From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Fri Oct 22 11:15:34 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 o9M3FX1F029393 for ; Fri, 22 Oct 2010 11:15:33 +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 o9LJQBWo014749; Thu, 21 Oct 2010 22:15:23 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3991561 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Thu, 21 Oct 2010 22:15:23 -0500 Received: from relay04.cites.uiuc.edu (relay04.cites.uiuc.edu [128.174.196.5]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o9M3FNSG018375 for ; Thu, 21 Oct 2010 22:15:23 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay04.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o9M3FGD4009131 for ; Thu, 21 Oct 2010 22:15:23 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 8A695108B0002; Thu, 21 Oct 2010 22:15:16 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101022031516.8A695108B0002@weather3.admin.niu.edu> Date: Thu, 21 Oct 2010 22:15:16 -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 Depression 16w Warning Nr 03// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN32 PGTW 220300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W WARNING NR 03// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL DEPRESSION (TD) 16W, LOCATED APPROXIMATELY 470 NM SOUTH-SOUTHWEST OF IWO TO, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A FULLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DISORGANIZED DEEP CONVECTION DISPLACED SOUTH OF THE CENTER. UPPER LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH INCREASING 20-30 KNOT NORTHEASTERLY VERTICAL WIND SHEAR (VWS) ASSOCIATED WITH THE TUTT CELL NEAR 18N 153E. THE CURRENT INTENSITY IS BASED ON DVORAK ESTIMATES OF 25 KNOTS FROM KNES AND PGTW. THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION BASED ON THE EXPOSED LLCC. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS BULLETIN. HOWEVER, THERE IS A HIGH DEGREE OF UNCERTAINTY IN THE EXTENDED TRACK AND INTENSITY FORECAST. B. TD 16W IS CURRENTLY TRACKING UNDER THE STEERING INFLUENCE OF THE LOW-LEVEL SUBTROPICAL RIDGE POSITIONED TO THE NORTH. THE SYSTEM IS EXPECTED TO TRACK WESTWARD THROUGH THE PERIOD WITH A WEST-NORTHWESTWARD TRACK IN THE LATER TAUS. TD 16W IS UNLIKELY TO RE-CURVE DUE TO A STRONG COLD SURGE AND LOW- LEVEL HIGH EXPECTED BY ALL MODELS TO BUILD INTO THE EAST CHINA SEA NEAR TAU 120. THE UNCERTAINTY IN THE EXTENDED TAUS IS BASED PRIMARILY ON THE STRENGTH OF THE SYSTEM. IF THE SYSTEM REMAINS WEAK, IT WILL TRACK MORE WESTWARD UNDER THE LOW-LEVEL FLOW. IF IT STRENGTHEN TO 55-65 KNOTS, THE SYSTEM MAY TRACK NORTHWESTWARD UNTIL IT ENCOUNTERS STRONG VERTICAL WIND SHEAR AND DE-COUPLES (THEN TRACKS SOUTHWESTWARD UNDER LOW-LEVEL NORTHEASTERLIES ASSOCIATED WITH THE COLD SURGE). MODEL GUIDANCE IS IN POOR AGREEMENT AND HAS BEEN ERRATIC. THE DYNAMIC MODELS ARE EITHER RE-CURVING THE SYSTEM (ECMWF, NOGAPS), RE-CURVING BUT DISSIPATING SOUTHEAST OF OKINAWA (GFS), OR TRACKING THE SYSTEM WESTWARD (UKMO, JGSM, WBAR). TD 16W IS FORECAST TO SLOWLY INTENSIFY THROUGH THE NEXT 36-48 HOURS DUE TO THE UNFAVORABLE CONDITIONS. C. IN THE EXTENDED TAUS, MODEL GUIDANCE DIVERGES. THIS FORECAST CONTINUES TO FAVOR A WEST-NORTHWESTWARD TO NORTHWESTWARD TURN FOLLOWED BY DISSIPATION AND DE-COUPLING. MODEL GUIDANCE HAS BEEN CONSISTENT WITH THE TIMING AND STRENGTH OF A STRONG COLD SURGE AND THE NORTHEASTERLY SURGE. THIS COLD SURGE SHOULD LEAD TO VERY STRONG VWS SOUTH OF JAPAN WHICH IS EXPECTED TO RAPIDLY WEAKEN THE SYSTEM WELL SOUTH OF JAPAN.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.