FXUS66 KPQR 260425
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
825 PM PST WED NOV 25 2009

.SYNOPSIS...A MOIST FRONTAL SYSTEM OVER THE NORTH WASHINGTON COAST
AND EXTENDING SOUTHWEST WELL OFFSHORE WILL REMAIN NEARLY STATIONARY
TONIGHT. THE FRONTAL SYSTEM WILL REACH THE NORTH OREGON COAST
THANKSGIVING MORNING...AND THEN REACH THE CASCADES BY EVENING. THE
HEAVIEST RAIN WILL BE ALONG THE NORTHERN OREGON AND SOUTH WASHINGTON
COAST RANGE. THE UPPER TROUGH SLIDES ACROSS THE FORECAST AREA LATE
THURSDAY NIGHT AND FRIDAY MORNING. A STALLED FRONT MAY BRING MORE 
PRECIPITATION MAINLY TO NORTHERN AREAS FOR THE WEEKEND...THEN A 
DRIER WEATHER PATTERN LOOKS POSSIBLE FOR MUCH OF NEXT WEEK. 

&&

.SHORT TERM...SURFACE HIGH PRESSURE CENTERED OVER THE NORTHERN
ROCKIES THIS EVENING MAINTAINING OFFSHORE GRADIENTS...ALBEIT NOT
OVERLY STRONG. KTTD-KDLS GRADIENT WAS -3.1 AT 03Z. BREEZY EAST WIND
IN THE GORGE WEST OF KCZK...WITH PEAK GUSTS THIS EVENING AROUND 25
KT. PATCHY FOG HAS ALREADY DEVELOPED IN THE WILLAMETTE VALLEY

MAIN WEATHER TOPIC IN THE SHORT-TERM IS THE FRONTAL SYSTEM THAT WILL
MOVE THROUGH THE DISTRICT ON THANKSGIVING. EVENING IR IMAGERY CLEARLY
SHOWED A WAVE MOVING ALONG THE FRONT NEAR VANCOUVER ISLAND. ANOTHER
AREA OF DEVELOPMENT APPEARS TO BE OCCURRING NEAR 40N AND 135W. THIS
LOW CENTER WILL MOVE NORTHEAST ALONG THE FRONT. THERE IS STILL SOME
QUESTION AS TO THE EXACT LOCATION AND STRENGTH OF THIS LOW. GFS
ENSEMBLES SHOW THE LOW CENTER MOVING ASHORE AROUND 18Z THU FROM THE
CENTRAL WASHINGTON COAST TO JUST WEST OF KAST. LATEST NAM MODEL IS A
LITTLE SLOWER AND HAS THE LOW NEAR THE MOUTH OF THE COLUMBIA RIVER
00Z FRI. 00Z GFS RUN EVEN WEAKER AND FURTHER SOUTH. NUDGED INLAND
POPS FOR THU AFTERNOON A LITTLE HIGHER BUT QPF NUMBERS LOOK GOOD.
FAIRLY JUICY SYSTEM WITH PRECIPITABLE WATER AMOUNTS UP TO 1.30
INCHES. THE LOW WILL ALSO SERVE AS A FOCUSING MECHANISM FOR RAINFALL.
EXPECT SOME PRETTY DECENT RAIN RATES OVER SOUTHWEST WASHINGTON AND
THE NORTH OREGON COAST AND COAST RANGE THANKSGIVING. THE LOW DOES NOT
LOOK LIKE A STRONG WIND PRODUCER. CURRENT FORECAST OF 35-45 MPH GUSTS
ALONG THE COASTAL HEADLANDS LOOKS SUFFICIENT.  

POST-FRONTAL AIR MASS MOVES IN THURSDAY NIGHT. 850 MB OROGRAPHIC
COMPONENT NOT VERY IMPRESSIVE...ESPECIALLY ON THE NEW GFS. SNOW
LEVELS DROP WELL BELOW THE PASSES BY FRIDAY MORNING...BUT QPF AMOUNTS
DO NOT LOOK LIKE ENOUGH TO GIVE SNOW ADVISORY AMOUNTS TO THE
CASCADES. WEISHAAR

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...MODELS IN
FAIRLY GOOD AGREEMENT THROUGH THE EXTENDED PERIOD. A BRIEF POST
FRONTAL RIDGE WILL BRING GENERALLY MOSTLY CLOUDY WEATHER TO THE
FORECAST AREA SUNDAY AND MOST OF MONDAY. A SHORTWAVE WILL PASS BY TO
THE NORTH LATE MONDAY AND TUESDAY BRINGING RAIN TO THE AREA...MAINLY
TO THE NORTH PART. THE RIDGE APPEARS TO REBOUND AGAIN FOR THE MIDDLE
OF NEXT WEEK...WITH ALL MODELS COMING INTO AGREEMENT FOR THIS
SOLUTION THROUGH THE END OF THE WEEK. BROWN

&&

.AVIATION...THE NEXT FRONT STALLS OFFSHORE TONIGHT AND MOVE ASHORE 
THU AFTERNOON TO EARLY EVENING.  WITH THE FRONT SO FAR 
OFFSHORE...ONLY THIN CLOUDS ARE OVER THE AREA ALLOWING REMNANT FOG 
PATCHES TO EXPAND. MOST NOTABLE IS THE ONE AROUND KMMV WITH HAS 
EXPANDED TO KSLE AND TO NEAR KUAO.  ANOTHER SEEMS TO BE LOCALIZED IN 
THE KHIO AREA.	THICKER CLOUDS EXPECTED TO ARRIVE LATER TONIGHT 
ELIMINATING THE FOG.  RAIN AND MVFR CONDITIONS ARE EXPECTED ALONG 
THE NORTH COAST THURS MORNING. THE FRONT MOVES ASHORE IN THE 
AFTERNOON WITH RAIN DECREASING BUT MVFR LIKELY TO CONTINUE.  INLAND 
AREAS...MAINLY VFR OVERNIGHT AND EARLY TOMORROW...UNTIL LOWER CLOUDS 
IMPACT THE AREA LATER FRI AFTERNOON AS THE FRONT MOVES THROUGH.

KPDX AND APPROACHES...EXPECT VFR CONDITIONS OVERNIGHT AND EARLY 
TOMORROW. LOCALIZED FOG ON WESTERN APPROACHES THROUGH 10Z OR SO. 
WHILE LIGHT EAST WIND SHOULD KEEP KPDX OUT OF FOG THREAT.

&&

.MARINE...SMALL CRAFT FOR WINDS BEGIN 18Z THURS...WITH THE SOUTHERN 
WATERS IMPACTED BY THE NEXT FRONTAL SYSTEM FIRST. SEAS SHOULD RISE 
TO NEAR 14 FT OVERNIGHT AND PEAKING AROUND 16 FT THU AS THE NEXT 
FRONTAL SYSTEM ARRIVES. SOUTHERLY GALES ARE POSSIBLE THURS AS LOW 
PRES MOVES INLAND...WITH BEST CHANCE SOUTH OF CASCADE HEAD. BUT 
MODELS ARE HAVING A DIFFICULT TIME WITH PLACEMENT AND STRENGTH OF 
THIS LOW.  SEAS NOT LIKELY TO DROP BELOW 10 FT UNTIL LATE WEEKEND OR 
EARLY NEXT WEEK.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR WIND CAPE SHOALWATER TO CASCADE
	 HEAD THU AND THU EVENING.
	SMALL CRAFT ADVISORY FOR WIND CASCADE HEAD TO FLORENCE 
	 EARLY THU MORNING THROUGH THU EVENING.
	SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE
	 SHOALWATER TO FLORENCE THROUGH THU NIGHT.
	SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER		     
	 BAR CONDITIONS THROUGH LATE THU NIGHT. 
  
&&

$$

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.