From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Wed Oct 27 11:41:28 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 o9R3fREe024845 for ; Wed, 27 Oct 2010 11:41:28 +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 o9QHnbHF000583; Tue, 26 Oct 2010 22:41:13 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 4075266 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Tue, 26 Oct 2010 22:41:12 -0500 Received: from relay03.cites.uiuc.edu (relay03.cites.uiuc.edu [128.174.4.69]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o9R3fCGa002284 for ; Tue, 26 Oct 2010 22:41:12 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay03.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o9R3f6lq021480 for ; Tue, 26 Oct 2010 22:41:12 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 155394050021; Tue, 26 Oct 2010 22:41:05 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101027034106.155394050021@weather3.admin.niu.edu> Date: Tue, 26 Oct 2010 22:41:05 -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 Typhoon 16w Warning Nr 23// To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN32 PGTW 270300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W WARNING NR 23// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TYPHOON (TY) 16W (CHABA), CURRENTLY LOCATED 375 NM SOUTH OF KADENA AB, OKINAWA, HAS SHOWN ERRATIC (NEARLY QUASI-STATIONARY) MOVEMENT DURING THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY INDICATES CONVECTION HAS DEEPENED AND CONSOLIDATED OVER THE SYSTEM DURING THE PAST SIX HOURS IN RESPONSE TO AN ENHANCED POLEWARD OUTFLOW CHANNEL. RECENT VISUAL SATELLITE IMAGERY SHOWS OVERSHOOTING CLOUD TOPS NEAR THE TY CORE AND THE BEGINNINGS OF AN EYE. THERE IS HIGH CONFIDENCE IN THE CURRENT POSITION BASED ON A 26/2228Z SSMIS 91H MICROWAVE IMAGE INDICATING A DEFINITIVE MICROWAVE EYE. THE CURRENT INTENSITY ANALYSIS IS BASED ON DVORAK CURRENT INTENSITY (CI) ESTIMATES OF 102 KNOTS FROM PGTW AND 90 KNOTS FROM RJTD. ANIMATED WATER VAPOR IMAGERY INDICATES WELL-DEVELOPED OUTFLOW CHANNELS EXIST ON ALL QUADRANTS OF THE STORM. CONTINENTAL POLAR (CP) AIR ENTRAINMENT FROM A RECENT COLD SURGE APPEARS TO BE MINIMAL THUS FAR, PRODUCING LITTLE IMPEDIMENT ON STORM DEVELOPMENT. THIS IS LIKELY AN EFFECT OF PARALLEL NORTHEASTERLY FLOW ALONG THE RYUKUS RATHER THAN PERPENDICULAR NORTHWESTERLIES. A TOTAL PRECIPITABLE WATER LOOP DOES SHOW ONE PULSE OF DRIER AIR MADE IT INTO THE SYSTEM CORE BUT WAS QUICKLY ABSORBED. RECENT SURFACE ANALYSIS SHOWS WINDS ARE BACKING AND INCREASING OVER THE RYUKUS INDICATING BOUNDARY LEVEL FLOW OF CP AIR INTO THE STORM WILL SOON INCREASE. VERTICAL WIND SHEAR IS MINIMAL SOUTH OF 28N, WHERE IT INCREASES RAPIDLY. A WESTERN EXTENSION OF THE SUB-TROPICAL RIDGE ACTED TO DRIVE THE STORM WESTWARD BETWEEN 26/06Z AND 26/18Z BUT HAS WEAKENED SIGNIFICANTLY, CREATING A ALLEY FOR THE STORM TO TURN POLEWARD. 3. FORECAST REASONING. A. THE TRACK FORECAST THROUGH TAU 36 HAS BEEN ACCELERATED SLIGHTLY FROM THE PREVIOUS FORECAST BASED ON INDICATIONS THE STORM WILL ACCELERATE AS IT UNDERGOES EXTRA-TROPICAL TRANSITION SOONER. B. AS TYPHOON 16W TURNS POLEWARD TOWARD A WEAKNESS IN THE RIDGE, IT WILL REMAIN EAST OF THE RYUKUS. NUMERICAL MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT WITH THIS SCENARIO. LACK OF COUPLING WITH THE MID-LATITUDE WESTERLIES WILL RESULT IN A SLOW AND GRADUAL TURN TO THE NORTH. INTERACTION WITH THE BAROCLINIC ZONE WILL COMMENCE AS THE STORM APPROACHES 28N. IN THE SAME REGION, THERE WILL BE A SHARP INCREASE IN VERTICAL WIND SHEAR, AS THE UPPER TROPOSPHERIC WESTERLIES INCREASE TO OVER 75 KNOTS NORTH OF 29N. THE COMBINATION OF INCREASING VERTICAL WIND SHEAR AND ENTRAINMENT OF MODIFIED CONTINENTAL POLAR AIR INTO THE BOUNDARY LEVEL WILL AFFECT A SHARP EXTRA-TROPICAL TRANSITION AND PRONOUNCED DECAY OF THE SYSTEM BETWEEN TAU 48 AND 72. TY 16W WILL COMPLETE EXTRA-TRANSITION AND BECOME A VIGOROUS BAROCLINIC LOW. NUMERICAL MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT IN THE EARLY TAUS. THE TRACK FORECAST THROUGH TAU 72 STAYS JUST WEST AND JUST FASTER THAN CONSENSUS THROUGH TAU 72. C. AFTER TAU 72, TY 16W IS EXPECTED TO TRACK BETWEEN THE JAPANESE ALPS AND THE KANTO PLAIN AS A SEVERE GALE TO STORM FORCE LOW BEFORE RETURNING TO THE WESTERN PACIFIC WELL SOUTH OF MISAWA, JAPAN. NUMERICAL MODEL GUIDANCE HAS COME INTO TIGHTER AGREEMENT IN THE LATER TAUS AND THE JTWC FORECAST TRACK HAS REMAINED PERSISTENT. THE FORECASTED SPEED IS FASTER THAN MODEL CONSENSUS AT TAU 96 AND 120 IN ANTICIPATION OF STEERING BY THE POLAR FRONT JET.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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. 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