH ATLC ALONG 24N TO THE FLORIDA STRAITS THEN
W-NW TO A 1016 MB HIGH CENTERED NEAR 26N88W. SKIES REMAIN MOSTLY
CLEAR THIS AFTERNOON DUE TO STRONG MIDDLE TO UPPER LEVEL
SUBSIDENCE AND MODERATELY DRY AIR ALOFT. SOUTHERLY RETURN FLOW
IS EXPECTED TO INCREASE ACROSS THE WESTERN GULF LATE FRIDAY INTO
SATURDAY AHEAD OF THE NEXT FRONT FORECAST TO EMERGE OFF THE NW
GULF COAST MONDAY.

CARIBBEAN SEA...
A RIDGE OF HIGH PRESSURE LIES NORTH OF THE CARIBBEAN SEA BASIN
ALONG 24N THAT IS PRODUCING 15-25 KT TRADEWIND EASTERLIES THIS
AFTERNOON. SURFACE WINDS JUST NORTH OF COLOMBIA ARE SOMEWHAT
ENHANCED BY THE LOCAL TOPOGRAPHY...AS IS TYPICALLY SEEN. NO DEEP
CONVECTION IS CURRENTLY OBSERVED ACROSS THE CARIBBEAN...HOWEVER
SOME LOW-TOPPED SHOWERS ARE OCCURRING ALONG THE EASTWARD FACING
SLOPES OF CENTRAL AMERICA AND AN AREA WITHIN 90 NM SURROUNDING
GRAND CAYMAN ISLAND. IN THE UPPER LEVELS...STRONGLY SUBSIDENT
ZONAL FLOW DOMINATES. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24
HOURS.

ATLANTIC OCEAN...
DEEP LAYER TROUGHING IS LOCATED N OF 28N ACROSS THE WESTERN
NORTH ATLC WITH MOSTLY NORTHWESTERLY AND MODERATELY SUBSIDENT
FLOW ALOFT DOMINATING W OF 50W. AT THE SURFACE...CONDITIONS
REMAIN FAIRLY BENIGN WITH LIGHT ANTICYCLONIC FLOW AROUND A RIDGE
AXIS EXTENDING ALONG 24N STEMMING FROM A 1022 MB HIGH CENTERED
IN THE CENTRAL ATLC NEAR 24N44W. STRONGER SOUTHWESTERLY SURFACE
FLOW IS NOTED N OF 30N WITH MOST OF THE ACTIVE CONVECTION
ASSOCIATED WITH A SURFACE TROUGH AND COLD FRONT LOCATED N OF 34N
BETWEEN 55W-70W. OVER THE EASTERN ATLC WEDGED WITHIN THE
SUBTROPICAL RIDGE IS A WEAK 1018 MB LOW CENTERED NEAR 26N33W.
SURFACE TROUGHING EXTENDS S-SW TO 20N36W WITH A SHEAR LINE
CONTINUING S OF 20N ALONG 18N40W TO 13N52W. ISOLATED SHOWERS ARE
OCCURRING WITHIN 90 NM EITHER SIDE OF THE BOUNDARIES SOUTH OF
THE LOW CENTER. A STATIONARY FRONT EXTENDS E-NE FROM THE LOW
ALONG 28N30W TO 28N25W AND CONNECTS WITH A COLD FRONT EXTENDING
INTO THE DISCUSSION AREA NEAR 32N20W. THE UPPER LEVEL PATTERN
ASSOCIATED WITH THIS COLD FRONT REMAINS UNFAVORABLE FOR ANY DEEP
CONVECTION...HOWEVER ISOLATED SHOWERS ARE OCCURRING OVER THE
AREA FROM 26N-29N BETWEEN 21W-33W AND WITHIN 60 NM EAST OF THE
COLD FRONT.

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

$$
HUFFMAN



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