[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041036
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT MAY 04 2013

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 8N13W THEN ALONG 5N15W TO 4N20W WHERE THE ITCZ BEGINS
AND CONTINUES ALONG 3N27W 2N40W THEN S OF THE EQUATOR NEAR 48W.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 3N TO
JUST S OF THE EQUATOR BETWEEN 11W AND THE PRIME MERIDIAN.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 1N-6N BETWEEN 15W-37W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH EXTENDS FROM THE CENTRAL PLAIN STATES TO OVER
THE LOWER MISSISSIPPI VALLEY INTO THE N GULF OF MEXICO N OF 27N
SUPPORTING A WEAK COLD FRONT THAT AT 04/0900 UTC ENTERS THE GULF
BETWEEN PENSACOLA AND PANAMA CITY FLORIDA TO 27N86W WHERE IT
DISSIPATES TO THE N COAST OF THE YUCATAN PENINSULA NEAR 21N87W.
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN
60 NM E OF THE FRONT WITH POSSIBLE ISOLATED SHOWERS WITHIN 75/90
NM W OF THE FRONT. NEAR ZONAL WESTERLY FLOW ALOFT COVERS THE
REMAINDER OF THE GULF. WATER VAPOR IMAGERY SHOWS MODERATE TO
STRONG SUBSTANCE WITH DRY STABLE AIR ALOFT OVER MOST OF THE GULF
LIMITING SHOWER ACTIVITY ASSOCIATED WITH THE ABOVE FRONT. A WEAK
SURFACE RIDGE COVERS THE W GULF ANCHORED BY A 1020 MB HIGH ALONG
THE COAST OF MEXICO NEAR TUXPAN. THIS SURFACE FLOW IS BANKING
LOW LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS OVER THE SW GULF
S OF 22N W OF 90W. THE FRONT WILL WEAKEN AS IT SLOWLY MOVES E
THROUGH TONIGHT. WINDS BEHIND THE FRONT WILL CONTINUE TO
DIMINISH. ANOTHER COLD FRONT IS EXPECTED TO MOVE INTO THE NW
GULF EARLY SUN THEN QUICKLY MOVE ACROSS THE N GULF THROUGH LATE
SUN FOLLOWED BY FRESH TO STRONG WINDS. WINDS AND SEAS WILL
DIMINISH OVER MUCH OF THE AREA MON THROUGH WED AS WEAK HIGH
PRESSURE SETTLES OVER THE GULF WATERS.

CARIBBEAN SEA...
A BROAD UPPER RIDGE ANCHORED IN THE TROPICAL ATLC NEAR 8N45W
EXTENDS A RIDGE AXIS INTO THE CARIBBEAN ACROSS THE WINDWARD
ISLANDS OFF THE N COAST OF SOUTH AMERICA TO OVER CENTRAL AMERICA
NEAR 13N84W. THIS IS GIVING MOST OF THE CARIBBEAN WESTERLY FLOW
ALOFT WITH SCATTERED TO BROKEN HIGH CLOUDS S OF 19N W OF 83W.
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN
90/120 NM OF LINE FROM 16N77W ACROSS HAITI TO 20N73W INCLUDING
THE WINDWARD PASSAGE. THE MONSOON TROUGH EXTENDS ACROSS PANAMA
AND COSTA RICA GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS S OF 13N W OF 80W TO INLAND OVER W
PANAMA...COSTA RICA AND S NICARAGUA. THIS IS LEAVING THE
REMAINDER OF THE NW CARIBBEAN WITH MOSTLY CLEAR SKIES THIS
MORNING. FRESH TO STRONG NW WINDS OVER THE NW CARIBBEAN WILL
DIMINISH THIS EVENING. OTHERWISE...LIGHT WINDS AND LOW SEAS WILL
CONTINUE OVER THE REMAINDER OF THE CENTRAL AND W CARIBBEAN
THROUGH MIDWEEK. TRADE WINDS ARE EXPECTED TO RETURN TO THE E
CARIBBEAN TUE AND WED AS HIGH PRESSURE OVER THE CENTRAL ATLC
BUILDS S AND SW.

