From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Fri Sep 3 11:04:31 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 o8334TFi019373 for ; Fri, 3 Sep 2010 11:04:30 +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 o82Invmr014070; Thu, 2 Sep 2010 22:04:14 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3207159 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Thu, 2 Sep 2010 22:04:13 -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 o8334Dol011243 for ; Thu, 2 Sep 2010 22:04:13 -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 o83346xV008774 for ; Thu, 2 Sep 2010 22:04:13 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id D72874050023; Thu, 2 Sep 2010 22:04:06 -0500 (CDT) X-Spam-Score: 67 X-Spam-Details: rule=no-quarantine_likelyspam policy=no-quarantine score=67 spamscore=67 ipscore=0 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=5.0.0-1005130000 definitions=main-1009020230 X-Spam-OrigSender: ldm@weather3.admin.niu.edu X-Spam-Bar: ******* Message-ID: <20100903030406.D72874050023@weather3.admin.niu.edu> Date: Thu, 2 Sep 2010 22:04:06 -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 10w/ To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list WDPN33 PGTW 030300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W/ WARNING NR 06// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL DEPRESSION (TD) 10W (TEN), LOCATED APPROXIMATELY 340 NM SOUTHEAST OF OKINAWA, JAPAN, HAS TRACKED NORTHWESTWARD AT 17 KTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL IMAGERY SHOWS THAT THE SYSTEM CONTINUES TO STRUGGLE DEVELOPING IN THE VICINITY OF THE TROPICAL UPPER TROPOSHERIC TROUGH (TUTT) TO THE WEST. FLARING, DEEP CONVECTION IS EVIDENT OVER THE LOW LEVEL CIRCULATION CENTER (LLCC), BUT ONLY WEAK INFLOW BANDING IS SEEN ON THE SOUTHERN SIDE. WATER VAPOR IMAGERY SHOWS THAT THE SYSTEM HAS SOME OUTFLOW TO THE EAST, BUT THAT THE TUTT IS IMPINGING ON THE OUTFLOW TO THE SOUTH AND WEST. A 022303Z SSMIS PASS SHOWS THAT THE SYSTEM HAS A SYMMETRICAL LLCC AND A SMALL POCKET OF DEEP CONVECTION NEAR THE CENTER. THE SYSTEM IS CURRENTLY TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE TO THE NORTHEAST. POSITION IS BASED ON THE 022303Z SSMIS PASS AND A POSITION FIX FROM PGTW WITH GOOD CONFIDENCE. INTENSITY IS BASED ON A DVORAK INTENSITY FIX FROM PGTW. 3. FORECAST REASONING. A. THE EXTENDED PORTION OF THE FORECAST IS NOW MORE TO THE WEST OF THE TRACK FORECAST AT 021800Z IN RESPONSE TO A WESTERN FINGER OF THE SUBTROPICAL RIDGE. THE INITIAL HALF OF THE FORECAST IS FUNDAMENTALLY THE SAME. B. TD 10W WILL CONTINUE TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE ENTRENCHED JUST SOUTH OF MAINLAND JAPAN AND IT SHOULD CONTINUE TO TRACK NORTHWESTWARD THROUGH TAU 36. EARLY NUMERICAL MODEL GUIDANCE IS SPLIT ON HOW THE SYSTEM WILL BEHAVE IN THE FIRST 24 HOURS, WITH ECMWF, GFS AND UKMET TRACKING THE SYSTEM MORE WESTWARD IN WHAT IS BELIEVED TO BE EXCESSIVE DIRECT INTERACTION WITH THE TUTT TO THE WEST. NOGAPS AND WBAR HAVE A TRACK THAT CLOSER APPROXIMATES THE SHAPE OF THE RIDGE TO THE NORTH. BETWEEN HOURS 36 AND 72 THE SYSTEM IS EXPECTED TO SLOW AND JOG TO THE WEST IN RESPONSE TO THE WESTERN EXTENT OF THE RIDGE THAT EXTENDS ACROSS THE MOUTH OF THE YELLOW SEA, WITH THE POSSIBILITY OF WEAKENING DUE TO COLDER WATER, REDUCED OUTFLOW, AND MILD VERTICAL WIND SHEAR FROM THE UPPER-LEVEL RIDGE. ALL OF THE MODELS WITH THE EXCEPTION OF UKMET (WHICH LOSES THE CIRCULATION AT 48 HOURS) AGREE WITH THIS MOTION, BUT IN VARYING DEGREES. C. AFTER TAU 72, TD 10W IS EXPECTED TO MEANDER INTO THE YELLOW SEA AS THE WESTERN EXTENT OF THE RIDGE BREAKS DOWN IN RESPONSE TO A PASSING MID-LATITUDE TROUGH. THE BAROCLINIC ZONE IS FORECASTED TO BE NEAR THE NORTHERN EXTENT OF THE YELLOW SEA, AND AS THE RIDGE TO THE EAST RECEDES FROM THE EARLIER MID-LATITUDE TROUGH, THE SYSTEM WILL BE LEFT IN A RELATIVELY WEAK STEERING ENVIRONMENT. THE SYSTEM IS EXPECTED TO CONTINUE TO WEAKEN IN THE COOLER WATERS IN THE NORTHERN YELLOW SEA AND START TO FEEL THE VERTICAL WINDSHEAR FROM THE BAROCLINIC ZONE. NUMERICAL MODEL GUIDANCE ALL SUPPORTS THE WEAK STEERING ENVIRONMENT, AND AS EXPECTED IN A WEAK ENVIRONMENT, THERE ARE MANY POSSIBLE SOLUTIONS, BUT ALL THE MODELS HAVE IT IN THE YELLOW SEA.// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.