From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Sat Oct 23 10:54:30 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 o9N2sTdJ024632 for ; Sat, 23 Oct 2010 10:54:30 +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 o9LB01iR021698; Fri, 22 Oct 2010 21:53:12 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 4004379 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Fri, 22 Oct 2010 21:53:12 -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 o9N2rCaY012722 for ; Fri, 22 Oct 2010 21:53:12 -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 o9N2r5Hc007008 for ; Fri, 22 Oct 2010 21:53:12 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 9E9C6108B0002; Fri, 22 Oct 2010 21:53:05 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101023025305.9E9C6108B0002@weather3.admin.niu.edu> Date: Fri, 22 Oct 2010 21:53:05 -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 Warning Nr 41// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 230300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W WARNING NR 41// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TYPHOON 15W (MEGI), LOCATED APPROXIMATELY 230 NM EAST- NORTHEAST OF HONG KONG, HAS TRACKED NORTHWARD AT 06 KNOTS DURING THE PAST SIX HOURS. ANIMATED MULTI-SPECTRAL IMAGERY INDICATES THE EYEWALL HAS COLLAPSED AND CORE CONVECTION HAS DECREASED MARKEDLY, ESPECIALLY OVER THE WESTERN HALF OF THE STORM. INFRARED ANIMATION SHOWS MARKED WARMING OF THE CLOUD TOPS OVER THE LOW LEVEL CIRCULATION CENTER, YET WATER VAPOR ANIMATION VERIFIES THAT BOTH POLEWARD AND EQUATORIAL OUTFLOW CHANNELS REMAIN WELL-DEVELOPED. RECENT MICROWAVE IMAGERY FROM A 222116Z SSMI/S PASS ALSO VERIFIES THAT THE MICROWAVE EYE HAS MAINTAINED INTEGRITY, BUT THE 91 GHZ IMAGE INDICATES THAT THE UPPER LEVELS ARE BEGINNING TO TILT AWAY FROM THE LLCC. THE SYSTEM REMAINS IN A REGION OF FAVORABLE SEA SURFACE TEMPERATURES AND LIGHT VERTICAL WINDSHEAR, BUT AT THE BOUNDARY LEVELS IT IS BEGINNING TO INGEST MODIFIED CONTINENTAL POLAR (CP) AIR FLOWING OFF THE SOUTHEAST COAST OF CHINA. SURFACE RADAR IMAGERY FROM TAIWAN INDICATES THE STORM IS MAINTAINING A NORTHERLY TRACK TOWARD THE CHAOZHOU PROVINCE. POSITION IS BASED PRIMARILY ON MULTISPECTRAL IMAGERY, WITH HELP FROM WEATHER RADAR IMAGERY FROM TAIWAN. INTENSITY ANALYSIS IS BASED ON A COMBINATION OF A DVORAK INTENSITY RATING OF 3.5 FROM PGTW AND SURFACE OBSERVATIONS FROM COASTAL CHINA. 3. A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE PREVIOUS PROGNOSTIC REASOING BULLETIN. B. TYPHOON 15W IS EXPECTED TO MAKE LANDFALL OVER SOUTHEASTERN CHINA NEAR TAU 12 AND STEADILY DISSIPATE OVER LAND. A DEEPENING UPPER LEVEL TROUGH OVER SOUTHEASTERN CHINA WILL SUPPRESS CONVECTION OVER THE NORTHWEST QUADRANT WHILE ENTRAINMENT OF CP AIR AT THE BOUNDARY LEVEL WILL WEAKEN THE STORM AS IT TRACKS INLAND. THE STORM IS EXPECTED TO TRACK ALONG THE WESTERN PERIPHERY OF A MID-LEVEL STEERING RIDGE AND DISSIPATE OVER LAND BY TAU 36. THE DYNAMIC AIDS ARE IN GOOD AGREEMENT THROUGH TAU 24 BUT DIVERGE SHARPLY AFTERWARD DUE TO DIFFERENT RESPONSES TO INTERACTION WITH THE BAROCLINIC ZONE. THE JGSM MODEL PRESENTS THE MOST COHERENT SCENARIO. THE FORECAST THROUGH TAU 24 IS BASED ON CONSENSUS, AND AFTERWARD ON THE JGSM MODEL AND CONSTANT RATE OF MOVEMENT. // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.