000
AXNT20 KNHC 140522
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT MAR 14 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 5N8W 2N18W CROSSING THE EQUATOR 
NEAR 26W EXTENDING TO 2S32W INTO NE BRAZIL NEAR 5S37W. SCATTERED 
MODERATE CONVECTION IS FROM 3N-5N BETWEEN 6W-10W. SCATTERED 
MODERATE CONVECTION IS ALSO FROM 2N-4N BETWEEN 14W-19W. SIMILAR 
CONVECTION IS S OF 2N BETWEEN 21W-33W.

...DISCUSSION...

GULF OF MEXICO...
DIFFLUENT WESTERLY FLOW ALOFT IS PRESENT ACROSS THE WESTERN 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 30N92W TO A 1011 MB SURFACE LOW NEAR 29N94W TO 
24N96W TO THE COAST OF MEXICO NEAR 21N97W. THE SURFACE LOW IS 
FORECAST TO MOVE NE OF THE DISCUSSION AREA DURING THE NEXT DAY. 
LOW LEVEL CONVERGENCE AND DEEP LAYER ATMOSPHERIC LIFT ARE 
SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 90 NM 
EITHER SIDE OF THE FRONT. TO THE NW OF THE FRONT...N TO NE 
SURFACE WINDS OF 15 TO 20 KT ARE OCCURRING OVER THE NW 
GULF...WHERE A RELATIVELY COOLER AND DRIER AIRMASS IS IN PLACE. 
THIS COOLER AIR IS OVER RELATIVELY WARMER WATERS...RESULTING IN 
LAYERS OF SCATTERED TO OVERCAST STRATOCUMULUS CLOUDS TO THE NW 
OF THE FRONT. TO THE SE OF THE FRONT...DEEP LAYER DRY AIR IS 
RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF 
THE CENTRAL AND SE GULF. THE FRONT IS FORECAST TO BEGIN MOVING 
SLOWLY EASTWARD AS A COLD FRONT DURING THE NEXT DAY.

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 16N-19N BETWEEN 77W-80W. 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 31N78W TO 32N76W TO NE OF THE 
DISCUSSION AREA. LOW LEVEL CONVERGENCE AND DEEP LAYER 
ATMOSPHERIC LIFT ARE SUPPORTING SCATTERED SHOWERS WITHIN 60 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. DEEP LAYER DRY AIR AND ATMOSPHERIC STABILITY IN THE 
VICINITY OF THE SURFACE HIGH AND UPPER LEVEL RIDGE ARE RESULTING 
IN GENERALLY FAIR WEATHER CONDITIONS TO THE SE OF THE FRONT. 
DURING THE NEXT DAY...THE SURFACE HIGH IS FORECAST TO MOVE 
EASTWARD AND BE LOCATED NEAR 32N56W AS A 1028 MB SURFACE HIGH AT 
15/0000 UTC. FARTHER TO THE E...AN UPPER LEVEL TROUGH IS N OF 
22N BETWEEN 26W-43W...WITH AN UPPER LEVEL LOW NEAR 30N36W. THE 
UPPER LEVEL LOW AND UPPER LEVEL TROUGH ARE ASSOCIATED WITH A 
1004 MB SURFACE LOW NEAR 29N38W...A DISSIPATING SURFACE COLD 
FRONT EXTENDING FROM 14N39W TO 24N32W TO 30N33W AND A SURFACE 
OCCLUDED FRONT EXTENDING FROM 30N33W TO 32N36W TO 31N38W TO 
30N38W. ATMOSPHERIC INSTABILITY...UPPER LEVEL DIFFLUENCE...AND 
LOW LEVEL CONVERGENCE IN THE VICINITY OF THE SURFACE LOW AND 
SURFACE FRONTS ARE SUPPORTING SCATTERED SHOWERS AND 
THUNDERSTORMS N OF 25N BETWEEN 29W-41W. THIS ACTIVITY IS BEING 
SUPPORTED BY UPPER LEVEL DIVERGENCE IN THE NE QUADRANT OF A 
110-120 KT UPPER LEVEL JET MAXIMUM LOCATED SE OF THE UPPER LOW. 
THE SURFACE LOW IS FORECAST TO MOVE NORTHEASTWARD DURING THE 
NEXT DAY AND BE LOCATED NEAR 28N37W AS A 1009 MB SURFACE LOW AT 
15/0000 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 
15N E OF 53W WITH AN UPPER LEVEL HIGH NEAR 11N23W. 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 S OF 3N BETWEEN 1W-10W.

$$
COHEN