[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251751
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N8W 3N15W CROSSING THE EQUATOR NEAR
23W EXTENDING JUST SOUTH OF THE EQUATOR TO 1S36W AND INTO NE
BRAZIL NEAR 3S42W. SCATTERED MODERATE TO STRONG CONVECTION IS
FROM THE EQUATOR TO 5N E OF 3W. ELSEWHERE...SCATTERED MODERATE
CONVECTION IS FROM THE EQUATOR TO 6N BETWEEN 10W-16W.

...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 1032 MB
SURFACE HIGH OVER THE W ATLC NEAR 34N69W EXTENDS A SURFACE RIDGE
ACROSS THE NRN GULF ALONG 30N AND IS RESULTING IN GENERALLY FAIR
WEATHER CONDITIONS. THE SURFACE FLOW AROUND THIS SURFACE RIDGE
IS RESULTING IN E TO SE WINDS OF 20 TO 25 KT ACROSS MOST OF THE
GULF WITH THE EXCEPTION OF 10 TO 15 KT WINDS IN THE FAR NE GULF
NEAR THE FLORIDA BIG BEND REGION. THIS OVERALL WEATHER PATTERN
IS FORECAST TO REMAIN IN PLACE THROUGH THE WEEKEND AS THE
SURFACE HIGH IN THE W ATLC REMAINS QUASI-STATIONARY AND PROVIDES
FRESH TO STRONG E TO SE SURFACE WINDS ACROSS THE REGION. THESE
WINDS WILL ADVECT LOW LEVEL MOISTURE AND INCREASE INSTABILITY
OVER THE NW GULF RESULTING IN SCATTERED SHOWERS AND TSTMS NEAR
THE TEXAS AND LOUISIANA COASTS THROUGH SUNDAY.

CARIBBEAN SEA...
A 1032 MB SURFACE HIGH CENTERED OVER THE W ATLC NEAR 34N69W IS
MAINTAINING FRESH TO STRONG TRADE WINDS ACROSS THE CARIBBEAN
SEA. THE STRONGEST WINDS ARE FOUND NEAR THE COAST OF COLOMBIA...
WHERE E TO NE SURFACE WINDS UP TO 30 KT ARE OCCURRING. A BROAD
UPPER LEVEL RIDGE ENCOMPASSES THE CARIBBEAN SEA AND OVERALL
ATMOSPHERIC STABILITY IS ASSOCIATED WITH THIS RIDGE RESULTING IN
GENERALLY FAIR WEATHER CONDITIONS. HOWEVER...THE TRADE WINDS ARE
ADVECTING POCKETS OF LOW LEVEL MOISTURE WITH ISOLATED SHOWERS
WESTWARD ACROSS THE CARIBBEAN. THE GREATEST CONCENTRATION OF
THESE SHOWERS ARE LOCATED OVER PUERTO RICO AND JAMAICA. ALSO...
UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS CONTINUE TO STREAM
NORTHEASTWARD ACROSS THE WRN CARIBBEAN...WITH UPPER LEVEL
DIVERGENCE SUPPORTING SCATTERED SHOWERS OVER THE GULF OF
HONDURAS S OF 17N W OF 85W...INCLUDING INLAND HONDURAS AND
NICARAGUA.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH OVER THE WRN AND CENTRAL ATLC IS ASSOCIATED
WITH A SURFACE COLD FRONT THAT EXTENDS FROM NE OF THE DISCUSSION
AREA TO 32N53W TO 27N60W AND CONTINUES AS A SURFACE STATIONARY
FRONT TO 26N70W. LOW LEVEL CONVERGENCE IS RESULTING IN SCATTERED
SHOWERS WITHIN 90 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 1032 MB SURFACE HIGH NEAR 34N69W
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 7N41W TO 20N37W TO 31N25W IS
RESULTING IN SCATTERED SHOWERS N OF 23N BETWEEN 20W-28W. ACROSS
THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS PRESENT WITH AN AXIS
EXTENDING FROM 10N14W TO 3N33W. UPPER LEVEL DIVERGENCE IN THE
VICINITY OF THIS UPPER LEVEL RIDGE IS ENHANCING THE CONVECTION
ASSOCIATED WITH THE ITCZ.

$$
HUFFMAN





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