From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Thu Oct 21 22:14:58 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 o9LEEuam018887 for ; Thu, 21 Oct 2010 22:14:57 +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 o9KBiuWT000583; Thu, 21 Oct 2010 09:14:12 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3981101 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Thu, 21 Oct 2010 09:14:12 -0500 Received: from relay08.cites.uiuc.edu (relay08.cites.uiuc.edu [128.174.196.9]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o9LEECVW008268 for ; Thu, 21 Oct 2010 09:14:12 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay08.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o9LEE5C4012969 for ; Thu, 21 Oct 2010 09:14:12 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id B76E54050429; Thu, 21 Oct 2010 09:14:05 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101021141405.B76E54050429@weather3.admin.niu.edu> Date: Thu, 21 Oct 2010 09:14:05 -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 15w (megi) Warning Nr 35// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 211500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (MEGI) WARNING NR 35// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TYPHOON (TY) 15W (MEGI), LOCATED APPROXIMATELY 245 NM EAST- SOUTHEAST OF HONG KONG, HAS TRACKED NORTH-NORTHEASTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS A RAGGED 40 NM EYE THAT IS RINGED BY FLARING POCKETS OF DEEP CONVECTION EMBEDDED WITHIN A SHALLOWER CLOUD DECK. THE SYSTEM HAS MAINTAINED A 100 KNOT INTENSITY BASED ON DVORAK FIXES FROM PGTW AND RJTD THAT INDICATE THE SYSTEM RANGES FROM 100 TO 115 KNOTS. BECAUSE THE EYE HAS ENLARGED THE CURRENT POSITION IS BASED ON A 211131Z SSMIS 37H MICROWAVE IMAGE, WHICH SHOWS THAT THE LOW LEVEL CIRCULATION CENTER IS TO THE EAST OF BOTH THE PGTW AND RJTD POSITIONS. THE CYCLONE CONTINUES TO TRACK POLEWARD TOWARDS A WEAKNESS IN THE DEEP LAYER STEERING RIDGE TO THE NORTH ALONG THE WESTERN EXTENT OF A DEEP LAYER STEERING RIDGE TO THE EAST. STRONG POLEWARD VENTING HAS AIDED THE CYCLONE IN MAINTAINING ITS INTENSITY OF 100 KNOTS. 3. FORECAST REASONING. A. NO CHANGE IN FORECAST PHILOSOPHY. B. MODEL GUIDANCE CONTIUNES TO SUPPORT A POLEWARD TRACK TOWARDS CHINA. THE CURRENT FORECAST HAS BEEN SHIFTED FURTHER EAST IN RESPONSE TO THE CURRENT MOTION OF THE SYSTEM TO THE NORTH-NORTHEAST. THIS PLACES THE FORECAST CLOSER TO THE MODEL CONSENSUS, BUT STILL TO THE WEST. THE SYSTEM WILL CONTINUE TO TRACK JUST EAST OF NORTH ALONG THE DEEP LAYER RIDGE TOWARDS THE BASE OF MID TO UPPER LEVEL SHORTWAVE TROUGH OVER SOUTHEASTERN ASIA. VERTICAL WIND SHEAR WILL BEGIN TO AFFECT THE SYSTEM JUST PRIOR TO LANDFALL. IN THE INTERIM, MODERATE TO STRONG POLEWARD OUTFLOW WILL MODIFY THE RATE OF WEAKENING. THE CYCLONE WILL QUICKLY DISSIPATE OVER SOUTHEASTERN ASIA ONCE DECOUPLED FROM ITS SHEARD DEEP CONVECTION, TRACKING WESTWARD WITH THE LOW LEVEL FLOW OUT OF THE ANTICYCLONE TO THE NORTH. C. TY 15W IS FORECAST TO DISSIPATE BY TAU 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.