Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 190305
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
803 PM PDT THU SEP 18 2014

.SYNOPSIS...DRIER WEATHER AS HIGH PRESSURE IS NOW BUILDING INTO THE
REGION. BUT EXCEPTION IS ACROSS SW WASHINGTON AND THE EXTREME NW
OREGON COAST ON FRI WHERE A FEW LIGHT SHOWERS MAY OCCUR AS A DYING
FRONT MOVES INTO WASHINGTON. THEN DRY AND WARM WITH OFFSHORE FLOW FOR
THIS WEEKEND. COOLER UNSETTLED WEATHER ON TAP FOR NEXT WEEK.
&&

.SHORT TERM...FOR TONIGHT...VISIBLE SATELLITE IMAGERY SHOWS THE
REGION CAUGHT BETWEEN A LOW PRESSURE SYSTEM MOVING SOUTHWARD OFF THE
CALIFORNIA COAST AND WESTERLY FLOW PUNCHING INTO BRITISH COLUMBIA.
ASIDE FROM THE CENTRAL OREGON COAST...MOSTLY CLOUDY TO CLOUDY SKIES
ABOUND. A LOOP OF DOPPLER RADAR SHOWS MOST SHOWER ACTIVITY HAS
WEAKENED AND MOVED EAST OF THE CASCADES. BUT MAY STILL HAVE A FEW
SHOWERS AROUND...SO WILL LEAVE 20 PCT PROBABILITY FOR TONIGHT OVER
THE MOUNTAINS. WITH CLEAR BREAKS IN THE CLOUD COVER...COMBINED WITH
LIGHT WINDS...WILL HAVE PATCHY FOG TONIGHT INTO FRI AM.

FOR FRIDAY...BUILDING 500MB HEIGHTS AND SURFACE HIGH PRESSURE NOSING
INTO THE REGION FROM THE SOUTHWEST SHOULD RESULT IN DECREASING CLOUD
COVER.A WEAK FRONT DIVING SOUTHEASTWARD WILL PUSH INTO SOUTHWEST
WASHINGTON MIDDAY FRIDAY...BRINGING A CHANCE FOR LIGHT RAIN TO
PRIMARILY THE COAST. MEASURABLE RAIN WILL BE POSSIBLE...BUT EVEN A
TENTH OF AN INCH APPEARS QUITE UNLIKELY.

FOR SATURDAY AND SUNDAY...INCREASING OFFSHORE FLOW WILL BRING MUCH
WARMER TEMPERATURES TO THE REGION. EXPECT THE WARMEST TEMPERATURES
ALONG THE COAST AND PERHAPS THE SOUTHERN WILLAMETTE VALLEY ON
SATURDAY. EUGENE WILL STAND A GOOD CHANCE TO ADD TO THEIR RECORD 35
DAYS OF 90F OR PLUS OR HIGHER IN 2014. AS THERMAL LOW PRESSURE SHIFTS
NORTHWARD TO OFF WASHINGTON LATE SATURDAY INTO SUNDAY...COOLER MARINE
AIR SHOULD SPREAD INTO COASTAL LOCATIONS AND PERHAPS THE SOUTHERN
WILLAMETTE VALLEY SUNDAY...THEN ACROSS REST OF REGION SUNDAY EVENING.

EAST WINDS SATURDAY AND MUCH LOWER RELATIVE HUMIDITIES FOR MUCH OF
THE WEEKEND SHOULD ONCE AGAIN PRODUCE CONDITIONS MORE FAVORABLE FOR
WILDFIRE GROWTH...BUT NOT LIKELY EXPLOSIVE GROWTH. AS A RESULT... AT
LEAST MODEST AMOUNTS OF SMOKE SHOULD SPREAD BACK INTO THE WILLAMETTE
VALLEY FROM THE 36 PIT AND DECEPTION COMPLEX FIRES. /NEUMAN

.LONG TERM...MONDAY THROUGH THURSDAY...COOLER TEMPERATURES AND AN
INCREASE IN CLOUDS ARE EXPECTED TO RETURN TO THE REGION ON MONDAY
AHEAD OF AN APPROACHING UPPER LEVEL TROUGH. THE MODELS CONTINUE TO
HINT AT A WIDESPREAD RAIN EVENT STARTING ON WEDNESDAY...WITH RAIN
LIKELY CONTINUING THROUGHOUT THE EXTENDED PERIOD. TEMPERATURES IN
THE EXTENDED WILL GENERALLY TREND TOWARDS SEASONAL NORMALS.

&&

.AVIATION...GENERALLY VFR CONDITIONS THIS EVENING...EXPECTED TO
CONTINUE PAST 06Z. KONP AND AREAS ALONG THE CENTRAL COAST HOWEVER
MAY SEE LIFR CONDITIONS WITH FOG DEVELOP BETWEEN 05Z AND 07Z... AND
CONTINUE THROUGH AROUND 16Z FRI. MVFR CIGS EXPECTED TO REDEVELOP
OVER A LARGE PART OF THE REST OF NW OREGON AGAIN LATER TONIGHT
BETWEEN 06Z AND 12Z...MOST LIKELY AT THE N AND W TAF SITES. AS LOW
LEVEL FLOW TURNS MORE NORTHERLY FRI MORNING EXPECT MVFR CIGS TO BE
SHORT LIVED WITH MOST AREAS GOING TO VFR BY 16Z.

KPDX AND APPROACHES...PRIMARILY VFR CONDITIONS LIKELY TO CONTINUE
THROUGH 10Z TONIGHT. MVFR CIGS EXPECTED TO REDEVELOP BETWEEN
10Z AND 13Z...AND CONTINUE THROUGH 16Z FRI.
&&

.MARINE...WINDS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT CRITERIA
THROUGH FRIDAY MORNING. THERMAL LOW PRESSURE IS EXPECTED TO
DEVELOP ALONG THE NORTHERN CALIFORNIA COAST LATE FRIDAY AND EXTEND
NORTH ALONG THE OREGON COAST FRIDAY NIGHT INTO SATURDAY. THIS WILL
LIKELY RESULT IN SMALL CRAFT ADVISORY NORTHERLIES SPREADING NORTH
THROUGH THE WATERS. WINDS WILL DECREASE SATURDAY NIGHT...BUT A
SOUTHERLY WIND REVERSAL WILL SPREAD UP THE COAST SATURDAY NIGHT AND
SUNDAY.

SEAS ARE EXPECTED TO BE AROUND 5 TO 6 FT TONIGHT AND FRIDAY WITH A
MIX OF A LONG PERIOD SOUTH SWELL AND A SHORTER PERIOD NW SWELL. SEAS
THEN EXPECTED TO BUILD TO 8 OR 9 FT SAT IN THE STRENGTHENING
NORTHERLIES...DROPPING BACK DOWN TO AROUND 5 FT SUNDAY.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&


$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

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 AS THE FORECAST AREA.


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