[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 030534
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN APR 03 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE SRN COAST OF LIBERIA NEAR
4N8W ALONG 2N20W 1N30W CROSSING THE EQUATOR NEAR 33W AND INTO NE
BRAZIL TO NEAR 3S42W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 100 NM S OF THE AXIS BETWEEN 11W-14W...AND
WITHIN 120 NM N OF THE AXIS BETWEEN 18W-31W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF OF MEXICO REMAINS MOSTLY CLEAR UNDER THE INFLUENCE OF
WEAK SURFACE RIDGING AROUND A 1018 MB HIGH CENTERED NEAR MOBILE
ALABAMA. PATCHES OF LOW-LEVEL CLOUDS ARE ACROSS THE WRN HALF OF
THE BASIN AS WELL JUST N OF WRN CUBA. SURFACE OBSERVATIONS FROM
CUBA INDICATE THAT ISOLATED SHOWERS/THUNDERSTORMS ARE ASSOCIATED
WITH SOME OF THESE CLOUDS. A FEW ISOLATED SHOWERS/THUNDERSTORMS
ARE ALSO IN THE FAR SW GULF FROM 19N-23N BETWEEN 96W-100W
INDICATED BY LIGHTNING DATA. THESE STORMS ARE ASSOCIATED WITH A
SHORTWAVE UPPER TROUGH THAT EXTENDS DOWN THE ERN MEXICO
COASTLINE FROM 26N96W TO 19N98W. WEAK ANTI-CYCLONIC SURFACE FLOW
IS AROUND THE HIGH PRESSURE CENTER ACROSS THE NE GULF WITH
MAINLY E-SE WINDS OF 10-15 KT ACROSS THE REMAINDER OF THE BASIN.
ALOFT...MAINLY ZONAL WLY FLOW DOMINATES WITH SOME CONVERGING SW
AND NW WINDS BETWEEN THE BASE OF A LONGWAVE UPPER TROUGH OVER
THE W ATLC AND AN UPPER LEVEL RIDGE OVER THE CARIBBEAN. WATER
VAPOR IMAGERY ALSO INDICATES STRONG DRY AIR IN THIS CONVERGENCE
ZONE. WITH A LONGWAVE UPPER RIDGE APPROACHING THE AREA...SURFACE
RIDGING ALONG WITH MOSTLY FAIR WEATHER WILL REMAIN DURING THE
NEXT DAY OR SO BEFORE THE NEXT UPPER TROUGH AND ASSOCIATED
FRONTAL SYSTEM APPROACH THE AREA LATE MONDAY. SE RETURN FLOW IS
EXPECTED TO INCREASE AHEAD OF THIS FRONT.

CARIBBEAN SEA...
THE CARIBBEAN ALSO REMAINS UNDER MOSTLY FAIR CONDITIONS UNDER
THE INFLUENCE OF AN UPPER LEVEL RIDGE CENTERED JUST N OF ERN
VENEZUELA NEAR 12N63W. MAINLY SWLY FLOW ALOFT COVERS THE WRN
HALF OF THE BASIN AROUND THIS UPPER RIDGE WHICH IS DRAWING UPPER
LEVEL MOISTURE FROM THE E PACIFIC ACROSS THIS PORTION OF THE
BASIN SUPPORTING HIGH CLOUDS. THE ERN HALF OF THE BASIN IS UNDER
THE INFLUENCE OF VERY DRY AIR WHICH IS SUPPORTING CLEAR SKIES.
FRESH ELY TRADEWINDS ARE ACROSS THE MAJORITY OF THE BASIN. TOTAL
PRECIPITABLE WATER IMAGERY SHOWS ENHANCED MOISTURE OVER THE NW
CARIBBEAN AND OFF THE COASTS OF PANAMA AND COSTA RICA. WHILE NO
EVIDENCE OF SHOWERS IS PRESENT AT THIS TIME...THE POSSIBILITY OF
ISOLATED SHOWERS REMAINS DUE TO THIS ENHANCED MOISTURE. EXPECT
LITTLE CHANGE OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH IS IMPACTING THE W ATLC WITH A LONGWAVE
UPPER TROUGH OFF THE ERN SEABOARD ALONG 75W SUPPORTING A COLD
FRONT WHICH ENTERS THE DISCUSSION AREA NEAR 32N54W CONTINUING SW
TO THE SE BAHAMAS NEAR 23N74W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 90 NM EITHER SIDE OF THE FRONT N OF
27N. POSSIBLE ISOLATED SHOWERS ARE ALONG THE REMAINDER OF THE
FRONT. FARTHER E...A BROAD SURFACE RIDGE COVERS THE MAJORITY OF
THE CENTRAL AND ERN ATLC ANCHORED BY A 1028 MB HIGH NEAR 30N35W
WHICH IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE AREA.
ALOFT...AN UPPER LEVEL RIDGE EXTENDS NE FROM THE ERN CARIBBEAN
TO THE AZORES ISLANDS. THE FAR E ATLC IS COVERED BY AN UPPER
LEVEL TROUGH WITH AXIS EXTENDING W OF PORTUGAL ACROSS THE
MADEIRA ISLANDS WITH A PORTION THEN EXTENDING SW TO NRN SOUTH
AMERICA NEAR 7N55W. UPPER LEVEL MOISTURE IS BEING DRAWN NE
AROUND THE ERN SIDE OF THE TROUGH SUPPORTING HIGH CLOUDS NEAR
AND N OF THE WRN HALF OF THE ITCZ. THIS UPPER TROUGH ALSO
SUPPORTS A FRONTAL SYSTEM ACROSS SPAIN AND INTO NW AFRICA. BROAD
UPPER RIDGING COVERS THE TROPICAL ATLC S OF 17N E OF 43W. EXPECT
THE FRONTAL SYSTEM IN THE W ATLC TO CONTINUE TO MOVE EWD OVER
THE NEXT COUPLE OF DAYS.

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

$$
WALTON




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