[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112358
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 6N9W 3N15W 1N23W CROSSING THE EQUATOR
NEAR 26W...EXTENDING TO 1S36W AND INTO NE BRAZIL NEAR 2S46W.
SCATTERED MODERATE CONVECTION IS S OF 3N BETWEEN 19W-31W.
SCATTERED MODERATE CONVECTION IS ALSO S OF 2N BETWEEN 33W-38W.

...DISCUSSION...

GULF OF MEXICO...
STRONG WESTERLY FLOW ALOFT IS PRESENT ACROSS THE N GULF IN THE
BASE OF A VIGOROUS DEEP LAYER TROUGH MOVING EASTWARD ACROSS THE
E CONUS. A SURFACE COLD FRONT ASSOCIATED WITH THIS TROUGH
EXTENDS FROM S MISSISSIPPI NEAR 30N89W TO 27N91W TO 22N97W.
INCREASED NORTHERLY WINDS AND A RELATIVELY COOLER AND DRIER
AIRMASS ARE PRESENT N OF THIS FRONT. A 1015 MB SURFACE LOW IS
PRESENT IN THE SW GULF NEAR 21N97W WITH AN ASSOCIATED SURFACE
TROUGH EXTENDING FROM 21N97W TO 19N95W. THE SURFACE LOW AND
SURFACE TROUGH ARE BEING ENHANCED BY THE SOUTHWARD FUNNELING OF
THIS AIRMASS ACROSS THE W GULF. LOW LEVEL CONVERGENCE IS
SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE
COLD FRONT...WITH ISOLATED THUNDERSTORMS OCCURRING ALONG AND
WITHIN 60 NM E OF THE COLD FRONT N OF 28N. THIS ACTIVITY IS
BEING ENHANCED BY UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE
AFOREMENTIONED VIGOROUS DEEP LAYER TROUGH. AT THE SAME TIME...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.

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 E OF 68W. STRONG TRADE
WINDS S OF A 1028 MB SURFACE HIGH IN THE W ATLC NEAR 30N65W ARE
OCCURRING AND ARE FORECAST TO CONTINUE ACROSS MUCH OF THE
CARIBBEAN THROUGH THURSDAY.

ATLANTIC OCEAN...
SOUTHWESTERLY FLOW ALOFT CONTINUES TO STRENGTHEN ACROSS THE SW
NORTH ATLC AS THE VIGOROUS DEEP LAYER TROUGH OVER THE E CONUS
MOVES EASTWARD. A SURFACE COLD FRONT ASSOCIATED WITH THIS TROUGH
IS FORECAST TO ENTER THE SW NORTH ATLC DURING THE NEXT DAY...
FOLLOWED BY W TO NW WINDS AND RELATIVELY COOLER AND DRIER
CONDITIONS. FARTHER TO THE E...DEEP LAYER DRY AIR AND SUBSIDENCE
ARE PRESENT IN THE VICINITY OF A 1028 MB SURFACE HIGH NEAR
30N65W. TO THE E...A DEEP LAYER TROUGH IS PRESENT WITH AN
ASSOCIATED SURFACE COLD FRONT EXTENDING FROM 23N51W TO 28N40W TO
32N34W TO N OF THE DISCUSSION AREA. THIS COLD FRONT IS
DISSIPATING W OF 35W. LOW LEVEL CONVERGENCE IS SUPPORTING
SCATTERED SHOWERS WITHIN 30 NM EITHER SIDE OF THIS 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 24N BETWEEN 32W-38W. THIS ACTIVITY IS BEING
ENHANCED BY LOW LEVEL CONVERGENCE IN THE VICINITY OF A SURFACE
TROUGH EXTENDING FROM 25N40W TO 23N44W TO 21N46W. 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 6N46W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS HIGH IS
ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN




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