[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041054
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED APR 04 2012

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
SIERRA LEONE AT 7N12W TO 4N17W. THE ITCZ CONTINUES FROM 4N17W
ALONG 3N36W CROSSING THE EQUATOR AT 47W TO THE COAST OF BRAZIL
AT 1S50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
2N-4N BETWEEN 16W-21W. SCATTERED MODERATE CONVECTION IS FROM
3N-5N BETWEEN 31W-35W.

...DISCUSSION...

GULF OF MEXICO...
DRY AIR ALOFT IN SWLY FLOW COVERS THE GULF OF MEXICO BETWEEN AN
UPPER LEVEL RIDGE OVER THE CARIBBEAN AND ERN CONUS...AND A
STRONG UPPER LEVEL LOW OVER THE SW CONUS. THE DRY AIR ALOFT
IS HELPING PROVIDE FAIR SURFACE CONDITIONS AROUND WEAK SURFACE
RIDGING EXTENDING ACROSS THE NRN GULF FROM THE W ATLC.
HOWEVER...THE STRONG UPPER TROUGH OVER THE SW CONUS IS PRODUCING
STRONG SHOWERS/THUNDERSTORMS...SOME SEVERE...ACROSS MUCH OF
LOUISIANA. SOME OF THESE STORMS ARE EMERGING OVER WATER. THEY
CURRENTLY ARE FROM 29N-32N BETWEEN 87W-95W. SOME LOW-LEVEL CLOUD
COVER IS ALSO PRESENT OVER THE NW GULF WITH NO SHOWERS AT THIS
TIME. EXPECT WEAK SURFACE RIDGING TO REMAIN OVER THE BASIN UNTIL
A COLD FRONT MOVES ACROSS THE NRN GULF EARLY THURSDAY.

CARIBBEAN SEA...
MAINLY SWLY FLOW ALOFT COVERS THE CARIBBEAN AROUND A BROAD UPPER
LEVEL RIDGE EXTENDING FROM THE WRN TROPICAL ATLC ACROSS THE NRN
CARIBBEAN TO THE ERN CONUS. SOME MODERATE MOISTURE IS STREAMING
ACROSS THE AREA SUPPORTING HIGH CLOUDS. THE BURST OF CONVECTION
PREVIOUSLY OVER NRN CENTRAL AMERICA HAS WEAKENED WITH ONLY A
SMALL AREA REMAINING FROM 17N-19N BETWEEN 85W-88W. A SECOND
BURST OF STRONG CONVECTION HAS FORMED OVER WRN NICARAGUA.
THESE AREAS ARE ASSOCIATED WITH AN UPPER LEVEL TROUGH EXTENDING
FROM THE SW CONUS...DOWN MEXICO...AND DOWN CENTRAL AMERICA TO
COLOMBIA. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ALSO COVER
THE FAR SW CARIBBEAN OFF THE COASTS OF COSTA RICA...PANAMA...AND
COLOMBIA. A MODERATE PRESSURE GRADIENT IS SUPPORTING TRADEWIND
FLOW OF 15-20 KTS ACROSS MUCH OF THE BASIN. EXPECT POSSIBLE
SHOWERS/THUNDERSTORMS ACROSS THE WRN HALF OF BASIN WITH LITTLE
CHANGE ELSEWHERE.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE OVER THE ERN CONUS IS BEGINNING TO MOVE
OVER THE FAR WRN ATLC SUPPORTING WEAK SURFACE RIDGING AROUND A
1017 MB HIGH NEAR 29N74W. MOSTLY DRY AIR ALOFT IS KEEPING MUCH
OF THIS AREA FREE OF CLOUDS BESIDES AN AREA OF
SHOWERS/THUNDERSTORMS THAT HAS MOVED OFF THE N FLORIDA/GEORGIA
COAST. AN UPPER LEVEL TROUGH IS TO THE E ALONG 52W EXTENDING
FROM AN UPPER LEVEL LOW S OF NEWFOUNDLAND. THIS UPPER TROUGH
SUPPORTS A COLD FRONT ENTERING THE DISCUSSION AREA AT 32N46W
CONTINUING ALONG 26N53W 23N60W DISSIPATING TO 22N67W. A
PRE-FRONTAL SURFACE TROUGH IS E OF THE AXIS ALONG 28N48W TO
22N58W. ISOLATED SHOWERS ARE WITHIN 60 NM E OF THE FRONT WITH
SCATTERED SHOWERS WITHIN 120 NM E OF THE SURFACE TROUGH. GALE
FORCE WINDS ARE ALSO WITHIN 180 NM SE OF THE FRONT N OF 27N. AN
UPPER LEVEL RIDGE TO THE E ALONG 36W SUPPORTS A 1024 MB SURFACE
HIGH NEAR 34N31W...WHICH IS PROVIDING FAIR WEATHER ACROSS MUCH
OF THE ERN ATLC. ANOTHER UPPER LEVEL TROUGH EXTENDS OVER THE FAR
ERN ATLC FROM E OF PORTUGAL TO THE CANARY ISLANDS AT 28N16W TO
21N32W. THIS UPPER TROUGH IS CAUSING NO SIGNIFICANT WEATHER IN
THE DISCUSSION AREA.

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

$$
WALTON






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