000
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