000 AXNT20 KNHC 211210 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE SEP 21 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... HURRICANE IGOR IS CENTERED NEAR 44.5N 53.5W AT 21/1200 UTC MOVING NE AT 39 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 960 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. IGOR IS EMBEDDED WITHIN SOUTHWESTERLY SHEAR AS DEEP CONVECTION REMAINS DISPLACED N OF THE CENTER. SCATTERED MODERATE CONVECTION IS FROM 43N-47N BETWEEN 52W-56W. IGOR IS EXPECTED TO BECOME EXTRATROPICAL WITHIN THE NEXT 12 HOURS. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 AND THE FULL FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. TROPICAL STORM LISA IS CENTERED NEAR 17.7N 31.8 AT 21/0900 UTC OR ABOUT 460 NM WNW OF THE CAPE VERDE ISLANDS MOVING N AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. GRADUAL STRENGTHENING IS FORECAST OVER THE NEXT COUPLE OF DAYS AS THE TROPICAL CYCLONE REMAINS SOUTH OF AN EASTERN ATLC TROUGH IN A MINIMAL VERTICAL SHEAR ENVIRONMENT. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 14N-20N BETWEEN 27W-33W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 08N15W TO 13N18W TO 20N18W MOVING W AT 10-15 KT. A 1007 MB LOW IS ANALYZED ALONG THE WAVE AXIS NEAR 15N18W. CIMSS WAVETRAK MODEL GUIDANCE INDICATES A NARROW AREA OF MAXIMUM 850 MB RELATIVE VORTICITY IS ASSOCIATED WITH THE WAVE AXIS LOCATED ALONG THE W AFRICA COAST FROM 08N-18N...WHILE A SURGE OF DEEP LAYER MOISTURE IS EMERGING OFF THE COAST EVIDENT IN TPW IMAGERY THIS MORNING. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 13N-18N BETWEEN 18W-21W. TROPICAL WAVE EXTENDS FROM 09N60W TO 18N63W MOVING W AT 15 KT. ENERGY ASSOCIATED WITH THIS WAVE HAS TRACKED WESTWARD ACROSS THE TROPICAL ATLC OVER THE PAST SEVERAL DAYS AND CONTINUES TO EXHIBIT BROAD CYCLONIC LOW-LEVEL FLOW OVER THE EASTERN CARIBBEAN. TOTAL PRECIPITABLE WATER VALUES REMAIN HIGH OVER THE SE CARIBBEAN SEA AND WINDWARD ISLANDS FROM 10N-14N BETWEEN 58W-65W. CONVECTION HAS CONTINUED TO INCREASE IN AREAL COVERAGE OVER THE PAST 6 HOURS WITH SCATTERED MODERATE AND STRONG CONVECTION FROM 08N-15N BETWEEN 58W-66W. ...ITCZ... A MONSOONAL TROUGH IS ANALYZED FROM SW OF T.S. LISA NEAR 16N33W TO 12N46W. THE ITCZ AXIS THEN RESUMES NEAR 12N48W AND EXTENDS TO 13N61W. WIDELY SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 04N-11N BETWEEN 21W-30W...AND FROM 11N-14N BETWEEN 32W-37W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE EXTENDS ACROSS THE GULF OF MEXICO AND FLORIDA PENINSULA STEMMING FROM AN UPPER LEVEL ANTICYCLONE CENTERED OVER NW MEXICO NEAR 25N108W. THIS ANTICYCLONE IS PROVIDING THE GULF WITH NW TO N UPPER LEVEL FLOW AND PRIMARILY STABLE CONDITIONS ALOFT WHILE SUPPORTING BROAD SURFACE RIDGING. HOWEVER...AN EMBEDDED SHORTWAVE TROUGH LOCATED OVER SE ALABAMA EXTENDS A WEAK MID-LEVEL TROUGH AXIS FROM THE FLORIDA PANHANDLE NEAR 30N87W TO THE NW GULF NEAR 27N94W. THIS MID-LEVEL TROUGHING IS GENERATING A BROAD AREA OF WIDELY SCATTERED SHOWERS N OF 22N W OF 87W DUE TO LOW-LEVEL SOUTHEASTERLY WARM AIR ADVECTION AND WEAK SURFACE TROUGHING EXTENDING ALONG THE TEXAS AND MEXICO GULF COASTS. CARIBBEAN SEA... WHILE UPPER LEVEL NORTHERLY FLOW IS OVER THE NW CARIBBEAN AND PORTIONS OF CENTRAL AMERICA W OF 82W...AN UPPER LEVEL TROUGH EXTENDS FROM THE W ATLC ACROSS CENTRAL CUBA TO NEAR 13N83W. DRY AIR ALOFT ASSOCIATED WITH THE TROUGHING IS PROVIDING FAIR CONDITIONS OVER CUBA THIS MORNING...HOWEVER AS THE TROUGH CONTINUES TO DIP INTO THE WESTERN CARIBBEAN WATERS...ISOLATED SHOWERS ARE FROM 14N-20N BETWEEN 75W-85W. FARTHER EAST...AHEAD OF THE TROUGH AXIS...MOIST SW UPPER LEVEL FLOW IS GENERATING AN EXTENSIVE AREA OF LOW-LEVEL CLOUDINESS AND ISOLATED SHOWERS AND TSTMS FROM 12N-20N BETWEEN 69W-75W...INCLUDING MOST OF HISPANIOLA. THIS AREA STRETCHES NORTHWARD INTO THE SW NORTH ATLC BETWEEN 66W-76W WHERE A WEAKNESS IN THE SUBTROPICAL RIDGE IS LOCATED. THE REMAINDER OF THE EASTERN CARIBBEAN IS INFLUENCED BY THE TROPICAL WAVE ALONG 63W THAT CONTINUES MOVING WESTWARD GENERATING SCATTERED SHOWERS AND TSTMS OVER THE LESSER ANTILLES AND AN AREA S OF 15N E OF 66W. ANOTHER AREA OF INTEREST IN THE CARIBBEAN SEA BASIN IS A SURFACE TROUGH ANALYZED FROM 14N76W TO THE COAST OF NICARAGUA NEAR 13N84W AND INLAND OVER INTERIOR PORTIONS OF CENTRAL AMERICA TO SOUTHERN GUATEMALA NEAR 14N91W. THIS MONSOON TROUGH DENOTES THE BOUNDARY BETWEEN SOUTHWESTERLY FLOW ORIGINATING IN THE E PACIFIC REGION AND EAST-NORTHEASTERLY FLOW OVER THE WESTERN CARIBBEAN. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE PRIMARILY S OF 14N W OF 75W. ATLANTIC OCEAN... A SHARP UPPER LEVEL TROUGH AXIS EXTENDS ACROSS THE W ATLC FROM 32N69W TO CENTRAL CUBA NEAR 22N80W AND INTO THE WESTERN CARIBBEAN SEA. THIS UPPER LEVEL TROUGHING IS SUPPORTING A SURFACE TROUGH ANALYZED FROM 32N60W TO 24N70W WITH THE ADVECTION OF MID-LEVEL MOISTURE AND POSSIBLE ISOLATED SHOWERS FROM 18N-23N BETWEEN 65W-73W. THE TROUGHING ALSO COINCIDES WITH AN OVERALL WEAKNESS IN THE SUBTROPICAL RIDGE BETWEEN 60W-70W...HOWEVER WEATHER CONDITIONS IN THIS AREA REMAIN FAIRLY BENIGN. ELSEWHERE ACROSS THE CENTRAL AND EASTERN ATLC...A SURFACE RIDGE DOMINATES ANCHORED BY A 1016 MB HIGH CENTERED NEAR 27N45W. THE RIDGE AXIS EXTENDS FROM THE HIGH CENTER E-NE TO 32N36W AND FROM THE HIGH CENTER SW TO 23N64W. THIS SURFACE HIGH IS SUPPORTED ALOFT BY A LARGE UPPER LEVEL ANTICYCLONE CENTERED NEAR 31N49W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN