000 AXNT20 KNHC 231223 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU SEP 23 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... TROPICAL DEPRESSION LISA IS CENTERED NEAR 17.7N 29.0W AT 23/0900 UTC OR ABOUT 300 NM WNW OF THE CAPE VERDE ISLANDS MOVING E AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. ALTHOUGH THE TROPICAL CYCLONE WAS DOWNGRADED TO DEPRESSION STATUS AT 23/0900 UTC...SOME ADDITIONAL STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS AS THE SYSTEM REMAINS SOUTHWEST OF AN EASTERN ATLC UPPER LEVEL TROUGH AND WITHIN A MARGINALLY LOW VERTICAL WIND SHEAR ENVIRONMENT. A NEW BURST OF SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 120 NM OF THE CENTER IN THE EASTERN SEMICIRCLE. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. TROPICAL WAVE EXTENDS FROM 10N73W TO 17N72W MOVING W AT 10-15 KT. A 1007 MB LOW IS ANALYZED ALONG THE WAVE AXIS CENTERED NEAR 13N73W. WHILE STRONG NORTHEAST TO EASTERLY FLOW IS OCCURRING AT THE SURFACE OVER THE EASTERN AND CENTRAL CARIBBEAN SEA N OF THE LOW CENTER...MODEL GUIDANCE INDICATES A MID-LEVEL..700 MB... CIRCULATION COINCIDES WITH THE SURFACE LOW. THESE FEATURES ARE FORECAST TO TRACK WNW OVER THE WESTERN CARIBBEAN SEA THE NEXT 24-36 HOURS. SCATTERED MODERATE AND ISOLATED CONVECTION IS FROM 11N-17N BETWEEN 69W-76W. ANOTHER 90 NM WIDE BAND OF SCATTERED MODERATE AND ISOLATED STRONG CONVECTION EXTENDS FROM THE NORTHERN EXTENT OF THE TROPICAL WAVE AXIS NEAR 17N72W TO 12N62W. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N24W TO 16N22W MOVING W AT 10 KT. THE WAVE CONTINUES MOVING SLOWLY WESTWARD AND UNDER THE INFLUENCE OF LOW-LEVEL SOUTHWESTERLY MONSOONAL FLOW FEEDING INTO NEARBY T.D. LISA. ISOLATED MODERATE CONVECTION IS WITHIN 90 NM EITHER SIDE OF A LINE FROM 14N25W TO 08N32W. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 12N34W 11N53W 12N69W. SCATTERED MODERATE CONVECTION IS FROM 06N-13N BETWEEN 17W-22W...AND FROM 06N-11N BETWEEN 35W-47W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL ANTICYCLONE IS CENTERED IN THE VICINITY OF THE TEXAS BIG BEND REGION NEAR 30N101W AND EXTENDS UPPER LEVEL RIDGING EASTWARD OVER THE NW GULF TO 92W. THIS UPPER LEVEL FEATURE IS PROVIDING STABLE NORTHEASTERLY FLOW ALOFT OVER THE NW GULF THIS MORNING. A SECOND UPPER LEVEL RIDGE IMPACTS THE EASTERN GULF E OF 88W WHICH IS ANCHORED IN THE SW NORTH ATLC NEAR 22N77W. BETWEEN BOTH THESE ANTICYCLONIC REGIMES...A NARROW UPPER LEVEL TROUGH IS LOCATED OVER THE CENTRAL GULF BETWEEN 88W-92W WITH A BROAD UPPER LEVEL LOW CENTERED NEAR 25N90W. THE UPPER LEVEL TROUGH AXIS EXTENDS FROM MOBILE BAY TO THE EASTERN BAY OF CAMPECHE NEAR 20N93W. AT THE SURFACE...A RIDGE AXIS EXTENDS FROM THE W ATLC ACROSS NORTHERN FLORIDA TO THE TEXAS GULF COAST NEAR BROWNSVILLE AND IS PROVIDING MUCH OF THE -0.GUL F WITH 15-20 KT E TO SE WINDS. ISOLATED SHOWERS AND TSTMS CONTINUE ACROSS THE CENTRAL GULF WATERS FROM 21N-27N...STRETCHING FROM THE FLORIDA KEYS WESTWARD TO THE NE MEXICO GULF COAST. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED IN THE SW NORTH ATLC NEAR 22N77W EXTENDS AN UPPER LEVEL RIDGE AXIS OVER EASTERN CUBA TO THE NICARAGUA/HONDURAS BORDER NEAR 14N85W. EASTERLY UPPER LEVEL FLOW TURNS NORTHERLY OVER THE NW CARIBBEAN AND IS ADVECTING TROPICAL MOISTURE OVER MUCH OF THE WESTERN CARIBBEAN AND CUBA THIS MORNING. ATMOSPHERIC INSTABILITY AND CONVERGENT LOW-LEVEL TRADEWINDS ARE GENERATING A LARGE AREA OF SCATTERED SHOWERS AND TSTMS FROM 11N-19N BETWEEN 76W-86W. FARTHER EAST OVER THE CENTRAL CARIBBEAN...THE TROPICAL WAVE ALONG 73W AND ASSOCIATED 1007 MB LOW PRESSURE CENTERED NEAR 13N73W IS HIGHLIGHTED IN THE SPECIAL FEATURES SECTION ABOVE. THIS AREA IS QUICKLY ESCAPING THE INFLUENCE OF AN UPPER LEVEL LOW CENTERED NORTH OF PUERTO RICO NEAR 20N66W. THIS IN TURN IS PROVIDING THE TROPICAL WAVE AND LOW A MORE FAVORABLE ENVIRONMENT FOR DEVELOPING OVER THE NEXT 48 HOURS. UPPER LEVEL DIFFLUENCE S OF 17N IN THE MIDDLE TO UPPER LEVELS AND STRONG EASTERLY TRADES N OF 14N BETWEEN 65W-80W ARE GENERATING AN AREA OF SCATTERED SHOWERS AND TSTMS FROM 11N-18N BETWEEN 62W-86W. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE AXIS EXTENDS ACROSS THE W ATLC FROM CENTRAL CUBA NEAR 22N77W NE TO 28N66W. THIS UPPER LEVEL RIDGE IS DRAWING TROPICAL MOISTURE NORTHWARD ACROSS CUBA AND THE BAHAMAS TO NEAR BERMUDA. ISOLATED SHOWERS ARE PRIMARILY OVER THE STRAITS OF FLORIDA REMAINING S OF 26N W OF 77W. FARTHER NORTHEAST... ISOLATED SHOWERS STREAM W-NW TOWARD THE FLORIDA PENINSULA WITHIN 120 NM EITHER SIDE OF A LINE FROM 24N65W TO 28N80W. THE REMAINDER OF THE W ATLC IS UNDER THE INFLUENCE OF A BROAD SURFACE RIDGE LOCATED W OF 45W AND EXTENDING ACROSS THE FLORIDA PENINSULA INTO THE GULF OF MEXICO. IT REMAINS ANCHORED BY A QUASI-STATIONARY 1025 MB HIGH CENTERED NEAR 36N57W. A MID-LEVEL SHORTWAVE TROUGH IS LOCATED NORTH OF THE DISCUSSION AREA ACROSS THE CENTRAL ATLC WITH AXIS EXTENDING FROM 36N33W TO 30N39W. THIS TROUGHING SUPPORTS THE REMNANT 1009 MB LOW OF JULIA CENTERED NEAR 33N38W. WEAK SURFACE TROUGHING EXTENDS SW FROM THE LOW TO NEAR 27N41W. SCATTERED MODERATE CONVECTION IS FROM 33N-35N BETWEEN 35W-39W... WHILE ISOLATED SHOWERS LINGERING N OF 28N BETWEEN 35W-42W. ELSEWHERE OVER THE REMAINDER OF THE EASTERN ATLC...AN UPPER LEVEL LOW IS CENTERED NEAR 29N24W AND EXTENDS A TROUGH AXIS FROM THE UPPER LEVEL LOW TO 20N27W. THIS UPPER LEVEL FEATURE SUPPORTS A WEAK SURFACE TROUGH ANALYZED FROM 21N22W TO THE WESTERNMOST CANARY ISLANDS NEAR 28N18W. MOIST SOUTHWESTERLY FLOW ALOFT AND LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE SURFACE TROUGH IS GENERATING ISOLATED SHOWERS WITHIN 150 NM EITHER SIDE OF A LINE FROM 20N25W TO 32N19W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN