000 AXNT20 KNHC 122356 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON SEP 12 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURES... TROPICAL STORM MARIA WAS CENTERED NEAR 21.0N 67.5W AT 12/2100 UTC OR ABOUT 360 MI...580 KM ESE OF THE SOUTHEASTERN BAHAMAS AND 800 MI...1285 KM SSW OF BERMUDA MOVING NW AT 2 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 17N-23N BETWEEN 62W-68W INCLUDING THE US/UK VIRGIN ISLANDS AND PORTIONS OF THE NORTHERN LEEWARD ISLANDS. MARIA IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 2-4 INCHES WITH ISOLATED MAXIMUM AMOUNTS OF 6 INCHES OVER THE VIRGIN ISLANDS... PUERTO RICO...AND PORTIONS OF THE NORTHERN LEEWARD ISLANDS THROUGH TUE. MARIA SHOULD TURN NORTHWARD THEN NORTHEASTWARD AS IT RECURVES AHEAD OF THE UPPER LEVEL TROUGH MOVING OFF THE EASTERN CONS SEABOARD DURING THE NEXT FEW DAYS. SEE THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED FROM 23N52W TO 11N56W MOVING W AT 15-20 KT. THE WAVE IS EMBEDDED WITHIN AN AREA OF MAXIMUM DEEP LAYER MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. LAST VISIBLE SATELLITE IMAGERY OF THE DAY SHOWED BROAD CYCLONIC TURNING IN THE LOW-LEVEL CLOUD FIELD IN THE VICINITY OF THE WAVE AXIS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 70 NM ON EITHER SIDE OF THE WAVE AXIS. TROPICAL WAVE MOVING INLAND ACROSS THE SOUTHERN YUCATAN PENINSULA AND CENTRAL AMERICA ANALYZED FROM 19N89W TO 13N84W MOVING W AT 5-10 KT. LOW TO MID-LEVEL CYCLONIC TURNING OF THE CLOUD FIELD IS NOTED ALONG THE WAVE AXIS. ALTHOUGH MOST OF THE CONVECTION IS ISLAND...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE YUCATAN CHANNEL AND THE FAR EASTERN BAY OF CAMPECHE...AS WELL AS OVER THE FAR NW BASIN FROM 15N-20N W OF 82W INCLUDING THE GULF OF HONDURAS. HEAVY RAINFALL IS EXPECTED TO CONTINUE ACROSS INTERIOR PORTIONS OF BELIZE...HONDURAS...THE YUCATAN PENINSULA...AND GUATEMALA WITH THE POSSIBILITY OF FLASH FLOODING AND MUDSLIDES...ESPECIALLY OVER HIGHER TERRAIN. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST OF SENEGAL NEAR 13N17W ALONG 8N27W TO 6N41W. A WEAK 1012 MB LOW IS EMBEDDED IN THE MONSOON TROUGH NEAR 8N34N. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS MOVING OVER THE COASTAL WATERS OF FROM LIBERIA NORTHWARD TO SENEGAL WITHIN 150 NM OFFSHORE. OTHERWISE ...SCATTERED WEAK TO MODERATE CONVECTION IS WITHIN 180 NM ON EITHER SIDE OF THE MONSOON TROUGH W OF 23W. ...DISCUSSION... GULF OF MEXICO... VERY LITTLE CONVECTION AND LOW LEVEL MOISTURE REMAINS OVER THE SE GULF THIS EVENING...ASSOCIATED TO THE PASSAGE OF AN UPPER LEVEL TROUGH MOVING ACROSS THE EASTERN CONUS...SUPPORTING A STATIONARY FRONT PRE-FRONTAL TROUGH OUT OF THE AREA. WATER VAPOR IMAGERY INDICATES THAT VERY DRY AIR IS ASSOCIATED WITH THE UPPER LEVEL TROUGH AND THAT VERY STRONG SUBSIDENCE CONTINUES TO PROGRESS ACROSS THE NORTHERN HALF OF THE GULF THIS EVENING. THIS OVERALL DRYING IS SUPPORTIVE OF A SURFACE RIDGING ACROSS THE AREA FROM A 1020 MB HIGH CENTERED NEAR 28N90W. HOWEVER...A TROPICAL WAVE MOVING INLAND ACROSS THE SOUTHERN YUCATAN PENINSULA IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE YUCATAN CHANNEL AND THE FAR EASTERN BAY OF CAMPECHE. MARINE OBSERVATIONS ACROSS THE GULF INDICATE MOSTLY NE WINDS TO 15 KT...EXPECTED TO PERSIST THROUGH LATE WEDNESDAY AS THE RIDGE REMAINS FAIRLY STATIONARY. CARIBBEAN SEA... THE BROAD CYCLONIC WIND FIELD ASSOCIATED TO TROPICAL STORM MARIA CONTINUES TO IMPACT THE EASTERN CARIBBEAN W OF 68W...DRAWING SCATTERED SHOWERS THUNDERSTORMS NORTHWARD TO THE LESSER ANTILLES AND PUERTO RICO. THE N CENTRAL AND FAR SW CARIBBEAN REMAIN FAIR THIS EVENING...WITH THE EXCEPTION OF A FEW SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE IMMEDIATE COAST OF COLOMBIA. SIMILAR ACTIVITY IS OVER THE FAR NW BASIN FROM 15N-20N W OF 82W INCLUDING THE GULF OF HONDURAS...ASSOCIATED TO A TROPICAL WAVE NOW INLAND OVER THE SOUTHERN YUCATAN PENINSULA. HEAVY RAINFALL IS EXPECTED TO CONTINUE ACROSS INTERIOR PORTIONS OF BELIZE... HONDURAS...THE YUCATAN PENINSULA...AND GUATEMALA WITH THE POSSIBILITY OF FLASH FLOODING AND MUDSLIDES...ESPECIALLY OVER HIGHER TERRAIN. ATLANTIC OCEAN... A SHARP UPPER LEVEL TROUGH IS MOVING ACROSS THE EASTERN CONUS AND SUPPORTS A STATIONARY FRONT EXTENDING ACROSS THE SE CONUS COAST INTO THE NORTHERN FLORIDA. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED ALONG 31N78W TO INLAND OVER FLORIDA NEAR LAKE OKEECHOBEE. DESPITE THE LOCATION OF THE STATIONARY FRONT AND PRE-FRONTAL TROUGH...LOW LEVEL MOISTURE CONVERGENCE ALONG WITH LIFT PROVIDED BY THE UPPER LEVEL TROUGHING IS GENERATING SCATTERED SHOWERS AND TSTMS WITHIN 200 NM E OF THE TROUGH. FARTHER TO THE SE...TROPICAL STORM MARIA IS FORECAST TO CONTINUE TRACKING W-NW AND BEGIN A MORE NORTHWARD TRACK OVER THE NEXT FEW DAYS. AN UPPER LEVEL LOW CENTERED N OF MARIA NEAR 27N65W IS ADVECTING MIDDLE TO UPPER LEVEL MOISTURE OVER A LARGE PORTION OF THE W ATLC WITH WIDELY SCATTERED SHOWERS OCCURRING FROM 22N-29N BETWEEN 58W-66W. OTHERWISE THE REMAINDER OF THE ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED NEAR 30N52W AND A 1023 MB HIGH CENTERED NEAR 28N35W. A WEAK UPPER LEVEL LOW IS BETWEEN THESE TWO HIGH NEAR 27N40W WITHOUT ANY CONVECTION. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA