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Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 260529
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN MAY 26 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 
0445 UTC.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 11N15W 
TO 6N24W. THE ITCZ BEGINS FROM 6N24W AND CONTINUES ALONG 4N36W 
4N47W 3N51W. A LARGE BURST OF STRONG CONVECTION IS FROM 4N-9N 
BETWEEN 16W-24W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
IS FROM 5N-9N BETWEEN 48W-53W. 

...DISCUSSION...

GULF OF MEXICO...                                                
UPPER LEVEL RIDGING SPREADS OVER THE GULF OF MEXICO TONIGHT WITH 
AXIS NEAR 91W SUPPORTING SURFACE RIDGING EXTENDING FROM A HIGH 
CENTER OVER THE WEST ATLC. DRY AIR ALOFT COVERS A GOOD PORTION 
OF THE EASTERN HALF OF THE BASIN PROVIDING FAIR CONDITIONS AND 
CLEAR SKIES. DIFFLUENT FLOW ALOFT AROUND THE WEST SIDE OF THE 
UPPER RIDGE IS PROVIDING CLOUD COVER AND POSSIBLE ISOLATED 
SHOWERS OVER THE FAR WESTERN GULF. ISOLATED SHOWERS ARE ALSO IN 
THE BAY OF CAMPECHE NEAR A SURFACE TROUGH ALONG 22N89W TO 
18N90W. A CLUSTER OF STRONG SHOWERS/THUNDERSTORMS IS ALSO INLAND 
OVER SOUTHERN MEXICO FROM 16N-20N BETWEEN 92W-95W. MAINLY EAST 
TO SOUTHEAST WINDS ARE THROUGHOUT THE AREA RANGING FROM 10-15 
KT. A FEW 20 KT WINDS MAY BE PRESENT NEAR THE WESTERN COAST OF 
THE YUCATAN PENINSULA. SURFACE RIDGING WILL DOMINATE THE AREA 
THROUGHOUT THE WEEKEND. 

CARIBBEAN SEA...                                             
CLEAR SKIES SPREAD ACROSS A LARGE AREA OF THE CARIBBEAN 
INCLUDING THE NW AND SE CORNERS. HOWEVER...A COUPLE AREAS OF 
SHOWERS/THUNDERSTORMS ARE STILL PRESENT. THE FIRST AREA IS IN 
THE SW CARIBBEAN WHERE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
ARE FROM 12N-17N BETWEEN 80W-88W INCLUDING NICARAGUA AND 
HONDURAS. IT COINCIDES WITH AN AREA OF MAXIMUM MOISTURE IN TOTAL 
PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS ARE ALSO OVER SOUTHERN HAITI FROM 18N-19N BETWEEN 
71W-74W. THIS IS LIKELY ASSOCIATED WITH AN UPPER LEVEL TROUGH 
WHOSE AXIS IS ALONG 70W. MOIST SOUTHWESTERLY FLOW ALOFT COVERS 
THE EASTERN CARIBBEAN EAST OF 70W...BUT ONLY A FEW ISOLATED 
SHOWERS ARE NOTED WITHIN THE TRADEWIND FLOW OF 15 KT. LITTLE 
CHANGE IS EXPECTED ACROSS THE BASIN. MOISTURE IS EXPECTED TO 
REMAIN OVER THE SW CARIBBEAN AS WELL AS THE FAR EASTERN PORTION 
LIKELY ASSOCIATED WITH THE UPPER TROUGH CURRENTLY ALONG 70W. 

HISPANIOLA...                                           
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS CONTINUE OVER SOUTHERN 
HAITI FROM 18N-19N BETWEEN 71W-74W. THIS IS THE LAST ACTIVITY 
THAT REMAINS FROM AFTERNOON CONVECTION. AN UPPER LEVEL TROUGH 
LIES OVER THE ISLAND ALONG 70W...WHICH MAY BE CONTRIBUTING TO 
THE LATE ACTIVITY. THE UPPER TROUGH SHOULD MOVE EAST OVER THE 
NEXT 24 HOURS...WHICH WILL BRING IN DRIER AIR ALOFT. 
HOWEVER...MODEL GUIDANCE INDICATES LOW-LEVEL MOISTURE EAST OF 
THE LESSER ANTILLES WILL BEGIN MOVING WEST AND MAY REACH 
HISPANIOLA WITHIN 48 HOURS. 

ATLANTIC OCEAN...                                                
AN UPPER LEVEL RIDGE IN THE GULF OF MEXICO SUPPORTS SURFACE 
RIDGING IN THE FAR WESTERN ATLC AROUND A 1024 MB HIGH NEAR 
32N79W. AN UPPER LEVEL TROUGH TO THE EAST ALONG 70W SUPPORTS A 
COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N66W AND 
CONTINUES ALONG 27N70W 24N77W. ISOLATED SHOWERS AND 
THUNDERSTORMS ARE UP TO 300 NM EAST OF THE AXIS NORTH OF 25N. AN 
UPPER LEVEL RIDGE DOMINATES THE CENTRAL ATLC ALONG 49W 
SUPPORTING BROAD SURFACE RIDGING ACROSS THIS AREA AROUND A 1037 
MB HIGH NEAR 41N41W. AN UPPER LEVEL TROUGH EXTENDS INTO THE 
EASTERN ATLC FROM NEAR 35N22W TO 28N43W. IT SUPPORTS A WEAK 
SURFACE TROUGH ALONG 30N40W TO 27N40W. NO SHOWER ACTIVITY IS 
ASSOCIATED WITH THE TROUGH. THE REMAINDER OF THE BASIN IS ALSO 
INFLUENCED BY SURFACE RIDGING SUPPORTED BY BROAD UPPER RIDGING 
ACROSS WEST AFRICA. BROAD UPPER RIDGING ALSO COVERS THE TROPICAL 
ATLC. 

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

$$
WALTON