From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Sat Oct 23 10:46:27 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 o9N2kPki024188 for ; Sat, 23 Oct 2010 10:46:26 +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 o9LB01iH021698; Fri, 22 Oct 2010 21:46:16 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 4004302 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Fri, 22 Oct 2010 21:46:16 -0500 Received: from relay01.cites.uiuc.edu (relay01.cites.uiuc.edu [128.174.4.23]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o9N2kFx2012097 for ; Fri, 22 Oct 2010 21:46:15 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay01.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o9N2k70a023510 for ; Fri, 22 Oct 2010 21:46:15 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 4EF78108B0002; Fri, 22 Oct 2010 21:46:07 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101023024607.4EF78108B0002@weather3.admin.niu.edu> Date: Fri, 22 Oct 2010 21:46:07 -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 07// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN32 PGTW 230300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W WARNING NR 07// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL DEPRESSION (TD) 16W, LOCATED APPROXIMATELY 730 NM SOUTHEAST OF KADENA, HAS TRACKED WEST-SOUTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 222139Z SSMIS MICROWAVE IMAGE SHOW A BROAD, ILL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC). THERE IS LOW CONFIDENCE IN THE INITIAL POSITION BASED ON THE AFOREMENTIONED SSMIS IMAGE. THE INITIAL INTENSITY IS BASED ON RJTD AND PGTW DVORAK INTENSITY ESTIMATES OF 25 KNOTS. UPPER LEVEL ANALYSIS INDICATES THE LLCC IS LOCATED IN AN AREA OF MODERATE VERTICAL WIND SHEAR AND SUBSIDENCE TO THE NORTH INDUCED BY A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT). 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE IN FORECAST PHILOSOPHY SINCE THE PREVIOUS BULLETIN. HOWEVER, THERE CONTINUES TO BE A HIGH DEGREE OF UNCERTAINTY IN THE EXTENDED TRACK AND INTENSITY FORECAST. B. TD 16W IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR) TO THE NORTH AND IS EXPECTED TO CONTINUE TRACKING WESTWARD OVER THE NEXT 36 TO 48 HOURS. AFTER TAU 48, AN UPPER LEVEL MID-LATITUDE TROUGH IS EXPECTED TO WEAKEN THE STR AND CAUSE TD 16W TO TRACK POLEWARD. AS THE TUTT CELL CONTINUES TO MOVE WESTWARD AND ALLOWS VERTICAL WIND SHEAR AND SUBSIDENCE TO CONSEQUENTLY RELAX, THE SYSTEM SHOULD BEGIN TO STEADILY INTENSIFY. C. AS TD 16W INTENSIFIES, IT IS EXPECTED TO TRACK POLEWARD ALONG THE WESTERN PERIPHERY OF A MID-LEVEL STEERING RIDGE. POLEWARD OUTFLOW INTO THE UPPER LEVEL TROUGH SHOULD INCREASE BY TAU 72 AND INCREASE THE INTENSIFICATION RATE. THE MODELS CONTINUE TO SHOW UNCERTAINTY AS THEY ARE SPREAD IN THE TIMING OF THE POLEWARD TURN. NOGAPS, GFS, UKMO, AND ECMWF MODELS ARE TRACKING THE SYSTEM POLEWARD. THE GFDN AND JGSM MODELS ARE OUTLIERS AND ERRONEOUSLY TRACK TD 16W WESTWARD ALONG A STRONGER STR. THIS FORECAST IS IN AGREEMENT WITH THE MODELS TRACKING MORE POLEWARD GIVEN THE EXPECTATION OF A DEEPER MID-LATITUDE TROUGH. ADDITIONALLY, THERE IS UNCERTAINTY IN THE LATER TAUS OF THE INTENSITY FORECAST. THIS IS DUE TO AN EXPECTED COLD SURGE ORIGINATING OVER NORTHERN CHINA, WHICH MAY INCREASE VERTICAL WIND SHEAR IN THE LATER TAUS AND CAUSE THE SYSTEM TO INTENSITY LESS THAN PREVIOUSLY PREDICTED.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.