[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152309
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN FEB 15 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
2245 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N8W 2N13W 1N21W CROSSING THE
EQUATOR NEAR 42W...AND INTO NE BRAZIL NEAR 1S47W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 1N-4N BETWEEN 5W-9W.
SCATTERED MODERATE CONVECTION S OF 1N BETWEEN 18W-20W. SCATTERED
MODERATE CONVECTION IS ALSO S OF 3N BETWEEN 36W-41W.

...DISCUSSION...

GULF OF MEXICO...
STRONG W TO NW FLOW ALOFT IS PRESENT ACROSS THE N GULF. ALSO...A
SURFACE COLD FRONT EXTENDS FROM THE NW GULF NEAR 25N98W TO
26N94W TO A 1014 MB SURFACE LOW NEAR 28N91W...WITH A SURFACE
WARM FRONT EXTENDING FROM THE SURFACE LOW TO 28N86W AND A
SURFACE STATIONARY FRONT EXTENDING FROM 28N86W TO THE W FLORIDA
PENINSULA NEAR 28N83W. THE SURFACE LOW IS FORECAST TO MOVE
NORTHEASTWARD INTO THE W ATLC DURING THE NEXT DAY AND
STRENGTHEN. LOW LEVEL CONVERGENCE NEAR THE SURFACE LOW AND
SURFACE FRONTS IS SUPPORTING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS THE N GULF N OF 27N E OF 92W. NORTHEASTERLY
SURFACE WINDS AND A RELATIVELY COOLER AND DRIER AIRMASS ARE
PRESENT N OF THE FRONT. ACROSS THE S GULF...SUBSIDENCE...STABLE
ATMOSPHERIC CONDITIONS...AND DEEP LAYER DRY AIR ARE RESULTING IN
GENERALLY FAIR WEATHER CONDITIONS. ALSO...SE TO S SURFACE WINDS
ARE PRESENT ACROSS MUCH OF THE S GULF.

CARIBBEAN SEA...
A SHARP UPPER LEVEL TROUGH IS PRESENT OVER THE CARIBBEAN...WITH
THE AXIS OF THIS TROUGH EXTENDING FROM AN UPPER LOW NEAR 12N77W
TO 15N71W TO 18N67W. DEEP LAYER DRY AIR IS INHIBITING DEEP
CONVECTION ACROSS MUCH OF THE CARIBBEAN REGION. HOWEVER...LOW
LEVEL MOISTURE IS BEING TRANSPORTED WESTWARD ACROSS PORTIONS OF
THE CARIBBEAN...WITH ISOLATED SHOWERS OCCURRING FROM 13N-19N
BETWEEN 68W-83W. STRONG TRADE WINDS CURRENTLY OVER THE CARIBBEAN
ARE FORECAST TO DIMINISH THROUGH MONDAY AS A 1022 MB SURFACE
HIGH IN THE CENTRAL ATLC NEAR 28N33W MOVES EASTWARD. DURING THE
NEXT DAY...COMPUTER MODEL GUIDANCE INDICATES THAT THE AREA OF
DEEP LAYER MOISTURE ASSOCIATED WITH A SURFACE TROUGH IN THE
TROPICAL ATLC ANALYZED ALONG 55W FROM 6N-13N WILL AFFECT THE
WINDWARD ISLANDS INCREASING THE CHANCE OF SHOWERS OVER THOSE
ISLANDS.

ATLANTIC OCEAN...
STRONG WESTERLY FLOW ALOFT IS PRESENT ACROSS THE SW NORTH ATLC.
A SURFACE COLD FRONT EXTENDS FROM THE E FLORIDA PENINSULA NEAR
28N81W TO 29N73W TO 32N68W TO NE OF THE DISCUSSION AREA. LOW
LEVEL CONVERGENCE ASSOCIATED WITH THIS SURFACE COLD FRONT IS
SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 28N
W OF 63W INCLUDING PORTIONS OF THE E FLORIDA PENINSULA. DURING
THE NEXT DAY...THIS COLD FRONT IS FORECAST TO MOVE EASTWARD AS
THE SURFACE LOW IN THE N GULF OF MEXICO NEAR 28N91W MOVES
NORTHEASTWARD AND STRENGTHENS. WINDS ASSOCIATED WITH THE COLD
FRONT ARE FORECAST TO REACH GALE FORCE N OF 28N BEGINNING AT
16/1800 UTC. TO THE E...A DEEP LAYER TROUGH IS PRESENT WITH AN
ASSOCIATED DISSIPATING SURFACE STATIONARY FRONT EXTENDING FROM
25N61W TO 26N51W TO 28N44W AND A SURFACE COLD FRONT EXTENDING
FROM 28N44W TO 30N38W TO 32N35W TO NE OF THE DISCUSSION AREA.
LOW-LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN
60 NM EITHER SIDE OF EACH OF THESE FRONTS. FARTHER TO THE
E...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE AND A 1022 MB
SURFACE HIGH NEAR 28N33W IS RESULTING IN FAIR WEATHER CONDITIONS
ACROSS MUCH OF THE E ATLC. ACROSS THE TROPICAL ATLC...A SURFACE
TROUGH IS ANALYZED ALONG 55W FROM 6N-13N. LOW LEVEL CONVERGENCE
AND DEEP LAYER MOISTURE ARE RESULTING IN SCATTERED SHOWERS
WITHIN 120 NM EITHER SIDE OF THIS SURFACE TROUGH. DURING THE
NEXT DAY...COMPUTER MODEL GUIDANCE INDICATES THAT THE AREA OF
DEEP LAYER MOISTURE ASSOCIATED WITH THIS SURFACE TROUGH WILL
AFFECT THE WINDWARD ISLANDS INCREASING THE CHANCE OF SHOWERS
OVER THOSE ISLANDS. ALSO...AN UPPER RIDGE IS S OF 9N BETWEEN
14W-43W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS UPPER RIDGE
IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN




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