From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Sun Sep 19 04:20:25 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 o8IKKOrW007826 for ; Sun, 19 Sep 2010 04:20:25 +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 o8HKE7Hn023157; Sat, 18 Sep 2010 15:20:01 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3461927 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Sat, 18 Sep 2010 15:20:01 -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 o8IKK17b007399 for ; Sat, 18 Sep 2010 15:20:01 -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 o8IKJs24012004 for ; Sat, 18 Sep 2010 15:20:00 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 31722405001E; Sat, 18 Sep 2010 15:19:54 -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=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=5.0.0-1005130000 definitions=main-1009180103 X-Spam-OrigSender: ldm@weather3.admin.niu.edu X-Spam-Bar: Message-ID: <20100918201954.31722405001E@weather3.admin.niu.edu> Date: Sat, 18 Sep 2010 15:19:54 -0500 Reply-To: wxmaster@COX.NET Sender: WX-TROPL Tropical Storm and Hurricane WX products From: LDM Weather Subject: Western Pacific: Synoptic Discussion For The Marianas To: WX-TROPL@LISTSERV.ILLINOIS.EDU Precedence: list 033 FXPQ60 PGUM 182019 AFDPQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TIYAN GU 619 AM CHST SUN SEP 19 2010 .SYNOPSIS... A WEAK UPPER TROUGH REMAINS EAST AND NORTH OF THE MARIANAS. EAST OF THE ISLANDS...TROPICAL DISTURBANCE 90W CENTERED NEAR 15N152E IS PRODUCING DEEP CONVECTION NEAR AND EAST OF THE CENTER. BUT IN THE MARIANAS WATERS...ONLY ISOLATED SHOWERS ARE PRESENT. && .DISCUSSION... GFS...UKMET AND NOGAPS AGREE THAT 90W WILL MOVE NORTH...TAKING MOST OF ITS WEATHER WITH IT. THE ECMWF TAKES 90W ON A MORE NW TRACK...BUT STILL KEEPS THE HEAVIEST WEATHER NE OF THE MARIANAS. NEITHER THE GFS NOR THE UKMET BRING MUCH QPF TO THE MARIANAS...SO WILL KEEP FINGERS CROSSED AND MAINTAIN THE FORECAST OF ISOLATED SHOWERS/THUNDER THROUGH TONIGHT...WHILE KEEPING A CLOSE EYE ON 90W. && .EASTERN MICRONESIA... LATEST ASCAT SATELLITE DATA REVEAL THE BROAD SURFACE TROUGH EAST OF THE MARIANAS IS NOW A LOW-LEVEL CIRCULATION AND JTWC INVEST AREA 90W. THIS FEATURE IS RE-DIRECTING MODERATE TO FRESH TRADE WINDS ASSOCIATED WITH A SURGE CROSSING THE DATE LINE TO FLOW MORE EASTWARD...PASSING NORTH OF EASTERN MICRONESIA. IN RESPONSE...THE ITCZ HAS SHIFTED NORTHWARD TO ALONG 10N. THEREFORE...CURRENT FORECAST FOR THE REGION HAS IMPROVED SOMEWHAT FROM THE PREVIOUS ONE. HOWEVER...SURFACE WAVES EMBEDDED WITHIN THE WEAKER EAST TO SOUTHEAST TRADES SOUTH OF THE ITCZ CAN STILL PRODUCE PERIODS OF SHOWERS AND A FEW THUNDERSTORMS FROM THE MARSHALLS WESTWARD TO CHUUK STATE INTO EARLY NEXT WEEK. WITH EVEN LIGHTER TRADES FARTHER UPSTREAM EAST OF THE DATE LINE...SURFACE CONVERGENCE SHOULD GRADUALLY DECREASE TOWARD MIDWEEK. INSTEAD...AN UPPER TROUGH DRIFTING WESTWARD WILL PROVOKE WIDELY SCATTERED TRADE-WIND SHOWERS. && .WESTERN MICRONESIA... THE SURFACE RIDGE OVER THE PHILIPPINE SEA HAS MOVED NORTHWEST OF THE AREA...ALLOWING NORTHEASTERLY TRADES TO PENETRATE ACROSS YAP AND PALAU THIS MORNING. A WEAK SURFACE TROUGH MIGRATING ALONG IS ANTICIPATED TO PROVIDE A PERIOD OF WET WEATHER FOR YAP BY THIS AFTERNOON...AND POSSIBLY KOROR ON MONDAY. FORECAST AFTER MONDAY CONTAINS UNCERTAINTY DEPENDING ON THE STATUS 90W EAST OF THE MARIANAS. IF 90W REMAIN QUASI-STATIONARY...THERE WILL BE A BETTER CHANCE FOR IT TO BECOME BETTER ORGANIZED AND FORMING A SURFACE RIDGE NEAR CHUUK. THIS WILL BLOCK THE TRADE-WIND FLOW FROM THE EAST AND CAUSE LIGHT AND VARIABLE WIND WITH FAIR WEATHER OVER WESTERN MICRONESIA. ON THE OTHER HAND...IF IT BEGINS TO DRIFT NORTHWESTWARD AS MOST MODELS SUGGEST...SURFACE WAVES OVER EASTERN MICRONESIA WILL BE ABLE TO APPROACH WESTWARD AND TRIGGER MORE SHOWERS. HAVE KEPT CLOUDS AND ISOLATED SHOWERS IN THE FORECAST FOR NOW. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...NONE. MARIANAS WATERS...NONE. && $$ MIDDLEBROOKE/CHAN +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.