From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Thu Sep 16 11:14:05 2010 Received: from vacuum.cso.uiuc.edu (vacuum.cso.uiuc.edu [128.174.5.113]) by cozumel.ust.hk (8.13.8/8.13.8) with ESMTP id o8G3E4Jp002686 for ; Thu, 16 Sep 2010 11:14:05 +0800 Received: from vacuum.cso.uiuc.edu (vacuum.cso.uiuc.edu [128.174.5.113]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o8FKbVLm000579; Wed, 15 Sep 2010 22:13:16 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3417835 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Wed, 15 Sep 2010 22:13:16 -0500 Received: from relay07.cites.uiuc.edu (relay07.cites.uiuc.edu [128.174.4.73]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o8G3DGRn014899 for ; Wed, 15 Sep 2010 22:13:16 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay07.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o8G3D95x008561 for ; Wed, 15 Sep 2010 22:13:16 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id D70EA405001E; Wed, 15 Sep 2010 22:13:09 -0500 (CDT) X-Spam-Score: 0 X-Spam-Details: rule=no-quarantine_notspam policy=no-quarantine score=0 spamscore=0 ipscore=0 phishscore=0 bulkscore=1 adultscore=0 classifier=spam adjust=0 reason=mlx engine=5.0.0-1005130000 definitions=main-1009150148 X-Spam-OrigSender: ldm@weather3.admin.niu.edu X-Spam-Bar: Message-ID: <20100916031309.D70EA405001E@weather3.admin.niu.edu> Date: Wed, 15 Sep 2010 22:13:09 -0500 Reply-To: wxmaster@COX.NET Sender: WX-TROPL Tropical Storm and Hurricane WX products From: SIU Weather Processor Subject: Pacific-NW: Subj/prognostic Reasoning For Tropical Storm 12w Warning Nr 06// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 160300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W WARNING NR 06// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL STORM (TS) 12W (FANAPI), LOCATED APPROXIMATELY 300 NM SOUTH OF OKINAWA, JAPAN, HAS TRACKED NORTHEASTWARD OVER THE PAST SIX HOURS AFTER PREVIOUSLY TRACKING SLOWLY WESTWARD. A MID-LATITUDE SHORT WAVE TROUGH CURRENTLY MOVING OVER KYUSHU HAS WEAKENED THE SUBTROPICAL RIDGE, CREATING A WEAK STEERING ENVIRONMENT AND ENABLING TS FANAPI TO TRACK SLOWLY NORTHWARD OVER THE PAST 12 HOURS. THE SYSTEM IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH AN ANTICYCLONE OVER THE SYSTEM CENTER, LOW VERTICAL WIND SHEAR, AND HIGH SEA SURFACE TEMPERATURES. AT THE SAME TIME, ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 152241Z SSMIS MICROWAVE IMAGE SHOW CONTINUED CONSOLIDATION AS WELL AS VIGOROUS CONVECTION IN THE EASTERN QUADRANT OF THE CYCLONE. DUE TO STRONG EQUATORWARD OUTFLOW INTO A TUTT CELL TO THE SOUTHWEST AND THE INTERACTION WITH THE TROUGH (WHICH IS STARTING TO ENHANCE POLEWARD OUTFLOW), THE SYSTEM HAS INTENSIFIED BY 15 KNOTS OVER THE PAST 12 HOURS. THE CURRENT POSITION IS BASED WITH GOOD CONFIDENCE ON VISUAL AND MICROWAVE IMAGERY. THE CURRENT INTENSITY IS BASED ON DVORAK ESTIMATES FROM PGTW, KNES, AND PGTW OF 55 KNOTS AS WELL AS FROM DROPSONDES DEPLOYED BY WC-130 AIRCRAFT CONDUCTING SCIENTIFIC RESEARCH. 3. FORECAST REASONING. A. THE TRACK HAS SHIFTED SIGNIFICANTLY TO THE WEST-SOUTHWEST SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE IN RESPONSE TO EXPECTED STRENGTHENING OF A SUBTROPICAL RIDGE LOCATED OVER CHINA. B. TS 12W IS EXPECTED TO FURTHER INTENSIFY AND REACH TYPHOON INTENSITY OVER THE NEXT 36 HOURS, WHILE DRIFTING ALONG THE SOUTHWESTERN PERIPHERY OF THE LOW TO MID-LEVEL STEERING RIDGE, AS IT CONTINUES TO TAP INTO THE POLEWARD OUTFLOW AHEAD OF THE PASSING TROUGH. AS THE SYSTEM TURNS WESTWARD, IT WILL START TO LOSE ACCESS TO THE POLEWARD OUTFLOW THOUGH FANAPI WILL STILL BE IN A FAVORABLE ENVIRONMENT SUSTAINED BY STRONG EQUATORWARD OUTFLOW. NUMERICAL MODEL GUIDANCE IS IN INCREASINGLY TIGHTER AGREEMENT WITH THE OVERALL WESTWARD TRACK. THE JTWC TRACK IS BASED ON CONSENSUS WITH A SLIGHT INCREASE IN SPEED AFTER TAU 24 AND THE INTENSITY FORECAST IS SLIGHTLY HIGHER THAN THE NEAR-TERM INTENSITY GUIDANCE. C. BEYOND 72 HOURS, TROPICAL STORM 12W IS EXPECTED TO MAKE LANDFALL AND WEAKEN OVER THE RUGGED TERRAIN OF TAIWAN. BY TAU 96, INCREASING VERTICAL WIND SHEAR WILL FURTHER WEAKEN THE SYSTEM TO TROPICAL STROM STRENGTH AS IT MOVES THROUGH THE TAIWAN STRAIT DISSIPATES OVER CHINA.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from WX-TROPL send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with "unsub wx-tropl" in the body of your message. For help with WX-TROPL write to cnovy@cox.net. For more information on tropical weather products, see the NHC Homepage at http://www.nhc.noaa.gov.