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#63997 (Received by flhurricane at: 10:17 PM 01.Jan.2006) TCDAT5 TROPICAL STORM ZETA DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 10 PM EST SUN JAN 01 2006 THIS IS LIKE PREVIOUS TROPICAL CYCLONE EPSILON ALL OVER AGAIN. MOST OF THE CONVENTIONAL GUIDANCE SUGGESTED THAT ZETA SHOULD HAVE BEEN DISSIPATED BY NOW...WELL IT IS NOT INDEED...AND ZETA IS PRETTY MUCH ALIVE AT THIS TIME. SATELLITE IMAGES STILL INDICATE A WELL-DEFINED CIRCULATION AND ALTHOUGH THE CONVECTION IS NOT VERY DEEP...THE CLOUD PATTERN REMAINS ORGANIZED WITH AN ESTABLISHED OUTFLOW IN THE NORTHERN SEMICIRCLE. IN FACT...THE LATEST QUIKSCAT AND AMSU DATA SUGGEST THAT ZETA COULD BE A LITTLE STRONGER THAN THE INITIAL INTENSITY OF 45 KNOTS GIVEN IN THIS ADVISORY. THE INITIAL INTENSITY IS BASED ON CONTINUITY AND SUBJECTIVE DVORAK ESTIMATES. ACCORDING TO THE SHIPS MODEL WHICH DISSIPATES ZETA BY 48 HOURS...THE COOLER THAN NORMAL 200 MB TEMPERATURE IS THE ONLY PARAMETER CONTRIBUTING TO THE MAINTENANCE OF THE CYCLONE. ON THE OTHER HAND...THE GFDL INSISTS ON MAKING ZETA A HURRICANE IN A COUPLE OF DAYS AND IT IS HARD TO GO AGAINST IT. HOWEVER...WITH STRONG WESTERLIES ALOFT AND DRY AIR HEADING FOR ZETA...I HAVE NO CHOICE BUT TO FORECAST WEAKENING AGAIN AND AGAIN. ZETA APPEARS TO BE MOVING TOWARD THE SOUTHWEST AT 3 KNOTS AROUND THE WESTERN CIRCULATION OF A MID-LEVEL TROUGH. AS THE CYCLONE WEAKENS AND BECOME A SHALLOWER SYSTEM...IT SHOULD BE STEERED SLOWLY WESTWARD BY THE TRADE WINDS UNTIL DISSIPATION. MOST OF THE TROPICAL STORM FORCE WINDS ARE OCCURRING IN THE NORTHERN SEMICIRCLE AS INDICATED BY QUIKSCAT. THE WIND RADII HAVE BEEN ADJUSTED ACCORDINGLY. FORECASTER AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 02/0300Z 24.7N 38.7W 45 KT 12HR VT 02/1200Z 24.6N 39.1W 35 KT 24HR VT 03/0000Z 24.0N 40.0W 30 KT 36HR VT 03/1200Z 24.0N 41.5W 25 KT 48HR VT 04/0000Z 24.0N 43.0W 25 KT...REMNANT LOW 72HR VT 05/0000Z...DISSIPATED |