000 AGXX40 KNHC 061842 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 240 PM EDT WED JUL 06 2011 SW N ATLC... THE 1134 UTC WINDSAT PASS SHOWS 20 TO 25 KT WINDS LIE E OF A TROUGH TO 72W N OF THE BAHAMAS. SHIPS LAHE2 AND WJBJ CONFIRM THESE CONDITIONS. THE FORECAST THIS AFTERNOON WILL BE UPDATED TO INCLUDE THE LATEST INFORMATION. THIS PASS IS GENERALLY STRONGER THAN THE 12Z MODEL WINDS SUGGEST. THE TROUGH IS FORECAST TO MOVE W TO 80W BY THU MORNING BEFORE GETTING CAUGHT IN THE LEADING EDGE OF A MID-LEVEL TROUGH OVER THE SE UNITED STATES. THE MODELS SUGGEST THAT THIS TROUGH AND ENERGY ASSOCIATED WITH THE NORTHERN EDGE OF THE TROPICAL WAVE IN THE ATLC WILL MERGE AS THEY MOVE INTO THE LEADING EDGE OF THE MID-LEVEL TROUGH...AMPLIFYING THE PRES GRADIENT BETWEEN THE SE UNITED STATES TROUGHING AND THE WESTWARD EXPANDING RIDGE ALONG 31W. THIS WILL RESULT IN FRESH S-SW WINDS OVER NW WATERS FRI AND SAT. THIS PATTERN WILL CONTINUE TO BRING SCATTERED SHOWERS AND TSTMS ON AND AROUND THE FL PENINSULA INTO THE WEEKEND. A TROPICAL WAVE OVER THE TROPICAL N ATLC FROM 20N53W TO 11N58W WILL MOVE THROUGH WATERS S OF 23N E OF THE WINDWARD PASSAGE THROUGH FRI. THE WAVE WILL REACH 80W SUN AND PASS THROUGH THE STRAITS OF FLORIDA. FRESH E TO SE WINDS WILL TRACK WESTWARD WITH THE SYSTEM. CARIBBEAN AND TROPICAL N ATLC W OF 55W... WEAK SURFACE TROUGH ENTERING EXTREME SE CORNER OF BASIN EXPECTED TO BRING TEMPORARY FRESH SE BREEZE AND SCATTERED TSTMS INTO BASIN S OF 14N E OF 65W. THE TROUGH WILL CONTINUE W TODAY AND TONIGHT BUT WEAKENS FURTHER AND BECOMES DIFFUSE THU. A TROPICAL WAVE OVER THE TROPICAL N ATLC FROM 20N53W TO 11N58W WILL MOVE NW INTO THE E CARIBBEAN THU...PASS 70W FRI AND MOVE THROUGH THE GREATER ANTILLES...PASSING 80W SUN. THE ISOLATED MODERATE CONVECTION CURRENTLY WITHIN ABOUT 210 NM EITHER SIDE OF THE WAVE IS EXPECTED TO BECOME MORE INTENSE AS THE SYSTEM MOVES WESTWARD...PACKING STRONGER WINDS AND MORE COVERAGE OF CONVECTION OVER THE NORTHERN CARIBBEAN. A SECOND TROPICAL WAVE LIES ALONG 41W S OF 12N. THIS WAVE WILL MOVE INTO THE TROPICAL N ATLC FRI AND THE E CARIBBEAN OVER THE WEEKEND. THE 06Z GFS...UKMET...AND NOGAPS DEVELOP A CLOSED LOW-LEVEL WIND FIELD ALONG THE WAVE NEAR 10N THU BEFORE IT REACHES THE ISLANDS. THE 12Z UKMET HAS BACKED OFF A BIT ON THE STRENGTH OF THE SYSTEM WHILE THE 12Z GFS IS REASONABLY CONSISTENT WITH ITS OLD RUN...CREATING 30 KT OF WIND ON THE N SIDE OF THE LOW. FOR NOW...THIS SOLUTION SEEMS STRONG. THE 12Z ECMWF BARELY CARRIES FRESH WINDS WITH THE WAVE AND NEVER CLOSES OFF A LOW. THE HPC-NHC MEDIUM RANGE CONFERENCE CALL PREFERRED A WEAKER SOLUTION THAN THE GFS BY KEEPING AN OPEN WAVE...BUT TRACKED THE SYSTEM AT THE SAME FORWARD SPEED AS THE GFS WHICH IS GENERALLY ON THE FAST EDGE OF THE GUIDANCE. GULF