From owner-wx-tropl@LISTSERV.ILLINOIS.EDU Thu Dec 30 04:49:58 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 oBTKnvNU006110 for ; Thu, 30 Dec 2010 04:49:58 +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 oBTFCX6L000588; Wed, 29 Dec 2010 14:49:43 -0600 (CST) Received: by LISTSERV.ILLINOIS.EDU (LISTSERV-TCP/IP release 14.5) with spool id 4907086 for WX-TROPL@LISTSERV.ILLINOIS.EDU; Wed, 29 Dec 2010 14:49:43 -0600 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 oBTKnhQ4000947 for ; Wed, 29 Dec 2010 14:49:43 -0600 (CST) 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 oBTKnaux025270 for ; Wed, 29 Dec 2010 14:49:43 -0600 (CST) Received: by weather3.admin.niu.edu (Postfix, from userid 501) id B5F47144B0001; Wed, 29 Dec 2010 14:49:36 -0600 (CST) X-Proofpoint-Spam-Reason: safe Message-ID: <20101229204936.B5F47144B0001@weather3.admin.niu.edu> Date: Wed, 29 Dec 2010 14:49:36 -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 146 FXPQ60 PGUM 292049 AFDPQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TIYAN GU 649 AM CHST THU DEC 30 2010 .SYNOPSIS...A FEW SHOWERS COULD BE SEEN ON RADAR THIS MORNING OVER THE LOCAL AREA. ISOLATED SHOWERS AND EAST TRADE-WINDS ARE EXPECTED TODAY. && .DISCUSSION... NORTHEAST WINDS OF THIS MORNING WILL GRADUALLY GIVE WAY TO EASTERLIES BY NOON TIME. SOUTHEASTERLY WINDS PREVAIL TONIGHT THROUGH SATURDAY THEN EAST SATURDAY NIGHT. WINDS WILL BE LIGHT DURING THE DAY SATURDAY AS A NEUTRAL POINT PASSES CLOSE TO SAIPAN. QUANDARY EXIST AS TO FINAL POSITION OF A SOUTHWARD MOVING SHEAR LINE EXPECTED IN THE AREA THIS WEEKEND. A FEW DAYS AGO MODELS PREDICTED THAT THE SHEAR LINE WOULD MAKE IT TO GUAM. LATER MODEL OUTPUT KEPT THE SHEAR LINE NORTH OF SAIPAN. NOW GFS AND NGPS BRING THE SHEAR LINE DOWN TO JUST NORTH OF SAIPAN. GFS-E AND ECMWF PUSH IT DOWN TO GUAM SUNDAY NIGHT AT LEAST IN THE WIND FIELD. GFS-E RAIN PATTERN KEEPS RAINFALL SAIPAN NORTHWARD. WILL KEEP CURRENT FORECAST AND PROG SHEAR LINE TO REMAIN NORTH OF SAIPAN. AT THIS TIME KEPT SHOWERS ISOLATED THROUGH FORECAST. GFS AND NGPS HAS BEEN SHOWING FOR THE LAST FEW DAY WHAT APPEARS TO BE A TROUGH PASSING SOUTH OF GUAM MONDAY AND TUESDAY. IT SEEMS THAT THE BULK OF THE MOISTURE REMAINS SOUTH OF THE MARIANAS THEREFORE WILL KEEP SHOWERS ISOLATED FOR THAT TIME PERIOD. DID INTRODUCE MOSTLY CLOUDY SKIES MONDAY NIGHT AND TUESDAY. && .MARINE... EAST TRADE-WIND SWELL AND A NORTHWEST SWELL WILL PERSIST THROUGH THE FORECAST. THE TRADE-WIND SWELL WILL BE A MINOR PLAYER IN THE COMING FORECAST WITH THE NORTHWEST SWELL BECOMING THE HEAVY HITTER. THE NORTHWEST SWELL WILL REMAIN AROUND FOUR FEET THROUGH SATURDAY NIGHT. A STORM SYSTEM IS EXPECTED TO DEVELOP ACROSS THE NORTHWEST PACIFIC OVER THE NEXT FEW DAYS. STRONG WINDS BEHIND AN ASSOCIATED COLD FRONT WILL GENERATE SWELL ACROSS THE NORTHWEST PACIFIC WHICH WILL ENTER THE LOCAL AREA LATE SATURDAY NIGHT AND SUNDAY. BY MONDAY THIS SWELL IS PREDICTED TO REACH 9 TO 10 FEET. IT WILL REMAIN THIS WAY FOR AT LEAST THE FIRST HALF OF NEXT WEEK. THE SWELL PERIOD IS EXPECTED TO BE 13 TO 14 SECONDS. THIS SWELL HEIGHT AND PERIOD WOULD GENERATE SURF OF UP TO 14 FEET ON WEST AND NORTH FACING REEFS. THEREFORE HIGH SURF ADVISORIES WILL MOST LIKELY BE NEEDED PART OF NEXT WEEK. WHILE IT IS EXPECTED THAT THE SURF WILL PEAK AROUND 14 FEET FOR MOST OF THE TIME THERE COULD BE PERIODS OF SLIGHTLY HIGHER SURF...ESPECIALLY AROUND TIMES OF HIGH TIDE. TIDE TABLE FOR THIS TIME SHOW THAT THE LEVEL OF THE HIGH TIDE WILL BE AROUND TWO FEET. THIS ADDED TO 14 FEET WILL EQUAL 16 FEET. SURF OF THIS HEIGHT WILL MOST LIKELY CAUSE BRIEF PERIODS INUNDATION ON A FEW BEACHES ON NORTH AND WEST FACING SHORES. THERE ARE STILL A FEW DAYS TO SORT THINGS OUT BUT THIS WILL BE WATCHED FOR THIS POSSIBILITY. THE LARGE SWELL WILL ALSO HELP RAISE SEAS TO SMALL CRAFT ADVISORY LEVEL AT THAT TIME. && .EASTERN MICRONESIA... SATELLITE IMAGERY SHOWS DEVELOPING MID-LEVEL CLOUD COVER ALONG WEAK CONVERGING TRADE WINDS OVER THE FORECAST LOCATIONS BUT SHOWERS CONTINUE TO BE SPARSE WITHIN THIS REGION. CONVECTION FORMING SOUTHEAST OF KOSRAE WILL PASS TO THE SOUTH OF THE AREA THROUGH THE DAY. OTHERWISE....GENERALLY DRY CONDITIONS WITH A SLIGHT INCREASE IN TRADE WINDS WILL CONTINUE OVER THE NEXT COUPLE OF DAYS. MODELS SHOW THE NEXT DISTURBANCE IS EXPECTED TO AFFECT POHNPEI OVER THE WEEKEND BUT FORECAST CONFIDENCE IS STILL FAIRLY LOW AS MODEL SOLUTIONS DIVERGE APPRECIABLY DURING THIS PERIOD. SWELL GENERATED BY A STRONG LOW PROGGED TO DEVELOP EAST OF JAPAN IS EXPECTED TO ARRIVE AT POHNPEI EARLY MONDAY MORNING AND KOSRAE BY MONDAY NIGHT MAY ALLOW SURF TO RISE ABOVE ADVISORY LEVELS. ALTHOUGH A DOWNWARD TREND IN SWELL HAS BEEN NOTICED IN THE PAST FEW WAVE WATCH RUNS...THE NORTH SWELL WILL STILL BE SUFFICIENT TO CREATE HIGH SURF CONDITIONS AT POHNPEI AND KOSRAE EARLY NEXT WEEK. && .WESTERN MICRONESIA... DELAYED ONSET OF SCATTERED SHOWERS FOR THE AFTERNOON HOURS AT KOROR AND TONIGHT FOR YAP AS IR IMAGERY SHOWS LIMITED SHOWER ACTIVITY EARLY THIS MORNING. MODELS ARE IN FAIR AGREEMENT IN INITIALIZING WIDESPREAD CONVECTION OVER KOROR LATER TODAY AND THIS EVENING AS THE TROUGH AXIS MOVES CLOSER THE AREA. SIMILARLY DRY CONDITIONS OVER EASTERN MICRONESIA WILL ALSO CONTINUE AT CHUUK THROUGH FRIDAY NIGHT BEFORE SHOWER ACTIVITY INCREASES OVER THE WEEKEND. NORTH SWELL WILL ARRIVE SUNDAY FOR BOTH YAP AND KOROR WITH AN ADVISORY ISSUANCE LIKELY NEEDED BY SATURDAY AFTERNOON. SWELL SHOULD ARRIVE LATE SUNDAY NIGHT AT CHUUK...WITH AN ADVISORY LIKELY BY SUNDAY. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...NONE. MARIANAS WATERS...NONE. && $$ ZIOBRO/WILLIAMS +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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. 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