000 AGXX40 KNHC 201900 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EST SAT FEB 20 2010 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... THE RIDGE N OF THE 1013 MB LOW PRES SYSTEM IN THE NW GULF OF MEXICO IS BEGINNING TO ERODE. THE 1620 UTC ASCAT PASS SHOWED WINDS PRIMARILY IN THE 15-20 KT RANGE N OF THE WARM FRONT TO THE COAST...WITH A FEW BARBS SHOWING 20 TO 25 KT CLOSER TO THE FRONT. THIS LOW AND ITS ASSOCIATED WARM FRONT WILL WEAKEN AND LIFT N AND WINDS WILL DIMINISH TO 20 KT N OF THE FRONT OVER THE NEXT 12-24 HOURS. A STRONG AND DEEP LAYERED MIDDLE-UPPER LEVEL LOW ACROSS THE WRN U.S. WILL SHIFT E-SE NEXT 24 HOURS AND SUPPORT THE DEVELOPMENT OF A SURFACE LOW ACROSS N TEXAS-OK SUN...WHICH WILL THEN MOVE NE ACROSS THE MS VALLEY AND INTO THE ERN U.S. SUN-MON AND DRAG A COLD FRONT INTO THE NW GULF SUN AFTERNOON/EVENING. THE FRONT IS FORECAST TO MOVE VERY QUICKLY ACROSS THE GULF AND REACH A PSN FROM NEAR MOBILE ALABAMA TO WESTERN BAY OF CAMPECHE MON AFTERNOON. THE ASSOCIATED SHORTWAVE ENERGY ALOFT WILL BE FORCED E INTO THE ATLC ON TUE BY ZONAL FLOW...FORCING THE BOUNDARY E OF FL BY WED MORNING. LATEST MODEL GUIDANCE INDICATES THAT THE FRONT WILL NOT BE AS STRONG COMPARED TO RECENT BOUNDARIES. AS THE STEERING FLOW BECOMES MORE ZONAL...A NEW SHORTWAVE SYSTEM DROPS INTO THE BACKSIDE OF THE TROUGH FROM THE SOUTHERN ROCKIES. THE GFS CARRIES GALE FORCE WINDS IN THE NW GULF OVER NIGHT TUE AND INTO THE SW GULF WED AS A SURFACE LOW PRES REFLECTION OF THE SHORTWAVE ENERGY DEEPENS OVER THE NW CARIBBEAN. THE ECMWF HAS TRENDED TOWARD THE GFS SOLUTION HERE BY DEVELOPING A LOW IN THE CARIBBEAN AND NOW HAS A LARGER AREA OF 30 KT WINDS IN THE WESTERN GULF BEHIND THE FRONT. HOWEVER...THE GFS ALSO DEVELOPS A WEAKER LOW OVER THE SOUTH CENTRAL GULF WED MORNING THAT MAY BE OVER ENHANCING ITS WINDS. A COMPROMISE BETWEEN THE GFS AND ECMWF IS PREFERRED. CARIBBEAN SEA... WEAKENING FRONTAL BOUNDARY STRETCHED FROM CENTRAL ATLC SW ACROSS THE EXTREME NE CARIB...THROUGH THE VIRGIN ISLANDS...TO NEAR 17N70W. SCATTERED HEAVY SHOWERS CAN BE FOUND WITHIN 90 NM S AND 20 NM N OF THE BOUNDARY. THE 1442 UTC ASCAT PASS SHOWED NELY WINDS OF 20-25 KT FUNNELING THROUGH THE MONA PASSAGE N OF THE FRONT AND LIKELY EXTENDING TO NEAR 75W. THESE WINDS WILL SLOWLY DIMINISH THROUGH THE WEEKEND AS THE RIDGE OVER FL SLIDES E AND WEAKENS...LEAVING THE STRONGEST FLOW CONFINED TO THE SW CARIB OFF OF COLOMBIA. MEANWHILE...MODERATE TRADES ACROSS THE NE CARIBBEAN WILL INCREASE TO NEAR 20 KT AND SHIFT SE SUN THROUGH WED. THE WEAK COLD FRONT PASSING THROUGH THE GULF MON IS EXPECTED TO GRADUALLY DISSIPATE AFTER IT REACHES THE YUCATAN CHANNEL TUE. THEN...LOW PRES IS EXPECTED TO DEVELOP OVER THE NW CARIBBEAN BY EARLY WED ASSOCIATED WITH THE SYSTEM DISCUSSED IN THE GULF OF MEXICO SECTION. THIS LOW WILL MOVE NE THROUGH WESTERN CUBA WED NIGHT WITH THE FRONTAL BOUNDARY LYING ROM 22N81W TO 16N84W WED NIGHT AND FROM THE WINDWARD PASSAGE TO NEAR 11N81W THU NIGHT. THIS IS A BLEND OF THE ECMWF AND GFS FORECASTS. N WINDS OF 20 TO 25 KT ARE EXPECTED BEHIND THE FRONT. SW N ATLC AND TROPICAL ATLC W OF 55W... LARGE LOW PRES SYSTEM ACROSS THE NW ATLC EXTENDS INTO FAR N PORTIONS OF THE FORECAST AREA...WHERE THE 1438 UTC ASCAT PASS NW WINDS TO 25 KT LINGERING OVER NE WATERS. THIS PATTERN CONTINUES TO GENERATE NWLY SWELL AIMED TOWARD THE CENTRAL ATLANTIC...AND LARGE SEAS ARE NOT PROPAGATING INTO THE CARIBBEAN ISLANDS AND ADJACENT WATERS AS PER RECENT FRONTAL SYSTEMS. HOWEVER...A BRIEF PULSE OF MODERATE NWLY SWELL HAS HIT THE NE CARIBBEAN REGION IN THE PAST 24 HOURS...AND IS SLOWLY FADING. COMBINED SEAS ACROSS THE NORTHERN PORTION OF THE TROPICAL N ATLC WERE 7 TO 10 FT AT 1800 UTC AND WILL BEGIN TO SLOWLY SUBSIDE TONIGHT. WINDS AND SEAS WILL GRADUALLY DISSIPATE AS LOW LIFTS OUT AND NEXT S/W MOVE DUE E ACROSS THE W ATLC. W OF 70W...WINDS ARE LIGHT AND VARIABLE N OF 23N BUT ACCELERATE TO 15-20 KT ALONG THE COAST OF CUBA AND THROUGH THE WINDWARD PASSAGE AS SUGGESTED SHIPS PINX AND 9HRJ9 ALONG THE NE COAST. THE NEXT GULF OF MEXICO FRONT IS EXPECTED TO RACE E OF FL TUE. THE MODELS AGREE ON DEVELOPING A SURFACE WAVE ALONG THE FRONT. THE ECMWF HAS BACKED OFF ON THE DEVELOPMENT OF THIS WAVE CONSIDERABLY SINCE ITS 0000 UTC RUN. NOW...THE GFS IS THE STRONGER SOLUTION. THE FORECAST CALLS FOR A BLEND OF THE TWO. THE FRONT IS EXPECTED TO LIE FROM 31N74W TO 1007 MB LOW PRES NEAR 26N76W TO 23N82W TUE MORNING. THE SURFACE WAVE SHOULD MAKE ITS WAY TO 25N65W BY WED MORNING WITH THE FRONT EXTENDING INTO THE WINDWARD PASSAGE. THE SYSTEM MOVES E OF THE AREA AND DISSIPATES BY THU. MEANWHILE...A NEW FRONT MOVES OFF THE N FL COAST WED MORNING WITHIN WINDS EXPECTED TO BUILD BEHIND IT TO 20-25 KT THROUGH THU. AGAIN...A BLEND OF THE GFS AND ECMWF SEEMS BEST. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER