From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Wed Sep 8 22:02:41 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 o88E2d7O010585 for ; Wed, 8 Sep 2010 22:02:40 +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 o8836xIK001569; Wed, 8 Sep 2010 09:02:28 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3287063 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Wed, 8 Sep 2010 09:02:28 -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 o88E2SlZ024589 for ; Wed, 8 Sep 2010 09:02:28 -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 o88E2GhU004014 for ; Wed, 8 Sep 2010 09:02:26 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id B35C84050020; Wed, 8 Sep 2010 09:02:16 -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-1009080078 X-Spam-OrigSender: ldm@weather3.admin.niu.edu X-Spam-Bar: Message-ID: <20100908140216.B35C84050020@weather3.admin.niu.edu> Date: Wed, 8 Sep 2010 09:02:16 -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 Tropical Storm 11w Warning Nr 03// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 081500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W WARNING NR 03// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL STORM (TS) 11W (ELEVEN), LOCATED APPROXIMATELY 305 NM EAST-SOUTHEAST OF HONG KONG, HAS TRACKED WESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES A PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTIVE BANDING PRIMARILY OVER THE SOUTHERN SEMI-CIRCLE. ANIMATED WATER VAPOR IMAGERY INDICATES THAT THE TUTT CELL, WHICH HAD PROVIDED IMPROVED POLEWARD (EASTWARD) OUTFLOW, HAS TRACKED WEST OVER TAIWAN AND IS PRODUCING WEAK TO MODERATE (10-15 KNOT) NORTHERLY VERTICAL WIND SHEAR (VWS). A 080849Z SSMIS COMPOSITE IMAGE AND A 081059Z AMSU IMAGE SHOW CURVED BANDING WRAPPING INTO THE EXPOSED LLCC, WHICH IS LOCATED ON THE NORTHERN EDGE OF THE DEEP CONVECTION. RADAR IMAGERY ALSO SUPPORTS THE CURRENT POSITION WITH GOOD CONFIDENCE. THE CURRENT INTENSITY IS BASED ON DVORAK ESTIMATES OF 35 KNOTS FROM BOTH PGTW AND KNES AS WELL AS AN EARLIER 080211Z ASCAT IMAGE SHOWING NUMEROUS 30-35 KNOT WIND VECTORS AROUND THE CENTER. 3. FORECAST REASONING. A. NO CHANGE IN FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 11W IS TRACKING WESTWARD UNDER THE STEERING INFLUENCE OF THE LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR), WHICH EXTENDS WESTWARD ALONG 28-30N LATITUDE INTO EASTERN CHINA FROM A HIGH CENTERED NEAR 27N 140E. GFS IS INDICATING A SHARP TURN NORTHWARD AFTER TAU 12. MODEL FIELDS INDICATE GFS IS WEAKENING THE SYSTEM TOO RAPIDLY AND IS LOSING THE CIRCULATION COMPLETELY BY TAU 36. NOGAPS IS TURNING THE SYSTEM SHARPLY NORTHWARD AFTER TAU 24 AND ALSO WEAKENS THE SYSTEM TOO RAPIDLY. NOGAPS/GFS ARE INITIALIZING THE STR WELL BUT APPEAR TO BE WEAKENING THE STR TOO RAPIDLY, DRIVING THE SYSTEM DIRECTLY INTO THE EXISTING STR. THIS HAS BEEN A CONTINUING PROBLEM OVER THE PAST 24 HOURS. THE REMAINING MODELS (ECMWF, JGSM, GFDN AND WBAR) ARE IN GOOD AGREEMENT AND INDICATE A NORTHWESTWARD TRACK THAT MAKES SENSE WITH THE LATEST 500/700MB ANALYSIS OF THE STR. TS 11W IS EXPECTED TO STRENGTHEN TO A PEAK INTENSITY OF 40 TO 45 KNOTS BY TAU 24 AS THE TUTT CELL WEAKENS AND NORTHERLY VWS DECREASES. THE SYSTEM IS FORECAST TO MAKE LANDFALL BY TAU 36 AND WILL DISSIPATE BY TAU 48. THE FORECAST TRACK IS FASTER THAN THE MODEL CONSENSUS AND LEFT OF CONSENSUS DUE TO THE AFOREMENTIONED NOGAPS/GFS POLEWARD BIAS.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.