OF MEXICO... A WELL-DEFINED UPPER LEVEL VORTEX LINGERS NEAR 27N91W WITH A DRY AIR MASS AND STRONG VERTICAL SHEAR INTO SW GULF. THE VORTEX MAY SLOW AND WEAKEN THE TROPICAL WAVE OVER THE YUCATAN OVER THE NEXT DAY OR TWO AS IT STUBBORNLY HOLDS ITS PLACE UNTIL SAT WHEN THE MODELS HAVE IT MOVING W OUT OF BASIN. THE VORTEX NOT ONLY ENHANCES MOISTURE ADVECTION FROM DEEP E PAC TROPICS ACROSS YUCATAN PENINSULA INTO SE GULF OF MEXICO AND SOUTH FLORIDA BUT ALSO PROMPTS STRONG UPPER LEVEL DIVERGENCE WHICH MAKES REGION RIPE FOR INCREASE CONVECTION. THE MODELS SUGGEST SOME ENERGY WILL BE SHED FROM THE NORTHERN EDGE OF THE TROPICAL WAVE EARLY IN THE FORECAST PERIOD AND CARRIED NE INTO THE LEADING EDGE OF THE MID-LEVEL TROUGH OVER THE SE UNITED STATES. THE 06Z GFS IS STRONGER THAN THE PREVIOUS OFFICIAL FORECAST WITH SURFACE WINDS ON THE EASTERN SIDE OF THIS ENERGY WHILE THE 00Z ECMWF DEVELOPED A SURFACE LOW REFLECTION OF THIS ENERGY AND FRESH S WINDS ON ITS E SIDE. THE 12Z ECMWF HAS BACKED OFF ON THE CLOSED LOW-LEVEL CIRCULATION...BUT CONTINUE TO BRIEFLY ALLOW FOR 20 KT WINDS IN THE EASTERN GULF ZONE. THE 12Z GFS IS NOW VERY SIMILAR TO THIS SOLN AND ALSO BRIEFLY SHOWS 20 KT. THE CURRENT OFFICIAL FORECAST TRENDS TOWARD A STRONGER SOLUTION BUT STAYS AWAY FROM INCREASING WINDS TO 20 KT. THIS MAY BE RE-EXAMINED THIS AFTERNOON. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER 000 AGXX40 KNHC 061842 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 240 PM EDT WED JUL 06 2011 SW N ATLC... THE 1134 UTC WINDSAT PASS SHOWS 20 TO 25 KT WINDS LIE E OF A TROUGH TO 72W N OF THE BAHAMAS. SHIPS LAHE2 AND WJBJ CONFIRM THESE CONDITIONS. THE FORECAST THIS AFTERNOON WILL BE UPDATED TO INCLUDE THE LATEST INFORMATION. THIS PASS IS GENERALLY STRONGER THAN THE 12Z MODEL WINDS SUGGEST. THE TROUGH IS FORECAST TO MOVE W TO 80W BY THU MORNING BEFORE GETTING CAUGHT IN THE LEADING EDGE OF A MID-LEVEL TROUGH OVER THE SE UNITED STATES. THE MODELS SUGGEST THAT THIS TROUGH AND ENERGY ASSOCIATED WITH THE NORTHERN EDGE OF THE TROPICAL WAVE IN THE ATLC WILL MERGE AS THEY MOVE INTO THE LEADING EDGE OF THE MID-LEVEL TROUGH...AMPLIFYING THE PRES GRADIENT BETWEEN THE SE UNITED STATES TROUGHING AND THE WESTWARD EXPANDING RIDGE ALONG 31W. THIS WILL RESULT IN FRESH S-SW WINDS OVER NW WATERS FRI AND SAT. THIS PATTERN WILL CONTINUE TO BRING SCATTERED SHOWERS AND TSTMS ON AND AROUND THE FL PENINSULA INTO THE WEEKEND. A TROPICAL WAVE OVER THE TROPICAL N ATLC FROM 20N53W TO 11N58W WILL MOVE THROUGH WATERS S OF 23N E OF THE WINDWARD PASSAGE THROUGH FRI. THE WAVE WILL REACH 80W SUN AND PASS THROUGH THE STRAITS OF FLORIDA. FRESH E TO SE WINDS WILL TRACK WESTWARD WITH THE SYSTEM. CARIBBEAN AND TROPICAL N ATLC W OF 55W... WEAK SURFACE TROUGH ENTERING EXTREME SE CORNER OF BASIN EXPECTED TO BRING TEMPORARY FRESH SE BREEZE AND SCATTERED TSTMS INTO BASIN S OF 14N E OF 65W. THE TROUGH WILL CONTINUE W TODAY AND TONIGHT BUT WEAKENS FURTHER AND BECOMES DIFFUSE THU. A TROPICAL WAVE OVER THE TROPICAL N ATLC FROM 20N53W TO 11N58W WILL MOVE NW INTO THE E CARIBBEAN THU...PASS 70W FRI AND MOVE THROUGH THE GREATER ANTILLES...PASSING 80W SUN. THE ISOLATED MODERATE CONVECTION CURRENTLY WITHIN ABOUT 210 NM EITHER SIDE OF THE WAVE IS EXPECTED TO BECOME MORE INTENSE AS THE SYSTEM MOVES WESTWARD...PACKING STRONGER WINDS AND MORE COVERAGE OF CONVECTION OVER THE NORTHERN CARIBBEAN. A SECOND TROPICAL WAVE LIES ALONG 41W S OF 12N. THIS WAVE WILL MOVE INTO THE TROPICAL N ATLC FRI AND THE E CARIBBEAN OVER THE WEEKEND. THE 06Z GFS...UKMET...AND NOGAPS DEVELOP A CLOSED LOW-LEVEL WIND FIELD ALONG THE WAVE NEAR 10N THU BEFORE IT REACHES THE ISLANDS. THE 12Z UKMET HAS BACKED OFF A BIT ON THE STRENGTH OF THE SYSTEM WHILE THE 12Z GFS IS REASONABLY CONSISTENT WITH ITS OLD RUN...CREATING 30 KT OF WIND ON THE N SIDE OF THE LOW. FOR NOW...THIS SOLUTION SEEMS STRONG. THE 12Z ECMWF BARELY CARRIES FRESH WINDS WITH THE WAVE AND NEVER CLOSES OFF A LOW. THE HPC-NHC MEDIUM RANGE CONFERENCE CALL PREFERRED A WEAKER SOLUTION THAN THE GFS BY KEEPING AN OPEN WAVE...BUT TRACKED THE SYSTEM AT THE SAME FORWARD SPEED AS THE GFS WHICH IS GENERALLY ON THE FAST EDGE OF THE GUIDANCE. GULF OF MEXICO... A WELL-DEFINED UPPER LEVEL VORTEX LINGERS NEAR 27N91W WITH A DRY AIR MASS AND STRONG VERTICAL SHEAR INTO SW GULF. THE VORTEX MAY SLOW AND WEAKEN THE TROPICAL WAVE OVER THE YUCATAN OVER THE NEXT DAY OR TWO AS IT STUBBORNLY HOLDS ITS PLACE UNTIL SAT WHEN THE MODELS HAVE IT MOVING W OUT OF BASIN. THE VORTEX NOT ONLY ENHANCES MOISTURE ADVECTION FROM DEEP E PAC TROPICS ACROSS YUCATAN PENINSULA INTO SE GULF OF MEXICO AND SOUTH FLORIDA BUT ALSO PROMPTS STRONG UPPER LEVEL DIVERGENCE WHICH MAKES REGION RIPE FOR INCREASE CONVECTION. THE MODELS SUGGEST SOME ENERGY WILL BE SHED FROM THE NORTHERN EDGE OF THE TROPICAL WAVE EARLY IN THE FORECAST PERIOD AND CARRIED NE INTO THE LEADING EDGE OF THE MID-LEVEL TROUGH OVER THE SE UNITED STATES. THE 06Z GFS IS STRONGER THAN THE PREVIOUS OFFICIAL FORECAST WITH SURFACE WINDS ON THE EASTERN SIDE OF THIS ENERGY WHILE THE 00Z ECMWF DEVELOPED A SURFACE LOW REFLECTION OF THIS ENERGY AND FRESH S WINDS ON ITS E SIDE. THE 12Z ECMWF HAS BACKED OFF ON THE CLOSED LOW-LEVEL CIRCULATION...BUT CONTINUE TO BRIEFLY ALLOW FOR 20 KT WINDS IN THE EASTERN GULF ZONE. THE 12Z GFS IS NOW VERY SIMILAR TO THIS SOLN AND ALSO BRIEFLY SHOWS 20 KT. THE CURRENT OFFICIAL FORECAST TRENDS TOWARD A STRONGER SOLUTION BUT STAYS AWAY FROM INCREASING WINDS TO 20 KT. THIS MAY BE RE-EXAMINED THIS AFTERNOON. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER