From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Fri Oct 22 09:57:31 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 o9M1vUI2024377 for ; Fri, 22 Oct 2010 09:57:30 +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 o9LJQBTo014749; Thu, 21 Oct 2010 20:57:18 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3990874 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Thu, 21 Oct 2010 20:57:18 -0500 Received: from relay09.cites.uiuc.edu (relay09.cites.uiuc.edu [128.174.4.86]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o9M1vIjv013239 for ; Thu, 21 Oct 2010 20:57:18 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay09.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o9M1vBUr022569 for ; Thu, 21 Oct 2010 20:57:17 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 6E5DE108B0002; Thu, 21 Oct 2010 20:57:10 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101022015711.6E5DE108B0002@weather3.admin.niu.edu> Date: Thu, 21 Oct 2010 20:57:10 -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 15w (megi) Warning Nr 37// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 220300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (MEGI) WARNING NR 37// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TYPHOON (TY) 15W (MEGI), LOCATED APPROXIMATELY 240 NM EAST- SOUTHEAST OF HONG KONG, HAS TRACKED NORTHWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A 25-NM RAGGED EYE SURROUNDED BY A SYMMETRIC RING OF INTENSE CONVECTION. IMAGERY INDICATES SOME PRESSURE ON THE WESTERN PERIPHERY OF THE SYSTEM DUE TO UPPER-LEVEL WESTERLIES AND MODERATE VERTICAL WIND SHEAR (VWS). ANIMATED WATER IMAGERY CONTINUES TO DEPICT EXCELLENT POLEWARD OUTFLOW ENHANCED BY THE STRONG SOUTHWESTERLY FLOW OVER EASTERN ASIA. THERE IS GOOD CONFIDENCE IN THE CURRENT POSITION BASED ON THE EYE AND TAIWAN RADAR FIXES. THE CURRENT INTENSITY OF 105 KNOTS IS BASED ON THE THE PGTW CURRENT INTENSITY OF 102 KNOTS (FINAL T 77 KNOTS) AND THE RJTD/KNES ESTIMATES OF 115 KNOTS. 3. FORECAST REASONING. A. NO CHANGE IN FORECAST PHILOSOPHY. B. TY 15W IS CURRENTLY TRACKING SLOWLY POLEWARD ALONG THE WESTERN PERIPHERY OF THE MID-LEVEL SUBTROPICAL RIDGE (STR) POSITIONED EAST. THE 21/12Z 500MB ANALYSIS AND SOUNDINGS (E.G., FROM ISHIGAKI-JIMA) INDICATE WESTERLY FLOW OVER SOUTHEAST CHINA WITH A SHORTWAVE TROUGH OVER EASTERN CHINA AND SUPPORT A STRONG STEERING STR. THE TROUGH IS PROPAGATING NORTHEAST AND THE RIDGE IS MAINTAINING STRENGTH, THEREFORE, THE SYSTEM IS EXPECTED TO CONTINUE TRACKING POLEWARD THROUGH THE FORECAST PERIOD. DYNAMIC GUIDANCE IS TIGHTLY CLUSTERED AND SUPPORTS THIS FORECAST. TY 15W IS EXPECTED TO WEAKEN THROUGH THE PERIOD DUE TO INCREASING VWS AND SHOULD DISSIPATE OVER LAND BETWEEN TAU 48 AND 72.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.