[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110512
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST WED FEB 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0445 UTC.

...THE ITCZ...
ITCZ IS CENTERED ALONG 6N10W 2N20W 1N36W CROSSING THE EQUATOR
NEAR 42W...AND INTO NE BRAZIL NEAR 2S46W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS S OF 3N BETWEEN 19W-27W.
SCATTERED MODERATE CONVECTION IS S OF 2N BETWEEN 28W-37W.

...DISCUSSION...

GULF OF MEXICO...
SOUTHWESTERLY FLOW ALOFT CONTINUES TO STRENGTHEN ACROSS THE NW
GULF AS A VIGOROUS DEEP LAYER TROUGH OVER THE CENTRAL AND
SOUTHERN PLAINS OF THE CONUS MOVES EASTWARD. INCREASING
ATMOSPHERIC LIFT ASSOCIATED WITH THIS FEATURE IS RESULTING IN
SCATTERED SHOWERS ACROSS THE NW GULF N OF 27N W OF 93W. AT THE
SAME TIME...SE SURFACE WINDS OF 20 TO 25 KT ARE AFFECTING MUCH
OF THE GULF. ALSO...A SURFACE RIDGE IS PRESENT OVER THE E GULF.
SUBSIDENCE ASSOCIATED WITH THIS RIDGE IS COMBINING WITH DRY AIR
AND STABLE ATMOSPHERIC CONDITIONS ALOFT TO INHIBIT DEEP
CONVECTION ACROSS MUCH OF THE S AND E GULF. DURING THE NEXT
DAY...A COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED DEEP LAYER
TROUGH WILL MOVE INTO THE NW GULF...FOLLOWED BY INCREASED NW AND
N WINDS IN THE WAKE OF THE FRONT. IN 24 HOURS...A 1019 MB
SURFACE HIGH IS EXPECTED TO BE PRESENT OVER THE NW GULF NEAR
28N94W.

CARIBBEAN SEA...
GENERALLY FAIR WEATHER IS PRESENT ACROSS THE W CARIBBEAN...WHERE
DEEP LAYER DRY AIR AND CONFLUENT WESTERLY FLOW ARE PRESENT.
UPPER LEVEL MOISTURE CONTINUES TO BE ADVECTED NORTHEASTWARD INTO
THE E CARIBBEAN...WITH SCATTERED SHOWERS S OF 14N E OF 66W.
ALSO...A SURFACE TROUGH EXTENDS FROM 17N69W TO W PUERTO RICO
NEAR 18N67W INTO THE SW NORTH ATLC...WITH LOW LEVEL CONVERGENCE
SUPPORTING SCATTERED SHOWERS WITHIN 120 NM EITHER SIDE OF THE
SURFACE TROUGH...INCLUDING PORTIONS OF PUERTO RICO. STRONG TRADE
WINDS S OF A 1031 MB SURFACE HIGH IN THE W ATLC NEAR 34N67W ARE
OCCURRING AND ARE FORECAST TO CONTINUE ACROSS MUCH OF THE
CARIBBEAN THROUGH THURSDAY.

ATLANTIC OCEAN...
DEEP LAYER DRY AND SUBSIDENCE ARE PRESENT ACROSS THE SW NORTH
ATLC...WHERE A SURFACE RIDGE EXTENDS SOUTHWESTWARD FROM A 1031
MB SURFACE HIGH NEAR 34N67W. TO THE E...A DEEP LAYER TROUGH IS
PRESENT WITH AN ASSOCIATED COLD FRONT EXTENDING FROM 24N60W TO
27N49W TO 32N41W TO N OF THE DISCUSSION AREA. LOW LEVEL
CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER
SIDE OF THE COLD FRONT. ALSO...UPPER LEVEL DIVERGENCE IN THE NE
QUADRANT OF AN UPPER LEVEL JET MAXIMUM SE OF THE COLD FRONT IS
SUPPORTING SCATTERED SHOWERS N OF 28N BETWEEN 36W-39W. THIS
ACTIVITY IS BEING ENHANCED BY LOW LEVEL CONVERGENCE IN THE
VICINITY OF A SURFACE TROUGH EXTENDING FROM 28N40W TO 24N44W TO
21N45W. ALSO...A SURFACE TROUGH EXTENDS FROM 20N64W TO W PUERTO
RICO NEAR 18N67W INTO THE E CARIBBEAN...WITH LOW LEVEL
CONVERGENCE SUPPORTING SCATTERED SHOWERS WITHIN 120 NM EITHER
SIDE OF THE SURFACE TROUGH...INCLUDING PORTIONS OF PUERTO RICO.
FARTHER E...FAIR WEATHER CONDITIONS ARE OCCURRING ACROSS MUCH OF
THE E ATLC...WHERE SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE IS
PRESENT. ACROSS THE TROPICAL ATLC...AN UPPER HIGH IS PRESENT
NEAR 3N48W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS HIGH IS
ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN


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