[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251048
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT APR 25 2009

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

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

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N8W 2N14W CROSSING THE EQUATOR NEAR
21W EXTENDING TO 1S28W 2S36W AND INTO NE BRAZIL NEAR 4S42W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 5N BETWEEN
5W-12W. SCATTERED MODERATE CONVECTION IS FROM 1N-4N BETWEEN
14W-19W. SCATTERED MODERATE CONVECTION IS ALSO S OF 3N BETWEEN
21W-28W. SCATTERED MODERATE CONVECTION IS ALSO S OF 2N BETWEEN
34W-47W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYER DRY AIR AND SW TO W FLOW ALOFT ARE PRESENT ACROSS
MUCH OF THE GULF REGION. SUBSIDENCE ASSOCIATED WITH A 1026 MB
SURFACE HIGH OVER N FLORIDA NEAR 30N83W AND A SURFACE RIDGE
ACROSS THE N GULF ALONG 29N IS CURRENTLY RESULTING IN GENERALLY
FAIR WEATHER CONDITIONS ACROSS MUCH OF THE GULF REGION. THE FLOW
AROUND THE AFOREMENTIONED SURFACE HIGH AND SURFACE RIDGE IS
RESULTING IN SE WINDS OF 20 TO 25 KT ACROSS PORTIONS OF THE NW
GULF...WITH E WINDS OF 20 TO 25 KT OVER THE E GULF S OF 25N
EXCEPT 25 TO 30 KT ACROSS THE STRAITS OF FLORIDA. DURING THE
NEXT DAY...THE 1026 MB SURFACE HIGH OVER N FLORIDA NEAR 30N83W
IS FORECAST TO DISSIPATE. HOWEVER...THE SURFACE RIDGE ALONG 29N
IS FORECAST TO DRIFT NE OF THE GULF REGION AND STRENGTHEN DURING
THE NEXT DAY...WITH FRESH TO STRONG E TO SE SURFACE WINDS ACROSS
THE GULF THROUGH TUESDAY. THESE WINDS WILL ADVECT LOW LEVEL
MOISTURE ACROSS THE GULF REGION. INCREASING INSTABILITY OVER THE
NW GULF WILL RESULT IN SCATTERED THUNDERSTORMS NEAR THE TEXAS
COAST THROUGH SUNDAY.

CARIBBEAN SEA...
A 1031 MB SURFACE HIGH OVER THE W ATLC NEAR 33N70W IS
MAINTAINING FRESH TO STRONG TRADE WINDS ACROSS THE CARIBBEAN
SEA. THE STRONGEST WINDS ARE FOUND NEAR THE COAST OF
COLOMBIA...WHERE NE TO E SURFACE WINDS UP TO 30 KT ARE
OCCURRING. A BROAD UPPER LEVEL RIDGE IS PRESENT ACROSS THE
CARIBBEAN SEA. ATMOSPHERIC STABILITY ASSOCIATED WITH THIS RIDGE
IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF
THE CARIBBEAN. HOWEVER...THE TRADE WINDS ARE ADVECTING POCKETS
OF LOW LEVEL MOISTURE WITH ISOLATED SHOWERS WESTWARD ACROSS THE
CARIBBEAN. THE GREATEST CONCENTRATION OF THESE SHOWERS IS FROM
15N-18N BETWEEN 63W-74W. ALSO...UPPER LEVEL MOISTURE AND HIGH
LEVEL CLOUDS CONTINUE TO STREAM NORTHEASTWARD ACROSS THE WESTERN
CARIBBEAN...WITH UPPER LEVEL DIVERGENCE SUPPORTING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OVER THE GULF OF HONDURAS S
OF 18N W OF 87W INCLUDING S BELIZE AND NE GUATEMALA.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH OVER THE WESTERN AND CENTRAL ATLC IS
ASSOCIATED WITH A SURFACE COLD FRONT THAT EXTENDS FROM NE OF THE
DISCUSSION AREA TO 32N55W TO 28N62W...A SURFACE STATIONARY FRONT
THAT EXTENDS FROM 28N62W TO 26N70W...AND A SURFACE WARM FRONT
THAT EXTENDS FROM 26N70W TO SW OF THE BAHAMAS NEAR 23N77W. LOW
LEVEL CONVERGENCE IS RESULTING IN SCATTERED SHOWERS WITHIN 60 NM
EITHER SIDE OF THESE FRONTS. THIS ACTIVITY IS ALSO BEING
SUPPORTED BY UPPER LEVEL DIVERGENCE IN THE NE QUADRANT OF A
75-85 KT UPPER LEVEL WIND SPEED MAXIMUM OVER THE SW NORTH ATLC.
TO THE W OF THE FRONTS...DEEP LAYER DRY AIR AND SUBSIDENCE
ASSOCIATED WITH A 1031 MB SURFACE HIGH NEAR 33N70W ARE RESULTING
IN GENERALLY FAIR WEATHER CONDITIONS. FARTHER TO THE
E...SUBSIDENCE IN THE VICINITY OF A SURFACE RIDGE IS RESULTING
IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE CENTRAL
AND E ATLC. HOWEVER...ATMOSPHERIC INSTABILITY AND UPPER LEVEL
DIVERGENCE IN THE VICINITY OF A SHARP UPPER LEVEL TROUGH WITH AN
AXIS EXTENDING FROM 4N44W TO 19N37W TO 32N23W TO NE OF THE
DISCUSSION AREA IS RESULTING IN SCATTERED SHOWERS N OF 23N
BETWEEN 25W-33W. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE
IS PRESENT WITH AN AXIS EXTENDING FROM 10N14W TO 4N25W TO 1N39W.
UPPER LEVEL DIVERGENCE IN THE VICINITY OF THIS UPPER LEVEL RIDGE
IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN


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