000 AGXX40 KNHC 050728 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 330 AM EDT MON JUL 05 2010 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC FROM 07N TO 22N BETWEEN 55W AND 65W...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... OBSERVATIONS FROM SHIPS AND PLATFORMS IN THE N CENTRAL GULF OF MEXICO AT 0000 UTC SHOWED A CLOSED LOW LEVEL CIRCULATION AROUND THE LOW PRES SYSTEM NEAR 27.7N 90.3W. SINCE THEN...THE OBSERVATIONS SHOW THE LOW LEVEL CIRCULATION HAS BECOME MORE ELONGATED...BUT WINDS TO 20 KT CONTINUE TO BE OBSERVED IN THE E SEMICIRCLE WITHIN 90 NM. THE LOW WAS ANALYZED AS 1011 MB NEAR 28.1N 90.8W AT 0600 UTC. THE LOW IS FORECAST TO GRADUALLY WEAKEN AND LIFT NW TOWARD THE SW LOUISIANA COAST WITH THE SYSTEM MOVING ONSHORE TONIGHT. THE GLOBAL MODELS ARE HAVING A HARD TIME PROPERLY DEPICTING THIS SMALL LOW...BUT THE AVAILABLE GUIDANCE IS GENERALLY IN AGREEMENT ON THE FORECAST. CONFIDENCE IS NOT GREAT IN THE DETAILS HERE...ESPECIALLY GIVEN THAT THE MODELS CONTINUE TO FORECAST THE LOW TO MAKE A NORTH TURN THAT IT KEEPS DELAYING. THEREFORE...THE FORECAST MAY BE TOO FAST TO MOVE THE SYSTEM INLAND. THE HIGHEST WAVE HEIGHT OBSERVATION WAS TO 6 FT AT 0600 UTC...BUT MAX SEAS ARE BELIEVED TO BE IN THE 7-8 FT RANGE WITHIN THE REGION OF 20 KT WINDS PROVIDED THERE IS NO OIL OVER THE WATER TO INHIBIT THE PRODUCTION OF WIND WAVES. THE LOW LEVEL BOUNDARY THAT EXTENDS E FROM THE LOW IS EXPECTED TO BE THE FOCUS OF PRECIPITATION OVER AS THE SYSTEM LIFTS NORTHWESTWARD AND MOVES INLAND. THE TROPICAL WAVE IN THE WESTERN CARIBBEAN IS EXPECTED TO PASS THROUGH THE YUCATAN CHANNEL TODAY. MUCH OF THE GLOBAL GUIDANCE ALLOWS THE MID LEVEL ENERGY ON THE NORTHERN EDGE OF THIS WAVE TO BE LURED NORTHWARD INTO THE WEAK TROUGHING ASSOCIATED WITH THE LOW LINGERING IN THE N CENTRAL GULF. THE OPERATIONAL GFS HAS BEEN MORE CONSISTENT WITH THIS SOLUTION THAN ECMWF. THE 00Z ECMWF HAS NOW TRENDED TOWARD THE GFS...ABANDONING ITS MORE CLOSED OFF SOLUTION FROM 1200 UTC THAT CARRIED A STRENGTHENING LOW CENTER NW ACROSS THE WESTERN GULF...WELL SEPARATED FROM THE TROUGHING ASSOCIATED WITH THE LOW CURRENTLY IN THE N CENTRAL GULF. NOW THAT THERE IS MORE AGREEMENT AMONG THE GUIDANCE ON ALLOWING THE TROUGHING TO THE N TO INFLUENCE THE TIMING OF AND STRENGTH OF THE SYSTEM...CONFIDENCE HAS BECOME HIGHER IN A TRACK THAT IS SLIGHTLY MORE TO THE E THAN PREVIOUSLY FORECAST. THIS SOLUTION ALSO SUGGESTS A MORE ELONGATED LOW LEVEL CIRCULATION TRACKING NORTH-NORTHWESTWARD FROM THE YUCATAN CHANNEL. HOWEVER...THE PRES GRADIENT ON THE E SIDE OF THE SYSTEM BETWEEN IT AND RIDGING OVER THE NE GULF WILL ALLOW FOR SOUTHERLY WINDS TO BUILD TO THE 25-30 KT RANGE IN THE CENTRAL GULF. THE GFS PARALLEL AND ECMWF ARE CONSIDERABLY SLOWER THAN THE OPERATIONAL GFS AND THE UKMET TO CARRY THE SYSTEM NORTHWARD. THE GFS AND UKMET MAY BE GIVING MUCH MORE CREDIT TO THE TROUGHING CURRENTLY IN THE CENTRAL GULF THAN IT WARRANTS...SO THE SLOWER SOLUTIONS SEEM MORE REASONABLE. THE PMDHMD FROM HPC PREFERS THE SLOWER SOLUTIONS. THEY RECOMMENDED THE 00Z ECMWF AND GFS ENSEMBLE MEAN SOLUTIONS WHICH SEEMS REASONABLE. SW N ATLC... A WEAK FRONT STRETCHES FROM 27N65W TO CAPE CANAVERAL. THE FRONT IS EXPECTED TO DISSIPATE OVERNIGHT MON NIGHT WITH A REMNANT TROUGH FORECAST TO MOVE NORTHWARD THROUGH THE NORTHERN BAHAMAS AND OFF THE NE FLORIDA COAST. THE UKMET AND OPERATIONAL GFS CONTINUE TO DEVELOP A SHORT LIVED LOW PRES SYSTEM HERE AND CARRY IT NORTH OF 30N WED OR WED NIGHT. THE OTHER MODELS SHOW A MORE OPEN TROUGH. THE PARALLEL GFS AND THE ECMWF CARRY MORE OF THE MID LEVEL ENERGY E TOWARD FLORIDA. SINCE MUCH OF THE GUIDANCE SUGGESTS THAT THE ENERGY ON THE NORTHERN EDGE OF THE TROPICAL WAVE CURRENTLY PASSING THROUGH THE LESSER ANTILLES WILL BE DRAWN INTO THE MID LEVEL TROUGH HERE...THESE SOLUTIONS HAVE BEEN GIVEN A LITTLE MORE WEIGHT. CONFIDENCE IS LOW HERE...BUT THE TREND SEEMS TO BE TOWARD KEEPING THE LOW LEVEL TROUGH OFFSHORE AND TOWARD A WEAKER SYSTEM WITH WINDS HELD BELOW 20 KT. CARIBBEAN SEA AND TROPICAL ATLC... THE TROPICAL WAVE ALONG 83W IN THE WESTERN CARIBBEAN HAS A WELL DEFINED MID LEVEL LOW ON ITS NORTHERN END...BUT OBSERVATIONS AT THE SURFACE SHOW AN OPEN CIRCULATION WITH WINDS IN THE 1O-15 KT RANGE. THE MODELS ARE IN GOOD AGREEMENT ON THE TRACK OF THE WAVE NW TOWARD THE YUCATAN CHANNEL TODAY...WITH 20 KT WINDS LINGERING BEHIND IT IN THE CHANNEL AND THE GULF OF HONDURAS INTO WED/THU. THE NEXT WAVE IS CURRENTLY PASSING THROUGH THE LESSER ANTILLES AND WILL MOVE THROUGH THE EASTERN CARIBBEAN TODAY...REACHING THE CENTRAL CARIBBEAN TUE AND WED AND MOVE INTO THE WESTERN CARIBBEAN BY THU. AS IT DOES...IT WILL ENHANCE NE TO E TRADES. CONFIDENCE BECOMES LOWER IN THE TIMING AND STRENGTH OF THE WINDS WITH THIS WAVE BY WED/THU WHEN THE DEPTH OF THE TROUGHING IN THE GULF OF MEXICO MAY BEGIN TO IMPACT THE WAVE. RELIED MORE HEAVILY ON THE FAVORED ECMWF/GFS ENSEMBLE BLEND AT THAT TIME. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER