000 AGXX40 KNHC 061851 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 245 PM EDT FRI APR 6 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. THE GULF OF MEXICO... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS SWEEPING ACROSS THE NORTH CENTRAL GULF OF MEXICO. THIS FEATURE IS ENTERING THE GULF OF MEXICO AT THE SAME TIME AS A DEEP LAYER TROUGH...ORIENTED ALONG THE LINE FROM THE NORTHEASTERN GULF OF MEXICO-TO-THE YUCATAN PENINSULA AND NORTHWESTERN CARIBBEAN SEA...CONTINUES ITS EASTWARD MOVEMENT. THE DEEP LAYER TROUGH MOVING THROUGH THE EASTERN GULF OF MEXICO AT THIS TIME IS PROVIDING THE ENERGY FOR THE CURRENT COLD FRONT. THE CURRENT COLD FRONT PASSES THROUGH 31N70W TO THE SOUTHERN TIP OF FLORIDA...THROUGH THE YUCATAN CHANNEL...TO THE GULF OF HONDURAS. UPPER LEVEL ANTICYCLONIC FLOW AROUND A 65W RIDGE FROM 20N NORTHWARD COVERS THE ATLANTIC OCEAN. THE SEA HEIGHTS IN THE GULF OF MEXICO STARTED OUT THIS MORNING AT 9 TO 11 FT... BUT THEY HAVE GONE DOWN RECENTLY AND ARE FROM 5 TO 7 FT NOW. THE SEAS ARE FORECAST TO STAY IN THE 6 TO 7 FT RANGE FOR SATURDAY EAST OF 90W...AND NORTH OF 27N WEST OF 90W. THE SEAS ARE FORECAST TO BUILD TO 8 TO 10 FT NORTH OF 26N EAST OF 68W BY SATURDAY. THE 07/1200 UTC GFS MODEL RUN SHOWS A 500 MB TROUGH EXTENDING FROM NORTHEASTERN FLORIDA TO KEY WEST FLORIDA TO BELIZE THAT FLATTENS OUT AND BECOMES COMPARATIVELY LESS PRONOUNCED THAN IT IS RIGHT NOW DURING THE NEXT 24 HOURS FOR SATURDAY. THE 300 MB TO 200 MB FLOW CONSISTS OF UPPER LEVEL SOUTHWESTERLY FLOW. THE COLD FRONT WILL HAVE CLEARED THE GULF OF MEXICO...AND PASS THROUGH 31N64W TO 25N69W TO 22N72W NEAR THE CAICOS ISLANDS. THE 500 MB FLOW BECOMES ZONAL BY SUNDAY. THE SURFACE WIND FLOW IN THE GULF OF MEXICO IS NORTHEASTERLY TO EASTERLY AT 20 TO 25 KT NORTH OF 26N WEST OF 90W FROM SATURDAY INTO SUNDAY. A SURFACE LOW PRESSURE CENTER OR A BROAD TROUGH STARTS TO FORM INTO SUNDAY ALONG 95W FROM 25N TO 26N...THUS THE INCREASE IN WIND SPEEDS IN THE NORTHWESTERN CORNER OF THE GULF OF MEXICO. THE SEA HEIGHTS START TO BUILD FROM SATURDAY INTO SUNDAY FROM 9 TO 11 FT NORTH OF 26N WEST OF 92W...AND THEN THE AREA OF 8 TO 10 FT SEAS SHRINKS IN SIZE FROM 25N TO 28N WEST OF 93W FROM SUNDAY INTO MONDAY. A SURFACE TROUGH IS STARTING TO ORGANIZE FROM THE LOWER RIO GRANDE VALLEY OF TEXAS TO COASTAL MEXICO NEAR 20N97W. THE SURFACE WIND FLOW IN THE GULF OF MEXICO GOES FROM EASTERLY NEAR FLORIDA TO SOUTHEASTERLY CLOSER TO 90W...AND THEN PURELY SOUTHEASTERLY WEST OF 90W. THE SAME SHORTWAVE TROUGH FROM TEXAS TO MEXICO MOVES EASTWARD FROM TUESDAY INTO WEDNESDAY AND RUNS ROUGHLY FROM 22N93W TO 26N92W BEYOND 30N92W. THE SURFACE WIND FLOW BECOMES SOUTHERLY AT 20 TO 25 KT IN THE GULF OF MEXICO NORTH OF 21N BETWEEN 83W AND 90W. A COLD FRONT PASSES THROUGH 30N90W TO 26N94W INTO MEXICO NEAR 25N99W JUST SOUTH OF THE TEXAS BORDER. THE CARIBBEAN SEA... THE GFS MODEL SHOWS A BROAD AREA OF SURFACE LOW PRESSURE ALONG THE COLOMBIA COAST NEAR 10N76W FROM THE START OF THE PERIOD TODAY ON FRIDAY UNTIL THE END OF THE PERIOD ON WEDNESDAY. THE MODEL BUILDS SOME 20 KT WINDS FROM 12N TO 14N BETWEEN 66W AND 70W ON SATURDAY AND INTO SUNDAY. THE AREA OF 20 KT EXPANDS ON MONDAY TO COVER FROM 12N TO 15N BETWEEN 66W AND 76W...STAYING THAT SAME WAY ON TUESDAY...AND SHRINKING IN SIZE A BIT BY WEDNESDAY FROM 12N TO 15N BETWEEN 68W AND 76W. THE SURFACE WIND FLOW STARTS OUT ON FRIDAY AS EASTERLY SOUTH OF 17N BETWEEN 60W AND 80W...AND VARIABLE ELSEWHERE. BROAD CYCLONIC FLOW IS SOUTH OF 17N BETWEEN 60W AND 80W ON SATURDAY AND SUNDAY...AND VARIABLE IN DIRECTION ELSEWHERE ON BOTH DAYS. EASTERLY WIND FLOW IS SOUTH OF 17N BETWEEN 60W AND 75W...BECOMING CYCLONIC SOUTH OF 17N WEST OF 75W IN RESPONSE TO THE BROAD LOW PRESSURE ALONG THE COLOMBIA COAST IN THE MODEL. THIS PATTERN STARTS ON MONDAY AND CONTINUES UNTIL WEDNESDAY. THE SEA HEIGHTS ARE FORECAST TO RISE ON MONDAY TO 6 TO 8 FT FROM 12N TO 15N BETWEEN 70W AND 78W...AND STAY THAT WAY UNTIL THE LAST HALF OF WEDNESDAY WITH ONLY 5 TO 6 FT SEAS. THE FRONT WILL CONTINUE ACROSS EASTERN CUBA NEAR 21N77W TO 18N80W NORTHWEST OF JAMAICA...WEAKENING IN THE WESTERN CARIBBEAN SEA TO 13N/14N ALONG 82W/83W. PERIODS OF NORTHERLY WINDS 15 TO 20 KT EAST OF 90W IN THE GULF OF MEXICO WILL BE EXPERIENCED UNDER BROAD SURFACE ANTICYCLONIC WIND FLOW. THE SEAS ARE FORECAST TO STAY IN THE 6 TO 7 FT RANGE FOR SATURDAY EAST OF 90W AND NORTH OF 27N WEST OF 90W. THE 500 MB FLOW BECOMES ZONAL BY SUNDAY. THE ATLANTIC OCEAN... THE 500 MB FLOW BECOMES ZONAL BY SUNDAY AND STAYS THAT WAY UNTIL TUESDAY. THE 300 MB TO 200 MB UPPER LEVEL FLOW CONTINUES TO BE SOUTHWESTERLY...WHEN THE FLOW BECOMES MORE SOUTHWESTERLY IN RESPONSE TO A SHORTWAVE TROUGH THAT IS BEGINNING TO BECOME COMPARATIVELY BETTER DEVELOPED IN MEXICO...FROM THE TEXAS BIG BEND TO 25N103W TO 20N102W.THE ATLANTIC OCEAN COLD FRONT PASSES THROUGH 25N65W TO THE HAITI/DOMINICAN REPUBLIC BORDER ALONG 20N72W...AND A WEAK TROUGH OF SOME KIND APPEARS TO CONTINUE TO 15N78W IN THE CARIBBEAN SEA. THE SEAS ARE FORECAST TO BUILD TO 10 TO 12 FT AND MAYBE HIGHER NORTH OF 28N EAST OF 75W FROM SATURDAY INTO SUNDAY. THE ATLANTIC OCEAN COLD FRONT/TROUGH WILL BE COMPARATIVELY WEAKER AND PASS THROUGH 25N65W...AGAIN TO THE HAITI/DOMINICAN REPUBLIC BORDER NEAR 20N72W...AND IT MAY OR MAY NOT EXTEND INTO THE CARIBBEAN SEA. THE GULF OF MEXICO SURFACE LOW PRESSURE CENTER REMAINS ROUGHLY IN THE AREA OF 25N94W...BUT NOT WELL ORGANIZED. ONE TROUGH MAY EXTEND TO THE EAST OF THIS LOW CENTER TO SOUTHWESTERN FLORIDA AND ONE MAY EXTEND INTO THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO. THE SEA HEIGHTS IN THE CARIBBEAN SEA ARE FORECAST TO RISE TO 6 TO 8 FT FROM 12N TO 15N BETWEEN 70W AND 78W...AND STAY THAT WAY UNTIL THE LAST HALF OF WEDNESDAY WITH ONLY 5 TO 6 FT SEAS. THE SEA HEIGHTS IN THE ATLANTIC OCEAN ARE FORECAST TO BE AT LEAST 8 FT NORTH OF 27N EAST OF 69W FROM SUNDAY INTO MONDAY. THE ATLANTIC OCEAN TROUGH MAY OR MAY NOT CONTINUE TO HANG ON...AND IF IT DOES EXIST BY TUESDAY ITS POSITION WILL NOT HAVE MOVED MUCH FROM THE MONDAY POSITION. THE SEA HEIGHTS WILL BE LOWER THAN 8 FT HALFWAY DURING THE PERIOD FROM MONDAY TO TUESDAY. SOUTHERLY WINDS AT 20 KT ALSO DEVELOP IN THE ATLANTIC OCEAN NORTH OF 27N WEST OF 73W. THE SEAS BEGIN TO BUILD TO 7 TO 8 FT NORTH OF 25N BETWEEN 85W AND 89W FROM TUESDAY INTO WEDNESDAY WITH THE 20 KT SOUTHERLY WINDS. SEAS LESS THAN 8 FT IN THE ATLANTIC OCEAN FROM TUESDAY TO WEDNESDAY. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER MT