From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Tue Nov 16 02:31:50 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 oAFIVnMw011531 for ; Tue, 16 Nov 2010 02:31:50 +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 oAF3eO8k006383; Mon, 15 Nov 2010 12:31:38 -0600 (CST) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 4374358 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Mon, 15 Nov 2010 12:31:38 -0600 Received: from relay06.cites.uiuc.edu (relay06.cites.uiuc.edu [128.174.196.8]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id oAFIVcxa026756 for ; Mon, 15 Nov 2010 12:31:38 -0600 (CST) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay06.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id oAFIVUYl011796 for ; Mon, 15 Nov 2010 12:31:38 -0600 (CST) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 0DDBC4050021; Mon, 15 Nov 2010 12:31:29 -0600 (CST) X-Proofpoint-Spam-Reason: safe Message-ID: <20101115183130.0DDBC4050021@weather3.admin.niu.edu> Date: Mon, 15 Nov 2010 12:31:29 -0600 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 766 FXPQ60 PGUM 151831 AFDPQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TIYAN GU 431 AM CHST TUE NOV 16 2010 .SYNOPSIS... LATEST IR SATELLITE IMAGERY HAS A RATHER DIFFUSE SHEAR LINE NEAR GUAM AND EASTWARD ALONG THE 12TH PARALLEL TO BEYOND 160E. RADAR IMAGERY REMAINS UNAVAILABLE. AN INFLOW ANTICYCLONE IS CENTERED EAST OF THE MARIANAS NEAR 17N153E. A WEAKNESS IN THE UPPER-LEVEL RIDGE IS PRESENT WEST OF THE MARIANAS NEAR 140E. && .DISCUSSION... NO SIGNIFICANT CHANGES TO FORECAST REASONING. SURFACE HIGH PRESSURE IS CURRENTLY BUILDING TO THE NORTH OF THE MARIANAS...BUT BELIEVE WINDS WILL SLACKEN A BIT AS THE WEEK PROGRESSES. GRIDS ALREADY REFLECT THIS. GFS AND ECMWF GUIDANCE HAVE LOW PRESSURE REPEATEDLY DEVELOPING EAST OF JAPAN DURING MID WEEK. THIS WILL WEAKEN THE SUBTROPICAL RIDGE. THE SUBTROPICAL RIDGE SHOULD RESTRENGTHEN NEXT WEEKEND. PRIMARY FORECAST CONCERN REVOLVES AROUND THE EXACT POSITION AND CONFIGURATION OF THE SHEAR LINE PRESENTLY NEAR GUAM. GFS BRINGS THE SHEAR LINE BACK TO THE NORTH AND INCREASES ASSOCIATED QPF WITH TIME. WV SATELLITE IMAGERY SUGGESTS THE MARIANAS WILL REMAIN BENEATH A SUBSIDENT UPPER-LEVEL RIDGE FOR AT LEAST A LITTLE WHILE...BUT GFS AND ECMWF WORK IN SOME UPPER-LEVEL DYNAMICS FROM THE WEST ON WEDNESDAY AND THURSDAY. HAVE ALSO SEEN ISENTROPIC LIFT AUGMENT SHEAR LINE ASSOCIATED QPF IN THE PAST. THIS WILL HAVE TO BE WATCHED. PRIME TIME FOR SCATTERED SHOWERS WOULD BE WEDNESDAY NIGHT AND THURSDAY MORNING. WILL HOLD OFF ON INCREASING POPS FOR NOW AS CONFIDENCE REMAINS LOW ON THE EXACT TIMING AND POSITIONING OF SUCH AN EVENT. BEYOND THU...GFS AND ECMWF LIFT THE SHEAR LINE BACK TO THE NORTH OF SAIPAN. && .MARINE... MARINE SWELL GRIDS IN GOOD SHAPE. MODERATE RIP CURRENT RISK LEVEL SURF IS STILL EXPECTED TO PREVAIL ON EAST FACING REEFS DURING THE NEXT COUPLE OF DAYS. IPAN BUOY COMES IN WITH SIGNIFICANT SWELL HEIGHTS BETWEEN 6.5 AND 7 FEET AND 85 DEGREE WATER TEMPERATURE. WAVE WATCH TABULAR DATA STILL CALLS FOR GRADUALLY DECLINING SURF ON EAST FACING REEFS FOR THE NEXT FEW DAYS. NORTH SWELL IS DUE IN FRI NITE...BUT SHOULD ONLY BE ENOUGH TO GENERATE SURF TO MODERATE RIP CURRENT RISK LEVELS ON RESPECTIVE EXPOSURES. ASCAT IMAGERY REMAINS UNAVAILABLE DUE TO AN INTERNET OUTAGE. && .EASTERN MICRONESIA... CONVECTION HAS CONSOLIDATED WEST OF MAJURO...NEAR KOSRAE AND SOUTH OF POHNPEI DURING THE PAST SEVERAL HOURS. ANIMATED SATELLITE IMAGERY SUGGESTS THAT SHOWERS SHOULD BEGIN TO WRAP UP NEAR KOSRAE AROUND MIDDAY TODAY WITH INCREASING CLOUDS OVER POHNPEI AS CONVECTIVE ACTIVITY NUDGES SLIGHTLY NORTHWARD TONIGHT. MODELS HINT AT INCREASED CLOUD COVER OVER ALL OF EASTERN MICRONESIA TOWARD THE END OF THE WEEK BUT ONLY A MARGINAL INCREASE IN SHOWER COVERAGE IS EXPECTED FOR NOW. && .WESTERN MICRONESIA... THE WEAK CIRCULATION CENTERED SOUTHEAST OF YAP AND KOROR YESTERDAY IS NO LONGER DISCERNIBLE IN IR IMAGERY BUT LATEST SURFACE ANALYSIS INDICATES A NEAR-EQUATORIAL TROUGH EXTENDING FROM SOUTHEAST OF YAP AND KOROR TO THE PHILIPPINES. IN RESPONSE TO THE PROXIMITY OF THE TROUGH...WIND SPEEDS HAVE DECREASED ON KOROR OVERNIGHT AND WILL LIKELY REMAIN AS SUCH TODAY. MODELS PROG THE TROUGH TO MOVE WESTWARD TODAY AND TONIGHT WITH SCATTERED SHOWERS DEVELOPING OVER KOROR TONIGHT AS EAST WINDS INCREASE. BY WEDNESDAY THE TROUGH WILL MOVE OUT OF THE AREA AND SHOWERS WILL BECOME ISOLATED. THE TROUGH WILL BE FARTHER SOUTH OF YAP. THUS ISOLATED SHOWERS ARE EXPECTED OVER YAP FOR THE NEXT SEVERAL DAYS. A SLOW MOVING TROUGH NEAR CHUUK HAS KEPT SCATTERED SHOWERS AND A FEW THUNDERSTORMS LOCKED IN PLACE OVER WATERS SOUTH OF WENO. SATELLITE IMAGERY SHOWS LITTLE CHANGE IN THE PLACEMENT OF SHOWERS DURING THE PAST SEVERAL HOURS. MODELS ALSO CONFINE THE SHOWERS JUST TO THE SOUTH OF WENO. ACCORDINGLY...HAVE DECIDED TO SPLIT THE CHUUK MARINE ZONE. FOR TODAY...WILL FORECAST ISOLATED SHOWERS OVER THE NORTHERN HALF OF CHUUK WATERS AND SCATTERED SHOWERS OVER THE SOUTHERN HALF. THE TROUGH SHOULD EXIT TO THE WEST LATER TODAY AND PULL THE SCATTERED SHOWERS OUT OF THE AREA TEMPORARILY UNTIL A BAND OF CONVECTION STRETCHING EASTWARD FROM SOUTH OF POHNPEI TO KOSRAE PASSES OVER THE AREA WEDNESDAY NIGHT. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...NONE. MARIANAS WATERS...NONE. && $$ MCELROY/W. AYDLETT +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.