[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT MAY 19 2012

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURE...

A 1009 MB LOW PRESSURE SYSTEM IS NEARLY STATIONARY OFF THE COAST
OF SOUTH CAROLINA NEAR 32N77W...OR ABOUT 120 MILES SOUTHEAST OF
MYRTLE BEACH. SCATTERED MODERATE TO HEAVY SHOWERS AND ISOLATED
THUNDERSTORMS EXTEND UP TO 100 NM OVER THE N AND NW QUADRANTS...
AFFECTING MOSTLY THE COASTAL WATERS OF THE CAROLINAS FROM
31N-34N. DRY AIR INTRUSION IS OBSERVED OVER THE ERN AND SRN
QUADRANTS NEARLY EXPOSING THE LOW LEVEL CENTER ON VISIBLE
IMAGERY. THIS DRY AIR PUNCH IS RELATED TO AN ELONGATED UPPER
TROUGH/WAVE EXTENDING ACROSS THE NRN GULF AND FLORIDA PENINSULA
...TO THE ERN CONUS SEABOARD ON WATER VAPOR IMAGERY. WHILE THIS
SYSTEM CURRENTLY EXHIBITS BAROCLINIC CHARACTERISTICS...
ADDITIONAL DEVELOPMENT OF THIS SYSTEM IS POSSIBLE...AND IT COULD
BECOME A TROPICAL DEPRESSION OR TROPICAL STORM AS IT MOVES
SLOWLY SOUTHWARD OR WESTWARD OVER THE NEXT DAY OR SO. THIS
SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS. FOR ADDITIONAL INFORMATION ON THIS SYSTEM...
PLEASE SEE PRODUCTS FROM YOUR LOCAL NATIONAL WEATHER SERVICE
OFFICE.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 12N23W TO 5N28W MOVING W NEAR 5-10
KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYERED
MOISTURE AS EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY.
HOWEVER...NO DEEP CONVECTION IS OBSERVED EXCEPT A FEW WEAK
ISOLATED SHOWERS IN THE VICINITY OF THE WAVE AXIS.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO 200 NM OFF THE
COAST OF MAURITANIA JUST N OF SENEGAL. THE ITCZ AXIS BEGINS W OF
THE TROPICAL WAVE NEAR 6N31W TO 3N43W. CLUSTERS OF SCATTERED
WEAK TO ISOLATED MODERATE CONVECTION ARE FROM 5N-8N E OF 30W AND
FROM 7N-15N E OF 22W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL ZONAL FLOW COVERS THE REGION THIS AFTERNOON. WATER
VAPOR IMAGERY DEPICTS A BROAD ELONGATED UPPER TROUGH/WAVE
EMBEDDED IN THE FLOW N OF 22N. THIS FEATURE CARRIES VERY DRY AIR
AND STRONG SUBSIDENCE ALOFT INTO THE BASIN. THEREFORE...THE
WEATHER ACROSS THE AREA IS UNDER FAIR CONDITIONS EXCEPT FOR THE
SE CORNER OF THE GULF INCLUDING THE YUCATAN CHANNEL AND THE
STRAITS OF FLORIDA S OF 25N E OF 87W. THE ACTIVITY ON THIS
REGION IS RELATED TO A SURFACE TROUGH EXTENDING ACROSS THE FAR
NW CARIBBEAN BASIN. DOPPLER RADAR IMAGERY FROM CUBA AND
SATELLITE IMAGERY INDICATE SCATTERED MODERATE TO ISOLATED HEAVY
SHOWERS AND THUNDERSTORMS IN THIS AREA...EXPECTED TO LINGER OVER
THE NEXT 24 HOURS. OTHERWISE...FAIR WEATHER CONDITIONS WILL
PERSIST ACROSS THE REMAINDER OF THE GULF THROUGH THE MIDDLE OF
NEXT WEEK.

CARIBBEAN SEA...
ANTICYCLONIC FLOW ALOFT COVERS THE ENTIRE CARIBBEAN BASIN
ANCHORED OVER CENTRAL AMERICA. THIS FLOW IS KEEPING MOST OF THE
DISCUSSION AREA CLEAR OF ACTIVE WEATHER EXCEPT THE NW...SW...AND
NE BASINS. A 1008 MB LOW IS OFF THE COAST OF BELIZE NEAR 16N88W
WITH A SURFACE TROUGH EXTENDING NNE TO WRN CUBA NEAR 23N83W.
SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE MOSTLY
E OF THE TROUGH/LOW N OF 15N W OF 80W. SIMILAR CONVECTION IS
OBSERVED OVER THE MONA PASSAGE AND WITHIN 50-100 NM OFF THE SRN
COAST OF DOMINICAN REPUBLIC...PUERTO RICO AND THE US/UK VIRGIN
ISLANDS...ASSOCIATED TO A BROAD AREA OF CYCLONIC TURNING AROUND
A TROUGH AXIS ANALYZED OVER THE WRN ATLC WATERS. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE OVER THE IMMEDIATE COAST
OF PANAMA AND COSTA RICA RELATED TO A SURFACE TROUGH ANALYZED
INLAND ACROSS PANAMA TO NRN COLOMBIA. OTHERWISE...ESE MODERATE
TO FRESH TRADE WINDS ARE ACROSS THE BASIN. THE TRADE WINDS WILL
PERSIST THROUGH WEDNESDAY. THE SURFACE LOW IS EXPECTED TO REMAIN
NEARLY STATIONARY OVER THE NEXT 24 HOURS...ALLOWING FOR THE
POSSIBILITY OF COASTAL FLOODING ACROSS HONDURAS...GUATEMALA...
BELIZE AND THE ERN YUCATAN PENINSULA.

ATLANTIC OCEAN...
A LOW PRESSURE SYSTEM IS OFF THE COAST OF SOUTH CAROLINA WITH
SOME POTENTIAL OF DEVELOPMENT. SEE SPECIAL FEATURE SECTION ABOVE
FOR MORE DETAILS. A SURFACE TROUGH IS ANALYZED OVER THE WRN ATLC
EXTENDING FROM NEAR 27N71W ACROSS THE SE BAHAMAS TO ERN CUBA
NEAR 20N76W. THE BROAD CYCLONIC SURFACE WIND FIELD AROUND THE
TROUGH AXIS...COMBINED WITH STRONG UPPER LEVEL DIFFLUENCE ALOFT
IS GENERATING A BROAD AREA OF SCATTERED MODERATE TO HEAVY
SHOWERS AND THUNDERSTORMS WITHIN 150-230 NM ON EITHER SIDE OF AN
IMAGINARY  LINE EXTENDING FROM 30N66W ALONG 25N70W TO THE
CENTRAL BAHAMAS NEAR 24N76W TO CUBA AROUND 22N79W. COMPUTER
MODELS ARE IN GOOD AGREEMENT WITH THE CONVECTION LASTING THROUGH
THE WEEKEND AND EARLY NEXT WEEK. OTHERWISE...A VERY BROAD
SURFACE RIDGE DOMINATES THE REMAINDER OF THE ATLC ANCHORED BY A
1035 MB HIGH NEAR 37N38W.

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

$$

GARCIA




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