Hurricane HECTOR
ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM HURRICANE HECTOR DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092006 800 AM PDT FRI AUG 18 2006 TRMM AND AQUA MICROWAVE PASSES FROM AROUND 1000 UTC SHOW THAT THE EYEWALL OF HECTOR HAS BECOME OPEN IN THE WESTERN SEMICIRCLE. THE CONVENTIONAL SATELLITE PRESENTATION HAS ALSO BECOME DEGRADED WITH THE CONVECTIVE PATTERN LOOKING A LITTLE ASYMMETRIC. T-NUMBERS FROM SAB/TAFB HAVE DROPPED A LITTLE AND SUPPORT AN INITIAL INTENSITY OF 85 KT. THE INTENSITY FORECAST APPEARS RELATIVELY STRAIGHTFORWARD. THE CYCLONE WILL SOON BE PASSING THE 26.5C ISOTHERM WHICH SHOULD CONTRIBUTE TO WEAKENING. IN ADDITION VERTICAL WIND SHEAR IS FORECAST TO INCREASE FROM A NORTHWESTERLY DIRECTION WHICH WOULD ALSO HELP WEAKEN THE HURRICANE. SHIPS WEAKENS HECTOR RATHER QUICKLY IN THE SHORT-TERM COMPARED TO SIX HOURS AGO... WHICH MAY BE A BIT TOO FAST DUE TO DIAGNOSED SHEAR VALUES THAT APPEARS TO BE OVERESTIMATED. ON THE OTHER HAND... GFDL HOLDS ONTO HECTOR AS A HURRICANE FOR 2 DAYS WHICH SEEMS WAY TOO HIGH. THE INTENSITY FORECAST WILL BE A LITTLE ABOVE SHIPS...WHICH PROBABLY HAS THE RIGHT IDEA...AND AGREES WELL WITH THE FSU SUPERENSEMBLE. THE INITIAL MOTION IS BASICALLY THE SAME AS BEFORE... ABOUT 290/12. THE HURRICANE REMAINS ON THE SOUTHWEST FLANK OF A MIDDLE- TROPOSPHERIC RIDGE OVER MEXICO. HECTOR COULD TURN A LITTLE MORE TO THE NORTHWEST IN ABOUT 24 HOURS AS IT APPROACHES A WEAKNESS IN THE SUBTROPICAL RIDGE. THE NOGAPS AND UKMET ARE ON TWO EXTREMES OF THE MODEL GUIDANCE ENVELOPE... WITH THE NOGAPS PLOWING HECTOR NORTHWESTWARD INTO THE WEAKNESS IN THE RIDGE ALMOST IMMEDIATELY... WHILE THE UKMET IS SEEMINGLY UNAFFECTED AND CONTINUES MOVING WEST-NORTHWESTWARD. THE OFFICIAL FORECAST IS NUDGED A LITTLE BIT SOUTH OF THE PREVIOUS FORECAST AND LIES ALONG THE SOUTHERN PORTION OF THE GUIDANCE CONSENSUS. FORECAST POSITIONS AND MAX WINDS INITIAL 18/1500Z 16.1N 125.8W 85 KT 12HR VT 19/0000Z 16.9N 127.4W 80 KT 24HR VT 19/1200Z 17.8N 129.2W 70 KT 36HR VT 20/0000Z 18.7N 130.8W 60 KT 48HR VT 20/1200Z 19.6N 132.3W 45 KT 72HR VT 21/1200Z 21.0N 134.5W 30 KT...DISSIPATING 96HR VT 22/1200Z 22.0N 137.0W 20 KT...REMNANT LOW 120HR VT 23/1200Z 22.5N 140.0W 20 KT...REMNANT LOW $$ FORECASTER BLAKE/KNABB NNNN