FXUS66 KPQR 120425 AFDPQR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PORTLAND OR 825 PM PST THU MAR 11 2010 .SYNOPSIS...A NEARLY STATIONARY FRONTAL BOUNDARY WILL REMAIN FROM SW WASHINGTON TO THE CENTRAL OREGON COAST TONIGHT. THE FRONT WILL BECOME NORTH-TO-SOUTH ORIENTED LATE TONIGHT...THEN MOVE INLAND AS A COLD FRONT FRIDAY. THE UPPER TROUGH MOVES THROUGH FRIDAY NIGHT. HIGH PRESSURE STARTS TO BUILD OVER THE AREA SATURDAY AFTERNOON. WARMER AND DRIER CONDITIONS PREVAIL SUNDAY THROUGH EARLY NEXT WEEK. && .SHORT TERM...WATER VAPOR IMAGERY THIS EVENING SHOWS A CLASSIC BAROCLINC ZONE EXTENDING FROM SWRN WASHINGTON TO THE CENTRAL OREGON COAST...THEN OUT TO ABOUT 30N AND 140W. SECONDARY LOW PRESSURE AREA WITH PLENTY OF COLD AIR FEEDING INTO THE SOUTH PART OF THE BAROCLINIC BAND. NICE INFLECTION POINT WITH SOME DARKENING AT 42N 133W. LATEST AVAILABLE AMSU TOTAL PRECIPITABLE WATER VALUES INDICATE AROUND .80 TO .90 INCHES OFF THE SOUTH OREGON COAST. HOURLY RAINFALL RATES THIS EVENING HAVE NOT BEEN TOO OVERLY DRAMATIC...ON THE ORDER OF A TENTH TO A QUARTER INCH ALONG THE CENTRAL COAST AND IN THE CENTRAL OREGON COAST RANGE. HOURLY VALUES AROUND A TENTH TO 0.15 ALONG THE NORTH OREGON AND SOUTH WASHINGTON COAST. BAROCLINIC BAND WILL REMAIN NEARLY STATIONARY TONIGHT. GFS SHOWS HIGHEST QPF RIBBON ALONG THE CENTRAL COAST AT 06Z. AS THE SECONDARY LOW MERGES WITH THE FRNOTAL ZONE...THE BOUNDARY WILL BECOME MORE ORIENTED NORTH TO SOUTH...PULLING THE HEAVIER PRECIP BACK TOWARD THE COAST AND WEST SLOPES OF THE COAST RANGE BY 12Z FRI. COASTAL RIVERS SHOULD SEE EXPERIENCE GOOD RESPONSES WITH A 6-12 HOUR DOSE OF DECENT QPF. AT THIS POINT EXPECTED AMOUNTS FROM 06Z TO 18Z MAX OUT AT AROUND AN INCH TO 1.25 INCHES FOR THE CENTRAL COAST AND COAST RANGE. WOULD NOT BE SURPRISED TO SEE UPWARDS OF 1.5 INCHES IN THE 12-HOUR PERIOD. THE SNOW ADVISORY FOR THE S WA CASCADES EXPIRED AS SCHEDULED AT 04Z. LATEST OBS FROM SNOTELS AND OTHER SOURCES INDICATE TEMPS IN THE MID 30S ABOVE 3000 FT. CURRENT HIGH WIND WARNING FOR THE CENTRAL OREGON COAST LOOKS MARGINAL BUT WILL LEAVE AS IS. LATEST NAM RUN SHOWS 35-40 KT BOUNDARY LAYER WIND ALONG THE CENTRAL COAST AT 12Z AND 55-60 KT AT 925 MB JUST OFFSHORE. GFS CONTINUES TO BE A LITTLE WEAKER WITH THE WIND FIELD. APPEARS AS THOUGH THE LATTEST GFS IS A LITTLE SLOWER MOVING THE FRONT INLAND COMPARED TO THE PREVIOUS COUPLE OF RUNS. THIS MAKES SENSE AS THE FRONT BECOMES PARALLEL TO THE UPPER FLOW AND THE WAVE RIDES UP THE FRONTAL ZONE. 00Z GFS NOW SHOWS THE FRONT ON THE COAST AROUND 18Z FRI AND TO THE CASCADES BY 00Z SAT. THERE IS SOME HINT OF SPLITTING AS THE FRONT COMES INLAND. SNOW LEVELS WILL DROP QUICKLY BEHIND THE FRONT. HOWEVER...THE OROGRAPHIC COMPONENT STILL DOES NOT LOOK ALL THAT IMPRESSIVE...EXCEPT POSSIBLY IN THE S WA CASCADES WHERE THE GFS INDICATES 20-30 KT 850 MB FLOW. MAY VERY WELL SEE SNOW ADVISORY AMOUNTS IN THE S WA AND N OREGON CAASCADES LATE FRI THROUGH FRI NIGHT. THE UPPER TROUGH MOVES THROUGH LATER FRI NIGHT WITH DECREASING SHOWERS SAT AS THE MOIST LOW LEVEL AIR MASS STABILIZES. WEISHAAR .LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...REASONABLY GOOD AGREEMENT AMONGST GUIDANCE FOR LATE THIS WEEKEND THROUGH MON...SHOWING A RIDGE HOLDING IN OVER THE INTERIOR PAC NW...WITH A DEEP TROUGH PROGRESSING SLOWLY FROM 150W TO 140W.WITH A BAROCLINIC ZONE OFFSHORE THROUGH MON...SO WILL GO A WITH PREDOMINANTLY DRY AND MILD FORECAST SUN AND MON. GENERAL TREND FOR TUE ON SHOWS A SHORTWAVE AND COLD FRONT LIFTING NE AND PUSHING INLAND...BUT TIMING BECOMES AN ISSUE WITH GFS THE MOST PROGRESSIVE WITH THE SYSTEM. GIVEN THE DEVELOPING MODEL DISCREPANCIES...WILL TREND FORECAST TOWARD CLIMATOLOGY AFTER TUE. && .AVIATION...MVFR TO IFR CONDITIONS DOMINATE ALONG THE COAST AND N WILLAMETTE VALLEY...WITH GENERALLY VFR CONDITION IN THE S WILLAMETTE VALLEY THIS EVENING. AS MAINI PRECIPITATION SHIELD CONTINUES TO LIFT N OVERNIGHT...EXPECT CONDITIONS TO IMPROVE IN THE N WILLAMETTE VALLEY...BUT NOT LIKELY TO IMPROVE MUCH IF AT ALL ON THE COAST. MVFR CIGS AND MVFR TO IFR VISIBILITIES IN RAIN EXPECTED TO ACCOMPANY THE FRONT FRI MORNING. KPDX AND APPROACHES...PREVAILING MVFR CONDITIONS...OCCASIONALLY DOWN TO IFR...ARE EXPECTED EARLY TONIGHT...THEN SOME TEMPORARY IMPROVEMENT EXPECTED LATE TONIGHT BEFORE THE COLD FRONT APPROACHES FRI MORNING. && .MARINE...WINDS EXPECTED TO RISE AGAIN OVERNIGHT...REACHING GALE FORCE IN THE EARLY MORNING HOURS AS COLD FRONT PUSHES ACROSS THE WATERS. THE GALES ARE EXPECTED TO SPREAD N LATE TONIGHT...REACHING UP TO ABOUT CAPE FALCON...WHILE FURTHER N FRONT WILL BE OCCLUDED AND WINDS NOT EXPECTED TO BE AS HIGH. WINDS WILL BE SLOW TO DROP OFF BEHIND THE FRONT FRI THOUGH AS A SURFACE LOW TRAILING THE FRONT MOVES THROUGH THE WA COASTAL WATERS FRI NIGHT. IN THE NORTHERN PART OF THE WATERS...THIS MAY POSE A BETTER SHOT FOR GALE FORCE WINDS LATER IN THE DAY. A WESTERLY SWELL TRAIN WITH RELATIVELY LONG PERIODS IN THE MID TEENS CONTINUES TO PUSH ASHORE THIS EVENING. BIGGEST SEAS HAVE BEEN OVER THE NORTHERN WATERS...WITH BUOY 46029 PEAKING AT 25 FT AT 03Z. WHILE WAVEWATCH HAS NOT HANDLED THE HEIGHT OF THE SWELL WELL...IT DOES NOT SHOW SEAS SUBSIDING APPRECIABLY UNTIL FRI MORNING. GIVEN THAT BUOY 46089 IS STILL RUNNING OVER 20 FT AS WELL AND BUOY 46050 REMAINS NEAR CRITERIA...WILL EXTEND THE HIGH SURF ADVISORY THROUGH THE REST OF THE NIGHT. && .PQR WATCHES/WARNINGS/ADVISORIES... OR/WA...HIGH SURF ADVISORY NORTH AND CENTRAL OREGON COAST AND S WA COAST UNTIL 7 AM FRI. HIGH WIND WARNING CENTRAL OREGON COAST MIDNIGHT TONIGHT THROUGH 10 AM FRI. PZ...SMALL CRAFT ADVISORIES FOR WIND AND HAZARDOUS SEAS CAPE SHOALWATER FLORENCE UNTIL MIDNIGHT. GALE WARNING CAPE SHOALWATER TO FLORENCE MIDNIGHT TONIGHT TO 4 PM FRI. SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR TONIGHT AND FRI. && $$ MORE WEATHER INFORMATION ONLINE AT... HTTP://WEATHER.GOV/PORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.