000 AXNT20 KNHC 202339 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED MAR 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2300 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 10N14W TO 4N21W. THE ITCZ BEGINS FROM 4N21W AND CONTINUES ALONG 3N25W 5N37W 1N50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 160 NM NORTH...AND 75 NM SOUTH OF THE AXIS BETWEEN 37W- 50W. ...DISCUSSION... THE GULF OF MEXICO... AS OF 2100 UTC...THE FORMING COLD FRONT PREVIOUSLY ACROSS THE GULF OF MEXICO HAS MOSTLY CAUGHT UP WITH THE ORIGINAL FRONTAL BOUNDARY TO THE SOUTH SO THAT ONLY ONE FRONT EXISTS. THE FRONT CURRENTLY EXTENDS FROM A 1009 MB LOW OVER EASTERN FLORIDA NEAR 28N81W AND CONTINUES TOWARDS THE SW GULF ALONG 29N82W 25N89W 24N95W AND BECOMES STATIONARY ACROSS MEXICO AS IT REACHES THE COAST AT 23N98W. HEAVY SHOWERS AND THUNDERSTORMS ARE WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 84W-90W WITH WIDESPREAD SHOWERS CONTINUING UP TO 100 NM OF THE AXIS BETWEEN 80W-85W. WIDESPREAD SHOWERS ALSO CONTINUE ACROSS NE FLORIDA AND INTO THE WEST ATLC. A SMALL BUT HEAVY THUNDERSTORM HAS ALSO POPPED UP OVER SE FLORIDA. STRONG NE WINDS ARE NOTED NORTH OF THE FRONT REACHING 20-25 KT. ALOFT...THE FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH WITH AXIS FROM MISSISSIPPI TO MEXICO NEAR 23N98W. THE REMAINDER OF THE BASIN BOTH NORTH AND SOUTH OF THE FRONT HAS MOSTLY CLEAR SKIES AND FAIR WEATHER DUE TO DRY AIR WRAPPING AROUND THE WESTERN SIDE OF THE UPPER TROUGH...AND ACROSS THE SOUTHERN GULF SOUTH OF THE UPPER TROUGH. THE EASTERN PORTION OF THE FRONT IS EXPECTED TO CONTINUE MOVING SE ACROSS THE BASIN...WHILE THE WESTERN PORTION STALLS AND MAY DRIFT NORTH WITH MODERATE MOISTURE REMAINING IN THAT AREA. SURFACE RIDGING IS ALSO EXPECTED TO BUILD IN FROM THE NORTH PROVIDING ANTI- CYCLONIC WINDS THROUGHOUT THE BASIN. THE CARIBBEAN SEA... MOSTLY FAIR WEATHER IS ACROSS THE CARIBBEAN DUE TO DRY AIR ALOFT AROUND A BROAD UPPER LEVEL RIDGE COVERING THE BASIN. ONLY A SMALL AREA OF LOW-LEVEL MOISTURE IS PRESENT ACROSS THE FAR EASTERN CARIBBEAN AND ACROSS A FEW OF THE NORTHERN ISLANDS. POSSIBLE ISOLATED SHOWERS ARE EAST OF 66W FROM 12N-16N...AND ACROSS PUERTO RICO...HISPANIOLA...AND JAMAICA. A LIGHT PRESSURE GRADIENT ACROSS THE AREA IS PRODUCING WEAK TRADEWINDS OF 10-15 KT THROUGHOUT. LITTLE CHANGE IS EXPECTED EXCEPT FOR A POSSIBLE INCREASE IN MOISTURE AND SHOWER ACTIVITY ACROSS THE NORTHERN CARIBBEAN AS THE FRONTAL BOUNDARY IN THE GULF MOVES THROUGH THE WEST ATLC JUST NORTH OF THE BASIN. THE ATLANTIC OCEAN... THE FRONTAL BOUNDARY IN THE GULF OF MEXICO CONTINUES INTO THE WEST ATLC AS A STATIONARY FRONT. AS OF 2100 UTC...THE STATIONARY FRONT EXTENDS FROM THE 1009 MB LOW OVER EASTERN FLORIDA NEAR 28N81W TO 32N70W WHERE IT CONTINUES NORTH OUT OF THE AREA. ISOLATED SHOWERS ARE ALONG THE AXIS WITH MORE SCATTERED ACTIVITY CONTINUING TO THE COAST OF FLORIDA AND ACROSS THE NE PORTION OF THE STATE. THE FRONT SHOULD BEGIN MOVING EAST AGAIN AS THE UPPER TROUGH OVER THE GULF SHIFTS EASTWARD. A WEAK SPOT 1013 MB SURFACE LOW IS ANALYZED SOUTH OF THE FRONT NEAR 26N70W. THE CIRCULATION IS PRESENT IN SATELLITE IMAGERY AND HAS VERY LIGHT WINDS AROUND IT. THE LOW WILL LIKELY DISSIPATE SHORTLY. AN AREA OF SHOWERS IS ALSO EAST OF THE FRONT FROM 22N-27N BETWEEN 54W- 66W. THIS ACTIVITY IS NEAR A 1020 MB HIGH CENTER NEAR 30N50W...WHICH IS DOMINATING THE REMAINDER OF THE WEST AND CENTRAL ATLC. THE HIGH IS SUPPORTED BY BROAD UPPER RIDGING EXTENDING FROM THE CARIBBEAN AND CONTINUING INTO THE CENTRAL ATLC ALONG 53W. FARTHER EAST...AN UPPER TROUGH ALONG 30W SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N29W AND CONTINUES ALONG 27N36W 26N43W. POSSIBLE ISOLATED SHOWERS ARE ALONG THE AXIS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON