000 AXNT20 KNHC 180544 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST FRI SAT 18 2012 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 0500 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SIERRA LEONE NEAR 8N13W TO 4N17W. THE ITCZ CONTINUES FROM 4N17W CROSSING THE EQUATOR AT 27W CONTINUING TO THE COAST OF BRAZIL NEAR 5S36W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 1N-4N BETWEEN 21W-31W...AND FROM 2N-6N BETWEEN 32W-40W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL RIDGING CONTINUES TO COVER THE GULF OF MEXICO TONIGHT WITH AXIS EXTENDING FROM CENTRAL AMERICA. THIS PATTERN IS DRAWING UPPER LEVEL MOISTURE ACROSS CENTRAL MEXICO AND THE NRN GULF. HOWEVER...A SHORTWAVE UPPER TROUGH IS MOVING ACROSS SE TEXAS SUPPORTING STRONG SHOWERS/THUNDERSTORMS NEAR A STATIONARY FRONT THAT DRAPES ACROSS THE NRN GULF. THE FRONT EXTENDS FROM NRN FLORIDA NEAR 29N83W TO TEXAS ALONG 28N90W 28N97W 26N98W. AS OF 0300 UTC...THE ERN PORTION OF THE FRONT HAS BEGUN TO DISSIPATE. RADAR IMAGERY INDICATES THE STRONGEST SHOWER/THUNDERSTORM ACTIVITY IS S OF WRN LOUISIANA FROM 28N-29N BETWEEN 93W-96W. SCATTERED SHOWERS ARE ALSO N OF 26N W OF 91W WITH A FEW ISOLATED SHOWERS ACROSS THE ERN GULF FROM 27N-29N E OF 85W. A LONGWAVE UPPER TROUGH CURRENTLY OVER ARIZONA IS EXPECTED TO MOVE EWD OVER THE NEXT COUPLE OF DAYS. DURING THE NEXT 6-12 HOURS AS THE LONGWAVE MOVES E...A SURFACE LOW IS EXPECTED TO FORM ALONG THE TEXAS COAST. THE LOW IS EXPECTED TO MOVE NE PUSHING A COLD FRONT ACROSS THE GULF OF MEXICO. STRONG WINDS ARE EXPECTED BEHIND THE FRONT WITH LIKELY SHOWER/THUNDERSTORM ACTIVITY ALONG IT. CARIBBEAN SEA... UPPER LEVEL RIDGING COVERS THE FAR WRN CARIBBEAN WITH AXIS UP CENTRAL AMERICA ALONG 86W. AN UPPER LEVEL TROUGH COVERS THE ERN CARIBBEAN EXTENDING FROM THE LEEWARD ISLANDS TO THE SW CARIBBEAN DUE TO STRONG DRY AIR ALOFT ACROSS THE BASIN SURFACE CONDITIONS STILL REMAIN FAIR. TRADEWIND FLOW OF 15-20 KTS IS PRESENT ACROSS THE ERN CARIBBEAN BECOMING 10-15 KTS ACROSS THE CENTRAL AND NW CARIBBEAN WITH STRONGER WINDS NEAR THE COAST OF COLOMBIA. A FEW CLUSTERS OF LOW-LEVEL CLOUDS ARE NOTED S OF JAMAICA AND PUERTO RICO WITH POSSIBLE ISOLATED SHOWERS. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. A COLD FRONT EXPECTED TO MOVE ACROSS THE GULF OF MEXICO THROUGHOUT THE WEEKEND WILL REACH THE NW CARIBBEAN EARLY MONDAY. ATLANTIC OCEAN... BROAD UPPER LEVEL RIDGING EXTENDING FROM THE WRN CARIBBEAN COVERS THE WRN ATLC SUPPORTING WEAK SURFACE RIDGING AROUND A 1020 MB SURFACE HIGH NEAR 26N66W PROVIDING FAIR WEATHER ACROSS THE W ATLC S OF 28N. TO THE N...A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N69W CONTINUING TO THE FLORIDA COAST AT 29N81W. SCATTERED SHOWERS ARE WITHIN 120 NM EITHER SIDE THE AXIS. THE FRONT IS SUPPORTED BY A SHORTWAVE UPPER TROUGH TO THE N ALONG 65W. A WEAK SURFACE TROUGH IS ANALYZED N OF THE LEEWARD ISLANDS ALONG 23N60W TO 20N63W WITH ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE THE AXIS. ACROSS THE CENTRAL ATLC...A SHARP UPPER LEVEL TROUGH IS ALONG 45W SUPPORTING A SURFACE TROUGH ALONG 28N47W TO 17N51W. MOST OF THE SHOWER ACTIVITY IS TO THE E WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 19N BETWEEN 41W-47W. THIS UPPER TROUGH MAY ALSO BE ENHANCING SOME OF THE CONVECTION N OF THE ITCZ REGION. FARTHER E...AN UPPER LEVEL RIDGE COVERS THE ERN ATLC WITH AXIS ALONG 27W SUPPORTING A SURFACE RIDGE ANCHORED BY A 1030 MB AZORES HIGH NEAR 41N24W. THE RIDGE IS PROVING MOSTLY FAIR WEATHER ACROSS THE FAR ERN ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON