[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 282335
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON MAR 28 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2330 UTC.

...ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE COAST OF SIERRA LEONE NEAR
8N13W SW ALONG 4N20W EQ40W INTO NE BRAZIL NEAR 3S48W. ISOLATED
MODERATE CONVECTION IS WITHIN 70 NM ON EITHER SIDE OF THE AXIS
BETWEEN 20W-28W. SCATTERED MODERATE CONVECTION IS S OF 3N W OF
32W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL SHORTWAVE MOVES ACROSS THE FAR NW GULF WATERS
NOTED ON WATER VAPOR IMAGERY. THIS FEATURE SUPPORTS A 1010 MB
SURFACE LOW CENTERED OVER THE NORTHERN FLORIDA PENINSULA BETWEEN
TALLAHASSEE AND JACKSONVILLE. A COLD FRONT EXTENDS W-SW ACROSS
THE GULF FROM THE LOW CENTER TO SOUTHERN TEXAS ALONG 29N85W
26N90W WHERE IT CONTINUES AS A DISSIPATING COLD FRONT TO NEAR
26N97W. DESPITE THE EXTENSION OF THE FRONT...MOST OF THE
INSTABILITY AND LOW-LEVEL CONVERGENCE IS FOCUSED WITHIN 140 NM
EAST OF THE FRONT N OF 25N E OF 88W...AFFECTING THE COASTAL
WATERS FROM TAMPA TO FORT MYERS BEACH. THIS FRONTAL SYSTEM IS
EXPECTED TO CONTINUE TO MOVE EASTWARD THROUGH THE NEXT 24 HOURS
WITH CONVECTION MOVING ACROSS THE FLORIDA STRAITS LATE TONIGHT.

CARIBBEAN SEA...
DRY AIR AND STRONG SUBSIDENCE ALOFT IS NOTED ACROSS THE
CARIBBEAN SEA THIS EVENING. GIVEN THE OVERALL STABILITY OF THE
ATMOSPHERE ALOFT...AT SURFACE...FRESH TO STRONG TRADEWINDS
PERSIST WITH VERY FEW AREAS OF SHOWER ACTIVITY THIS AFTERNOON.
THE FLOW TURNS SE W OF 75W IN RESPONSE OF THE WEATHER SYSTEM
MENTIONED IN THE GULF OF MEXICO DISCUSSION. THE APPROACH OF A
WEAK SURFACE TROUGH TO THE LESSER ANTILLES...CURRENTLY LOCATED
IN THE TROPICAL ATLC ALONG 58W FROM 11N TO 18N...IS PROVIDING A
FEW ISOLATED SHOWERS TO THE GROUP OF ISLANDS FROM SAINT VINCENT
AND GRENADINES TO ANTIGUA AND BARBUDA. SIMILAR CONVECTION IS
NOTED WITHIN 120 NM S OF PUERTO RICO AND THE MONA PASSAGE. THE
ACTIVITY OVER THE LESSER ANTILLES IS EXPECTED TO INCREASE
OVERNIGHT AS THE SURFACE TROUGH MOVES OVER THE AREA.

ATLANTIC OCEAN...
A WESTERN NORTH ATLC DEEP LAYER TROUGH IS LOCATED WELL NORTH OF
THE DISCUSSION AREA AND EXTENDS A FRONTAL SYSTEM THAT ENTERS OUR
NORTHERN BORDER NEAR 31N74W AS A STATIONARY FRONT TO THE
NORTHERN FLORIDA COAST NEAR 30N81W. MOSAIC DOPPLER RADAR IMAGERY
AND LIGHTNING DATA INDICATED NUMEROUS SHOWERS AND SCATTERED
TSTMS OCCURRING OVER THE AREA BETWEEN THE FLORIDA COAST AND THE
NORTHERN BAHAMAS N OF 25N W OF 77W. THIS FRONTAL BOUNDARY IS
EXPECTED TO BECOME COLD AND CONTINUE TO TRACK EASTWARD WITH
CONVECTION MOVING ACROSS THE W ATLC OVER THE NEXT 24 HOURS.
ALSO...COMPUTER MODELS SUGGEST MODERATE CONVECTION LINGERING
OVER THE FAR W ATLC DURING THE TIME PERIOD. ELSEWHERE ACROSS THE
AREA...THE REMAINDER OF THE ATLC BASIN IN UNDER THE INFLUENCE OF
A BROAD SURFACE RIDGE ANCHORED BY A 1028 MB HIGH CENTERED NEAR
31N29W. THIS FEATURE EXTENDS A RIDGE AXIS FROM THE HIGH CENTER
TO THE SOUTHERN BAHAMAS BRINGING MOSTLY FAIR WEATHER CONDITIONS
TO THE ATLC N OF 5N E OF 70W.

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

$$

GARCIA




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