000 AGXX40 KNHC 051755 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 200 PM EDT THU AUG 05 2010 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. UPDATE FOR MEDR CONFERENCE CALL... MEDIUM RANGE FORECAST COORDINATED BETWEEN NHC AND HPC DECIDED ON A SPOT LOW ON THE TROPICAL WAVE OVER THE ATLC HIGH SEAS WATERS BY DAY 3...WITH A POSITION NEAR 21N44W SUN MORN AND MOVING W-NW TOWARD 22N53W BY TUE MORNING. THIS SOLUTION IS CLOSER TO THE 12Z GFS THAN TO THE 00Z ECMWF. PREVIOUS DISCUSSION --------------------------------------------------------------- GULF OF MEXICO... AN E-W RIDGE WILL EXTEND ACROSS THE NORTHERN GULF WATERS THROUGH THE PERIOD WITH HIGH PRES CENTERS OCCASIONALLY FORMING ALONG THE RIDGE AXIS MAINLY OVER THE NW GULF WATERS. EXPECTING MOSTLY 5 TO 10 KT AND SEAS 1 TO 2 FT THROUGH SUN...EXCEPT NE WINDS 15 TO 20 KT ENHANCED ALONG NW YUCATAN COAST AND E BAY OF CAMPECHE DURING EVENINGS BUILDING TO 3 FT SEAS IN BAY OF CAMPECHE TILL ABOUT MIDNIGHT EACH NIGHT. THE NORTHERN EXTENSION OF TROPICAL WAVE WILL MOVE W THROUGH THE SE AND S CENTRAL WATERS FRI AND SAT AND THE BAY OF CAMPECHE SUN THROUGH MON. THE GFS AND CMC BREAK AWAY THE NORTHERN VORTICITY CENTER FROM THE TROPICAL WAVE SUN NIGHT AND CARRY IT NW ALONG THE NE MEXICAN COAST MON. THE GFS INTENSIFIES THIS VORT CENTER AND BUILDS 15 KT WINDS AT THE SURFACE ACROSS THE SW GULF ZONE BRIEFLY ON SUN NIGHT/MON MORNING AS A RESULT. THE CMC IS NOT AS AGGRESSIVE WITH THE VORT CENTER. UNTIL THE OTHER MODELS PICK UP ON THE PATTERN OF THE GFS...WILL SIDE WITH THE ECMWF WHICH IS KEEPS WINDS IN THE 10 KT OR LESS RANGE WITH A LOWER CHANCE OF HEAVY PRECIPITATION AND A FASTER MOVING WAVE. THE MODELS DIVERGE MOST SIGNIFICANTLY OVER THE NE GULF OF MEXICO SUN AND MON WHEN THE CMC..ECMWF...AND UKMET ALL PINCH OFF A MID LEVEL LOW FROM THE COLD FRONT THAT DIVES INTO THE SE TOWARD THE NE GULF OF MEXICO. THE GFS IS WEAKER WITH THE COLD FRONT AND DOES NOT PINCH OFF SUCH A LOW. THE CMC APPEARS OVERDONE BY DEVELOPING NEAR GALE FORCE WINDS WITH THE SYSTEM. THE FORECAST WILL SIDE WITH THE MODEL CONSENSUS BY DEVELOPING A WEAK LOW CENTER OVER THE NE GULF AND RETROGRADING IT WESTWARD ACROSS THE GULF COASTAL PLAIN LIKE THE ECMWF. SW N ATLC AND TROPICAL N ATLC... MINIMAL GALE CONDITIONS LIE ON THE E SIDE OF THE REMNANTS OF TROPICAL STORM COLIN WHICH CONTINUES TO BE IDENTIFIED AS AN AREA OF LOW PRES. THE LOW IS FORECAST TO MOVE N-NW THROUGH THE EASTERN EDGE OF THE SW N ATLC ZONE WITH THE TIGHTEST GRADIENT E OF THE CENTER. THE LOW SHOULD MOVE N OF AREA SAT NIGHT TO THE SW OF BERMUDA. THERE IS A CONSIDERABLE AMOUNT OF DISAGREEMENT IN THE FORECAST ON THE STRENGTH AND TRACK OF THE TROPICAL WAVE CURRENTLY PASSING 35W AND INTO THE FORECAST AREA. THE MODELS CURRENTLY DEPICT A RIBBON OF MID LEVEL VORTICITY IN THE REGION OF THE ITCZ AND THEY AGREE ON ALLOWING THE TROPICAL WAVE TO LIFT THE ENERGY NORTHWARD AS THE WAVE PASSES THROUGH AND BREAK IT UP INTO SEVERAL VORT CENTERS. HOWEVER...THE MODELS DO NOT AGREE ON HOW MANY VORT CENTERS OR HOW STRONG THEY WILL BE. THE GFS AND UKMET CARRY A MORE ROBUST CENTER TO THE N-NW INTO THE CENTRAL ATLC COMPARED TO THE ECMWF WHICH CARRIES AN OPEN WAVE TOWARD THE NE PORTION OF THE TROPICAL N ATLC ZONE BY MON NIGHT. THE CMC IS CLOSER TO THE MORE SOUTHERLY ECMWF TRACK BUT IS SLOWER AND MORE AGGRESSIVE. CONFIDENCE IS VERY LOW IN ANY ONE SOLUTION AND THE ENSEMBLE MEANS SEEM TO RESEMBLE THE FORECASTS OF THEIR PARENT MODELS. FOR NOW...WILL KEEP AN OPEN WAVE AND BLEND THE TRACK SOMEWHERE BETWEEN THE MORE SOUTHERLY ECMWF AND NORTHERLY GFS. CARIBBEAN SEA... A TROPICAL WAVE ALONG 78W WILL MOVE W THROUGH GULF OF HONDURAS FRI NIGHT. 20 KT WINDS ARE FOUND WITHIN 300 NM E OF THE WAVE AT THIS TIME AND ARE EXPECTED TO TRACK INTO THE EASTERN CARIBBEAN TONIGHT. THE PRES GRADIENT ACROSS THE EASTERN CARIBBEAN HAS DIMINISHED WITH THE COLIN REMNANT LOW PASSING TO THE NW OF AREA. ONLY 15 KT TRADES ARE IN PLACE THERE NOW AND EXPECTED TO SPREAD INTO THE CENTRAL CARIBBEAN TONIGHT UNTIL EARLY SAT WHEN THE RIDGE FILLS IN SLIGHTLY TO THE S OF THE LOW. WINDS WILL GENERALLY BE IN THE 10 TO 15 KT RANGE THROUGH THE CARIBBEAN SAT THROUGH MON...WITH 20 KT WINDS EXPECTED IN THE USUAL PLACES ALONG THE COASTS OF COLOMBIA AND HISPANIOLA...ESPECIALLY IN THE OVERNIGHT HOURS. WARNINGS... SW N ATLC... .AMZ080...GALE WARNING N OF 23N E OF 68W... CARIBBEAN... .NONE. .GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER NELSON/SCHAUER