From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Thu Oct 28 04:56:26 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 o9RKuOZN026706 for ; Thu, 28 Oct 2010 04:56:25 +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 o9RHpuN9021767; Wed, 27 Oct 2010 15:56:08 -0500 (CDT) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 4092165 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Wed, 27 Oct 2010 15:56:08 -0500 Received: from relay07.cites.uiuc.edu (relay07.cites.uiuc.edu [128.174.4.73]) by vacuum.cso.uiuc.edu (8.14.2/8.14.2) with ESMTP id o9RKu7OL006708 for ; Wed, 27 Oct 2010 15:56:07 -0500 (CDT) Received: from weather3.admin.niu.edu (weather3.admin.niu.edu [131.156.8.48]) by relay07.cites.uiuc.edu (8.14.4/8.14.2) with ESMTP id o9RKu1eP013238 for ; Wed, 27 Oct 2010 15:56:07 -0500 (CDT) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id 4DD5C4050024; Wed, 27 Oct 2010 15:56:01 -0500 (CDT) X-Proofpoint-Spam-Reason: safe Message-ID: <20101027205601.4DD5C4050024@weather3.admin.niu.edu> Date: Wed, 27 Oct 2010 15:56:01 -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 321 FXPQ60 PGUM 272055 AFDPQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TIYAN GU 655 AM CHST THU OCT 28 2010 .SYNOPSIS...ISOLATED SHOWERS EXPECTED THE NEXT FEW DAYS. THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS ACROSS THE MARIANAS TODAY AND TONIGHT. ISOLATED SHOWERS COULD BE SEEN ON RADAR OVER THE ISLANDS THIS MORNING. A FEW BRIEF THUNDERSTORMS DEVELOPED NEAR GUAM AND ROTA BEFORE SUNRISE. AN UPPER-LEVEL LOW IS LOCATED TO THE SOUTHEAST OF THE MARIANAS NEAR 11N148E. && .DISCUSSION... A FEW CHANGES MADE TO THE FORECAST. THE UPPER-LEVEL LOW SOUTHEAST OF THE MARIANAS THIS MORNING WILL MOVE WEST DURING THE DAY. ALL THE MODELS ARE CONSISTENT WITH LOCATING IT JUST SOUTH OF GUAM LATE TONIGHT. THIS UPPER-LOW APPEARED TO HELP SPARK OFF A FEW THUNDERSTORMS NEAR GUAM AND ROTA AFTER MIDNIGHT. EARLY MORNING SATELLITE IMAGERY SHOWS MORE CONVECTION JUST NORTH OF THE UPPER LOW. CONVECTION IS RATHER SPOTTY SO THE POSSIBILITY OF THUNDERSTORMS IS ONLY SLIGHT. LOOKING AT THE POSITION OF CONVECTION IN RELATION TO THE UPPER LOW...IT WOULD APPEAR THAT MOST IF NOT ALL OF THE THUNDERSTORMS WOULD DEVELOP MOSTLY OVER ROTA AND GUAM. FELT THE DIFFERENCE WAS TOO SMALL TO SPLIT THE ZONES...SO INCLUDED MENTION OF THUNDER FOR ALL ISLANDS. MODELS KEEP THINGS FAIRLY QUIET WITH ONLY ISOLATED SHOWERS EXPECTED THROUGH THE END OF THE FORECAST. && .MARINE...TRADE-WIND SWELL WILL CONTINUE THROUGH THE END OF THE FORECAST. THIS WILL GENERATE A MODERATE RISK OF RIP CURRENTS ON NORTH AND EAST FACING REEFS. SWELL ASSOCIATED WITH DISTANT TYPHOON CHABA IS SPREADING ACROSS THE PHILIPPINE SEA. THE MAIN PART OF THE SWELL WILL PUSH DOWN TO PALAU AND YAP WHILE THE MARIANAS WILL ONLY BE ON THE EDGE OF THE SWELL. EXPECT A NORTHWEST SWELL OF ABOUT 3 FEET TO ENTER THE LOCAL AREA FRIDAY NIGHT AND CONTINUE INTO NEXT WEEK. CURRENT CALCULATIONS GENERATE SURF OF 4 TO 6 FEET ON WEST FACING REEFS THIS WEEKEND. AT THE PRESENT TIME THIS APPEARS REASONABLE BUT ADJUSTMENTS EITHER UP OR DOWN MAYBE NEEDED SINCE THIS IS A MODEL ESTIMATE. IF THE MODEL DID NOT ESTIMATE THE WIND FIELD ASSOCIATED WITH THE TYPHOON CORRECTLY THAN THE PREDICTED SURF COULD BE IN ERROR. && .EASTERN MICRONESIA... A VIGOROUS LOW PRESSURE SYSTEM NORTHEAST OF WAKE ISLAND ALONG WITH ITS ASSOCIATED SURFACE TROUGH EXTENDING SOUTHWARD TO NEAR 5N180 ARE RE-DIRECTING THE STRONGEST TRADE WINDS TO THE NORTH OF EASTERN MICRONESIA. THEREFORE...WEAKER CONVERGENCE FROM LIGHT TO GENTLE TRADES WILL PROMOTE RELATIVELY DRIER CONDITIONS FOR THE REGION DURING THE NEXT FEW DAYS. AS THE LOW PRESSURE SYSTEM/TROUGH COMBINATION CONTINUES TO MOVE WESTWARD...THE SOUTHERN BRANCH OF THE TROUGH IS EXPECTED TO REACH THE MARSHALL ISLANDS BY THE WEEKEND. INCREASING CONVERGENCE NEAR THE TROUGH AXIS WILL LIKELY CAUSE SHOWERY WEATHER FOR MAJURO AND KOSRAE OVER THE WEEKEND...AND EVENTUALLY FOR POHNPEI BY EARLY NEXT WEEK. FINALLY...A MUCH DRIER TRADE SURGE FROM THE SOUTHERN HEMISPHERE MIGHT INTRODUCE A DRYING TREND FOR MAJURO AND KOSRAE LATER NEXT WEEK. BUILDING TRADE-WIND SWELL COULD RESULT IN HIGHER SURF ALONG NORTH AND EAST FACING SHORES OF MAJURO OVER THE WEEKEND BUT SHOULD BE BELOW ADVISORY LEVELS. && .WESTERN MICRONESIA... A WEAK SURFACE TROUGH ALONG WITH DIVERGENT WINDS SOUTH OF AN UPPER TROUGH WILL KEEP SCATTERED CONVECTION OVER CHUUK THRU AT LEAST THIS EVENING. THEN WEAKER TRADES FROM THE EAST ARE GOING TO DECREASE SHOWER COVERAGE BY THE WEEKEND. THINGS COULD BECOME WETTER AGAIN NEXT WEEK AS ANOTHER SURFACE TROUGH APPROACHES THE ISLAND FROM THE EAST. A SURFACE RIDGE TO THE SOUTHEAST OF DISTANT TYPHOON CHABA PERSISTS OVER THE PHILIPPINE SEA JUST NORTHWEST OF KOROR AND YAP. GENTLE TO MODERATE TRADES FLOWING ACROSS THE MARIANAS ARE MERGING TOWARD THE RIDGE AXIS. AIDED BY AN UPPER TROUGH OVER THE AREA...ISOLATED CONVECTIVE ACTIVITY CAN BE ANTICIPATED FOR YAP THRU TODAY...AND KOROR INTO FRIDAY. SHOWER COVERAGE OVER KOROR MIGHT INCREASE FURTHER BY THIS EVENING AS WELL. WITH THE SURFACE RIDGE DISSIPATING OVER THE WEEKEND...THIS SHOULD ALLOW GENTLE TRADES WITH ISOLATED PASSING SHOWERS TO FLOW ACROSS THE AREA. LONG-PERIOD NW SWELLS FROM TYPHOON CHABA WILL CREATE A HIGH SURF EVENT FOR BOTH PALAU AND YAP INTO THE WEEKEND. A HIGH SURF ADVISORY HAD BEEN ISSUED ACCORDINGLY AND WILL NEED TO BE UPDATED LATER THIS AFTERNOON. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...NONE. MARIANAS WATERS...NONE. && $$ ZIOBRO/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.