000
AXNT20 KNHC 150511
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0445 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N10W 2N17W CROSSING THE EQUATOR 
NEAR 24W EXTENDING TO 2S34W INTO NE BRAZIL NEAR 5S39W. SCATTERED 
MODERATE CONVECTION IS FROM 5N-7N BETWEEN 12W-14W. SCATTERED 
MODERATE CONVECTION IS ALSO FROM 2N-5N BETWEEN 15W-19W. SIMILAR 
CONVECTION IS S OF 2N BETWEEN 9W-15W.

...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 STATIONARY FRONT IN THE W GULF THAT 
EXTENDS FROM S LOUISIANA NEAR 29N91W TO 25N94W TO A 1011 MB 
SURFACE LOW NEAR 20N96W TO THE COAST OF MEXICO NEAR 20N97W. LOW 
LEVEL CONVERGENCE AND DEEP LAYER ATMOSPHERIC LIFT ARE SUPPORTING 
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 90 NM EITHER 
SIDE OF THE FRONT. AT 16/0000 UTC...THE SURFACE LOW IS FORECAST 
TO HAVE DISSIPATED. TO THE W OF THE FRONT...INCREASED NW TO N 
SURFACE WINDS AND A RELATIVELY COOLER AND DRIER AIRMASS ARE 
PRESENT. THIS 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 13N-16N BETWEEN 63W-72W. ALSO...INCREASED UPPER 
LEVEL MOISTURE IS STREAMING NORTHEASTWARD ACROSS PORTIONS OF THE 
SW CARIBBEAN.

ATLANTIC OCEAN...
SOUTHWESTERLY FLOW ALOFT IS PRESENT ACROSS THE FAR W ATLC. DEEP 
LAYER ATMOSPHERIC LIFT IN THIS FLOW IS SUPPORTING A SURFACE 
STATIONARY FRONT EXTENDING FROM THE E FLORIDA PENINSULA NEAR 
30N81W TO 31N78W TO 32N77W 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 
1027 MB SURFACE HIGH NEAR 31N64W. THE SURFACE HIGH IS FORECAST 
TO BE LOCATED NEAR 31N64W AT 16/0000 UTC. 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 26N BETWEEN 23W-39W. THIS UPPER LEVEL  
TROUGH IS ASSOCIATED WITH A 1007 MB SURFACE LOW NEAR 31N34W AND 
A SURFACE TROUGH EXTENDING FROM 16N36W TO 24N29W TO 31N30W. 
ATMOSPHERIC INSTABILITY...UPPER LEVEL DIFFLUENCE...AND LOW LEVEL 
CONVERGENCE IN THE VICINITY OF THE SURFACE LOW AND SURFACE 
TROUGH ARE SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS N OF 
26N BETWEEN 26W-35W. THE SURFACE LOW IS FORECAST TO MOVE 
NORTHEASTWARD DURING THE NEXT DAY AND BE LOCATED NEAR 32N30W AS 
A 1007 MB SURFACE LOW AT 16/0000 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 13N E OF 51W WITH AN UPPER 
LEVEL HIGH NEAR 7N19W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH 
THE UPPER LEVEL HIGH AND UPPER LEVEL RIDGE IS ENHANCING THE 
CONVECTION ASSOCIATED WITH THE ITCZ...AS WELL AS SCATTERED 
SHOWERS FROM 2N-5N BETWEEN 2W-7W.

$$
COHEN