From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Fri Sep 17 19:05:57 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 o8HB5t3t006165 for ; Fri, 17 Sep 2010 19:05:56 +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 o8H50Qg0023157; Fri, 17 Sep 2010 06:05:12 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3442760 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Fri, 17 Sep 2010 06:05:12 -0500 Received: from relay10.cites.uiuc.edu (relay10.cites.uiuc.edu [128.174.196.10]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o8HB5CH8013583 for ; Fri, 17 Sep 2010 06:05:12 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay10.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o8HB55OL000976 for ; Fri, 17 Sep 2010 06:05:11 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 90F85405002B; Fri, 17 Sep 2010 06:05:05 -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=14 adultscore=0 classifier=spam adjust=0 reason=mlx engine=5.0.0-1005130000 definitions=main-1009170034 X-Spam-OrigSender: ldm@weather3.admin.niu.edu X-Spam-Bar: Message-ID: <20100917110505.90F85405002B@weather3.admin.niu.edu> Date: Fri, 17 Sep 2010 06:05:05 -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 Typhoon 12w Warning Nr 10// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 170300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W WARNING NR 10// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TYPHOON (TY) 12W (FANAPI), LOCATED APPROXIMATELY 400 NM EAST- SOUTHEAST OF TAIPEI, TAIWAN, HAS TRACKED NORTH-NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. THE SUBTROPICAL RIDGE OVER CHINA HAS BUILT RAPIDLY THROUGHOUT THE DAY, CAUSING THE CYCLONE TO TURN MORE NORTHWESTWARD. THERE IS HIGH CONFIDENCE IN THE CURRENT POSITION BASED ON ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A HIGH- RESOLUTION 162228Z MICROWAVE IMAGE. TY 12W HAS ALSO INTENSIFIED BY 20 KNOTS OVER THE PAST 12 HOURS DUE TO IMPROVED POLEWARD OUTFLOW INTO THE PASSING MID-LATITUDE TROUGH. THE RECENT VISIBLE IMAGERY AND AVAILABLE MICROWAVE IMAGES INDICATE WELL CONSOLIDATED CONVECTION AND THE BEGINNING STAGES OF AN EYE. THEREFORE, THE CURRENT INTENSITY OF 75 KNOTS IS BASED ON THE STRONG CONVECTIVE SIGNATURE AND SUPPORTED BY DVORAK ESTIMATES FROM KNES AND RJTD OF 4.5 AND PGTW OF 4.0. CURRENTLY, ANIMATED WATER VAPOR IMAGERY DOES SHOW THAT THE POLEWARD OUTFLOW HAS STARTED TO WANE AS THE TROUGH HAS LIFTED TO THE NORTHEAST AND THE SYSTEM IS PASSING OVER AN AREA OF LOWER OCEAN HEAT CONTENT. 3. FORECAST REASONING. A. NO CHANGE IN FORECAST PHILOSOPHY AND TRACK SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. AS THE MID-LATITUDE SHORT-WAVE TROUGH HAS PROPAGATED NORTHEASTWARD OF JAPAN, THE SUBTROPICAL STEERING RIDGE POSITIONED NORTH OF THE SYSTEM IS BECOMING THE DOMINANT STEERING INFLUENCE. THIS WILL ALLOW THE SYSTEM TO TRACK INCREASINGLY WESTWARD AND TO ACCELERATE UP TO 8-10 KNOTS OVER THE NEXT DAY. FANAPI SHOULD INTENSIFY TO A PEAK NEAR 90 KNOTS AROUND TAU 24 DUE TO A POCKET OF ROBUST OCEAN HEAT CONTENT. HOWEVER, THE SYSTEM IS NOT EXPECTED TO INTENSIFY FURTHER DUE TO INCREASING NORTHERLY VERTICAL WIND SHEAR ASSOCIATED WITH THE BUILDING RIDGE AND A LOSS OF POLEWARD OUTFLOW. THE AVAILABLE NUMERICAL GUIDANCE IS IN VERY TIGHT AGREEMENT, EVEN WBAR, WHICH NOW ALSO TRACKS THE SYSTEM OVER CENTRAL TAIWAN. C. IN THE EXTENDED PERIOD, TY 12W IS EXPECTED TO WEAKEN AFTER CROSSING TAIWAN BETWEEN TAU 48 AND TAU 72 BUT SHOULD MAINTAIN 55-60 KNOT INTENSITY AS IT CROSSES THE TAIWAN STRAIT. THE SYSTEM IS FORECAST TO MAKE LANDFALL OVER MAINLAND CHINA AFTER TAU 72 AND WILL DISSIPATE BY TAU 120.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.