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| #54600 (Received by flhurricane at: 10:37 AM 29.Oct.2005) TCDAT1 HURRICANE BETA DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT SAT OCT 29 2005 AN 1140Z TRMM OVERPASS SHOWS THAT BETA HAS A PINHOLE EYE UNDERNEATH ITS CENTRAL DENSE OVERCAST...WHICH HAS CONVECTIVE TOPS OF -80C JUST EAST OF THE CENTER. SATELLITE INTENSITY ESTIMATES ARE 77 KT FROM TAFB...65 KT FROM SAB...AND 55 KT FROM AFWA. BASED ON THESE AND ON THE EYE SIZE...THE INITIAL INTENSITY IS INCREASED TO 75 KT. THE INITIAL MOTION REMAINS 320/3...AND OVER THE PAST FEW HOURS BETA MAY BE MOVING A LITTLE LEFT OF THAT. WATER VAPOR IMAGERY SHOWS THAT THE SHORTWAVE TROUGH THAT WAS OVER THE EASTERN UNITED STATES YESTERDAY HAS MOVED INTO THE ATLANTIC...WITH SURFACE OBSERVATIONS AND RAWINSONDE DATA SHOWING RISING PRESSURES BEHIND THE TROUGH. THE DYNAMICAL MODELS FORECAST THIS TREND TO CONTINUE FOR 24-36 HR...WHICH SHOULD CAUSE BETA TO TURN MORE WESTWARD ON THE SOUTH SIDE OF THE NARROW BUT STRENGTHENING RIDGE. WHILE THERE CONTINUES TO BE SPREAD BETWEEN THE MORE NORTHWARD UKMET AND THE MORE SOUTHWARD GFS...THE DYNAMICAL MODELS AGREE THAT BETA WILL MAKE LANDFALL IN ABOUT 24 HR IN EASTERN OR NORTHEASTERN NICARAGUA. THE NEW FORECAST TRACK IS AN UPDATE OF THE PREVIOUS PACKAGE...CALLING FOR A GRADUAL WESTWARD TURN DURING THE FIRST 24 HR AND A WESTWARD MOTION ACROSS NICARAGUA AND HONDURAS THEREAFTER. THE NEW TRACK IS JUST NORTH OF THE MODEL CONSENSUS AND A BIT SLOWER. ANALYSES FROM CIMSS AT THE UNIVERSITY OF WISCONSIN INDICATE THAT THE EASTERLY VERTICAL SHEAR HAS DECREASED SINCE YESTERDAY...AND THE RAPID INTENSIFICATION INDEX ATTACHED TO THE SHIPS MODEL IS SHOWING A 62 PERCENT CHANCE OF 25 KT OR MORE STRENGTHENING DURING THE NEXT 24 HR. CONFIDENCE IN THIS HAPPENING IS INCREASED BY THE PRESENCE OF THE PINHOLE EYE. BOTH SHIPS AND THE GFDL BRING BETA TO 95 KT BY LANDFALL...AND THE INTENSITY FORECAST WILL FOLLOW THAT. HOWEVER... THERE IS A GOOD CHANCE THAT BETA WILL GET STRONGER THAN FORECAST AND MAKE LANDFALL AS A MAJOR HURRICANE. AFTER LANDFALL...BETA SHOULD WEAKEN AND EVENTUALLY DISSIPATE OVER THE MOUNTAINS OF CENTRAL AMERICA. REGARDLESS OF THE INTENSITY OF BETA AT LANDFALL...THIS TROPICAL CYCLONE WILL BRING TORRENTIAL RAINFALL TO PORTIONS OF CENTRAL AMERICA...PRIMARILY NICARAGUA AND HONDURAS...CAUSING CONSIDERABLE DAMAGE...AND LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. IN ADDITION...SOME OF THE DEEP TROPICAL MOISTURE ASSOCIATED WITH BETA MAY GET DRAWN INTO A DEVELOPING WINTER-TYPE LOW PRESSURE SYSTEM OVER THE GULF OF MEXICO BY THE MIDDLE OF NEXT WEEK. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 29/1500Z 13.9N 81.7W 75 KT 12HR VT 30/0000Z 14.2N 82.4W 85 KT 24HR VT 30/1200Z 14.4N 83.3W 95 KT...INLAND 36HR VT 31/0000Z 14.4N 84.4W 50 KT...INLAND 48HR VT 31/1200Z 14.4N 85.7W 30 KT...INLAND 72HR VT 01/1200Z 14.5N 87.5W 25 KT...INLAND DISSIPATING 96HR VT 02/1200Z 14.5N 89.0W 20 KT...INLAND REMNANT LOW 120HR VT 03/1200Z...DISSIPATED |
