From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Tue Oct 5 22:21:27 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 o95ELQvR008218 for ; Tue, 5 Oct 2010 22:21:26 +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 o955FgkS025335; Tue, 5 Oct 2010 09:21:12 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3749664 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Tue, 5 Oct 2010 09:21:12 -0500 Received: from relay08.cites.uiuc.edu (relay08.cites.uiuc.edu [128.174.196.9]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o95ELCAl010748 for ; Tue, 5 Oct 2010 09:21:12 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay08.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o95EL525024182 for ; Tue, 5 Oct 2010 09:21:11 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id A848C405016C; Tue, 5 Oct 2010 09:21:05 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101005142105.A848C405016C@weather3.admin.niu.edu> Date: Tue, 5 Oct 2010 09:21:05 -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 Tropical Depression 14w Warning Nr 03// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 051500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 14W WARNING NR 03// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL DEPRESSION (TD) 14W, LOCATED APPROXIMATELY 240 NM NORTH-NORTHEAST OF HUE, VIETNAM, HAS TRACKED NORTHWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS A WEAKENING, POORLY-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION SHEARED OVER THE EASTERN SEMI-CIRCLE OF THE PARTIALLY-EXPOSED LLCC. FORTUNATELY, A 051100Z SSMIS 91 GHZ IMAGE AND CMA ANIMATED RADAR IMAGERY SHOW THE WEAKLY-DEFINED CENTER WITH FAIR CONFIDENCE AND ALSO PROVIDE FURTHER EVIDENCE THAT THE SYSTEM HAS RAPIDLY WEAKENED OVER THE PAST 12 HOURS. THE CURRENT INTENSITY IS BASED ON PERSISTENCE, PRIMARILY FROM THE 050255Z ASCAT IMAGE SHOWING NUMEROUS 30 KNOT WIND VECTORS OVER THE NORTHWEST QUADRANT. DUE TO THE RAPIDLY DECAYING DEEP CONVECTION, DVORAK ESTIMATES ARE UNCLASSIFIABLE. 3. FORECAST REASONING. A. OVER THE PAST 12 HOURS THE FORECAST PHILOSOPHY HAS CHANGED SIGNIFICANTLY, REFLECTING MUCH SLOWER TRACK SPEEDS AND A MORE EASTWARD TRACK. ADDITIONALLY, THE PEAK INTENSITY HAS BEEN REDUCED TO 30 KNOTS. B. TD 14W IS SITUATED WITHIN A WEAK STEERING ENVIRONMENT AND WITHIN A HOSTILE ENVIRONMENT CHARACTERIZED BY MODERATE (25 KNOTS) VERTICAL WIND SHEAR (VWS) AND LAND INTERACTION. THE 05/00Z 700 MB ANALYSIS DEPICTS A WEAK RIDGE POSITIONED EAST OF THE SYSTEM WITH A COL REGION NORTH ASSOCIATED WITH A MIDLATITUDE SHORTWAVE TROUGH SITUATED OVER EASTERN ASIA. THIS TROUGH IS FORECAST TO PROVIDE A SHORT-TERM EASTWARD INFLUENCE THROUGH TAU 12-24. HOWEVER, AFTER THE TROUGH PROPAGATES EAST, THE RIDGE WILL BUILD NORTH OF THE SYSTEM PRODUCING QUASI-STATIONARY MOTION. ADDITIONALLY, STRONG UPPER-LEVEL WESTERLIES NORTH OF 20N IN COMBINATION WITH LOW-LEVEL NORTHEASTERLY FLOW, ASSOCIATED WITH A 1021 MB HIGH OVER CHINA, HAVE PRODUCED INCREASING VWS VALUES IN EXCESS OF 30 KNOTS JUST NORTH AND NORTHEAST OF THE SYSTEM. OVERALL, TD 14W APPEARS TO BE BOXED IN AN UNFAVORABLE ENVIRONMENT; ANY SUSTAINED MOTION NORTH OR NORTHEAST WILL RESULT IN INCREASING VWS AND FURTHER WEAKENING, THEREFORE, IT IS LIKELY THAT THE SYSTEM WILL CONTINUE TO WEAKEN AND DE-COUPLE OVER THE NEXT 1-2 DAYS AT THE LATEST WITH DISSIPATION EXPECTED BETWEEN TAU 36 AND 48. EARLIER DISSIPATION IS POSSIBLE AS WELL AS QUASI-STATIONARY MOTION. MODEL GUIDANCE SUPPORTS THE FORECAST REASONING. THIS FORECAST IS CONSISTENT WITH THE MODEL CONSENSUS.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.