ATLANTIC OCEAN...
A SHORTWAVE UPPER TROUGH EXTENDS FROM SE GEORGIA TO OFF THE
FLORIDA COAST OVER THE BAHAMAS NEAR 26N78W SUPPORTING A 1004 MB
SURFACE LOW THAT AT 04/0900 UTC IS CENTERED INLAND OVER FLORIDA
NEAR 28N81W WITH A SURFACE TROUGH EXTENDING INTO THE W ATLC
ALONG 26N79W TO THE N COAST OF CUBA NEAR 22N79W. A WARM FRONT
EXTENDS E FROM THE SURFACE LOW ALONG 29N79W TO A STATIONARY
FRONT NEAR 28N77W WHERE IT CONTINUES ALONG 23N67W TO 23N62W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE BETWEEN THE SURFACE
TROUGH AND THE FRONTAL BOUNDARY N OF 24N. THIS SHORTWAVE UPPER
TROUGH IS AMPLIFYING AN UPPER RIDGE THAT EXTENDS FROM E OF THE
BAHAMAS NEAR 27N72W N-NW TO BEYOND 32N76W. THIS UPPER RIDGE IS
PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS WITHIN 200 NM N OF THE FRONT.
NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES THE REMAINDER OF THE
ATLC BASIN. AN UPPER TROUGH N OF THE DISCUSSION AREA IS
SUPPORTING A REMNANT SURFACE TROUGH THAT EXTENDS FROM THE
CENTRAL ATLC NEAR 31N42W ALONG 25N51W TO 23N61W. DENSE CLOUD
COVER WITH POSSIBLE SHOWERS COVERS THE ATLC MOSTLY FROM 20N-30N
BETWEEN 35W-71W. A SURFACE RIDGE COVERS THE E ATLC ANCHORED BY A
1020 MB HIGH NEAR 29N22W AND A 1021 MB HIGH OFF THE COAST OF
PORTUGAL. THE COMBINATION OF HIGH PRESSURE BUILDING OVER THE NW
ATLC AND THE LOW OVER FLORIDA WILL CONTINUE TO BRING STRONG TO
GALE FORCE WINDS AND LARGE SEAS ACROSS MUCH OF THE W ATLC INTO
EARLY TONIGHT. THE FLORIDA LOW IS FORECAST TO DRIFT TO NE
FLORIDA TONIGHT THEN ACROSS SE GEORGIA SUN. THE FRONT WILL ALSO
LIFT N THROUGH TONIGHT REACHING FROM NEAR 32N80W TO 25N73W SUN
AND THE NE OF THE REGION BY MON WITH AS A WEAK PRESSURE PATTERN
SETTLING IN ACROSS THE REGION THROUGH WED. A COLD FRONT WILL
MOVE ACROSS THE FAR NW AND N CENTRAL ATLC LATE MON AND TUE.

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

AT THE REQUEST OF METEO-FRANCE AND THE METEROLOGICAL SERVICES OF
HAITI AND THE DOMINICAN REPUBLIC...THE TROPICAL ANALYSIS AND
FORECAST BRANCH (TAFB) WILL BEGIN PROVIDING...ON A TEMPORARY
BASIS...A SEPARATE DETAILED SECTION WITHIN THE ATLANTIC TROPICAL
WEATHER DISCUSSION (TWDAT). IT WILL COVER BOTH HAITI AND THE
DOMINICAN REPUBLIC DUE TO THE SHARED GEOGRAPHY OF BOTH COUNTRIES
ON THE ISLAND OF HISPANIOLA.

THE SECTION BEGINS ON MAY 15 2013 AT 1800 UTC...2 PM EDT. IT
WILL PROVIDE GUIDANCE FOR SIGNIFICANT WEATHER EVENTS THAT ARE
EXPECTED TO IMPACT THE REGION THROUGH 48 HOURS...WITH THE FOCUS
ON ASSESSING THE POTENTIAL FOR HEAVY RAINFALL.

$$
PAW

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