000 AGXX40 KNHC 181826 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 230 PM EDT THU AUG 18 2011 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... AN E-W RIDGE WILL MEANDER ACROSS THE N WATERS THROUGH THE PERIOD WITH LIGHT AND VARIABLE WINDS NEAR THE RIDGE AXIS. EASTERLY WINDS WILL PULSE AT 10 TO 15 KT ELSEWHERE WITH THE DIURNAL EFFECTS EACH EVENING ALONG THE NW YUCATAN COAST. NHC CURRENT THINKING IS THAT THE DEVELOPING LOW PRESSURE OVER THE W CARIBBEAN WILL TRACK WELL INLAND OVER CENTRAL AMERICA SUN AND MON WITH ONLY THE NORTHERN EXTENSION OF THE ASSOCIATED TROPICAL WAVE PASSING THROUGH THE BAY OF CAMPECHE. SOME SE SWELL WILL MIGRATE NW THROUGH THE YUCATAN CHANNEL AS EARLY AS SAT MORNING. N ATLC S OF 31N W OF 55W... A RIDGE EXTENDS ROUGHLY FROM BERMUDA TO NE FLORIDA. AN APPROACHING SHORT WAVE TROUGH WILL MAINTAIN THE GRADIENT INTO FRI NIGHT...THEREAFTER THE RIDGE WILL GRADUALLY WEAKEN THROUGH MON. WINDS WILL BEGIN TO BACK TO THE NE AND INCREASE OVER THE WATERS S OF 25N BETWEEN 65W AND 55W SAT NIGHT AS A SIGNIFICANT TROPICAL WAVE APPROACHES THE AREA FROM THE SE. GFS GUIDANCE IS VERY AGGRESSIVE. I TONED DOWN THE STRENGTH OF THE WINDS AND GENERALLY FORECAST NE TO E WINDS 15 TO 20 KT OVER WATERS S OF 27N ON SUN INCREASING TO 20 TO 25 KT NEAR TROPICAL WAVE AXIS. EXPECT INITIAL SEAS SUN AT 4 TO 7 FT TO BUILD 7 TO 11 FT TO THE E OF WAVE AXIS SUN NIGHT...AND 8 TO 12 FT ON MON. EXPECT SCATTERED TSTMS NEAR WAVE AXIS...AND ANY ASSOCIATED SURFACE LOW THAT DEVELOPS ALONG THE WAVE. CARIBBEAN SEA AND TROPICAL ATLC S OF 22N W OF 55W... WELL DEFINED MID LEVEL CYCLONIC TURNING CONTINUES ALONG A TROPICAL WAVE OVER THE W CARIBBEAN ALONG 80W. RECON IS INVESTIGATING THE AREA AS A SURFACE LOW IS EXPECTED TO FORM IN THE VICINITY OF 16N81.5W BY SUNSET TODAY. NHC GUIDANCE MOVES THE LOW PRES W THROUGH THE GULF OF HONDURAS TO NEAR 16N83W AT SUNRISE FRI...NEAR 16.5N85W FRI EVENING...NEAR 17N87W SUNRISE SAT...AND INLAND NEAR 17N88W SAT EVENING WITH POSSIBILITY OF TROPICAL CYCLONE DEVELOPMENT. WILL FORECAST 20 TO 30 KT NEAR LOW AND A NE TO SE WINDS SHIFT AT 15 TO 20 KT ELSEWHERE ALONG AND E OF THE WAVE AXIS. A TROPICAL WAVE IN THE CENTRAL ATLC WILL W REACH ALONG 55W SAT...AND ENTER THE NE CARIBBEAN SUN REACHING ALONG 68W MON. GFS GUIDANCE IS MOST AGGRESSIVE AND DEVELOPS A STRONG SURFACE LOW ALONG THE SAT. DEPICTED A 1008 MB SURFACE LOW AT 16N53W SAT MORNING AND A 1006 MB LOW AT 16N61.5W SUNRISE SUN...AND NEAR 18N67.5W SUNRISE MON...WITH CYCLONIC WINDS OF 20 TO 25 KT. WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN AND TROPICAL N ATLC... .NONE. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER NELSON