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Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 210547
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE MAY 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0515 UTC.

...TROPICAL WAVES...                                     
TROPICAL WAVE EXTENDS FROM 7N36W TO EQ38W MOVING W AT 10-15 KT. 
WAVE COINCIDES WITH A WEAK MOISTURE MAXIMUM ON THE TOTAL 
PRECIPITABLE WATER IMAGERY WITH CURVATURE EVIDENT ON THE 700 MB 
STREAMLINES AND SATELLITE DERIVED WINDS. WAVE ALSO DISRUPTS THE 
ITCZ. 

TROPICAL WAVE EXTENDS FROM 14N63W TO INLAND OVER SOUTH AMERICA 
TO NEAR 6N65W MOVING W AT 5-10 KT. WAVE COINCIDES WITH A 
MOISTURE MAXIMUM ON THE TOTAL PRECIPITABLE WATER IMAGERY THAT IS 
BEGINNING TO SHIFT NORTHWARD OVER THE E CARIBBEAN WITH A WEAK 
CURVATURE ON THE 700 MB STREAMLINES. SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS DOT THE W TROPICAL ATLC/E CARIBBEAN S OF 18N 
BETWEEN 57W-65W. 

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL 
ATLC NEAR 12N16W CONTINUING ALONG 4N23W TO 4N27W WHERE THE ITCZ 
BEGINS AND CONTINUES ALONG 5N31W TO 4N35W THEN RESUMES W OF THE 
TROPICAL WAVE NEAR 1N39W THEN S OF THE EQUATOR NEAR 40W TO 
INLAND OVER SOUTH AMERICA NEAR 2S45W. CLUSTERS OF SCATTERED 
SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 150 NM ALONG THE 
COAST OF W AFRICA S OF 11N E OF THE PRIME MERIDIAN. CLUSTERS OF  
ISOLATED MODERATE CONVECTION ARE FROM 2N-6N BETWEEN 12W-20W... 
FROM 3N-7N BETWEEN 25W-38W...AND FROM 2N TO THE EQUATOR BETWEEN 
40W-45W.  

...DISCUSSION...

GULF OF MEXICO...                                               
A SHORTWAVE UPPER TROUGH EXTENDS FROM SE GEORGIA TO OVER THE 
FLORIDA PENINSULA TO NEAR MIAMI. SCATTERED SHOWERS AND EMBEDDED 
THUNDERSTORMS OVER THE FLORIDA PENINSULA HAVE DISSIPATED OVER 
ALL BUT SE FLORIDA. A BROAD UPPER RIDGE EXTENDS ALONG THE E 
COAST OF MEXICO AND TEXAS COVERING THE REMAINDER OF THE GULF. A 
SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA TO 
OVER THE E GULF WITH SOUTHERLY RETURN FLOW COVERING THE 
REMAINDER OF THE GULF. WATER VAPOR IMAGERY INDICATES STRONG 
SUBSIDENCE AND DRY STABLE AIR ALOFT DOMINATING THE GULF 
TONIGHT...THUS CLEAR SKIES FOR ALL BUT THE FAR W GULF WHERE LOW 
LEVEL CLOUDS ARE WITHIN 90/120 NM ALONG THE COAST OF TEXAS AND 
MEXICO N OF 21N. MODEL GUIDANCE CONTINUES TO SHOW HIGH MOISTURE 
AND PRECIPITATION POTENTIAL OVER THE FAR E GULF AND OVER THE 
FLORIDA PENINSULA THROUGH EARLY WED BEFORE THE UPPER TROUGH IS 
EXPECTED TO MOVE E OF FLORIDA. A COLD FRONT MAY DROP INTO THE NE 
GULF FRI SLOWLY SINKING S THROUGH SAT. 

CARIBBEAN SEA...                                               
AN UPPER RIDGE EXTENDS ALONG THE N COAST OF SOUTH AMERICA GIVING 
THE CARIBBEAN S OF 16N SW FLOW ALOFT. THE AREA N OF 16N IS UNDER 
NEAR ZONAL WESTERLY FLOW ALOFT. THE UPPER FLOW IS DRAWING 
TROPICAL MOISTURE ALOFT OVER THE S CARIBBEAN AND IS GENERATING 
SCATTERED SHOWERS/THUNDERSTORMS S OF 12N BETWEEN 67W-84W. 
AFTERNOON THUNDERSTORMS CONTINUE OVER PORTIONS OF CUBA AND 
WITHIN 75 NM ALONG THE S COAST BETWEEN GUANTANAMO AND THE GULF 
OF ANA MARIA. ISOLATED SHOWERS ARE FROM 16N-19N BETWEEN 75W-81W. 
THE E CARIBBEAN IS COVERED IN THE TROPICAL WAVE SECTION ABOVE. 
SURFACE RIDGE OVER THE W ATLC WILL MAINTAIN MODERATE TO FRESH 
TRADE WINDS OVER THE REGION WITH STRONGER WINDS AT TIMES OFF THE 
COAST OF COLOMBIA AND IN THE GULF OF HONDURAS THROUGH MID WEEK. 

HISPANIOLA...                                           
CURRENTLY AFTERNOON SHOWERS AND THUNDERSTORMS HAVE DISSIPATED 
WITH SOME ISOLATED SHOWERS WITHIN 30 NM ALONG THE SE COAST OF 
THE DOMINICAN REPUBLIC BETWEEN THE MONA PASSAGE AND LA ROMANA. 
MODEL GUIDANCE INDICATES A SIMILAR PATTERN WILL PERSIST TOMORROW 
WITH THE MOST LIKELY PRECIPITATION TO BE DURING THE AFTERNOON 
AND EARLY EVENING HOURS ACROSS THE ISLAND WHEN PEAK DAYTIME 
HEATING AND INSTABILITY OCCUR. ANY AREAS THAT RECEIVE MEASURABLE 
AMOUNTS OF RAINFALL WILL LIKELY BE PRONE TO LOCALIZED FLOODING. 
MOISTURE FROM A TROPICAL WAVE MAY INCREASE ACTIVITY OVER THE 
ISLAND TUE INTO WED.

ATLANTIC OCEAN...                                               
A SHORTWAVE UPPER TROUGH OVER THE FLORIDA PENINSULA IS AMPLIFYING 
AN UPPER RIDGE OVER THE FAR W ATLC THAT EXTENDS FROM THE BAHAMA 
ISLANDS NEAR 24N75W TO BEYOND 32N78W AND IS ENHANCING THE 
SCATTERED SHOWERS/THUNDERSTORMS FROM 24N-32N BETWEEN 79W-81W 
INCLUDING SE FLORIDA. A SURFACE RIDGE EXTENDS FROM A 1026 MB 
HIGH NEAR 33N62W ACROSS CENTRAL FLORIDA INTO THE GULF OF MEXICO. 
A BROAD UPPER TROUGH COVERS THE REMAINDER OF THE W ATLC INTO THE 
CENTRAL ATLC SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 
32N48W ALONG 28N55W TO 27N60W. SCATTERED SHOWERS ARE WITHIN 45 
NM OF THE FRONT E OF 54W. A WEAK SURFACE TROUGH IS TO THE SE 
EXTENDING FROM 29N48W THROUGH AN EQUALLY WEAK 1019 MB SURFACE 
LOW NEAR 27N48W TO 24N46W. THIS FEATURE IS NOT PRODUCING ANY 
SIGNIFICANT WEATHER. A BROAD SURFACE RIDGE COVERS THE E ATLC 
ANCHORED BY A 1036 MB HIGH N OF THE AZORES. A COLD FRONT MAY 
MOVE INTO THE NW PORTION FRI SLOWLY MOVING E ACROSS THE WATERS N 
OF 27N THROUGH SAT.

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

$$
PAW