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| #64700 (Received by flhurricane at: 10:17 AM 05.Jan.2006) TCDAT5 TROPICAL STORM ZETA DISCUSSION NUMBER 25 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 10 AM EST THU JAN 05 2006 A 05/0836Z QUIKSCAT OVERPASS THAT CAME IN SHORTLY AFTER THE PREVIOUS ADVISORY HAD BEEN ISSUED INDICATED SEVERAL 30-35 KT UNCONTAMINATED WIND VECTORS NORTH THROUGH EAST OF THE CENTER. SINCE THAT TIME... CONVECTION HAS CONTINUED TO INCREASE TO THE EAST OF THE FULLY EXPOSED LOW-LEVEL CENTER. THE 12Z DVORAK SATELLITE SHEAR PATTERN CURRENT INTENSITY ESTIMATE FROM THE TAFB WAS 35 KT... AND CONVECTION HAS DEVELOPED EVEN CLOSER TO THE CENTER SINCE THAT ANALYSIS WAS MADE. IN ADDITION... SHIP ZCIH7 LOCATED ABOUT 135 NMI NORTH OF THE CENTER REPORTED AN EAST WIND OF 30 KT... WHICH MATCHED UP WELL WITH NEARBY QUIKSCAT WINDS. SO...REGRETFULLY...THE INTENSITY HAS BEEN INCREASED TO 35 KT AND ZETA IS A TROPICAL STORM ONCE AGAIN. THIS INTENSITY IS ALSO SUPPORTED BY A 05/0915Z UW-CIMSS AMSU INTENSITY ESTIMATE OF 1006 MB AND 38 KT. THE INITIAL MOTION IS 300/07 KT. THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. ZETA IS EXPECTED TO CONTINUE MOVING WEST-NORTHWESTWARD TO NORTHWESTWARD AROUND THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER RIDGE SITUATED TO THE NORTHEAST OF THE TROPICAL STORM. WATER VAPOR IMAGERY AND UW-CIMSS SATELLITE WIND ANALYSES INDICATE A SHARP MID-LEVEL SHORTWAVE TROUGH LOCATED ALONG 56W LONGITUDE MOVING QUICKLY EASTWARD. THIS SYSTEM IS EXPECTED TO GRADUALLY LIFT ZETA POLEWARD AND/OR SHEAR THE SYSTEM APART... LEAVING BEHIND A REMNANT LOW PRESSURE SYSTEM BY 24-36 HOURS. BY 72 HOURS...THE REMNANT LOW MAY EVEN BECOME ABSORBED INTO A FRONTAL SYSTEM THAT IS ACCOMPANYING THE SHORTWAVE TROUGH. THE SHIPS MODEL'S 850-200 MB SHEAR OF 68 KT IS NOT THE ACTUAL SHEAR AFFECTING ZETA. THE GLOBAL MODELS INDICATE THE 850-300 MB WESTERLY SHEAR TO ONLY BE AROUND 30-35 KT. AS A RESULT... ZETA MIGHT BE ABLE TO MAINTAIN TROPICAL STORM INTENSITY FOR ANOTHER 12 HOURS OR SO BEFORE THE CYCLONE ENCOUNTERS VERY HOSTILE MID-LEVEL WESTERLY WINDS BEHIND THE APPROACHING SHORTWAVE TROUGH PREVIOUSLY MENTIONED. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 05/1500Z 22.4N 47.6W 35 KT 12HR VT 06/0000Z 23.3N 48.5W 30 KT 24HR VT 06/1200Z 24.3N 49.7W 25 KT...DISSIPATING 36HR VT 07/0000Z 25.3N 51.1W 25 KT...REMNANT LOW 48HR VT 07/1200Z 26.3N 53.6W 20 KT...REMNANT LOW 72HR VT 08/1200Z 29.0N 56.5W 20 KT...REMNANT LOW 96HR VT 09/1200Z...DISSIPATED OR ABSORBED |
