From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Wed Sep 15 22:27:43 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 o8FERfhx007189 for ; Wed, 15 Sep 2010 22:27:42 +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 o8FBdd1f000579; Wed, 15 Sep 2010 09:27:25 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3403092 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Wed, 15 Sep 2010 09:27:25 -0500 Received: from relay02.cites.uiuc.edu (relay02.cites.uiuc.edu [128.174.196.4]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o8FERPWg017803 for ; Wed, 15 Sep 2010 09:27:25 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay02.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o8FERIbQ027202 for ; Wed, 15 Sep 2010 09:27:24 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 4589B405001E; Wed, 15 Sep 2010 09:27:18 -0500 (CDT) X-Spam-Score: 0 X-Spam-Details: rule=no-quarantine_notspam policy=no-quarantine score=0 spamscore=0 ipscore=0 phishscore=0 bulkscore=6 adultscore=0 classifier=spam adjust=0 reason=mlx engine=5.0.0-1005130000 definitions=main-1009150064 X-Spam-OrigSender: ldm@weather3.admin.niu.edu X-Spam-Bar: Message-ID: <20100915142718.4589B405001E@weather3.admin.niu.edu> Date: Wed, 15 Sep 2010 09:27:18 -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 Storm 12w Warning Nr 04// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN31 PGTW 151500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W WARNING NR 04// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL STORM (TS) 12W (FANAPI), LOCATED APPROXIMATELY 335 NM SOUTH OF OKINAWA, JAPAN HAS TRACKED NORTHWESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY AND A 151009Z SSMIS 91 GHZ MICROWAVE IMAGE DEPICT TIGHTLY CURVED CONVECTIVE BANDING WRAPPING IN FROM ALL QUADRANTS WITH DEEP CONVECTION BUILDING OVER THE SYSTEM CENTER. OVER THE PAST SIX HOURS THE SYSTEM HAS SLOWED CONSIDERABLY DUE TO A WEAKENING STEERING ENVIRONMENT. THE CURRENT POSITION IS BASED ON THE AFOREMENTIONED MICROWAVE PASS WITH FAIR CONFIDENCE. THE CURRENT INTENSITY IS BASED ON DVORAK ESTIMATES FROM PGTW, KNES, AND PGTW OF 35 KNOTS. UPPER LEVEL ANALYSIS REVEALS TS 12W IS EXPERIENCING IMPROVED EQUATORWARD OUTFLOW ASSOCIATED WITH THE TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL APPROACHING FROM THE EAST AND A TUTT CELL MOVING AWAY FROM THE SYSTEM TO THE WEST. ANIMATED WATER VAPOR IMAGERY INDICATES AN APPROACHING MID-LATITUDE UPPER LEVEL TROUGH MAY BE STARTING TO ENHANCE POLEWARD OUTFLOW. OVERALL THE SYSTEM IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH AN ANTICYCLONE OVER THE SYSTEM CENTER, LOW VERTICAL WIND SHEAR, AND HIGH SEA SURFACE TEMPERATURES. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 12W IS CURRENTLY TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A LOW TO MID-LEVEL STEERING RIDGE ANCHORED SOUTH OF JAPAN. NEAR TAU 12, A MID-LATITUDE TROUGH IS FORECAST TO WEAKEN THE STEERING RIDGE CAUSING THE SYSTEM TO SLOW AND TRACK POLEWARD. WITHIN THIS WEAKENED STEERING ENVIRONMENT, TS 12W IS EXPECTED TO INTENSIFY AS POLEWARD OUTFLOW IS ENHANCED BY THE MID-LATITUDE WESTERLY FLOW DIGGING DOWN TOWARD THE SYSTEM, AND EQUATORWARD OUTFLOW CONTINUES TO IMPROVE DUE TO THE TUTT CELL TO THE EAST. AFTER TAU 48 THE SYSTEM IS EXPECTED TO TURN BACK TOWARD THE NORTHWEST AS THE SUBTROPICAL RIDGE BUILDS BACK IN NORTH OF THE SYSTEM. C. BY TAU 72, TS 12W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF THE REBUILDING SUBTROPICAL RIDGE EXTENDING INTO EASTERN CHINA. THE SYSTEM IS FORECAST TO CONTINUE INTENSIFYING THROUGHOUT THE FORECAST PERIOD DUE TO FAVORABLE ENVIRONMENTAL CONDITIONS. NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH THE OVERALL TRACK PHILOSOPHY, BUT CONTINUES TO DEPICT UNCERTAINTY WITH THE TIMING OF THE TURN BACK TO THE NORTHWEST. GFDN AND GFS DEPICT A SLOWER TURN, WHILE ECMWF AND NOGAPS DEPICT A MORE RAPID TURN. THIS FORECAST FAVORS A QUICKER TURN BACK TO THE NORTHWEST AND IS CLOSE TO 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.