From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Thu Sep 9 22:42:29 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 o89EgSD0019741 for ; Thu, 9 Sep 2010 22:42:28 +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 o89D04UG001501; Thu, 9 Sep 2010 09:42:17 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3306376 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Thu, 9 Sep 2010 09:42:17 -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 o89EgHgF005301 for ; Thu, 9 Sep 2010 09:42:17 -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 o89Eg77X000149 for ; Thu, 9 Sep 2010 09:42:15 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 31ECD405001E; Thu, 9 Sep 2010 09:42:07 -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-1009090062 X-Spam-OrigSender: ldm@weather3.admin.niu.edu X-Spam-Bar: Message-ID: <20100909144207.31ECD405001E@weather3.admin.niu.edu> Date: Thu, 9 Sep 2010 09:42:07 -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 11w Warning Nr 07// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 091500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W WARNING NR 07// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TYPHOON (TY) 11W (MERANTI), LOCATED APPROXIMATELY 180 NM SOUTHWEST OF TAIPEI, TAIWAN, HAS TRACKED NORTH-NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY SHOWS A MIDGET SYSTEM WITH A WELL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC) AND A 091128Z SSMIS DEPICTS A DEEP CONVECTIVE MICROWAVE EYE. THE INITIAL POSITION IS BASED ON A RADAR FIX FROM TAIWAN AND THE AFOREMENTIONED SSMIS IMAGE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS BASED ON THE CONVECTIVE SIGNATURE AND NOT ON DVORAK ESTIMATES BECAUSE THEY ARE UNDERESTIMATING THIS MIDGET SYSTEM. UPPER LEVEL ANALYSIS INDICATES A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL HAS CONTINUED TO MOVE FARTHER NORTHWESTWARD, WHICH HAS ALLOWED IMPROVED POLEWARD OUTFLOW AND DECREASED VERTICAL WIND SHEAR (VWS). ADDITIONALLY, TY 11W CONTINUES TO MAINTAIN A GOOD EQUATORWARD OUTFLOW CHANNEL, ALLOWING IT TO RAPIDLY INTENSIFY. 3. FORECAST REASONING. A. THE CURRENT INTENSITY HAS INCREASED SIGNIFICANTLY SINCE THE PREVIOUS FORECAST BECAUSE OF THE DECREASED VWS AND DUAL OUTFLOW CHANNELS. THE FORECAST TRACK PHILOSOPHY HAS GENERALLY REMAINED THE SAME EXCEPT FOR AN INCREASE IN TRACK SPEED DUE TO A STRAIGHTER TRACK. B. TY 11W IS CURRENTLY TRACKING ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL STEERING RIDGE AND IS EXPECTED TO MAKE LANDFALL IN APPROXIMATELY 12 HOURS OVER SOUTHEASTERN CHINA. TY 11W SHOULD BEGIN TO FEEL THE AFFECTS OF LAND AND BEGIN TO WEAKEN BY TAU 12. BY TAU 36, TY MERANTI IS EXPECTED TO DISSIPATE AS A SIGNIFICANT TROPICAL CYCLONE OVER THE MOUNTAINOUS TERRAIN OF CHINA. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE EXCEPTION OF THE UKMO MODEL WHICH ERRONEOUSLY TRACKS THE SYSTEM NORTHEASTWARD TOWARDS TAIWAN BEFORE TURNING IT NORTHWARD. THIS FORECAST IS SLIGHTLY WEST OF CONSENSUS TO ACCOUNT FOR THE UKMO MODEL AND IS WITHIN THE TIGHT MODEL PACKING OF WBAR, ECMWF, NOGAPS, JGSM, AND GFS.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.