000 AXNT20 KNHC 251752 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT SEP 25 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION MATTHEW IS CENTERED NEAR 16.7N 88.6W AT 25/1800 UTC OR ABOUT 52 NM SSW OF BELIZE CITY MOVING WNW AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. RAINFALL ASSOCIATED WITH MATTHEW CONTINUES TO BE THE MAIN THREAT TO CENTRAL AMERICA AND IS LIKELY TO CONTINUE EVEN AFTER MATTHEW HAS DISSIPATED. TOTAL RAIN ACCUMULATIONS OF 6 TO 10 INCHES OVER PORTIONS OF HONDURAS...GUATEMALA...BELIZE AND ISOLATED MAXIMUM AMOUNTS OF UP TO 15 INCHES ARE POSSIBLE OVER THE NEXT COUPLE OF DAYS. THESE RAINS COULD PRODUCE LIFE THREATENING FLASH FLOODS AND MUD SLIDES. CURRENTLY...NUMEROUS STRONG CONVECTION IS OVER GUATEMALA FROM 15N-17N BETWEEN 88W-92W...WITH NUMEROUS MODERATE/SCATTERED STRONG CONVECTION FROM 11N-19N BETWEEN 88W-94W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS ALSO E OF THE SYSTEM FROM 7N-21N BETWEEN 81W-87W. TROPICAL STORM LISA IS CENTERED NEAR 22.7N 28.2W AT 25/1500 UTC OR ABOUT 470 NM NNW OF THE CAPE VERDE ISLANDS MOVING N AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 990 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. LISA REMAINS SMALL WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 21N-24N BETWEEN 26W-30W...AND FROM 25N-27N BETWEEN 27W-30W. LISA IS ALREADY EXPERIENCING UPPER LEVEL WLY SHEAR WHICH IS FORECAST TO CONTINUE...AND WILL FURTHER WEAKEN LISA OVER THE NEXT SEVERAL DAYS. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 6N12W 6N21W 3N32W 6N45W 7N52W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 14W-35W. ...DISCUSSION... GULF OF MEXICO... MAINLY ELY SURFACE FLOW OF 10-15 KT COVERS MUCH OF THE GULF OF MEXICO WITH SOME CYCLONIC FLOW AROUND A WEAK SURFACE TROUGH EXTENDING FROM THE FLORIDA PANHANDLE NEAR 31N84W INTO THE CENTRAL GULF TO NEAR 23N91W. THE TROUGH IS SUPPORTED BY A SHORTWAVE UPPER TROUGH EXTENDING FROM THE FLORIDA BIG BEND TO NEAR 25N94W. UPPER DIFFLUENCE AROUND THE TROUGH ALONG WITH SIGNIFICANT MOISTURE ACROSS THE AREA IS ENHANCING SCATTERED SHOWERS/THUNDERSTORMS FROM 25N-30N BETWEEN 83W-92W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO OFF THE TEXAN COAST FROM 26N-29N BETWEEN 91W-97W...AND WITHIN 120 NM OF THE ERN MEXICAN COAST. ELSEWHERE ALOFT...MAINLY ANTI-CYCLONIC FLOW IS ACROSS THE BASIN CENTERED OVER CENTRAL MEXICO NEAR 22N98W. EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE ACROSS MUCH OF THE BASIN AS MOISTURE ASSOCIATED WITH T.S. MATTHEW PUSHES NWD...AND A FRONTAL BOUNDARY AND ASSOCIATED LONGWAVE UPPER TROUGH CURRENTLY OVER THE ERN CONUS DIPS S. CARIBBEAN SEA... T.S. MATTHEW CONTINUES TO IMPACT MUCH OF CENTRAL AMERICA BRINGING STRONG SHOWERS/ISOLATED THUNDERSTORMS S OF 21N W OF 80W. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. ALOFT...UPPER LEVEL RIDGING IS ACROSS THE NW CARIBBEAN AROUND AN UPPER LEVEL ANTI-CYCLONE CENTERED OVER CENTRAL MEXICO. AN UPPER LEVEL TROUGH IS ACROSS GUATEMALA ASSOCIATED WITH MATTHEW. A SECOND UPPER LEVEL TROUGH IS ACROSS THE CENTRAL CARIBBEAN CENTERED OVER HAITI PRODUCING SCATTERED SHOWERS/THUNDERSTORMS FROM N OF COLOMBIA TO 20N BETWEEN 67W-78W. FARTHER E...A WEAK UPPER LEVEL TROUGH ACROSS THE LESSER ANTILLES IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS S OF 13N BETWEEN 61W-65W...AND FROM 15N-16N BETWEEN 58W-62W. EXPECT CONTINUED SHOWER ACTIVITY ACROSS MUCH OF THE BASIN OVER THE NEXT SEVERAL DAYS. ATLANTIC OCEAN... SURFACE RIDGING AROUND A 1022 MB BERMUDA HIGH CENTERED NEAR 34N59W DOMINATES THE SW ATLC. A FEW ISOLATED SHOWERS ARE ACROSS THE FLORIDA PENINSULA...AND N OF HISPANIOLA AROUND AN UPPER LEVEL LOW CENTERED OF HAITI. A WEAK 1013 MB LOW IS CENTERED NEAR 30N48W SUPPORTING A FEW ISOLATED SHOWERS WITHIN 60 NM OF THE CENTER. A SECOND 1011 MB LOW IS CENTERED N OF THE ITCZ AXIS NEAR 12N34W ENHANCING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 100 NM OF THE CENTER. TO THE NE...T.S. LISA CONTINUES TO PRODUCE DISTURBED WEATHER. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. ALOFT...AN UPPER LEVEL TROUGH IS N OF THE BAHAMAS EXTENDING INTO THE NW ATLC. AN UPPER LEVEL RIDGE COVERS THE CENTRAL ATLC CENTERED NEAR 35N57W. A LONGWAVE UPPER TROUGH IS TO THE E EXTENDING FROM THE AZORES TO NEAR 24N49W. UPPER LEVEL RIDGING COVERS THE FAR ERN ATLC CENTERED OVER THE CAPE VERDE ISLANDS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON/MONTALVO