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Atlantic Tropical Weather Discussion (Text)

000
AXNT20 KNHC 251142
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT MAY 25 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-BISSAU NEAR 
12N16W TO 7N20W. THE ITCZ BEGINS AT 7N20W AND CONTINUES ALONG 
7N33W 2N50W 2N57W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 
4N-8N BETWEEN 20W-37W. ISOLATED MODERATE/STRONG CONVECTION IS 
FROM EQ-6N BETWEEN 42W-48W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION IS FROM 6N-9N BETWEEN 48W-57W. 

...DISCUSSION...

GULF OF MEXICO...                                                
UPPER LEVEL RIDGING SPREADS OVER THE GULF OF MEXICO TONIGHT WITH 
AXIS NEAR 93W SUPPORTING SURFACE RIDGING EXTENDING FROM A HIGH 
CEN  TER OVER THE GREAT LAKES REGION. DRY AIR ALOFT COVERS A 
GOOD PORTION OF THE BASIN PROVIDING FAIR CONDITIONS AND CLEAR 
SKIES. DIFFLUENT FLOW ALOFT AROUND THE WEST SIDE OF THE UPPER 
RIDGE CONTINUES TO PRODUCE SCATTERED SHOWERS/THUNDERSTORMS ALONG 
THE EASTERN MEXICO COAST FROM 21N-26N BETWEEN 96W-100W. ISOLATED 
SHOWERS ARE ALSO IN THE BAY OF CAMPECHE NEAR A SURFACE TROUGH 
ALONG 20N93W TO 16N91W. LIGHT NE WINDS OF 5-10 KT SPREAD ACROSS 
THE EASTERN GULF BECOMING EASTERLY ACROSS THE CENTRAL AND 
WESTERN PORTIONS AND REACHING 15 KT. A FEW 20 KT WINDS ARE 
POSSIBLE IN THE SW GULF. 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/THUNDERSTORMS ARE FROM 
9N-14N BETWEEN 78W-84W. THIS IS LIKELY INFLUENCED BY THE MONSOON 
TROUGH WHICH EXTENDS THROUGH COSTA RICA AND PANAMA TO NORTHERN 
COLOMBIA. IT ALSO COINCIDES WITH AN AREA OF MAXIMUM MOISTURE IN 
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS ARE ALSO OVER THE NE CARIBBEAN FROM 16N-19N EAST 
OF 68W. THIS ACTIVITY IS ALSO WITHIN AN AREA OF ENHANCED 
MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. THE 
REMAINDER OF THE AREA HAS MOSTLY CLEAR SKIES WITH ONLY A FEW LOW-
LEVEL ISOLATED SHOWERS MOVING WITHIN TRADEWIND FLOW OF 15-20 KT. 
LITTLE CHANGE IS EXPECTED ACROSS THE BASIN. MOISTURE IS EXPECTED 
TO REMAIN OVER THE SW CARIBBEAN AS WELL AS THE NE CORNER. A 
SURFACE TROUGH/FRONTAL BOUNDARY IN THE WEST ATLC WILL MOVE 
EASTWARD JUST NORTH OF THE BASIN AND MAY INFLUENCE 
SHOWERS/THUNDERSTORMS ACROSS THE NORTHERN ISLANDS. 

HISPANIOLA...                                                  
NO SHOWER ACTIVITY IS ACROSS HISPANIOLA AT THIS TIME. WATER 
VAPOR IMAGERY INDICATES MODERATE MOISTURE ALOFT...AND TOTAL 
PRECIPITABLE WATER IMAGERY INDICATES A SIMILAR SCENARIO WITH 
HIGHER MOISTURE JUST TO THE EAST. MODEL GUIDANCE INDICATES THAT 
THIS AREA OF HIGHER MOISTURE TO THE EAST WILL DRIFT WEST TOWARDS 
THE ISLAND...WHICH COINCIDES WITH SURFACE TROUGHING TO THE 
NORTH. THIS COMBINATION MAY LEAD TO A GREATER CHANCE OF 
SHOWERS/THUNDERSTORMS BY THE END OF THE WEEKEND. 

ATLANTIC OCEAN...                                                
AN UPPER LEVEL TROUGH ALONG 73W SUPPORTS A COLD FRONT ALONG 
32N72W 29N76W 28N80W. A SURFACE TROUGH IS TO THE EAST ALONG 
32N71W TO 24N76W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
EXTEND UP TO 230 NM EAST OF THE TROUGH AXIS TO THE NORTH OF 26N. 
AN UPPER LEVEL RIDGE DOMINATES THE CENTRAL ATLC ALONG 50W 
SUPPORTING BROAD SURFACE RIDGING ACROSS THIS AREA. AN UPPER 
LEVEL LOW NEAR 31N34W SUPPORTS A WEAK 1022 MB SURFACE LOW NEAR 
30N38W WITH A SURFACE TROUGH EXTENDING FROM THE LOW CENTER ALONG 
28N36W 22N44W. ISOLATED SHOWERS ARE POSSIBLE ALONG THE AXIS WITH 
AN AREA OF SCATTERED SHOWERS TO THE EAST FROM 26N-31N BETWEEN 
31W-36W. 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