000 AXNT20 KNHC 250542 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 10N14W TO 8N19W. THE ITCZ BEGINS AT 8N19W AND CONTINUES ALONG 6N35W 6N48W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 5N-6N BETWEEN 19W-23W...AND FROM 3N-7N BETWEEN 25W-36W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-7N BETWEEN 43W- 45W...EQ-2N BETWEEN 41W-46W...AND FROM 3N-6N BETWEEN 48W-52W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL RIDGING SPREADS OVER THE GULF OF MEXICO TONIGHT WITH AXIS NEAR 94W SUPPORTING SURFACE RIDGING EXTENDING FROM A HIGH CENTER 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 A LARGE AREA OF SHOWERS/THUNDERSTORMS OVER NE MEXICO NEAR A SQUALL LINE FROM 26N98W TO 24N101W...AS OF 0300 UTC. 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 ALONG THE WEST COAST OF THE YUCATAN PENINSULA. A FEW SHOWERS/THUNDERSTORMS ARE STILL ACROSS SOUTHERN MEXICO AS WELL FROM 17N-19N BETWEEN 91W- 95W. SURFACE RIDGING WILL DOMINATE THE AREA THROUGHOUT THE WEEKEND. CARIBBEAN SEA... MUCH OF THE LATER AFTERNOON CONVECTION HAS DIED DOWN NOW. HOWEVER...SEVERAL AREAS OF SHOWERS/THUNDERSTORMS ARE STILL PRESENT. THE FIRST AREA IS OFF THE COAST OF NICARAGUA WHERE SCATTERED SHOWERS/THUNDERSTORMS ARE FROM 11N-15N BETWEEN 78W- 83W. THIS AREA LIES NEAR THE BASE OF A BROAD UPPER LEVEL TROUGH ACROSS THE AREA. 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 66W. 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... DEEP CONVECTION FROM AFTERNOON HEATING AND INSTABILITY HAS NOW DIED DOWN WITH ONLY POSSIBLE LOW-LEVEL ISOLATED SHOWERS REMAINING. 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 75W SUPPORTS A FRONTAL BOUNDARY JUST NORTH OF THE DISCUSSION AREA ALONG WITH A SURFACE TROUGH TO THE EAST ALONG 32N72W TO 85N79W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS EXTEND UP TO 230 NM EAST...75 NM WEST OF THE AXIS TO THE NORTH OF 29N. AN UPPER LEVEL RIDGE DOMINATES THE CENTRAL ATLC ALONG 50W SUPPORTING BROAD SURFACE RIDGING ACROSS THIS AREA. AN UPPER LEVEL LOW NEAR 31N35W SUPPORTS A DISSIPATING STATIONARY FRONT THAT ENTERS THE AREA NEAR 31N37W AND CONTINUES ALONG 28N35W 22N45W. ISOLATED SHOWERS ARE POSSIBLE ALONG THE AXIS WITH AN AREA OF SCATTERED SHOWERS TO THE EAST FROM 28N-32N BETWEEN 29W-34W. 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 HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON