000 AGXX40 KNHC 051851 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 251 PM EDT FRI JUL 5 2013 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS. ...GULF OF MEXICO... MODEL PREFERENCE: GFS/ECMWF/OFFICIAL BLEND WITH HIGH CONFIDENCE. AN UPPER TROUGH EXTENDING FROM THE CENTRAL PLAINS TO NW PORTION OF THE GULF OF MEXICO CONTINUES TO BE THE MAIN FEATURE INFLUENCING WINDS/SEAS AND WEATHER OVER MUCH OF THE GULF TODAY. AT THE SURFACE...A WEAK TROUGH EXTENDS FROM SE LOUISIANA TO A WEAK 1012 MB LOW IN THE SW GULF AT NEAR 24N95W. THE SOUTHERLY FLOW ON THE EAST SIDE OF THE TROUGH CONTINUES TO ADVECT TROPICAL MOISTURE OVER MUCH OF THE CENTRAL AND EASTERN GULF...SUPPORTING SCATTERED TO NUMEROUS SHOWERS AND TSTMS OVER MUCH OF THE CENTRAL GULF...AND OVER PORTIONS OF THE EASTERN GULF. THE EARLIER SE-S WINDS OF 20-25 KT IN THE FAR NE GULF HAVE DIMINISHED DURING THE DAY. LATEST BUOY AND PLATFORM OBSERVATIONS INDICATED SE-S WINDS OF 15-20 KT OVER THE NORTHERN AND CENTRAL SECTIONS OF THE MIDDLE AND EASTERN GULF. A PARTIAL ASCAT PASS FROM 15 UTC THIS MORNING REVEALED SIMILAR WIND CONDITIONS OVER THOSE AREA. WINDS ELSEWHERE ARE LIGHTER...SE-S AT 10-15 KT ELSEWHERE IN THE MIDDLE AND EASTERN GULF AND N-NE AT 5-10 KT IN THE WESTERN GULF...EXCEPT SW-W 5-10 KT TO THE SW OF THE 1012 MB LOW. THE OBSERVATIONS SHOW THAT THE HIGHEST SEAS ARE IN THE 5-7 FT RANGE IN THE MIDDLE GULF PER BUOY 42001 AT 26N90W...AND 4-5 FT ELSEWHERE EXCEPT LOWER SEAS OF 1-2 FT W OF THE SURFACE TROUGH AND LOW. THE GLOBAL MODELS SUGGEST THAT THE TROUGH AND LOW WILL MOVE SLOWLY NW TOWARDS THE TEXAS COAST BY LATE SAT NIGHT INTO SUN. EVEN THE 12 UTC GFS ENSEMBLE GUIDANCE AS WELL AS THE 00 UTC ECMWF ENSEMBLE GUIDANCE SUGGEST THIS SCENARIO. EARLIER IT WAS THOUGHT THAT A MORE NORTHERN LOW ALONG THE TROUGH WOULD BE THE MAIN LOW TO APPROACH THE TEXAS...BUT NOW IT APPEARS BASED ON SATELLITE IMAGERY DURING THE MORNING AND AFTERNOON...AND LATEST MODEL GUIDANCE THAT THE LOW AT 24N95W IS BECOMING THE LOW FEATURE OF INTEREST FOR THE NEXT 36 HRS OR SO. IT APPEARS THE LOW WILL MOVE TOWARDS NE MEXICO OR EXTREME SOUTHERN TEXAS LATE SAT NIGHT AS THE TROUGH ALSO MOVES INLAND TEXAS. THE FORECAST FOR THIS SCENARIO IS SUBJECT TO CHANGES IN NEAR FUTURE FORECASTS IF GUIDANCE AND/OR SATELLITE TRENDS INDICATE SO. OTHERWISE...ATLANTIC HIGH PRES EXTENDING W ACROSS THE NE GULF WILL BUILD WESTWARD TO THE NW GULF SUN THROUGH WED WITH GENERALLY GENTLE TO MODERATE E-SE WINDS THROUGHOUT THE AREA...EXCEPT