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