From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Wed Oct 27 22:50:28 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 o9REoQho029530 for ; Wed, 27 Oct 2010 22:50:27 +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 o9R3WWYw021767; Wed, 27 Oct 2010 09:50:12 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 4084755 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Wed, 27 Oct 2010 09:50:12 -0500 Received: from relay06.cites.uiuc.edu (relay06.cites.uiuc.edu [128.174.196.8]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o9REoCru026473 for ; Wed, 27 Oct 2010 09:50:12 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay06.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o9REo4cT016755 for ; Wed, 27 Oct 2010 09:50:12 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id D2184405001E; Wed, 27 Oct 2010 09:50:04 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101027145004.D2184405001E@weather3.admin.niu.edu> Date: Wed, 27 Oct 2010 09:50:04 -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 16w Warning Nr 25// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN32 PGTW 271500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W WARNING NR 25// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TYPHOON (TY) 16W (CHABA), LOCATED APPROXIMATELY 240 NM SOUTH OF KADENA AIR BASE, JAPAN, HAS TRACKED NORTHWARD AT 07 KNOTS OVER THE PAST SIX HOURS. THE SYSTEM HAS STEADILY INTENSIFIED TO 110 KNOTS AND IS NOW TRACKING POLEWARD ALONG THE WESTERN EXTENSION OF A DEEP LAYER STEERING RIDGE TO THE EAST. A 12 NM EYE IS NOW VISIBLE IN INFRARED SATELLITE IMAGERY. DUAL OUTFLOW CHANNELS HAVE SUPPORTED INTENSIFICATION. POLEWARD OUTFLOW REMAINS PARTICULARLY VIGOROUS INTO AN UPPER LEVEL LONGWAVE TROUGH OVER THE NORTH CENTRAL PACIFIC. DVORAK ESTIMATES HAVE CLIMBED TO A 5.5 FROM RJTD AND 6.0 FROM PGTW, INDICATING THE SYSTEM'S INITIAL INTENSITY NOW RANGES FROM 102 T0 115 KNOTS. THE SYNOPTIC SCALE COLD SURGE APPEARS TO HAVE HAD ALMOST NO IMPACT ON INTENSIFICATION THUS FAR. 3. FORECAST REASONING. A. THE PREVIOUS TWO FORECASTS REMAIN CONSISTENT WITH ONE ANOTHER AND CLOSE TO, BUT SLIGHTLY FASTER THAN, THE MODEL CONSENSUS, ACCOUTING FOR THE TENDENCY OF THE CONSENSUS TO BE SLOW IN A RECURVATURE SCENARIO. 120-HOUR FORECAST POSIT HAS BEEN DROPPED SINCE THE SYSTEM WILL BE HUNDREDS OF NAUTICAL MILES DOWNSTREAM OF JAPAN AND EXTRATROPICAL. B. THE SYSTEM IS FORECAST TO CONTINUE TO TRACK POLEWARD ALONG THE WESTERN EDGE OF THE STEERING RIDGE TO THE EAST TOWARDS A TROUGH- INDUCED WEAKNESS. THE SYSTEM WILL MAINTAIN ITS CURRENT INTENSITY FOR THE NEXT 12 HOURS, IF NOT INTENSIFY SLIGHTLY, DUE TO SUSTAINED DUAL OUTFLOW AND LOW TO MODERATE VERTICAL WIND SHEAR (VWS). AROUND TAU 36 VWS WILL ELEVATE AS THE SYSTEM APPROACHES A STRONG POLAR JET, WHICH WILL RAPIDLY WEAKEN THE SYSTEM. THE SYSTEM WILL ALSO BEGIN TO ACCELERATE NORTHEASTWARD AS IT CRESTS THE STEERING RIDGE, AND WILL BEGIN EXTRATROPICAL TRANSITION AS IT INTERACTS WITH A BAROCLINIC BOUNDARY RUNNING SOUTH OF JAPAN. C. 500 MB HEIGHT FIELDS SHOW CAPTURE OF THE SYSTEM BY THE TROUGH AS EARLY AS 29/12Z, SUGGESTING THE SYSTEM COULD COMPLETE EXTRATROPICAL TRANSITION FASTER THAN FORECAST. NONETHELESS, THE TYPHOON IS STILL EXPECTED TO BE FULLY EXTRATROPICAL PRIOR TO PASSAGE OVER THE KANTO REGION OF HONSHU. MODEL GUIDANCE DOES NOT SUPPORT RE- INTENSIFICATION AS A BAROCLINIC SYSTEM AT THIS TIME.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.