NE-E WINDS IN THE SW GULF ALONG WITH RATHER LOW SEA HEIGHTS. THE OFFICIAL GRIDS WILL REFLECT A GENERAL BLEND OF ECMWF AND GFS. SLIGHT ADJUSTMENTS WERE MADE TO WAVE HEIGHTS IN THE UPWARD TREND OVER THE MIDDLE PORTION OF THE CENTRAL GULF...AND IN THE FAR NE PORTION THROUGH EARLY SAT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC... MODEL PREFERENCE: GFS BLEND WITH PREVIOUS OFFICIAL GRIDS. HIGH CONFIDENCE. BUOY OBSERVATIONS AND SCATTEROMETER DATA CONTINUE TO SHOW FRESH TO STRONG TRADES CONTINUING OVER THE CENTRAL CARIBBEAN...FRESH E TO SE WINDS OVER THE NW CARIBBEAN...AND FRESH NE TO E WINDS OVER TROPICAL N ATLC W OF 55W. BUOY OBSERVATIONS SHOW SEAS MAXING OUT TO 8-9 FT IN THE CENTRAL AND SW PORTIONS OF THE CARIBBEAN WHERE NE-E TRADES OF 20-25 KT ARE EVIDENT. SEAS TO 8 FT ARE ALSO NOTED IN THE FAR WRN PART OF THE TROPICAL N ATLC NEAR THE WINDWARD ISLANDS. ONLY MINOR FLUCTUATIONS ARE EXPECTED WITH THESE WINDS THROUGH THE WEEKEND. A WEAK TROPICAL WAVE ANALYZED ALONG 80W FROM 12N TO 19N IS MOVING W AT 15 KT. BEING THAT THE WAVE IS ALREADY DIFFICULT TO DETECT AT THE SURFACE...THE FUTURE ATMOSPHERIC ENVIRONMENT APPEARS THAT IS WILL MAKE IT EVEN MORE DIFFICULT TO DISCERN A MORE NOTICEABLE SURFACE SIGNAL. WILL FORECAST THE WAVE TO BECOME DIFFUSE AS IT MOVES ACROSS THE REST OF THE NW CARIBBEAN SEA THROUGH SUN. AN INCREASING THE GRADIENT IN ITS WAKE SHOULD KICK UP SEAS TO 10 FT IN THE SW CARIBBEAN BY EARLY SAT BEFORE SUBSIDING TO 8 FT DURING SAT...AND BUILDING BACK UP TO 10 FT LATE MON NIGHT AND CONTINUING INTO WED. ANOTHER TROPICAL WAVE CURRENTLY E OF THE TROPICAL N ATLC WATERS ALONG A POSITION FROM NEAR 18N46W TO 10N53W IS MOVING W AROUND 15 KT. THIS WAVE WILL MOVE ACROSS THE TROPICAL N ATLC TONIGHT THROUGH SAT NIGHT...AND IS EXPECTED TO ENTERS THE EASTERN CARIBBEAN SUN. THE WAVE WILL THEN MOVE ACROSS THE REST OF THE EASTERN CARIBBEAN MON AND TUE AS IT ALSO BEGINS TO ACQUIRE A WEAK SIGNAL AT THE SURFACE. A WEAK TROUGH MID-UPPER LEVEL TROUGH PRECEDES THIS WAVE BY ABOUT 4 DEG...HOWEVER ONLY WIDELY SCATTERED SHOWERS ARE POSSIBLE WITH IT ACROSS MUCH OF THE NRN AND CENTRAL TROPICAL N ATLC. SCATTERED SHOWERS AND TSTMS ARE CURRENTLY E OF THE TROPICAL N ATLC IN ASSOCIATED WITH THE TROPICAL WAVE. HIGH PRES BUILDING IN BEHIND THIS WAVE WILL SUPPORT A PRES GRADIENT WITH TRADES AT ABOUT 15-20 KT IN ITS WAKE OVER THE EASTERN CARIBBEAN PORTION SUN...WITH WINDS INCREASING TO 20-25 KT MON THROUGH WED MAINLY OVER THE WESTERN PART OF THE EASTERN CARIBBEAN SEA WITH SEAS THERE TO AROUND 7 FT. ...SW N ATLANTIC W OF 55W INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS BLEND WITH PREVIOUS OFFICIAL GRIDS. HIGH CONFIDENCE...EXCEPT AVERAGE CONFIDENCE WITH EXACT LOCATION OF SURFACE TROUGH ASSOCIATED WITH THE UPPER LOW NEXT WEEK A WEAKENING SMALL UPPER LOW JUST E OF WEST PALM BEACH WITH A NARROW TROUGH TO ALONG 79W S TO CENTRAL CUBA IS BEING SQUEEZED BETWEEN A DEEP LAYER ANTICYCLONE MOVING WELL N OF THE AREA NEAR 36N68W AND A SHARP UPPER TROUGH OVER THE WESTERN GULF OF MEXICO. SCATTERED SHOWERS AND TSTMS ARE SUPPORTED BY THE NARROW TROUGH AND LOW...AND CONFINED TO THE SW WATERS FROM SOUTHERN PORTION OF THE BAHAMAS TO S FLORIDA. GUST WINDS ARE POSSIBLE WITH THIS ACTIVITY. AT THE SURFACE...A STATIONARY HIGH OF 1028 MB REMAINS N OF THE FORECAST WATERS AT 33N69W. THE NORTHERN PORTIONS OF WEAK TROPICAL WAVES MOVING THROUGH THE CARIBBEAN ARE MAINTAINING FRESH TO AT TIMES STRONG TRADES MAINLY S OF 22N...WITH SEAS PEAKING AT 8 FT PER BUOYS IN THE VICINITY. THE FRESH TO STRONG E WINDS ARE REACHING AS FAR W AS THE SOUTHERN BAHAMAS AND TCI. N OF 22N...WINDS AND SEAS DECREASE CLOSER INTO THE RIDGE. LITTLE CHANGE IS EXPECTED INTO EARLY NEXT WEEK WITH REGARD TO WINDS AND SEAS. THE OTHER WEATHER PRODUCING FEATURE OF INTEREST IS ANOTHER UPPER LOW TRACKING WESTWARD SITUATED NEAR 23.5N60W. THIS FEATURE WILL CONTINUE TO TRACK IN A GENERAL WESTWARD DIRECTION THROUGH LATE SUN NIGHT...AT WHICH TIME IT WILL BEGIN TO MOVE ACROSS THE CENTRAL BAHAMAS. THE GFS 250 MB GUIDANCE...PROGS THE LOW PASSING ACROSS THE BAHAMAS MON AND TUE...AND MOVE ACROSS S FLORIDA LATE TUE AND WED. COLD TEMPS ALOFT WITH THE LOW WILL MAKE THE ATMOSPHERE UNSTABLE IN ITS VICINITY. AS A RESULT...IT CAN BE EXPECTED FOR IT TO INDUCE A NEW ROUND OF SCATTERED SHOWERS AND TSTMS S OF 26N WITH THE RELATED SURFACE TROUGH AS WELL THAT WILL BE DEPICTED IN THE LATEST GRIDS. THIS ACTIVITY WILL AFFECT THE BAHAMAS AS WELL AS THE WATERS BETWEEN THE BAHAMAS AND S FLORIDA. IN THE MEDIUM RANGE PERIOD AT DAY 5 (WED)...A FAR EASTERN ATLC TROPICAL WAVE IS EXPECTED TO BE NEAR THE FAR SE PORTION OF THE AREA. MORE DETAILED INFORMATION ON THIS FEATURE WILL BE PROVIDED IN FUTURE DISCUSSIONS AND FORECASTS AS FUTURE GUIDANCE BECOMES AVAILABLE. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...NONE. GMZ019...NONE. GMZ021...NONE. GMZ023...NONE. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ .FORECASTER AGUIRRE. NATIONAL HURRICANE CENTER.