[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291745
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE MAR 29 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 07N13W 06N15W 03N18W CROSSING THE
EQUATOR NEAR 32W THEN INTO NE BRAZIL NEAR 02S43W. SCATTERED
MODERATE CONVECTION IS FROM THE EQUATOR TO 03N BETWEEN 13W-19W.
ISOLATED MODERATE CONVECTION IS WITHIN 150 NM N OF THE AXIS
BETWEEN 22W-32W AND FROM THE EQUATOR TO 02N BETWEEN 32W-45W.

...DISCUSSION...

GULF OF MEXICO...
A WEAK UPPER LEVEL SHORTWAVE TROUGH IS POSITIONED ALOFT OVER THE
SW NORTH ATLC WATERS WITH CONTINUES TO SUPPORT A VERY WEAK
STATIONARY FRONTAL BOUNDARY THAT EXTENDS ALONG 29N FROM DAYTONA
BEACH FLORIDA WESTWARD INTO THE NE GULF WATERS NEAR 29N87W.
LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE FRONT IS
GENERATING POSSIBLE ISOLATED SHOWERS N OF 27N E OF 88W. ALSO...
LIGHTNING DATA IS DETECTING A SMALL AREA OF SCATTERED SHOWERS
AND ISOLATED TSTMS FROM 26N-28N BETWEEN 86W-89W. THE REMAINDER
OF THE GULF IS CONTINUING TO SEE SOUTHERLY FLOW IN THE RANGE OF
10-15 KT THIS AFTERNOON UNDER BROAD UPPER LEVEL RIDGING ALOFT.
THE RIDGE IS PRODUCING MOIST SOUTHWESTERLY FLOW OVER MOST OF THE
WESTERN GULF WITH INCREASED CLOUDINESS AND WARM AIR ADVECTION
AHEAD OF THE NEXT COLD FRONT FORECAST TO ENTER THE NW GULF
WATERS EARLY WEDNESDAY.

CARIBBEAN SEA...
THE MAIN FEATURE IN THE CARIBBEAN SEA THIS AFTERNOON IS THE W-NW
MOVEMENT OF A SURFACE TROUGH ANALYZED FROM 11N62W TO 19N62W
ACROSS THE LESSER ANTILLES. THIS WEAKNESS IS LOCATED ON THE
SOUTHWESTERN PERIPHERY OF A CENTRAL ATLC RIDGE AND IS FORECAST
TO MOVE INTO THE VICINITY OF THE US/UK VIRGIN ISLANDS AND PUERTO
RICO OVER THE NEXT 24 TO 36 HOURS. ISOLATED TO WIDELY SCATTERED
SHOWERS ARE OCCURRING FROM 12N-19N BETWEEN 60W-64W...WITH THIS
AREA OF GRADUALLY TRANSLATE WEST-NORTHWESTWARD THROUGH LATE
TUESDAY. THIS SHOWER ACTIVITY WILL BE FAIRLY LIMITED IN VERTICAL
EXTENT DUE TO VERY DRY AIR AND SUBSIDENCE ALOFT. THE UPPER AIR
SOUNDING AT 29/1200 UTC FROM SAN JUAN PUERTO RICO INDICATED THIS
DRY AIR ABOVE APPROXIMATELY 700 MB. ELSEWHERE...THE REMAINDER OF
THE CARIBBEAN IS EXPERIENCING MOSTLY FAIR WEATHER CONDITIONS DUE
TO SUCH DRY AIR ALOFT. WATER VAPOR IMAGERY INDICATES THE DRY AIR
EXTENDS WESTWARD TO 90W OVER PORTIONS OF CENTRAL AMERICA.
OTHERWISE...FRESH TO STRONG TRADES CONTINUE AND ARE EXPECTED TO
PERSIST THROUGH THE WEEKEND.

ATLANTIC OCEAN...
A WESTERN NORTH ATLC DEEP LAYER TROUGH IS LOCATED MOSTLY NORTH
OF THE DISCUSSION AREA...HOWEVER...THE ASSOCIATED COLD FRONT
EXTENDS INTO THE AREA NEAR 32N63W SW TO 31N67W THEN BECOMES
STATIONARY TO THE FLORIDA COAST NEAR DAYTONA BEACH. ISOLATED
SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT. A
PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM 30N68W TO GRAND
BAHAMA ISLAND NEAR 27N78W THEN INLAND TO LAKE OKEECHOBEE.
LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE SURFACE TROUGH IS
GENERATING WIDELY SCATTERED SHOWERS WITHIN 120 NM EITHER SIDE OF
THE SURFACE TROUGH AXIS. THIS ACTIVITY CONTINUES TO BE ENHANCED
BY A WEAK UPPER LEVEL SHORTWAVE TROUGH WITH AXIS ALONG 79W. THE
REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE
OF A SURFACE RIDGE ANCHORED BY A 1029 MB HIGH CENTERED NEAR
33N28W. THE SURFACE RIDGE AXIS EXTENDS SW FROM THE HIGH CENTER
THROUGH 30N35W TO 25N65W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN




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