From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Mon Dec 13 09:53:37 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 oBD1raLv025374 for ; Mon, 13 Dec 2010 09:53:37 +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 oBCMJFOP027712; Sun, 12 Dec 2010 19:53:11 -0600 (CST) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 4744540 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Sun, 12 Dec 2010 19:53:11 -0600 Received: from relay05.cites.uiuc.edu (relay05.cites.uiuc.edu [128.174.4.40]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id oBD1rBQC028039 for ; Sun, 12 Dec 2010 19:53:11 -0600 (CST) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay05.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id oBD1r4EN015384 for ; Sun, 12 Dec 2010 19:53:10 -0600 (CST) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 983093FE0863; Sun, 12 Dec 2010 19:53:04 -0600 (CST) X-Proofpoint-Spam-Reason: safe Message-ID: <20101213015304.983093FE0863@weather3.admin.niu.edu> Date: Sun, 12 Dec 2010 19:53:04 -0600 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 19w To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 130300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 19W /WARNING NR 03// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL DEPRESSION (TD) 19W, LOCATED APPROXIMATELY 240 NM EAST OF HO CHI MINH, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY INDICATES THAT THE DEEP CONVECTION HAS SIGNIFICANTLY DECREASED WITHIN THE PAST SIX HOURS AND HAS SHEARED 90 NM TO THE WEST-NORTHWEST OF AN ILL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL INTENSITY WAS BASED ON PGTW AND KNES DVORAK ESTIMATES OF 25 KNOTS. ADDITIONALLY, A SHIP LOCATED 30 NM TO THE NORTH-NORTHWEST OF THE LLCC WAS REPORTING 20-KNOT NORTH- NORTHEASTERLY WINDS AND A SEA LEVEL PRESSURE OF 1005 MB. TD 19W IS LOCATED SOUTH OF THE UPPER-LEVEL RIDGE AXIS AND IS UNDER MODERATE TO HIGH VERTICAL WIND SHEAR (VWS). 3. FORECAST REASONING. A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TD 19W IS TRACKING WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE LOW-LEVEL (700 MB) SUBTROPICAL RIDGE (STR) POSITIONED NORTH OF THE SYSTEM. A 12/12Z 700MB ANALYSIS DEPICTS THE STR EXTENDING ACROSS THE NORTHERN SOUTH CHINA SEA INTO NORTHERN VIETNAM. AVAILABLE MODEL GUIDANCE (TO INCLUDE NOGAPS, ECMWF, GFS, JGSM AND UKMO) IS CONSISTENT IN MAINTAINING THE STR THROUGH THE FORECAST PERIOD. THEREFORE, TD 19W IS FORECAST TO CONTINUE TRACKING GENERALLY WESTWARD. A DECREASE IN THE VWS SHOULD ALLOW THE SYSTEM TO RE-COUPLE WITH THE DEEP CONVECTION AND MAINTAIN INTENSITY, THEN DISSIPATE OVER VIETNAM BY TAU 24.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.