000 WTPZ42 KNHC 250240 TCDEP2 HURRICANE BUD DISCUSSION NUMBER 17 NWS NATIONAL HURRICANE CENTER MIAMI FL EP022012 800 PM PDT THU MAY 24 2012 CONVENTIONAL AND MICROWAVE SATELLITE IMAGERY INDICATES BUD HAS EVOLVED INTO AN ANNULAR HURRICANE WITH LITTLE TO NO OUTER BANDING FEATURES. DEEP CONVECTION HAS INCREASED THIS AFTERNOON AND EVENING WITH AN EYE BECOMING MORE PRONOUNCED IN VISIBLE AND INFRARED IMAGERY. SATELLITE INTENSITY ESTIMATES ARE T6.0/115 KT FROM TAFB...T5.5/102 KT FROM SAB...AND UW-CIMSS ADT VALUES HAVE BEEN AVERAGING T5.7/107 KT OVER THE PAST 3 HOURS. ALSO...AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT ON ITS FINAL OUTBOUND LEG OBSERVED 700 MB FLIGHT-LEVEL WINDS OF 120 KT IN THE EASTERN QUADRANT. SFMR SURFACE WINDS IN THAT SAME AREA WERE ONLY AROUND 85 KT...WHICH IS MUCH LOWER THAN ONE WOULD EXPECT USING THE STANDARD 90 PERCENT REDUCTION FACTOR. THIS WAS LIKELY DUE TO SOME NORTHEASTWARD TILT TO AND ELONGATION OF THE EYE...AND THE LACK OF SIGNIFICANT CONVECTION. SINCE THAT TIME...HOWEVER...CONVECTION HAS INCREASED MARKEDLY IN THE EASTERN SEMICIRCLE AND A 24/2229Z TRMM OVERPASS INDICATED A CIRCULAR EYE OF ABOUT 20 NMI DIAMETER. ALTHOUGH THE DEEPEST CONVECTION APPEARS TO BE SOMEWHAT TRANSIENT... THERE IS LIKELY ENOUGH CONVECTION TO MIX DOWN AT LEAST 85 PERCENT OF THE FLIGHT-LEVEL WINDS...WHICH SUPPORTS MAKING BUD A 100-KT MAJOR HURRICANE. THE INITIAL MOTION ESTIMATE IS 030 DEGREES AT 9 KT. BUD IS EXPECTED TO MOVE NORTH-NORTHEASTWARD AND THEN NORTHWARD OVER THE NEXT 24-36 HOURS AS THE CYCLONE REMAINS CAUGHT BETWEEN A DEEP-LAYER RIDGE TO ITS EAST ACROSS CENTRAL AMERICA AND SOUTHEASTERN MEXICO AND A MID-LEVEL TROUGH TO ITS WEST ACROSS NORTHWESTERN MEXICO AND BAJA CALIFORNIA. NHC MODEL GUIDANCE IS IN EXCELLENT AGREEMENT ON BUD MAKING LANDFALL ALONG THE SOUTHWESTERN COAST OF MEXICO IN 24-30 HOURS. AFTER THAT...HOWEVER...THE MODEL GUIDANCE DIVERGES WITH THE GFS AND THE REGIONAL MODELS TAKING BUD INLAND OVER MEXICO WHILE THE ECMWF AND UKMET BRING THE EXPECTED REMNANTS OF BUD BACK OVER WATER BY 48-72 HOURS. GIVEN THAT THE SIERRA MADRE MOUNTAINS WILL LIKELY CAUSE THE LOW-LEVEL AND UPPER-LEVEL CIRCULATIONS OF BUD TO DECOUPLE SHORTLY AFTER LANDFALL...WITH THE MID-/UPPER-LEVEL CIRCULATIONS CONTINUING NORTHEASTWARD...THE OFFICIAL FORECAST REMAINS SIMILAR TO THE PREVIOUS ADVISORY TRACKS AND THE ECMWF AND UKMET MODELS BY TURNING BUD SLOWLY SOUTHWARD BY 36 HOURS AFTER IT MAKES LANDFALL. BUD HAS LIKELY PEAKED IN INTENSITY...AND SLOW WEAKENING SHOULD ENSUE BY 12 HOURS OR SO AS MODEST SOUTHWESTERLY SHEAR AND DRY MID-LEVEL AIR IMPINGE ON THE SMALL INNER CORE OF THIS ANNULAR HURRICANE. HOWEVER...BUD IS STILL EXPECTED TO BE A HURRICANE BY THE TIME IT MAKES LANDFALL ALONG THE COAST OF MEXICO. FASTER WEAKENING WILL OCCUR ONCE THE CENTER MOVES INLAND AND INTERACTS WITH THE HIGH MOUNTAINOUS TERRAIN OF SOUTHWESTERN MEXICO...AND THE OFFICIAL FORECAST HAS BUD DEGENERATING INTO A REMNANT LOW BY DAYS 3-4... IF NOT SOONER. GIVEN THE SLOW FORWARD SPEED OF BUD WHEN IT MAKES LANDFALL... TORRENTIAL RAINFALL CAUSING DANGEROUS MUD SLIDES APPEARS LIKELY ACROSS PORTIONS OF SOUTHWESTERN MEXICO IN THE STATES OF MICHOACAN...COLIMA...JALISCO...AND SOUTHERN NAYARIT. FORECAST POSITIONS AND MAX WINDS INIT 25/0300Z 17.1N 105.9W 100 KT 115 MPH 12H 25/1200Z 18.1N 105.6W 95 KT 110 MPH 24H 26/0000Z 19.4N 105.2W 85 KT 100 MPH 36H 26/1200Z 20.2N 105.1W 60 KT 70 MPH...INLAND 48H 27/0000Z 20.3N 105.2W 40 KT 45 MPH...INLAND 72H 28/0000Z 19.5N 105.4W 30 KT 35 MPH...OVER WATER 96H 29/0000Z 19.1N 105.4W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 30/0000Z...DISSIPATED $$ FORECASTER STEWART