000 AXNT20 KNHC 041115 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED MAY 04 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1030 UTC. ...ITCZ... THE ITCZ AXIS EXTENDS FROM THE SIERRA LEONE COAST NEAR 7N12W...S WESTWARD ALONG 3N20W EQ30W 1S40W INTO NE BRAZIL NEAR 2S50W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 150 NM N OF THE AXIS BETWEEN 20W-44W...AND WITHIN 200 NM S OF THE AXIS W OF 25W. ...DISCUSSION... GULF OF MEXICO... A DEEP LAYERED TROUGH MOVES ACROSS THE EASTERN CONUS THIS MORNING. A SHORT WAVE ASSOCIATED WITH THE TROUGH MOVES ACROSS SE STATES SUPPORTING A COLD FRONT THAT EXTENDS ACROSS THIS REGION AND ENTERS THE GULF OF MEXICO THROUGH NORTHERN FLORIDA NEAR 30N82W CONTINUING SSW TO 25N88W. THEN...IT CONTINUES AS A STATIONARY FRONT INTO THE BAY OF CAMPECHE ALONG 22N92W 18N93W. SCATTERED WEAK SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE ALONG THE FRONT FROM 23N-27N. SIMILAR ACTIVITY IS WITHIN 100 NM W OF THE STATIONARY FRONT S OF 24N. AN AREA OF LOW LEVEL STRATUS CLOUDS AND PATCHY FOG HAVE DEVELOP WEST OF THE FRONT FROM 25N-29N BETWEEN 86W-93W WITH VISIBILITIES DOWN TO 3 SM. ALSO...SCATTERED WEAK SHOWERS ARE EMERGING OFF THE WESTERN YUCATAN PENINSULA INTO THE BAY OF CAMPECHE. GUSTY NNE WINDS UP TO 30 KT ARE OBSERVED BEHIND THE COLD FRONT N OF 26N. ESE WINDS 10-15 KT ARE AHEAD OF THE COLD FRONT. WATER VAPOR IMAGERY CONTINUES TO SHOW DRY STABLE AIR ALOFT OVER THE E GULF...PROVIDING FAIR WEATHER CONDITIONS TO THE AREA E OF THE FRONT. THIS FRONT IS EXPECTED TO EXTEND FROM SW FLORIDA TO THE EASTERN BAY OF CAMPECHE IN THE NEXT 24 HOURS...THEN BEGIN TO DISSIPATE OVER THE SE GULF ON THURSDAY. CARIBBEAN SEA... LOW LEVEL MOISTURE CONTINUES TO LINGER OVER THE E CARIBBEAN FROM 12N-17N E OF 71W AS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. WITHIN THIS AREA OF MOISTURE...SCATTERED WEAK SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 80 NM ON EITHER SIDE OF A LINE FROM 16N71W TO 14N61W INCLUDING THE LESSER ANTILLES. THIS AREA OF CONVECTION IS SUPPORTED BY LOW LEVEL CONVERGENCE OF THE TRADE WINDS AND WEAK MID LEVEL TROUGHINESS. THIS AREA OF CONVECTION IS EXPECTED TO REMAIN OVER THE EASTERN HALF OF THE CARIBBEAN BASIN OVER THE NEXT 24 HOURS. SIMILAR CONVECTION IS FOUND OVER THE COASTAL WATERS W OF HAITI AND N OF JAMAICA DUE TO AN UPPER LEVEL CYCLONIC CIRCULATION NEAR 20N77W. THE EASTERLY TRADE WINDS ARE BANKING LOW LEVEL CLOUDS WITH SCATTERED SHOWERS OVER COSTA RICA...PANAMA...AND HONDURAS. OTHERWISE...THE REMAINDER OF THE CARIBBEAN IS UNDER FAIR WEATHER CONDITIONS. SURFACE RIDGE OVER THE W ATLC WILL WEAKEN AND SHIFT SLOWLY S THROUGH WED NIGHT ALLOWING TRADE WINDS TO GRADUALLY DECREASE ACROSS THE CARIBBEAN. TRADE WINDS WILL RESTRENGTHEN ACROSS THE CENTRAL CARIBBEAN FRI NIGHT AND SAT AS HIGH PRESSURE REBUILDS N OF THE AREA. ATLANTIC OCEAN... THE MAIN FEATURE UNDER OBSERVATION THIS MORNING IS AN UPPER LEVEL CUT-OFF LOW MOVING ACROSS THE CENTRAL ATLC...SUPPORTING ITS SURFACE LOW REFLECTION...AN OCCLUDED 1008 MB LOW NEAR 32N50W. A COLD FRONT EXTENDS FROM THIS SYSTEM INTO THE AREA FROM 32N45W TO 25N50W TO 22N57W. SCATTERED SHOWERS AND THUNDERSTORMS ARE OCCURRING WITHIN 50 NM ON EITHER SIDE OF THE FRONT. THIS BOUNDARY IS FORECAST TO CONTINUE TO SLOWLY TRACK EASTWARD WITH CONVECTION OVER THE NEXT 24 HOURS...AS THE SURFACE LOW ENTERS OUR DISCUSSION AREA NEAR 30N52W. SURFACE RIDGING DOMINATES THE REST OF THE ATLC ON BOTH SIDES...ANCHORED BY A WEAKENING 1020 MB HIGH OVER THE WEST ATLC NEAR 31N73W AND A BROAD 1022 MB HIGH OVER THE EAST ATLC NEAR 32N25W. HOWEVER...A COLD FRONT IS EXPECTED TO MOVE OFF THE NORTHERN FLORIDA COAST THIS MORNING AND EXTEND FROM NEAR BERMUDA TO SOUTHERN FLORIDA LATE THU...THEN DISSIPATE FRIDAY. HIGH PRESSURE WILL REBUILD ON SUN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA