From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Fri Sep 17 16:11:26 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 o8H8BPJU023290 for ; Fri, 17 Sep 2010 16:11:25 +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 o8H50Qc6023157; Fri, 17 Sep 2010 03:11:05 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 3441672 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Fri, 17 Sep 2010 03:11:04 -0500 Received: from relay09.cites.uiuc.edu (relay09.cites.uiuc.edu [128.174.4.86]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o8H8B4dO002629 for ; Fri, 17 Sep 2010 03:11:04 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay09.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o8H8Avsp021893 for ; Fri, 17 Sep 2010 03:11:03 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 67974405001E; Fri, 17 Sep 2010 03:10:57 -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=63 adultscore=0 classifier=spam adjust=0 reason=mlx engine=5.0.0-1005130000 definitions=main-1009170009 X-Spam-OrigSender: ldm@weather3.admin.niu.edu X-Spam-Bar: Message-ID: <20100917081057.67974405001E@weather3.admin.niu.edu> Date: Fri, 17 Sep 2010 03:10:57 -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 883 FXPQ60 PGUM 170810 AFDPQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TIYAN GU 610 PM CHST FRI SEP 17 2010 .SYNOPSIS...LATEST SATELLITE IMAGERY AND RADAR SHOW ISLAND THUNDERSTORMS OVER THE GUAM REGION WHILE THE REST OF THE MARIANAS HAVE DRIED UP AHEAD OF THE NEXT BATCH OF WEATHER WELL TO THE EAST. WATER VAPOR IMAGERY SHOWS THAT WE ARE NOW BEGINNING TO RECEIVE OUR MOISTURE IN ADVANCE FROM THE APPROACHING TROUGH WITH THE HIGHER CLOUDS REACHING US BY TONIGHT...AND SUGGEST SOME VERY ISOLATED THUNDERSTORMS IN THE MARIANAS WATERS ARE POSSIBLE OVER THE NEXT 24 HOURS. WE STILL EXPECT THE PRIMARY THRUST OF WEATHER TO NOT REACH US UNTIL LATE SATURDAY OR SUNDAY...LASTING INTO MONDAY. && .DISCUSSION...KEPT THE FORECAST SCENARIO FROM THE LAST TWO RUNS ALTHOUGH THE TROUGH AXIS SEEMS TO HAVE REPOSITIONED ITSELF FURTHER TO THE EAST...AND THE LATEST FORECAST RUNS GIVE A SLIGHT HINT THAT THIS AREA MAY BREAK INTO TWO PARTS WITH THE NORTHERN HALF FORMING A TROPICAL CYCLONE NORTH OF 20N AND THE MARIANAS...TOWARDS IWO JIMA. THE SOUTHERN PART...MEANWHILE...IS EXPECTED TO CONTINUE OVER THE MARIANAS ON SUNDAY AND MONDAY WITH PERHAPS A LITTLE LESS STRENGTH. IN ANY CASE IT DOES NOT TAKE TOO MUCH OF AN IMPULSE TO CREATE SCATTERED SHOWERS DURING THIS TIME OF THE YEAR. ALTHOUGH QUITE A WAYS OFF...BOTH THE ECMWF AND GFS SUGGEST A MOIST TAIL MAY RESULT FROM THE CYCLONE DEVELOPMENT TO THE NORTH AND EITHER KEEP US OR BRING US BACK INTO SCATTERED SHOWERS LATER IN THE WEEK. JUST SOMETHING TO THINK ABOUT AS THE CIRCULATION HAS YET TO EVEN BREAK OUT OF THE TROUGH NOW LOCATED NEAR 159E. IN THE VICINITY OF OKINAWA...TYPHOON FANAPI CONTINUES TO INTENSIFY BUT I BELIEVE THAT ANY WESTERLY FETCH WILL BE TOO SMALL AND TOO FAR AWAY TO HAVE ANY SIGNIFICANT EFFECT ON THE MARIANAS. && .EASTERN MICRONESIA... DRIER TRADES ALREADY OVER MAJURO ARE EXPECTED TO PROMOTE FAIRER CONDITIONS WESTWARD OVER THE WEEKEND AT EASTERN MICRONESIA ...HOWEVER LATEST ASCAT SATELLITE IMAGERY CONTINUES TO SHOW A MODERATE TO FRESH TRADE-WIND SURGE APPROACHING THE DATE LINE BETWEEN 5N AND 15N. AN ITCZ FORMED ALONG THE SOUTHERN EDGE OF THE SURGE...ORIENTING NORTHEASTWARD FROM 5N175E TO WELL SOUTH OF THE HAWAIIAN ISLANDS. CONVECTION ASSOCIATED WITH THE LEADING EDGE OF THE ITCZ IS FLARING UP AROUND 5N175E EASTWARD TO BEYOND THE DATELINE. ANTICIPATE THIS CONVECTION TO SPREAD OVER MAJURO BY SATURDAY EVENING AND GRADUALLY EXTEND WESTWARD DURING EARLY NEXT WEEK. BECAUSE OF THIS CONVERGENCE AND MODEL AGREEMENT... HAVE INTRODUCED SCATTERED SHOWERS TO THE KOSRAE FORECAST ON SUNDAY...AND TO THE POHNPEI FORECAST ON SUNDAY NIGHT. && .WESTERN MICRONESIA... FOR KOROR AND YAP...A SURFACE RIDGE IS ANCHORED OVER WESTERN MICRONESIA WITH LIGHT AND VARIABLE WINDS. BOTH WV SATELLITE IMAGERY AND THE YAP SOUNDINGS INDICATE A DRYING TREND AT MID TO UPPER LEVELS ADVECTING NORTHWESTWARD FROM THE EQUATOR. THE COMBINATION OF THESE TWO INDICATORS SUPPORT QUIET WEATHER FOR BOTH YAP AND PALAU THRU THE WEEKEND. WITH TYPHOON FANAPI ALREADY NORTH OF 20N...THE SURFACE RIDGE IS SHIFTING NORTHWEST OF THE REGION. THIS SHOULD ALLOW GENTLE TO MODERATE TRADE WINDS TO FILTER BACK OVER WESTERN MICRONESIA. HOWEVER...TRADE-WIND DISTURBANCES EMBEDDED WITHIN THE TRADE-WIND FLOW MIGHT INTRODUCE MORE SHOWER ACTIVITY. FOR CHUUK...A WEAK SURFACE TROUGH MIGRATING SLOWLY WESTWARD ALONG GENTLE TRADE WIND FLOW WILL KEEP SOME SHOWERS OVER CHUUK THRU SATURDAY AFTERNOON...THEN THE DRIER TRADES ENTERING EASTERN MICRONESIA WILL REACH CHUUK EARLY NEXT WEEK. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...NONE. MARIANAS WATERS...NONE. && $$ EDSON/DEVITA +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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.