000
AXNT20 KNHC 151111
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN MAR 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1045 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N3W 2N16W CROSSING THE EQUATOR 
NEAR 22W EXTENDING TO 2S31W INTO NE BRAZIL NEAR 5S39W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS S OF 5N BETWEEN 3W-11W. 
SCATTERED MODERATE CONVECTION IS FROM 1N-4N BETWEEN 18W-24W. 
SCATTERED MODERATE CONVECTION IS ALSO S OF 1N BETWEEN 37W-39W.

...DISCUSSION...

GULF OF MEXICO...
SOUTHWESTERLY FLOW ALOFT IS PRESENT ACROSS THE WESTERN AND 
NORTHERN GULF REGION. DEEP LAYER ATMOSPHERIC LIFT IN THIS FLOW 
IS SUPPORTING A SURFACE COLD FRONT IN THE N AND W GULF THAT 
EXTENDS FROM S MISSISSIPPI NEAR 30N89W TO 25N93W TO THE COAST OF 
MEXICO NEAR 19N96W. LOW LEVEL CONVERGENCE AND DEEP LAYER 
ATMOSPHERIC LIFT ARE SUPPORTING SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS WITHIN 90 NM EITHER SIDE OF THE FRONT. TO THE W OF 
THE FRONT...INCREASED NE SURFACE WINDS AND A RELATIVELY COOLER 
AND DRIER AIRMASS ARE PRESENT...WITH A 1021 MB SURFACE HIGH OVER 
E MEXICO NEAR 23N98W. AT 16/0600 UTC...THE SURFACE HIGH IS 
FORECAST TO HAVE DISSIPATED. THE COOLER AIR IS OVER RELATIVELY 
WARMER WATERS...RESULTING IN LAYERS OF SCATTERED TO OVERCAST 
STRATOCUMULUS CLOUDS TO THE W OF THE FRONT. TO THE E OF THE 
FRONT...DEEP LAYER DRY AIR IS RESULTING IN GENERALLY FAIR 
WEATHER CONDITIONS ACROSS MUCH OF THE CENTRAL AND SE GULF.

CARIBBEAN SEA...
STRONG SURFACE HIGH PRESSURE BUILDING SOUTHWARD OVER THE W 
ATLC WILL MAINTAIN MODERATE TO STRONG TRADES OVER MUCH OF THE 
CARIBBEAN SEA THROUGH MONDAY. GENERALLY FAIR WEATHER CONDITIONS 
ARE OCCURRING ACROSS MUCH OF THE CARIBBEAN REGION...WHERE DEEP 
LAYER DRY AIR IS PRESENT. HOWEVER...THE TRADE WINDS ARE 
ADVECTING PATCHES OF LOW LEVEL MOISTURE WESTWARD ACROSS THE 
CARIBBEAN...WITH SCATTERED SHOWERS EMBEDDED WITHIN THESE PATCHES 
OF LOW LEVEL MOISTURE. THE GREATEST CONCENTRATION OF THESE 
SHOWERS IS FROM 17N-20N BETWEEN 77W-84W. ALSO...INCREASED UPPER 
LEVEL MOISTURE IS STREAMING NORTHEASTWARD ACROSS PORTIONS OF THE 
SW CARIBBEAN.

ATLANTIC OCEAN...
DIFFLUENT WESTERLY FLOW ALOFT IS PRESENT ACROSS THE FAR W ATLC. 
DEEP LAYER ATMOSPHERIC LIFT IN THIS FLOW IS SUPPORTING A SURFACE 
STATIONARY FRONT EXTENDING FROM NE FLORIDA NEAR 30N81W TO 31N79W 
TO 32N78W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE 
AND DEEP LAYER ATMOSPHERIC LIFT ARE SUPPORTING SCATTERED SHOWERS 
WITHIN 90 NM EITHER SIDE OF THIS FRONT. TO THE SE OF THIS 
FRONT...AN UPPER LEVEL RIDGE IS IN PLACE...WITH A 1026 MB 
SURFACE HIGH NEAR 30N63W. THIS SURFACE HIGH IS FORECAST TO MOVE 
SOUTHEASTWARD DURING THE NEXT DAY AND BE LOCATED NEAR 29N60W AT 
16/0600 UTC AS A 1026 MB SURFACE HIGH. DEEP LAYER DRY AIR AND 
ATMOSPHERIC STABILITY IN THE VICINITY OF THE UPPER LEVEL RIDGE 
AND SURFACE HIGH ARE RESULTING IN GENERALLY FAIR WEATHER 
CONDITIONS TO THE SE OF THE FRONT. FARTHER TO THE E...AN UPPER 
LEVEL TROUGH IS N OF 27N BETWEEN 23W-35W WITH AN UPPER LEVEL LOW 
NEAR 32N31W. THE UPPER LEVEL LOW AND UPPER LEVEL TROUGH ARE 
ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM 15N36W TO 24N28W 
TO 32N28W TO 32N29W TO A 1006 MB SURFACE LOW NEAR 31N33W...AS 
WELL AS A SURFACE STATIONARY FRONT EXTENDING FROM 32N36W TO NE 
OF THE DISCUSSION AREA. ATMOSPHERIC INSTABILITY...UPPER LEVEL 
DIFFLUENCE...AND LOW LEVEL CONVERGENCE IN THE VICINITY OF THE 
SURFACE LOW...SURFACE TROUGH...AND SURFACE STATIONARY FRONT ARE 
SUPPORTING SCATTERED SHOWERS N OF 27N BETWEEN 25W-34W. THE 
SURFACE LOW IS FORECAST TO MOVE NORTHEASTWARD DURING THE NEXT 
DAY AND BE LOCATED NEAR 33N30W AS A 1004 MB SURFACE LOW AT 
16/0600 UTC. FARTHER TO THE E...SUBSIDENCE ASSOCIATED WITH A 
SURFACE RIDGE IS RESULTING IN FAIR WEATHER CONDITIONS ACROSS THE 
E ATLC. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS S OF 
12N E OF 48W WITH AN UPPER LEVEL HIGH NEAR 7N16W. UPPER LEVEL 
DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL HIGH AND UPPER LEVEL 
RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN