000
AXNT20 KNHC 151149
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED MAY 15 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 
1045 UTC.

...ITCZ/MONSOON TROUGH...                                     

THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 11N15W 
TO 6N19W. THE ITCZ BEGINS FROM 6N19W AND CONTINUES ALONG 5N33W 
2N45W 1N54W. A LARGE CLUSTER OF STRONG CONVECTION IS MOVING OFF 
THE COAST OF AFRICA FROM 5N-10N EAST OF 16W. SCATTERED 
MODERATE/STRONG CONVECTION IS FROM 3N-6N BETWEEN 22W-378W. 
SIMILAR ACTIVITY IS FROM 3N-5N BETWEEN 38W-49W...AND FROM 4N-7N 
BETWEEN 49W-54W. 

...DISCUSSION...

GULF OF MEXICO...                                               
SURFACE RIDGING DOMINATES THE GULF OF MEXICO AROUND A 1023 MB 
HIGH SOUTH OF THE FLORIDA PANHANDLE NEAR 30N86W. AN UPPER LEVEL 
RIDGE ALONG 90W SUPPORTS THE SURFACE RIDGE. CLEAR SKIES ARE 
NOTED OVER THE MAJORITY OF THE BASIN EXCEPT FOR THE FAR WESTERN 
PORTION ALONG THE MEXICO AND TEXAS COAST WHERE ISOLATED SHOWERS 
ARE NOTED NORTH OF 96W WEST OF 93W. LIGHT ANTI-CYCLONIC WINDS 
ARE IN THE NE GULF AROUND THE HIGH CENTER INCREASING TO 15-20 KT 
ON THE OUTER PERIMETER. SURFACE RIDGING WILL CONTINUE TO 
DOMINATE THE BASIN FOR AT LEAST THE NEXT SEVERAL DAYS. 

CARIBBEAN SEA...                                                 
MOSTLY FAIR CONDITIONS SPREAD ACROSS THE CARIBBEAN DUE TO DRY 
AIR ALOFT AROUND AN UPPER LEVEL RIDGE COVERING MUCH OF THE GULF 
OF MEXICO AND CARIBBEAN...AND AN UPPER LEVEL TROUGH WITH AXIS 
JUST EAST OF THE LESSER ANTILLES. A FEW ISOLATED SHOWERS ARE 
NOTED SOUTH OF WESTERN CUBA AND ACROSS CENTRAL CUBA NEAR A 
DISSIPATING COLD FRONT ALONG 22N78W 22N80W. SIMILAR ACTIVITY IS 
ACROSS HISPANIOLA NEAR A PRE-FRONTAL TROUGH THAT EXTENDS TO THE 
NE COAST OF THE ISLAND. AN AREA OF ISOLATED SHOWERS IS ALSO IN 
THE NE CARIBBEAN FROM 16N-18N EAST OF 71W MOVING WESTWARD WITH 
THE TRADEWINDS. TRADEWIND FLOW OF 15-20 KT DOMINATES THE 
MAJORITY OF THE EASTERN AND CENTRAL CARIBBEAN WITH A FEW 25 KT 
WINDS NEAR THE COAST OF COLOMBIA. LITTLE CHANGE IS EXPECTED OVER 
THE NEXT 24 HOURS. ISOLATED TO SCATTERED SHOWERS MAY REMAIN OVER 
THE NE CARIBBEAN AS MODEL GUIDANCE INDICATES ENHANCED MOISTURE 
WILL STAY OVER THIS AREA.  

ATLANTIC OCEAN...                                               
SURFACE HIGH PRESSURE IS BEGINNING TO BUILD ACROSS THE FAR 
WESTERN ATLC AROUND A 1023 MB HIGH NEAR 31N76W. AN UPPER LEVEL 
TROUGH ALONG 63W SUPPORTS A COLD FRONT THAT ENTERS THE 
DISCUSSION AREA NEAR 32N61W AND CONTINUES TO THE BAHAMAS NEAR 
23N73W...AND DISSIPATES OVER CENTRAL CUBA NEAR 22N80W. A PRE-
FRONTAL SURFACE TROUGH IS EAST OF THE FRONT ALONG 30N60W 24N64W 
19N70W. WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ARE UP TO 
175 NM EAST...AND 75 NM WEST OF THE TROUGH AXIS NORTH OF 21N. 
ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE REMAINDER 
OF THE SURFACE TROUGH...AND WITHIN 30 NM OF THE FRONTAL 
BOUNDARY. A RIDGE TROUGH RIDGE PATTERN COVERS THE REMAINDER OF 
THE UPPER LEVELS ACROSS THE BASIN. THE FIRST RIDGE IS NARROW AND 
ALONG 53W. THE UPPER TROUGH IS ALONG 40W SUPPORTING A SURFACE 
TROUGH ALONG 31N40W 25N40W. SCATTERED SHOWERS ARE EAST OF THE 
TROUGH FROM 27N-31N BETWEEN 33W-41W.  THE SECOND UPPER RIDGE IS 
BROAD AND COVERS THE MAJORITY OF THE TROPICAL ATLC. AT THE 
SURFACE...A BROAD SURFACE RIDGE DOMINATES THE CENTRAL AND 
EASTERN ATLC ANCHORED BY A 1038 MB HIGH NEAR 45N39W. FAIR 
CONDITIONS SPREAD ACROSS THIS AREA EXCEPT FOR THE AREA OF 
SHOWERS NEAR THE SURFACE TROUGH THAT EXTENDS INTO THE SURFACE 
RIDGE.
 
FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

AT THE REQUEST OF METEO-FRANCE AND THE METEOROLOGICAL 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.

$$
WALTON