000 AGXX40 KNHC 071900 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 300 PM EDT WED SEP 07 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... BOTH BUOY DATA AND LATEST SATELLITE IMAGERY SHOW A STATIONARY FRONT EXTENDING FROM N CENTRAL FLORIDA SW TO 24N87W AND TO A 1007 MB LOW IN THE BAY OF CAMPECHE NEAR 20N93W. A PARTIAL ASCAT FROM 1510 UTC THIS MORNING CORROBORATED WELL WITH THE FRONTAL PLACEMENT. VISIBLE SATELLITE IMAGERY SHOWS EXPOSED LOW LEVEL CLOUDS E AND NE OF THE LOW IN THE EASTERN PORTION OF THE ZONE. THE LATEST BUOY OBSERVATIONS ARE REVEALING NE 15 KT WINDS TO THE NW OF THE FRONT. BUOY 42055 IN THE SW GULF AT 22.2N94.0W HAS NE 25 KT WITH COMBINED SEAS OF 9 FT. TO THE SE OF THE FRONT WINDS ARE S-SW 10-15 KT...EXCEPT WITHIN 75 NM SE OF THE FRONT W OF 86W WHERE HIGHER WINDS IN THE RANGE OF 15-20 KT ARE NOTED PER THE ASCAT PASS. SATELLITE IMAGERY ALSO SHOWS NUMEROUS SHOWERS AND TSTMS ALONG AND WITHIN 150 NM SE OF THE FRONT W OF 83W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 150 NM OF THE LOW IN THE SW SEMICIRCLE...AND WITHIN 120 NM OF THE LOW IN THE NE SEMICIRCLE. WITH THE UPPER TROUGH THAT STRETCHES FROM THE EASTERN U.S. SW TO THE MIDDLE GULF SHEARING OUT...THE FRONT WILL REMAIN STATIONARY THROUGH THU NIGHT WHILE WEAKENING AND EVENTUALLY DISSIPATING FRI INTO SAT. GLOBAL MODELS PICK UP ON THE LOW IN THE BAY OF CAMPECHE...BUT THE HIGHLY UNCERTAIN ASPECT OF THIS FORECAST WILL BE JUST HOW STRONG AND EXACTLY WHERE WILL THE LOW TRACK LATER THIS WEEK. PRESENTLY...THE LOW SITS UNDERNEATH THE EASTERN PERIPHERY OF AN UPPER ANTICYCLONE LOCATED OVER CENTRAL MEXICO. NLY FLOW ALOFT IS IMPINGING ON THE LOW SHEARING THE CONVECTIVE ACTIVITY TO THE NE AND E OF THE LOW. THE LATEST GFS KEEPS THE LOW NEARLY STATIONARY THROUGH FRI NIGHT...THEN TAKES IT WESTWARD TO INLAND MEXICO JUST S OF TAMPICO EARLY SUN. THE OTHER MODELS...FOR THE MOST PART...HOLD IT IN THE SW GULF THROUGH ABOUT THU NIGHT THEN TAKE IT IN A NLY DIRECTION SIMILAR TO THE RECENT LOW THAT EVENTUALLY DEVELOPED INTO TROPICAL STORM LEE. FOR THE SHORT TERM...THE MAIN ISSUE TO CONCENTRATE ON IS THE STRONG PRES GRADIENT MAINLY TO THE NW OF THE LOW AND FRONT WHERE HIGH PRES RIDGING NOSES SWD OVER EASTERN MEXICO. THIS WILL CONTINUE TO RESULT IN WINDS OF 20-30 KT WITHIN 180-240 NM IN THE W SEMICIRCLE...AND WITHIN ABOUT 120-150 NM IN THE E SEMICIRCLE OF THE LOW THROUGH IN THE SW GULF THROUGH SUN...AND THEN POSSIBLY INTO THE SOUTHERN PART OF THE NW GULF ZONE MON. WITH THE LONG DURATION OF THESE WINDS IN THE SW GULF SEAS ARE EXPECTED TO BUILD UP TO 12 FT THROUGH AT LEAST SUN WITHIN THE RADII OF 20-30 KT WINDS...BUT COULD BE MUCH HIGHER AS ALL WAVEWATCH GUIDANCE SUGGEST DEPENDING ON JUST HOW STRONG THE LOW BECOMES...OR INTENSIFIES INTO A TROPICAL CYCLONE AS MODELS SUGGEST. THE POTENTIAL FOR IT TO BECOME A TROPICAL CYCLONE WILL BR MENTIONED IN THE FORECAST THROUGH DAY 5. ELSEWHERE... CONDITIONS ARE EXPECTED TO REMAIN LIGHT AS A RIDGE REMAINS JUST NE OF THE GULF. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... A TROPICAL WAVE ALONG 59W FROM 12N TO 19N IN BETWEEN HURRICANE KATIA AND TROPICAL STORM MARIA IS MOVING WNW AT 17 KT. THE WAVE WILL PASS ACROSS THE LEEWARD ISLANDS AND NE CARIBBEAN TONIGHT INTO THU MORNING...WITH THE SOUTHERN PORTION MOVING ACROSS THE EASTERN CARIBBEAN THROUGH SAT...THEN APPROACH 75W SUN AND NEAR 79W MON. THE EASTERN EDGE OF AN ASCAT PASS FROM 1310 UTC THIS MORNING SHOWED NE-E 15-20 KT WINDS ACROSS THE NORTHERN PORTION OF THE WAVE AXIS. SATELLITE IMAGERY SHOWS SCATTERED SHOWERS AND TSTMS WITHIN 180 NM NW OF THE WAVE N OF 16N. MAJOR UPCOMING CHANGES WITH RESPECT TO WINDS AND SEAS EXPECTED IN THE TROPICAL N ATLC WILL BE ATTRIBUTE TO RECENTLY UPGRADE TROPICAL STORM MARIA LOCATED IN THE FAR EASTERN ATLC NEAR 13.0N 42.0W 1003 MB AT 1500 UTC THIS MORNING MOVING W AT 20 KT. MARIA IS FORECAST TO SLOWLY INTENSIFY AS IT ENTERS THE FAR EASTERN PORTION OF THE TROPICAL N ATLC BY LATE THU NIGHT...THEN REACH NEAR 15.5N 56.5W FRI MORNING...AND APPROACH THE LEEWARD ISLANDS BY LATE FRI...AND REACH TO NEAR 17.5N 62.0W BY EARLY SAT AND TO JUST NW OF THE TROPICAL N ATLC BY EARLY SUN. ELSEWHERE...LIGHT WINDS AND SEAS SHOULD VARY VERY LITTLE THROUGH MON. SW ATLC S OF 31N W OF 55W... THE MAIN FEATURE IS HURRICANE KATIA CENTERED NEAR 29.2N 68.8W 976 MB MOVING NW AT 9 KT PER THE NHC ADVISORY ISSUED AT 1500 UTC THIS MORNING. MAXIMUM WINDS WERE 75 KT GUSTS TO 90 KT. WITH IT... A VERY LARGE RADII OF 20-33 KT EXTENDS OUTWARD FROM KATIA TO WITHIN 300 NM OF KATIA AND 450 NM IN THE NE QUADRANT. THE ASCAT PASS FROM JUST PAST 15 UTC THIS MORNING CAPTURED A GOOD PORTION OF THIS WINDS. ALONG WITH THESE WINDS...LARGE SEAS IN VERY LARGE SWELLS ARE PROPAGATING OUTWARD FROM KATIA WITH BUOY 41047 AT 27.5N71.6W SHOWING SEAS AS HIGH AS 12-15 FT. KATIA IS FORECAST TO WEAKEN SLIGHTLY AS IT REACHES TO 30.6N 69.6W EARLY TONIGHT ...THEN MOVE TO JUST N OF AREA TO 32.8N 69.8W THU MORNING...AND TO 35.4N 69.0W BY FRI MORNING. HIGH PRES WILL BUILD ACROSS THE AREA IN THE WAKE OF KATIA THU THROUGH AT LEAST EARLY SAT...THEN BEGIN TO LIFT NWD IN ADVANCE OF NEWLY FORMED TROPICAL STORM MARIA IN THE EAST ATLANTIC. MARIA IS FORECAST TO MOVE INTO THE FAR SE PORTION N OF PUERTO RICO BEGINNING LATE SAT THROUGH MON. AHEAD OF MARIA...THE NORTHERN PORTION OF A TROPICAL WAVE CURRENTLY ALONG 59W S OF 20N IS FORECAST TO MOVE NW ACROSS THE NE CARIBBEAN SEA AND PUERTO RICO THROUGH THU...THEN TRACK MORE NW THROUGH THE SE BAHAMAS FRI AND CENTRAL BAHAMAS SAT. THE WAVE IS EXPECTED TO DAMPEN OUT AS IT POSSIBLY APPROACHES ANDROS ISLAND AND THE VICINITY OF S FLORIDA LATE SAT INTO SUN WITH LIGHT WIND CONDITIONS. WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN AND TROP N ATLC... .AMZ087...TROPICAL STORM CONDITIONS EXPECTED N OF 15N FRI AND SAT. SW N ATLC... .AMZ080...HURRICANE WARNING N OF 27N E OF 71W. .AMZ080...TROPICAL STORM CONDITIONS EXPECTED S OF 22N E OF 69W SAT AND SUN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER CHRISTENSEN