000 AXNT20 KNHC 122355 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI OCT 12 2012 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 2245 UTC. ...SPECIAL FEATURES... TROPICAL STORM RAPHAEL HAS FORMED NEAR 15.0N 63.1W AT 12/2330 UTC OR ABOUT 110 NM WSW OF DOMINICA...AND 190 NM SSE OF ST. CROIX. RAPHAEL IS MOVING NNW AT 10 KT. MINIMUM CENTRAL PRESSURE IS 1O06 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 40 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC. WATCHES AND WARNINGS HAVE BEEN PLACED OVER A GOOD PORITON OF THE EASTERN CARIBBEAN. THE SYSTEM IS CURRENTLY UNDER THE INFLUENCE OF SWLY SHEAR ALOFT...WHICH IS CAUSING THE MAJORITY OF THE CONVECTION TO BE EAST OF THE CENTER. WIDESPREAD MODERATE/STRONG CONVECTION IS FROM 9N-20N BETWEEN 54W-63W...AND FROM 16N-20N BETWEEN 63W-66W. MANY OF THE WINDWARD AND LEEWARD ISLANDS ARE AT RISK FOR HEAVY RAINFALL AND GUSTY WINDS...WHICH COULD LEAD TO FLOODING. TROPICAL DEPRESSION PATTY IS CENTERED NEAR 25.5N 72.1W AT 12/2100 UTC OR ABOUT 230 NM ENE OF THE CENTRAL BAHAMAS. PATTY IS STATIONARY AT THIS TIME. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC. THE LOW LEVEL CENTER REMAINS EXPOSED. ONLY A FEW SMALL AREAS OF SCATTERED MODERATE CONVECTION ARE FROM 24N-26N BETWEEN 68W-70W...AND FROM 26N-28N BETWEEN 70W-71W. ...TROPICAL WAVES... TROPICAL WAVE IS JUST WEST OF THE CAPE VERDE ISLANDS ALONG 16N26W TO 6N29W MOVING WEST AT 10-15 KT. THE WAVE COINCIDES WITH MAXIMUM MOISTURE VALUES SEEN IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS SE OF THE WAVE FROM 4N-9N BETWEEN 22W-27W. SCATTERED MODERATE/ISOLATED STRONG IS WEST OF THE WAVE AXIS FROM 7N-14N BETWEEN 27W-32W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SENEGAL AT 14N17W CONTINUING TO NEAR 11N24W. THE ITCZ BEGINS ON THE WEST SIDE OF A TROPICAL WAVE ALONG 10N33W TO 10N56W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN 32W-43W EXCEPT FOR A LARGER AREA OF STRONG CONVECTION FROM 7N-9N BETWEEN 39W-42W. ...DISCUSSION... GULF OF MEXICO... FAIR WEATHER CONTINUES ACROSS THE GULF OF MEXICO TONIGHT DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE COVERING THE BASIN CENTERED OVER MEXICO NEAR 21N100W. THE UPPER RIDGE SUPPORTS A BROAD SURFACE RIDGING WITH AXIS ALONG 89W. ONLY A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE NOTED IN THE FAR SW CORNER S OF 25N W OF 95W. MAINLY 10-15 KT WINDS ARE PRESENT AROUND THE RIDGE WITH SOME STRONGER WINDS NEAR THE YUCATAN PENINSULA. SURFACE RIDGING IS EXPECTED TO REMAIN ACROSS THE BASIN FOR THE NEXT COUPLE OF DAYS WITH WINDS INCREASING OVER THE EASTERN GULF. CARIBBEAN SEA... NEWLY FORMED TROPICAL STORM RAPHAEL IS IMPACTING THE EASTERN CARIBBEAN. SEE SPECIAL FEATURES ABOVE. THE REMAINDER OF THE BASIN IS UNDER MOSTLY FAIR CONDITIONS DUE TO DRY AIR SINKING INTO THE BASIN AROUND THE UPPER RIDGE IN THE GULF OF MEXICO AND WRAPPING AROUND AN UPPER LEVEL TROUGH OVER THE NW CARIBBEAN. A THIN SWATH OF MOISTURE IS AROUND THE EAST SIDE OF THE UPPER TROUGH SUPPORTING A FEW ISOLATED SHOWERS/THUNDERSTORMS FROM HONDURAS TO EASTERN CUBA. MORE SCATTERED ACTIVITY IS OVER THE LAND MASSES INCLUDING HONDURAS...NICARAGUA...EASTERN CUBA AND HISPANIOLA. ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO OVER COSTA RICA AND PANAMA ASSOCIATED WITH THE MONSOON TROUGH THAT EXTENDS FROM COSTA RICA TO NORTHERN PANAMA. AN UPPER LEVEL LOW IS SPINNING NEAR THE MONA PASSAGE HELPING PROVIDE DIFFLUENT FLOW AND SHEAR OVER THE EASTERN CARIBBEAN NEAR TROPICAL STORM RAPHAEL. ATLANTIC OCEAN... TROPICAL DEPRESSION PATTY REMAINS NE OF THE BAHAMAS SUPPORTING A FEW AREAS OF SHOWERS/THUNDERSTORMS MAINLY NE OF THE CENTER. A FEW SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO NORTH OF EASTERN CUBA. AN UPPER LEVEL TROUGH SITS WEST OF PATTY ALONG 75W PROVIDING DIFFLUENT FLOW NE OF PATTY WHERE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 27N BETWEEN 63W-68W. SHOWERS/THUNDERSTORMS ARE NORTH AND EAST OF THE FAR EASTERN CARIBBEAN ASSOCIATED WITH TROPICAL STORM RAPHAEL. SEE SPECIAL FEATURES ABOVE. AN UPPER LEVEL LOW IS WEST OF THE SYSTEM CENTERED OVER THE MONA PASSAGE. A SECOND UPPER LEVEL LOW IS TO THE NORTH OF THE SYSTEM NEAR 28N55W SUPPORTING A FEW ISOLATED SHOWERS N OF 27N BETWEEN 52W-56W. THE REMAINDER OF THE ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1026 MB HIGH CENTERED NEAR 34N41W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 44W. A BROAD UPPER LEVEL LOW IS CENTERED NEAR 24N32W SUPPORTING A FEW SHOWERS/THUNDERSTORMS NEAR THE UPPER LOW CENTER. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON