[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190547
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT MAR 19 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...ITCZ...

THE ITCZ AXIS IS ALONG 6N10W 1N20W CROSSING THE EQUATOR AT 28W
THEN CONTINUES ALONG 2S35W INTO NE BRAZIL NEAR 4S38W. SCATTERED
MODERATE TO STRONG CONVECTION IS INDICATED FROM THE EQUATOR TO
2N BETWEEN 18W AND 28W. ISOLATED MODERATE CONVECTION IS NOTED
WITHIN 90 NM EITHER SIDE OF THE AXIS E OF 18W TO THE COAST OF
AFRICA.

...DISCUSSION...

GULF OF MEXICO...
A 1024 MB SURFACE HIGH PRESSURE LOCATED NEAR 29N84W DOMINATES
MOST OF THE GULF OF MEXICO AND THE STATE OF FLORIDA PRODUCING
MAINLY FAIR WEATHER CONDITIONS. WINDS ARE LIGHT AND VARIABLE
NEAR THE HIGH PRES CENTER...WITH MODERATE TO FRESH EASTERLY AND
WINDS ON THE SOUTHERN PERIPHERY OF THE HIGH WITH SOUTHEASTERLY
RETURN FLOW OVER THE WESTERN GULF WATERS. THE BAND OF TRANSVERSE
HIGH CLOUDS NOTED EARLIER OVER THE SOUTHERN GULF HAS BECOME LESS
DEFINED AS THE AREA MOVES SE. MODERATE TO STRONG SUBSIDENCE AND
THE IMPLIED DRY AIR MASS IS SEEN N OF 25N INCLUDING THE GULF
COAST STATES AND FLORIDA WHERE WARM AND DRY WEATHER CONDITIONS
ARE EXPECTED TO CONTINUE THROUGH TODAY. THE SURFACE RIDGE IS
FORECAST TO REMAIN NEARLY STATIONARY OVER THE NEXT SEVERAL DAYS
AND CONTINUE TO PROVIDE OVERALL STABLE WEATHER CONDITIONS.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED WELL EAST OF
THE LESSER ANTILLES EXTENDS A RIDGE OVER MOST OF THE BASIN
PRODUCING SW TO W WINDS ALOFT. MODERATE TO STRONG SUBSIDENCE IS
ASSOCIATED WITH THIS RIDGE LIMITING THE DEVELOPMENT OF ANY DEEP
CONVECTION. SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW
WILL CONTINUE TO AFFECT THE REGION GENERATING ISOLATED TO
SCATTERED PASSING SHOWERS. A BAND OF LOW LEVEL MOISTURE IS NOTED
WITHIN THE COASTAL WATERS OF WESTERN VENEZUELA AND COLOMBIA.
SURFACE HIGH PRES LOCATED OVER THE NE GULF AND PORTIONS OF THE
SW NORTH ATLANTIC CONTINUES TO PRODUCE A LARGE AREA OF FRESH TO
STRONG NE TRADES OVER MUCH OF THE CARIBBEAN WITH THE STRONGEST
WINDS NEAR THE COAST OF COLOMBIA. A SHIP WITH CALL SIGN 5BDK2
REPORTED NE WINDS OF 25 KT WITHIN THE PAST HOUR AND A 0200 UTC
ASCAT PASS SHOWED SIMILAR WINDS NEAR THE COAST OF COLOMBIA. NE
WINDS OF 2O KT CAN BE FOUND OVER THE NW CARIBBEAN AND JUST SOUTH
OF DOMINICAN REPUBLIC. LOW LEVEL CONVERGENCE IS PUSHING ISOLATED
SHOWERS ONSHORE ALONG THE NICARAGUA...COSTA RICA...AND WESTERN
PANAMA COASTS. THE SURFACE FLOW IS FORECAST TO REMAIN QUITE
BRISK THROUGH THE WEEKEND AND INTO MON AS A STRONG HIGH PRES
BUILDS N OF AREA.

ATLANTIC OCEAN...
HIGH PRES AT THE SURFACE AND ALOFT DOMINATES THE WESTERN ATLC W
OF 65W WITH MOSTLY FAIR WEATHER CONDITIONS. THE COMBINATION OF
THIS HIGH AND A COUPLE OF WEAK LOW PRES SYSTEMS LOCATED NEAR
31N61W AND 23N64W IS RESULTING IN FRESH NE WINDS ACROSS THE
SOUTHERN BAHAMAS AND THE GREATER ANTILLES. THESE WINDS ARE
FORECAST TO PERSIST THROUGH SAT NIGHT...AND INCREASE LATE SUN
AND MON AS STRONG HIGH PRESSURE BUILDS IN FROM THE NORTH. THE
LOW PRES AREAS ARE FORECAST TO DISSIPATE OVER THE NEXT 12 HOURS
OR SO. SURFACE DATA AND A 0200 UTC ASCAT PASS INDICATED NE WINDS
OF 20 KT NEAR THE SE BAHAMAS AND 25 KT WINDS IN THE WINDWARD
PASSAGE. AN UPPER LEVEL TROUGH WITH AXIS EXTENDING FROM AN
UPPER-LEVEL LOW NEAR 29N61W TO JUST NE OF THE BAHAMAS. THE UPPER
LOW WAS SWEEPING TO THE SE AT 15 KT. UPPER DIFFLUENCE AHEAD OF
THE UPPER LEVEL TROUGH AND LOW IS AIDING IN THE DEVELOPMENT OF A
LARGE AREA OF SCATTERED SHOWERS AND TSTMS TO THE N OF A SURFACE
TROUGH FROM 16N58W TO 24N56W AND ALONG A STATIONARY FRONT FROM
21N42W TO 27N55W. THE AREA OF ACTIVITY WAS GENERALLY N OF 26N
BETWEEN 50W AND 57W. THE VIGOROUS UPPER LOW IS EXPECTED TO
RESULT IN THE DEVELOPMENT OF A NEW LOW PRES AREA NEAR 16N53W
LATER TODAY. FURTHER EAST...A CUT-OFF LOW IS NEAR 36N30W WITH A
NEGATIVELY TILTED TROUGH EXTENDING S AND SE TO NEAR 24N25W. THIS
UPPER LEVEL FEATURE IS PROVIDING MARGINAL SUPPORT FOR A
WEAKENING COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 31N25W
THEN CONTINUES SW TO 22N34W WHERE IT BECOMES A DISSIPATING
STATIONARY FRONT TO 21N42W...AND CONTINUES AS THE ACTIVE
STATIONARY FRONT NOTED ABOVE. A FEW SHOWERS ARE ALONG THE
FRONTAL BOUNDARY. A 1027 MB HIGH PRES SITUATED NEAR 34N44W
FOLLOWS THE FRONT. MODERATE TO FRESH TRADE WINDS ARE BLOWING
ACROSS THE TROPICAL ATLANTIC WITHIN 240 NM N OF THE FRONT.

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

$$
COBB




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