WTPA45 PHFO 190851 TCDCP5 TROPICAL STORM UNALA DISCUSSION NUMBER 3 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP022013 1100 PM HST SUN AUG 18 2013 UNALA HAD A VERY SMALL AREA OF DEEP CONVECTION REMAINING NEAR ITS NORTHERN QUADRANT...BUT THAT APPEARS TO BE DYING AT BULLETIN TIME. THIS SYSTEM IS STRUGGLING AT THIS HOUR AS IT CONTINUES TO PUSH RAPIDLY WESTWARD UNDER THE HOSTILE OUTFLOW FROM RECENTLY UPGRADED TYPHOON PEWA...CENTERED NEAR 13.9N 177.9E AT 19/0600Z ACCORDING TO THE JOINT TYPHOON WARNING CENTER /JTWC/. THE INCREASING VERTICAL WIND SHEAR IS OBVIOUSLY TAKING A TOLL ON UNALA...SINCE ALL OF THE SATELLITE FIX AGENCIES INDICATED A CURRENT INTENSITY OF ONLY 2.0. HOWEVER...THE TIGHT PRESSURE GRADIENT NORTH OF THE TROPICAL CYCLONE CENTER IS LIKELY MAINTAINING WINDS OF AT LEAST 35 KT OVER PORTIONS OF THE NORTHERN SEMICIRCLE AT THIS TIME. SCATTEROMETER PASSES FROM EARLIER TODAY SHOWED THIS TYPE OF WIND FIELD...SO WE DO NOT BELIEVE THE WINDS HAVE DECREASED BELOW GALE FORCE AT THIS TIME. THEREFORE... WE WILL MAINTAIN UNALA AS A MINIMAL TROPICAL STORM FOR THE INITIAL PERIOD IN THIS FORECAST. THE INITIAL MOTION IS 275/17. THE LATEST TRACK GUIDANCE FOR UNALA IS ALL TO THE RIGHT OF THE CURRENT FORECAST TRACK...WHICH IS IN LINE WITH THE PREVIOUS FORECAST ISSUED IN A SPECIAL ADVISORY AT 19/0500Z. IN COORDINATION WITH THE TYPHOON DUTY OFFICER AT JTWC...IT WAS DECIDED THAT A FUJIWARA INTERACTION BETWEEN TYPHOON PEWA AND UNALA WILL LIKELY STEER UNALA MORE WESTWARD AT AN ACCELERATED SPEED. ALSO...IN COORDINATION WITH JTWC...WE ANTICIPATED THE INTERACTION BETWEEN UNALA AND THE DOMINANT OUTFLOW FROM PEWA SHOULD CAUSE UNALA TO WEAKEN TO A TROPICAL DEPRESSION WITHIN 12 HOURS...AND TO DISSIPATE WITHIN 24 HOURS. PEWA HAS ALREADY CROSSED THE INTERNATIONAL DATELINE AS OF THIS BULLETIN TIME...AND THIS WILL BE THE FINAL ADVISORY FROM THE CENTRAL PACIFIC HURRICANE CENTER ON THIS SYSTEM. THE NEXT BULLETIN WILL BE ISSUED BY RSMC TOKYO JAPAN. FOR U.S. INTERESTS...SEE THE PUBLIC ADVISORIES ISSUED BY THE U.S. NWS WEATHER FORECAST OFFICE IN GUAM...AND DEPARTMENT OF DEFENSE WARNINGS ISSUED BY THE JOINT TYPHOON WARNING CENTER IN HONOLULU...HAWAII. FORECAST POSITIONS AND MAX WINDS INIT 19/0900Z 17.5N 179.6E 35 KT 40 MPH 12H 19/1800Z 17.7N 177.1E 25 KT 30 MPH 24H 20/0600Z...DISSIPATED $$ FORECASTER HOUSTON PALMBAYWEATHER.info
Posted on: Mon, 19 Aug 2013 08:52:17 +0000
Recently Viewed Topics
© 2015