000 AGXX40 KNHC 160716 RRA MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 215 AM EST SAT JAN 16 2010 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... THE GFS CONTINUES TO BE A FAST/EASTERLY OUTLIER WITH THE TRACK OF THE SURFACE LOW CURRENTLY IN THE NW GULF AS IT MOVES NE INTO THE SOUTHEASTERN U.S. THERE APPEARS TO BE CONVECTIVE FEEDBACK WITH THE SHORTWAVE ENERGY ON THE LEADING EDGE OF THE DEEP LAYER LOW THAT IS CAUSING THE RIDGE TO ITS E TO BREAKDOWN MORE RAPIDLY THAN THE OTHER MODELS. THIS CAUSES THE GFS TO SHIFT THE SURFACE TRACK MORE TO THE EAST. OVER THE LAST FEW DAYS...THE GFS HAS SHIFTED CLOSER TO THE MORE WESTERLY MODEL CONSENSUS...BUT IT STILL HAS NOT COME INTO THE FOLD. PMDHMD PREFERS THE CONSISTENT ECMWF SOLUTION HERE. PAST PERFORMANCE WITH SOUTHERN STREAM CUT OFF LOWS MOVING THROUGH MEXICO AND THE SW U.S. INTO THE GULF FAVORS A SLOW/WESTERLY SOLUTION AND THE ECMWF CONTINUES TO FIT THE BILL. THE GFS WIND FIELD SHIFTS THE STRONGEST WINDS FARTHER EAST THAN THE OTHER MODELS DUE TO THE FEEDBACK WHICH HAS ALSO CAUSED THE WW3 TO BE MORE PROGRESSIVE CARRYING THE HIGHEST WAVE HEIGHTS EAST IN THE GULF. THE ECMWF SHOWS GALE FORCE WINDS IN ONLY THE MIDDLE GULF OFFSHORE ZONE TODAY. THE 0240 UTC ASCAT PASS CONFIRMS GALES HAVE BEGUN IN THE MIDDLE GULF WHILE WINDS OF UP TO 41 KTS HAVE BEEN REPORTED IN THE NE QUADRANT OF THE LOW OVER THE NW GULF ZONE IN THE LAST FEW HOURS. THEREFORE...A STRONGER VERSION OF THE ECMWF WIND FIELD WAS USED FOR THE FORECAST. HIGH PRES MOVES IN RAPIDLY BEHIND THE FRONT AND SHIFTS INTO THE EASTERN GULF BY TUE/WED. CARIBBEAN AND TROPICAL N ATLC W OF 55W... A GALE WARNING IS IN EFFECT ALONG THE COAST OF COLOMBIA WITH 45 KT WINDS REPORTED AS RECENTLY AS 0300 UTC FROM SHIP V7DQ8 NEAR 12N74W. HIGH PRES BUILDING IN OVER THE CENTRAL ATLC BEHIND THE STATIONARY FRONT WEAKENING OVER PUERTO RICO WILL KEEP STRONG TRADE WINDS ACROSS CENTRAL CARIBBEAN WATERS TODAY. THIS STATIONARY FRONT CONTINUES TO BRING WARM CLOUD TOP SHOWERS TO THE DOMINICAN REPUBLIC...PUERTO RICO...AND THE VIRGIN ISLANDS WHICH MAY PERSIST FOR SEVERAL DAYS. OVER THE WEEKEND...EXPECT THE HIGH PRES TO BE FORCED SOUTHWARD BY A COLD FRONT OVER THE CENTRAL ATLC N OF THE HIGH SEAS FORECAST AREA. THE GRADIENT BETWEEN THIS HIGH AND THE LOW PRES SYSTEM OVER THE GULF OF MEXICO HAS ALREADY CAUSED WINDS TO TURN MORE SOUTHEASTERLY AND STRENGTHEN TO 25 KT IN THE NW CARIBBEAN...WITH WINDS NEAR GALE FORCE IN THE YUCATAN CHANNEL. THE PREFERRED TIMING OF THE COLD FRONT...SLOWER LIKE THE ECMWF...TAKES THE WEAKENED FRONT THROUGH THE YUCATAN CHANNEL SUN AS THE MAIN SURFACE LOW ASSOCIATED WITH THE SYSTEM RACES NORTHEASTWARD THROUGH THE SE U.S. SEE THE SECTION ABOVE FOR FORECAST REASONING ON THE GULF OF MEXICO LOW. THE FRONTAL BOUNDARY WILL WEAKEN AND LIFT NORTHWARD OVER THE NW CARIBBEAN MON AND THE DECREASED N TO S PRES GRAD WILL TAKE THE TRADE WINDS DOWN A NOTCH EARLY NEXT WEEK. SW N ATLC S OF 31N W OF 55W... 1027 MB HIGH PRES NEAR 31N64W DOMINATES THIS FORECAST AREA...WITH LIGHT WINDS E OF THE BAHAMAS N OF 27N AND INCREASING AS YOU MOVE SOUTH AWAY FROM THE FRONT TOWARD THE DISSIPATING STATIONARY FROM OVER THE NE CARIBBEAN. WINDS AREA ALSO INCREASING W OF THE BAHAMAS IN ASSOCIATED WITH THE BUILDING PRES GRAD BETWEEN THIS SURFACE HIGH AND LOW PRES DEVELOPING IN THE NW GULF OF MEXICO. LARGE DIFFERENCES IN THE FORECAST MODELS EXIST WITH THE TIMING OF THE INCREASE IN SE FLOW AHEAD OF THE SYSTEM DEEPENING OVER THE GULF OF MEXICO. AS MENTIONED IN THE GULF OF MEXICO SECTION...THE GFS APPEARS TOO FAR EAST WITH THE DEVELOPMENT OF ITS STRONGEST WINDS. A SLOWER SOLUTION LIKE THE ECMWF IS PREFERRED. THE ECMWF COMES CLOSE TO THE GALE FORCE WINDS IN THE SW N ATLC AS SUGGESTED BY THE GFS. THE UKMET SOLUTION...WHICH HAS ALSO BEEN REASONABLY CONSISTENT HERE...ALSO SHOWS A SOLID AREA OF 30 KT WINDS OFF THE N FL COAST. HAVING INHERITED A GALE WARNING FOR THE REGION...WILL NOT PULL DOWN THE GALE FLAG JUST YET. IT SHOULD BE NOTED THOUGH THAT THE MODELS HAVE GENERALLY BEEN OVERDONE WITH THE WINDS STRENGTH IN THE SOUTHERLY FLOW AHEAD OF FRONTS THIS COOL SEASON. ALSO...THE SREF AND GEFS SHOW LESS THAN A 10 PERCENT CHANCE OF GALE FORCE WINDS IN THE SW N ATLC ZONE. WARNINGS... ATLC... .GALE WARNING N OF 29N E OF FRONT OVERNIGHT SAT NIGHT...AMZ080. CARIBBEAN... .GALE WARNING FROM 10N TO 14N BETWEEN 73W AND 77W...AMZ084W AND AMZ086. GULF OF MEXICO... .GALE WARNING WITHIN 270 NM NE QUADRANT OF LOW AND ELSEWHERE N OF 23N BETWEEN 85W AND 90W...GMZ080 AND GMZ084W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER