000 AGXX40 KNHC 061809 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 210 PM EDT THU MAY 06 2010 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... A DETERIORATING FRONTAL BOUNDARY REMAINS NEARLY STATIONARY FROM JUST S OF CEDAR KEY TO NEAR 26N88W. A SLOW WWD MOVING LOW LEVEL TROUGH LIES OFF THE YUCATAN PENINSULA FROM 19N92W EXTENDING NEARLY TO THE SW TAIL OF THE FRONTAL BOUNDARY. ANTICYCLONIC FLOW TO THE E OF THESE FEATURES DOMINATED THE SE GULF WHILE A BROADER RIDGE NOSED FROM S OF THE MOUTH OF THE MISSISSIPPI RIVER SW TO THE UPPER MEXICAN COAST. WINDS ACROSS THE GULF WERE GENERALLY 10 KT OR LESS EXCEPT FOR SMALL AREAS NEAR 15 KT JUST W OF THE TROUGH OFF THE YUCATAN AND ACROSS THE FAR NW GULF BETWEEN BROWNSVILLE AND CORPUS CHRISTI...WHERE PEAK SEAS WHERE 3-4 FT. THE FRONTAL BOUNDARY IS EXPECTED TO BECOME NEARLY DIFFUSE OVER THE NE GULF DURING THE NEXT 24 HOURS WITH ITS MAIN WEATHER IMPACT BEING INCREASED LOW LEVEL MOISTURE CONVERGENCE AND ISOLATED SHOWERS. THE MID LEVEL SHORTWAVE TROUGH SUPPORTING THE SURFACE FRONT HAS SHIFTED E OVER THE FLORIDA PENINSULA. THIS MID LEVEL TROUGHING STALL E OF FLORIDA AND AMPLIFY FRI. THIS WILL PREVENT THE DEEP LAYER RIDGING FROM BECOMING VERY STRONG. AS A RESULT...THE WEAK RIDGING CURRENTLY OVER THE NW GULF WILL SLOWLY WEAKEN TONIGHT AS IT SHIFTS E-NE ALLOWING THE WEAK HIGH OFF THE SW COAST OF FLORIDA TO BECOME THE DOMINANT HIGH. MILD WINDS AND SEAS ARE EXPECTED ACROSS THE ENTIRE BASIN THROUGH THIS AFTERNOON BEFORE SURFACE TROUGHING BEGINS TO BUILD OVER W TEXAS AND NE MEXICO...INCREASING THE PRES GRADIENT OVER THE W AND SW GULF BETWEEN IT AND THE HIGH. LOOK FOR SELY RETURN FLOW ACROSS THE NW GULF TO INCREASE TO 15-20 KT AND NEAR 20 KT ALONG THE TEXAS COASTAL WATERS BY EVENING. AT THE SAME TIME...AN ENHANCED YUCATAN SEABREEZE WILL INCREASE WINDS TO 20 KT. YUCATAN SEABREEZE WINDS WILL CONTINUE TO FLARE TO 20 KT AT NIGHT THROUGH THE WEEKEND. A FRONTAL SYSTEM IS STILL FORECAST BY MODELS TO DRAG ALONG THE GULF COAST SAT...BUT LOW TO MID LEVEL RIDGING SHIFTING INTO WRN GULF WILL BLOCK SRN PROGRESS OF FRONT AND ALLOW IT TO DRAPE OVER THE RIDGE AND SPILL SE INTO THE NE GULF SAT NIGHT THEN SINK S FROM NEAR THE MOUTH OF THE MISSISSIPPI RIVER TO NEAR TAMPA BAY SUN EVENING. THIS IS LIKELY TO PRODUCE A BRIEF PERIOD OF LIGHT TO MODERATE NLY AND OFFSHORE FLOW OFF THE LA-MS-FL PANHANDLE COASTS SAT BEFORE VEERING ELY SUN. HOWEVER THIS FLOW WILL LIKELY NOT BE SUFFICIENT TO PROVIDE MUCH NLY PUSH FOR THE OIL WITHIN THE COASTAL ZONES THERE. SW N ATLANTIC S OF 31N W OF 55W... A 1021 MB HIGH NEAR 28N64W HAS AN ASSOCIATED RIDGE THAT EXTENDS SW THROUGH S FLORIDA. A DISSIPATING STATIONARY FRONT LIES FROM 31N78W TO SAINT AUGUSTINE FLORIDA. SCATTERED SHOWERS AND ISOLATED TSTMS ARE BECOMING REMOVED FROM THE FRONT TO THE E AND ARE LIFTING N OF 30N. THE WEAK HIGH PRES RIDGE ACROSS THE SW ATLC IS YIELDING LIGHT TO MODERATE WINDS ACROSS THIS PORTION OF THE BASIN AT 5 TO 15 KT...WITH 15 KT FLOW OCCURRING AROUND THE PERIPHERY OF THE RIDGE INVOF THE NE CARIBBEAN. A REMNANT FRONTAL TROUGH PERSISTS FROM THE CENTRAL ATLC SW ACROSS THE NRN WINDWARDS AND INTO THE SE CARIB WITH NELY TRADES AROUND 15 KT AND SEAS AT 6 FT N OF THE SHEARLINE AND E OF THE ISLANDS. THIS 15 KT FLOW ALSO SPREADS SW INTO THE NE CARIBBEAN AND W ACROSS HISPANIOLA AND INTO THE TURKS AND CAICOS. SEAS NEAR THE CENTER OF THE HIGH ARE 2-3 FT AND GROW SLOWLY TO 4-5 FT AROUND THE PERIPHERY OF THE HIGH. THE HIGH WILL MERGE WITH HIGH PRES TO ITS N BY TONIGHT AND SHIFT E AND WEAKEN NEXT FEW DAYS IN RESPONSE TO THE DEEP LAYERED RIDGE BEING NUDGED EWD BY THE UPPER TROUGH MOVING E OFF FLORIDA. THE ASSOCIATED SURFACE HIGH IS FORECAST TO WEAKEN CONSIDERABLY AS IT MOVES E...LEAVING AN ELONGATED AND NARROW RIDGE ALONG 26/27N. MEANWHILE...THE SHEAR LINE OVER THE EASTERN CARIBBEAN WILL LIFT NE INTO THE GREATER ANTILLES OVER THE WEEKEND AND INTO EARLY NEXT WEEK. THE INCREASED PRES GRADIENT BETWEEN THIS TROUGH AND THE RIDGE TO ITS N WILL ENHANCE THE ELY TRADES S OF 23N TO 15 KT...WHILE WINDS AND SEAS ARE GENERALLY MILD ELSEWHERE. CARIBBEAN SEA AND TROPICAL N ATLC... THE REMNANT FRONTAL TROUGH OVER THE TROPICAL N ATLC AND EXTENDING SW INTO THE EASTERN CARIBBEAN CONTINUES TO BE THE MAIN FOCUS OF SHOWER ACTIVITY ACROSS THE REGION...WITH SCATTERED TO LOCALLY NUMEROUS SHOWERS CURRENTLY INDICATED BY SATELLITE IMAGERY. THE 1350 UTC ASCAT PASS SHOWED NELY FLOW 15 KT WITHIN 150 NM N OF THIS SHEARLINE. THIS BOUNDARY IS EXPECTED TO WEAKEN AND SHIFT NW OVER THE NEXT FEW DAYS. LINGERING MOISTURE WILL CONTINUE TO MAKE THIS FEATURE A FOCUS FOR SHOWERS OVER THE NE CARIBBEAN THROUGH SAT AND INTO THE CENTRAL CARIBBEAN AND GREATER ANTILLES SUN AND MON. AS THE SURFACE HIGH DEVELOPS OVER THE SE GULF TONIGHT THE PRES GRADIENT WILL TIGHTEN ACROSS THE CENTRAL AND SW GULF AND THE 20 KT WIND FIELD WILL EXPAND BRIEFLY INTO THE SW GULF BEFORE THIS HIGH LIFTS N INTO THE NE GULF FRI AND COLLAPSES. THE RIDGING ALONG 26/27N OVER THE WEEKEND WILL MAINTAIN SUFFICIENT GRADIENT ALONG THE SRN CARIB TO PRODUCE 20 KT TRADES FROM THE ISLA MARGARITA AREA OFF VENEZUELA TO 80W...WHERE SEAS WILL LIKELY BUILD TO A PEAK NEAR 10 FT. OTHERWISE...TYPICAL MODERATE TRADES AND SEAS FOR MAY WILL PREVAIL ACROSS THE REMAINDER OF THE CARIB. A TROPICAL WAVE CURRENTLY MOVING INTO THE HIGH SEAS AREA NEAR 35W WILL CROSS 50W ON SUN AND MOVE INTO THE SOUTHERN PORTION OF THE TROPICAL N ATLC ZONE ON MON. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING/SCHAUER