000 AGXX40 KNHC 180627 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 230 AM EDT THU SEP 18 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO... CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... FRONTAL TROUGH EXTENDS ALONG 28N83W TO 27N90W THEN S TO 18N93W. NLY WINDS S OF 26N W OF TROUGH IN 15-20 KT RANGE PER QSCAT AND SSMI...BUT THE BUOYS NOT DETECTING THE STRONGEST WINDS. STILL EXPECT TROUGH TO DISSIPATE E OF 90W WHILE THE SEGMENT W OF 90W ORIENTATES ITSELF N-S MEANDERING ALONG 94W THROUGH THE WEEKEND. LATEST GUIDANCE A LITTLE STRONGER AND SUGGESTS A 15-20 KT WIND SHIFT ALONG TROUGH AXIS OVER THE NORTHERN WATERS. MAY ALSO SEE NE 15-20 KT OVER THE EXTREME NE WATERS MON NIGHT. CARIBBEAN AND TROPICAL ATLC... LATEST QSCAT AND SSMI DATA INDICATES A TROPICAL WAVE ALONG 70W IS MOSTLY ABOVE THE SURFACE ATTM AND NOT KICKING OFF CONVECTION EITHER. GRADIENT SUPPORTING 15-20 KT ALONG N COAST OF COLOMBIA WITH MAX SEAS 6 FT PER JASON PASS AT 0030Z. IN ANY EVENT UPPER LEVELS TO THE W COULD SUPPORT CONVECTION...SO WILL MOVE THE WAVE W AT 15 KT TO ALONG 77W FRI AND THROUGH GULF OF HONDURAS SAT AND SAT NIGHT. TROPICAL WAVE IN CENTRAL ATLC SHOULD REACH 55W AT SUNRISE SAT AND INTO E CARIBBEAN AT SUNRISE SUN...AND TO ALONG 67W MON. THIS WAVE NOT VERY IMPRESSIVE AT THE MOMENT AND NOT EXPECTED TO HAVE MUCH MARINE IMPACT AT LEAST INITIALLY. ANOTHER WAVE IN FAR E ATLC FORECAST TO REMAIN E OF 55W THROUGH LATE MON NIGHT. UPPER LOW ENHANCING IMPRESSIVE CONVECTION NE OF THE US/UK VIRGIN ISLANDS ATTM...AND UPPER LOW SEEMS TO BE SHIFTING W...SO CONVECTION MAY SHIFT OVER P.RICO LATER. A WIND SHIFT IS NOTED AT SURFACE...SO WILL MOVE MENTION LOW LEVEL TROUGH NW TROPICAL ZONE TODAY. SW N ATLC... THE PERSISTENT LOW LEVEL TROUGH EXTENDS FROM 24N78W TO 29N71W ATTM AND IS STILL EXPECTED TO WEAKEN SOME MORE AS IT CONTINUES MOVING W-NW WITH LITTLE ASSOCIATED CONVECTION. SURFACE FRONT OFF NE FL COAST WILL GET A RE-INFORCING N SURGE AND MOVE IT E MERGING FRI WITH WHATEVER REMAINS OF THE TROUGH. THE MERGED TROUGH WILL RETURN W TO THE FL COAST SAT NIGHT INTO SUN AS A RIDGE E OF TROUGH BUILDS W ALONG 29N. THE OTHER SIGNIFICANT FEATURE IS AN UPPER LOW NEAR 21N65W HAS A SURFACE TROUGH REFLECTED FROM 24N64W TO 19N63W. IMPRESSIVE CONVECTION HAS FED INTO GFS AND LATEST RUN MOVES THIS SURFACE TROUGH W THROUGH THE SE PORTION THROUGH SAT THEN THE TROUGH DISSIPATES. ELY WINDS INCREASE TO 15-20 KT E OF THE TROUGH...WHICH I THINK WOULD HAVE HAPPENED THAT FAR S OF THE RIDGE ANYWAY. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER NELSON. TROPICAL PREDICTION CENTER.