[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111107
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1045 UTC.

...THE ITCZ...
ITCZ IS CENTERED ALONG 6N10W 3N20W 1N33W CROSSING THE EQUATOR
NEAR 42W...AND INTO NE BRAZIL NEAR 2S46W. SCATTERED MODERATE
CONVECTION IS S OF 2N BETWEEN 12W-17W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS S OF 3N BETWEEN 20W-28W.
SCATTERED MODERATE CONVECTION IS S OF 2N BETWEEN 32W-39W.

...DISCUSSION...

GULF OF MEXICO...
STRONG SOUTHWESTERLY FLOW ALOFT IS PRESENT ACROSS THE NW GULF AS
A VIGOROUS DEEP LAYER TROUGH OVER THE CENTRAL AND SOUTHERN
PLAINS OF THE CONUS MOVES EASTWARD. ATMOSPHERIC LIFT ASSOCIATED
WITH THIS TROUGH IS RESULTING IN SCATTERED SHOWERS ACROSS THE NW
GULF N OF 26N W OF 92W. AT THE SAME TIME...SOUTHERLY SURFACE
WINDS OF 20 TO 25 KT ARE AFFECTING MUCH OF THE GULF. ALSO...A
SURFACE RIDGE IS PRESENT OVER THE S AND 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.

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 67W.
ALSO...A SURFACE TROUGH EXTENDS FROM 16N70W TO E HISPANIOLA NEAR
19N68W INTO THE SW NORTH ATLC...WITH LOW LEVEL CONVERGENCE
SUPPORTING SCATTERED SHOWERS WITHIN 120 NM EITHER SIDE OF THIS
SURFACE TROUGH...INCLUDING PORTIONS OF PUERTO RICO. STRONG TRADE
WINDS S OF A 1030 MB SURFACE HIGH IN THE W ATLC NEAR 32N65W ARE
OCCURRING AND ARE FORECAST TO CONTINUE ACROSS MUCH OF THE
CARIBBEAN THROUGH THURSDAY.

ATLANTIC OCEAN...
DEEP LAYER DRY AIR AND SUBSIDENCE ARE PRESENT ACROSS THE SW
NORTH ATLC...WHERE A SURFACE RIDGE EXTENDS SOUTHWESTWARD FROM A
1030 MB SURFACE HIGH NEAR 32N65W. TO THE E...A DEEP LAYER TROUGH
IS PRESENT WITH AN ASSOCIATED COLD FRONT EXTENDING FROM 23N60W
TO 27N45W TO 32N38W TO N OF THE DISCUSSION AREA. THIS FRONT IS
DISSIPATING W OF 51W. 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 26N BETWEEN 37W-43W. THIS ACTIVITY IS BEING
ENHANCED BY LOW LEVEL CONVERGENCE IN THE VICINITY OF A SURFACE
TROUGH EXTENDING FROM 27N41W TO 24N43W TO 20N45W. ALSO...A
SURFACE TROUGH EXTENDS FROM 21N66W TO E HISPANIOLA NEAR 19N68W
INTO THE E CARIBBEAN...WITH LOW LEVEL CONVERGENCE SUPPORTING
SCATTERED SHOWERS WITHIN 120 NM EITHER SIDE OF THIS 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 3N49W.
UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS HIGH IS ENHANCING
THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN




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