000 WTNT45 KNHC 250244 TCDAT5 TROPICAL STORM MATTHEW DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152010 1100 PM EDT FRI SEP 24 2010 SURFACE OBSERVATIONS AND DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT MATTHEW HAS NOT WEAKENED MUCH THIS EVENING. PUERTO LIMPERA IN EASTERN HONDURAS REPORTED A 10-MINUTE WIND OF 38-40 KNOTS AT 2300 AND 0000 UTC...AND THE AIRCRAFT FOUND A 850-MB FLIGHT LEVEL WIND MAXIMUM OF 58 KT AND A PEAK SFMR WINDS OF 51 KT OFFSHORE OF THE COAST OF HONDURAS JUST PRIOR TO 0000 UTC. BASED ON THESE DATA...AND THE FACT THAT THE CYCLONE HAS BEEN OVER LAND FOR ANOTHER 3 TO 4 HOURS...THE INITIAL INTENSITY IS SET TO 45 KT. WEAKENING IS EXPECTED OVERNIGHT WHILE THE CENTER REMAINS OVER LAND...BUT LITTLE CHANGE IN INTENSITY IS EXPECTED FROM 12 TO 24 HOURS AS THE CENTER IS FORECAST TO EMERGE INTO THE GULF OF HONDURAS BEFORE MOVING INTO BELIZE. BEYOND 24 HOURS...GRADUAL WEAKENING IS FORECAST AND THE LOW-LEVEL CENTER IS EXPECTED TO DISSIPATE OVER GUATEMALA OR EASTERN MEXICO IN 3 OR 4 DAYS. THE NHC FORECAST IS CLOSE TO THE DECAY SHIPS AND LGEM THROUGH THE PERIOD. SURFACE DATA...SATELLITE FIXES AND RADAR DATA FROM THE AIRCRAFT SUGGEST THAT THE CENTER OF MATTHEW IS A LITTLE TO THE NORTH OF THE PREVIOUS TRACK...AND THE INITIAL MOTION ESTIMATE IS 285/13. OVERALL...THE TRACK FORECAST REASONING REMAINS UNCHANGED...AS A STRONG MID-LEVEL RIDGE OVER THE GULF OF MEXICO WILL GENERALLY STEER MATTHEW WEST-NORTHWESTWARD FOR THE NEXT 36 HOURS OR SO. BY THE TIME MATTHEW MOVES INTO GUATEMALA AND MEXICO...THE STEERING FLOW WILL WEAKEN AS THE RIDGE BREAKS DOWN AND A SLOWER MOTION TOWARD THE WEST-NORTHWEST IS EXPECTED UNTIL DISSIPATION. THE NEW NHC FORECAST IS SHIFTED NORTH OF THE PREVIOUS ONE...BUT STILL LIES A LITTLE SOUTH OF THE CENTER OF THE GUIDANCE SUITE. THE FORWARD SPEED WAS TRENDED TOWARD THE TVCN MULTI-MODEL CONSENSUS. A LARGE AREA OF CLOUD TOPS COLDER THAN -80C HAVE RECENTLY DEVELOPED NEAR AND SOUTH OF THE CENTER OVER PORTIONS OF HONDURAS AND NICARAGUA...LIKELY PRODUCING EXTREMELY HEAVY RAINFALL IN THESE AREAS. THE HEAVY RAIN THREAT WILL PERSIST FOR SEVERAL DAYS...EVEN AFTER MATTHEW WEAKENS. FOR THE PAST FEW DAYS GLOBAL MODELS HAVE BEEN CONSISTENTLY DEPICTING A TROPICAL CYCLONE IN THE NORTHWESTERN CARIBBEAN SEA TOWARD THE MIDDLE OF NEXT WEEK. THE MOST RECENT RUNS INDICATE THAT ANY DEVELOPMENT THERE WOULD LIKELY NOT HAVE CONTINUITY WITH MATTHEW... BUT RATHER REPRESENT THE FORMATION OF A NEW TROPICAL CYCLONE. FORECAST POSITIONS AND MAX WINDS INITIAL 25/0300Z 15.2N 85.0W 45 KT...INLAND 12HR VT 25/1200Z 15.6N 87.0W 35 KT...INLAND 24HR VT 26/0000Z 16.2N 89.0W 35 KT...INLAND 36HR VT 26/1200Z 16.9N 90.7W 30 KT...INLAND 48HR VT 27/0000Z 17.2N 91.5W 25 KT...POST-TROP/REMNT LOW 72HR VT 28/0000Z 17.5N 92.5W 20 KT...DISSIPATING INLAND 96HR VT 29/0000Z...DISSIPATED $$ FORECASTER BRENNAN