From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Fri Sep 17 21:58:25 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 o8HDwOAa016682 for ; Fri, 17 Sep 2010 21:58:24 +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 o8H50Qnw023157; Fri, 17 Sep 2010 08:58:13 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3444204 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Fri, 17 Sep 2010 08:58:13 -0500 Received: from relay03.cites.uiuc.edu (relay03.cites.uiuc.edu [128.174.4.69]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o8HDwChp026576 for ; Fri, 17 Sep 2010 08:58:12 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay03.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o8HDw6FL024852 for ; Fri, 17 Sep 2010 08:58:12 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 2BCA0405001D; Fri, 17 Sep 2010 08:58:06 -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=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=5.0.0-1005130000 definitions=main-1009170068 X-Spam-OrigSender: ldm@weather3.admin.niu.edu X-Spam-Bar: Message-ID: <20100917135806.2BCA0405001D@weather3.admin.niu.edu> Date: Fri, 17 Sep 2010 08:58:06 -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 12// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 171500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W WARNING NR 12// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TYPHOON (TY) 12W (FANAPI), LOCATED APPROXIMATELY 360 NM EAST- SOUTHEAST OF TAIPEI, TAIWAN, HAS TRACKED NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES THAT THE SYSTEM HAS CONTINUED TO CONSOLIDATE AND NOW HAS AN 11 NM EYE. A 170944Z SSMIS IMAGE SHOWS A NEAR COMPLETE EYEWALL WITH A SMALL GAP IN THE NORTH QUADRANT, AND EXCELLENT MULTIPLE CONVECTIVE BANDING OVER THE EASTERN SEMI-CIRCLE. UPPER- LEVEL FEATURE TRACK WINDS INDICATE THAT CONVERGENT NORTHEASTERLY FLOW ASSOCIATED WITH THE STRONG HIGH BUILDING NORTH OF THE SYSTEM IS LIKELY HINDERING DEVELOPMENT OVER THE NORTHWEST QUADRANT. VERTICAL WIND SHEAR (VWS) VALUES HAVE INCREASED 5-10 KNOTS OVER THE PAST 24 HOURS. THERE IS HIGH CONFIDENCE IN THE CURRENT POSITION AND 6-HOUR MOTION BASED ON THE EYE FEATURE. IN FACT, THE SYSTEM IS TRACKING WEST-NORTHWESTWARD OVER THE PAST FEW HOURS. THE CURRENT INTENSITY IS ASSESSED AT 85 KNOTS BASED ON AN AVERAGE OF DVORAK ESTIMATES RANGING FROM 77 TO 90 KNOTS FROM PGTW AND RJTD. 3. FORECAST REASONING. A. NO CHANGE IN FORECAST PHILOSOPHY AND TRACK SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THE 500MB ANALYSES OVER THE PAST 24 HOURS INDICATE THAT THE SUBTROPICAL RIDGE (STR) IS BUILDING ACROSS THE EAST CHINA SEA INTO WESTERN JAPAN (24-HOUR HEIGHT RISES OF 20-30 METERS) BEHIND THE MIDLATITUDE SHORT-WAVE TROUGH (WHICH HAD BRIEFLY INTERACTED WITH THE SYSTEM CAUSING A SHORT-TERM NORTHEASTWARD TRACK). THIS TROUGH IS FILLING AND KICKING OUT NORTHEASTWARD INTO NORTHEAST JAPAN. UPPER-LEVEL WINDS AT NAZE (28N 129E) HAVE SUBSEQUENTLY STRENGTHENED AND SHIFTED TO THE NORTH-NORTHEAST WITH INCREASING SUBSIDENCE THROUGH THE MID- AND UPPER-LEVELS. BASED ON THIS ANALYSIS AND THE TIGHT MODEL AGREEMENT, TY 12W IS FORECAST TO TRACK WESTWARD UNDER THE STEERING INFLUENCE OF THE DEEP STR THROUGH THE FORECAST PERIOD. TY 12W IS EXPECTED TO PEAK IN INTENSITY IN THE NEXT 12-24 HOURS AT 90-100 KNOTS. THE SYSTEM RETAINS GOOD EQUATORWARD OUTFLOW, HOWEVER, POLEWARD OUTFLOW IS WEAKENING AS THE HIGH BUILDS TO THE NORTH. VWS IS EXPECTED TO INCREASE AND WILL LIMIT INTENSIFICATION AFTER TAU 24 BUT PERHAPS AS EARLY AS TAU 12. THE SYSTEM WILL MAKE LANDFALL OVER TAIWAN AFTER TAU 36 AND SHOULD WEAKEN SIGNIFICANTLY BEFORE RE-EMERGING OVER THE THE TAIWAN STRAIT AS A 50-60 KNOT SYSTEM. FANAPI WILL CONTINUE TRACKING WESTWARD AND SHOULD MAKE LANDFALL OVER CHINA BY TAU 72. C. IN THE EXTENDED PERIOD, TY 12W IS EXPECTED TO DISSIPATE BY TAU 96.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.