000 AGXX40 KNHC 230635 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 235 AM EST TUE MAR 23 2010 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... THE ASCAT PASS FROM 0314 UTC SHOWED 20-25 KT NW WINDS IN THE EASTERN GULF ASSOCIATED WITH THE DEEP LAYERED LOW OVER THE MID ATLC STATES...BUT OBSERVATIONS AT 0600 UTC SHOW THAT THE WINDS HAVE DIMINISHED TO 20 KT EVERYWHERE BUT NEAR THE COAST AT TAMPA BAY AND SEAS ARE 8 TO 13 FT E OF 86W AND LESS THAN 8 FT ELSEWHERE. THE 1020 MB HIGH PRESSURE CURRENTLY OVER THE SW GULF WILL SHIFT NE ACROSS THE CENTRAL GULF TODAY WITH RETURN FLOW INCREASING AGAIN IN THE W GULF TODAY AND WED. THE 0314 UTC ASCAT PASS ALREADY AND A FEW OBSERVATIONS ALONG THE S TEXAS COAST SHOW S-SE WINDS PICKING UP TO 20 KT ALONG THE COAST W OF 96W. THE NEXT SYSTEM WILL MOVE INTO THE NW GULF ON THU. A CUT OFF LOW CURRENTLY IN THE PACIFIC OFF THE COAST OF NORTHERN BAJA CALIFORNIA WILL MEET UP WITH THE TROUGHING OVER THE PACIFIC NW CUT OFF FROM THE MAIN NORTHERN STREAM JET. LOOK FOR THE TWO TO ATTEMPT TO PHASE OVER THE SOUTHERN PLAINS ON WED WITH THE RESULTING TROUGH TURNING NEGATIVE TILT ALOFT OVER THE MISSISSIPPI VALLEY THU. THE GFS AND ECMWF NEVER FULLY PHASE THESE TWO SYSTEMS. AS A RESULT...THE SURFACE SYSTEM IS WEAKER THAN THE SYSTEM THAT SWEPT THROUGH THE GULF OVER THE WEEKEND. GALES ARE NOT EXPECTED. THE LONGWAVE PATTERN IS EXPECTED TO BECOME INCREASINGLY LESS AMPLIFIED AND MORE PROGRESSIVE. THE GFS HAS TRENDED TOWARD THE CONSISTENTLY FASTER ECMWF WITH THIS SYSTEM. BOTH MODELS TAKE THE COLD FRONT FROM THE NE GULF TO THE YUCATAN PENINSULA BY FRI AFTERNOON AND THEN CARRY THE NORTHERN PORTION OF THE FRONT QUICKLY INTO THE ATLC SAT WHILE THE PORTION OVER THE SOUTHERN GULF DISSIPATES. TROPICAL ATLC AND CARIBBEAN SEA... A COLD FRONT LIES FROM EASTERN CUBA TO ALONG THE COAST OF NICARAGUA S TO 12N. THE 0310 UTC ASCAT PASS SHOWS 20-25 KT WINDS ARE LIMITED TO W OF THE FRONT TO ABOUT 85W S OF 18N. THIS FRONT WILL RETREAT NORTHWARD AND DISSIPATE OVER THE NW CARIBBEAN BY WED MORNING. RETURN FLOW TURNS WINDS IN THE NW CARIBBEAN MORE SOUTHEASTERLY ON THU AHEAD OF THE SYSTEM PASSING INTO THE NW GULF OF MEXICO. THE GFS HAS TRENDED TOWARD CARRYING THIS COLD FRONT EASTWARD THROUGH THE GULF MORE QUICKLY...BUT DOES NOT ALLOW THE FRONT TO MOVE SOUTH INTO THE CARIBBEAN. THE ECMWF ONLY CLIPS THE NORTHERN CARIBBEAN LATE FRI NIGHT/SAT MORNING. THE MAIN SENSIBLE WEATHER IMPACT WILL BE THE CHANCE OF SHOWERS MOVING INTO THE CARIBBEAN. WINDS WILL BE 10 KT OR LESS N OF 20N IN THE CARIBBEAN REGARDLESS OF THE POSITION OF THE FRONT. ELSEWHERE IN THE CARIBBEAN...THE WINDSAT PASS FROM 0150 UTC SHOWED A SOLID AREA OF 25 TO 30 KT WINDS S OF 15N BETWEEN 70W AND 75W NEAR THE COAST OF COLOMBIA AND SEVERAL SHIP REPORTS SUGGEST 30 KT WINDS AS WELL. THE 0310 UTC ASCAT PASS SHOWS THE 20-25 KT NE WINDS EXTENDING AS FAR W AS 82W S OF 15N. STRONG EASTERLY TRADES WILL PERSIST HERE THROUGH FRI...WITH HIGHEST WINDS AND SEAS REMAINING NEAR THE COAST OF COLOMBIA. ON SAT...THE STRONG PRES GRADIENT BETWEEN THE SUBTROPICAL HIGH AND LOW PRES OVER COLOMBIA IS WEAKENED AS THE HIGH SHIFTS E AHEAD OF THE FRONT PASSING FROM THE GULF OF MEXICO INTO THE ATLC. MEANWHILE...20 KT TRADE WINDS WILL OCCUPY MUCH OF THE TROPICAL N ATLC ZONE THROUGH TOMORROW BEFORE SHIFTING SOUTHWARD WED THROUGH FRI...REMAINING S OF 14N SAT...AS THE COLD FRONT CURRENTLY OVER THE SW N ATLC MOVES EASTWARD NORTH OF THE AREA...SHOVING THE SUBTROPICAL RIDGE AND THE STRONGEST PRES GRADIENT SOUTHEASTWARD. SW N ATLC W OF 65W... THE GFS CONTINUES TO DEPICT A STRONG SURFACE WAVE ALONG THE COLD FRONT OVER THE SW N ATLC WITH GALE FORCE WINDS IN ITS SE QUADRANT IN THE FIRST 12 HOURS OF ITS FORECAST THAT IS NOT PANNING OUT COMPARED TO OBSERVATIONS. THE 0134 UTC ASCAT PASS ONLY SHOWS WINDS TO 25 KT. WHILE THE ISSUE IS NOT AS SEVERE AS THE LAST FEW RUNS WHICH DUMPED OVER 4 INCHES OF PRECIPITATION IN 6 HOURS NEAR THE LOW...THIS STILL APPEARS TO BE A CONVECTIVE FEEDBACK PROBLEM. THE ECMWF CARRIES A MORE PROGRESSIVE WAVE ALONG THE COLD FRONT AND REFRAINS FROM GENERATING GALE FORCE WINDS. THE FORECAST FAVORS THE ECMWF THROUGH TUE AS A RESULT. HIGH PRES BUILDS BEHIND THE FRONT AND WINDS DIMINISH WED...BECOMING VARIABLE THU N OF 25N AS THE NW SWELL PUSHES E OUT OF THE AREA. SOUTHERLY WINDS WILL INCREASE ACROSS THE AREA FRI AS THE PRES GRADIENT BUILDS BETWEEN THE HIGH TO THE E AND THE SYSTEM TRAVERSING THE GULF OF MEXICO TO THE W. THE FORECAST CALLS FOR THE COLD FRONT TO ENTER FAR NW WATERS FRI NIGHT AND QUICKLY TREK E THROUGH THE N PORTION OF THE FORECAST AREA ON SAT. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER