000 AXNT20 KNHC 252348 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION MATTHEW IS CENTERED INLAND OVER THE NORTHERN GUATEMALA REGION NEAR 17.4N 89.4W AT 25/2100 UTC OR ABOUT 105 MILES SOUTHWEST OF CHETUMAL MEXICO MOVING NW AT 12 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 AND MEXICO FROM 15N-19N BETWEEN 89W-92W...WITH NUMEROUS MODERATE/SCATTERED STRONG CONVECTION FROM 11N-21N BETWEEN 78W-94W. TROPICAL STORM LISA IS CENTERED NEAR 23.7N 28.4W AT 25/2100 UTC OR ABOUT 605 MILES NORTH-NORTHWEST OF THE CAPE VERDE ISLANDS MOVING N AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 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 23N-27N BETWEEN 25W-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 5N12W 6N20W 4N30W 5N40W 7N50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 18W-43W. A MESOSCALE COMPLEX IS ALONG THE WEST COAST OF AFRICA FROM SIERRA LEONE TO GUINEA-BISSAU BRINGING MODERATE TO ISOLATED STRONG CONVECTION WITHIN 100 NM OFFSHORE. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH ENTERS THE NE GULF THROUGH THE FLORIDA PANHANDLE NEAR 30N85W AND EXTENDS SW TO THE CENTRAL GULF NEAR 25N88W. THE TROUGH IS SUPPORTED BY A LONGWAVE UPPER TROUGH EXTENDING ALONG THE SE CONUS INTO THE NORTHERN GULF COAST. WEAK UPPER LEVEL CYCLONIC ROTATION IS EMBEDDED IN THE UPPER TROUGH NEAR 28N89W. ALSO...UPPER DIFFLUENCE AROUND THE TROUGH ALONG WITH SIGNIFICANT MOISTURE ACROSS THE AREA IS ENHANCING SCATTERED SHOWERS AND THUNDERSTORMS N OF 27N BETWEEN 84W-92W. SCATTERED SHOWERS AND THUNDERSTORMS ARE ALSO OFF THE MEXICO/TEXAS COAST FROM 21N-28N W OF 95W. EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE ACROSS MUCH OF THE SOUTHERN BASIN AS MOISTURE ASSOCIATED WITH T.D. MATTHEW MOVES OVER THIS REGION. CARIBBEAN SEA... SIGNIFICANT MOISTURE AND BROAD CYCLONIC FLOW ASSOCIATED WITH T.D. MATTHEW CONTINUES TO IMPACT MUCH OF THE WESTERN CARIBBEAN PRODUCING STRONG SHOWERS AND THUNDERSTORMS W OF 78W. WATER VAPOR IMAGERY SHOWS A BROAD UPPER LEVEL LOW CENTERED OVER THE FAR EASTERN CUBA ENHANCING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE CENTRAL CARIBBEAN BETWEEN 69W AND 78W. FARTHER E...A WEAK UPPER LEVEL TROUGH ACROSS THE LESSER ANTILLES IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS S OF 15N E OF 69W. EXPECT CONTINUED SHOWER AND THUNDERSTORM ACTIVITY ACROSS MUCH OF THE BASIN OVER THE NEXT SEVERAL DAYS. ATLANTIC OCEAN... SURFACE RIDGING AROUND A 1021 MB HIGH CENTERED E OF BERMUDA NEAR 34N58W DOMINATES THE SW ATLC. A FEW ISOLATED SHOWERS ARE ACROSS THE BAHAMAS AND N OF HISPANIOLA AROUND AN UPPER LEVEL LOW CENTERED OVER THE FAR EASTERN CUBA. A WEAK 1014 MB LOW IS CENTERED NEAR 29N48W SUPPORTING A FEW ISOLATED SHOWERS WITHIN 30 NM OF THE CENTER. A SECOND 1011 MB LOW IS CENTERED N OF THE ITCZ AXIS NEAR 12N34W ENHANCING SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 60 NM OF THE CENTER. T.S. LISA CONTINUES TO PRODUCE DISTURBED WEATHER OVER THE EAST ATLC. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. ALOFT...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 $$ GARCIA