Area Forecast Discussion
Issued by NWS Portland, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KPQR 271738 AAA
AFDPQR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
936 AM PST TUE JAN 27 2015

UPDATED MARINE AND AVIATION SECTIONS

.SYNOPSIS...A WEAK FRONTAL SYSTEM ALONG THE COAST WILL SLOWLY MOVE
INLAND MAINLY OVER THE NORTH PART OF THE FORECAST AREA TODAY AND
TONIGHT AND LINGER INTO WEDNESDAY AND WEDNESDAY NIGHT THEN MOSTLY
DISSIPATE AND MOVE OUT OF THE AREA THURSDAY. ANOTHER UPPER RIDGE IS
EXPECTED TO DEVELOP OVER THE PACIFIC NORTHWEST LATER IN THE WEEK AND
CONTINUE INTO THE WEEKEND FOR MORE DRY WEATHER. THE NEXT CHANCE FOR
RAIN IS PROBABLY NOT UNTIL NEXT SUNDAY AND MONDAY.
&&

.SHORT TERM...TODAY THROUGH THURSDAY...A WEAK SYSTEM HAS SLOWLY
SPREAD TO THE COAST THIS MORNING WITH SOME SPOTTY LIGHT PRECIPITATION
MAINLY NEAR THE COAST. THE SALEM SOUNDING THIS MORNING SHOWS THAT THE
MARINE LAYER AND INVERSION HAS RISEN THIS MORNING FROM THE CHANGE TO
A LIGHT ONSHORE FLOW...AND THIS HAS AFFECTED THE FOG COVERAGE THIS
MORNING. HAVE ENDED THE DENSE FOG ADVISORY AND AM JUST COVERING THE
REMAINING FOG WITH SHORT TERM FORECASTS. THE MAIN FOG THAT REMAINS IS
NORTH FROM ABOUT MCMINNVILLE TO SCAPPOOSE...WITH LOW OVERCAST IN THE
REMAINING AREAS.

THE SOUTHWESTERLY UPPER FLOW ASSOCIATED WITH THE WEAK SYSTEM ALONG
OUR COAST HAS SPREAD SOME MID AND HIGH CLOUDS NORTH ACROSS OREGON
FROM AN UPPER LOW IN CALIFORNIA AND THE GREAT BASIN. THIS STREAM OF
HIGHER MOISTURE WILL CONTINUE TO RIDE ACROSS THE AREA TODAY. THIS
COULD FEED A BIT OF MOISTURE INTO OUR WEAK FRONTAL BAND ALONG THE
COAST THAT IS FORECAST TO SLOWLY SPREAD INLAND MAINLY NORTH THE
REMAINDER OF TODAY AND TONIGHT. THE MODELS CONTINUE TO SHOW SOME
LIGHT PRECIPITATION FOCUSED ALONG THIS FRONTAL BAND INTO WEDNESDAY
NIGHT BEFORE DRYING OUT AND LIFTING NORTH THURSDAY. A WEAK ASSOCIATED
UPPER TROUGH TAKES UNTIL THURSDAY AND THURSDAY NIGHT BEFORE MOVE OUT
OF THE AREA...SO THIS STILL SEEMS REASONABLE. SO OVERALL WE SHOULD
SEE PLENTY OF CLOUDS THE NEXT COUPLE OF DAYS WITH LESS FOG
COVERAGE...EXCEPT PERHAPS IN THE SOUTH WILLAMETTE VALLEY. TOLLESON

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
THURSDAY NIGHT THROUGH MONDAY... FCST CONFIDENCE IS HIGH THAT AN
UPPER LEVEL RIDGE OVER THE NE PAC WILL STRENGTHEN AND BEGIN TO BUILD
INTO THE PAC NW STARTING THU NIGHT AND FRI. THE RIDGE AXIS IS
EXPECTED TO MOVE ONSHORE AND DIRECTLY OVERHEAD LATE FRI AND SAT. THIS
SHOULD MEAN A RETURN TO DRY WEATHER FROM THU NIGHT THROUGH SAT. THE
RIDGE WILL ALSO CREATE ANOTHER LOW LEVEL INVERSION...WHICH SHOULD
MEAN THAT THE INTERIOR LOWLANDS ARE AGAIN COOL AND MOSTLY SOCKED IN
WITH FOG AND LOW CLOUDS WHILE THE HIGHER TERRAIN AND COAST HAVE MORE
SUN AND ABOVE AVERAGE TEMPERATURES. THIS RIDGE IS NOT EXPECTED TO BE
NEARLY AS STRONG AS THE ONE SEEN THIS PAST WEEKEND...SO A REPEAT OF
THE RECORD SETTING WARM TEMPERATURES THAT MANY LOCATIONS SAW OVER THE
WEEKEND IS NOT EXPECTED. THE RIDGE IS CURRENTLY PROGGED TO BEGIN
SHIFTING EAST OF THE CASCADES LATE SAT INTO SUN. THIS WILL OPEN THE
DOOR FOR INCREASING CLOUDS AND PRECIPITATION CHANCES FOR LATER IN THE
WEEKEND AND EARLY NEXT WEEK. INCREASED POPS FOR THE SUN/MON TIME
FRAME AS THE FCST MODELS ARE STARTING TO SHOW DECENT AGREEMENT IN
BRINGING A WARM FRONT ONSHORE DURING THIS TIME PERIOD. PYLE
&&

.AVIATION...A MIX OF MVFR TO IFR CONDITIONS CONTINUE ALONG THE
COAST WITH DRIZZLE MOVING ONSHORE. INLAND...LIFR AND IFR FOG AND
STRATUS CONTINUE FOR MANY LOCATIONS...THOUGH STARTING TO SEE SOME
IMPROVEMENT INTO HIGH END IFR TO MVFR WITH SOME DESTABILIZATION OF
THE LOWER ATMOSPHERE. THIS TREND SHOULD GRADUALLY CONTINUE THIS
MORNING AND EARLY AFTERNOON. CANNOT RULE OUT A PERIOD OF VFR FOR
SOME LOCATIONS THIS AFTERNOON...BUT LOWER CONFIDENCE REMAINS IN
THIS SCENARIO. AFTER STABILIZING A BIT OVERNIGHT...WEAK FLOW AND
CONTINUING MOISTURE SHOULD COMBINE TO ALLOW LOWER MVFR TO IFR TO
PERSIST AT MOST INTERIOR TAF SITES.

KPDX AND APPROACHES...LIFR/IFR FOG CONTINUES THIS MORNING BUT
SHOULD IMPROVE TO HIGH IFR TO MVFR FROM 19-20Z TUE THROUGH
TONIGHT. SOME STABILIZATION AND LOWERING OF CIGS A BIT CAN BE
ANTICIPATED TONIGHT...BUT SUFFICIENT MIXING SHOULD PRECLUDE DENSE
FOG DEVELOPMENT TONIGHT. EAST WINDS WILL CONTINUE THIS MORNING
BEFORE TRANSITIONING TO LIGHT AND VARIABLE THIS AFTERNOON. CULLEN
&&

.MARINE...A WEAK FRONT WILL DROP SOUTHEASTWARD ACROSS THE WATERS
TODAY AND DISSIPATE IN PLACE TONIGHT. WINDS WILL BECOME NW BEHIND
THE BOUNDARY BUT REMAIN FAIRLY LIGHT...15 KT OR LESS. A VERY WEAK
LOW PRESSURE WILL DRIFT NORTHEASTWARD OFF THE OREGON COAST
WEDNESDAY...BUT AGAIN BRING FEW IMPACTS. SEAS REMAIN WELL BELOW 10
FT THROUGH THE WEEK AS WELL. HIGH PRESSURE OVER THE WATERS WILL
MAINTAIN A BENIGN MARINE PATTERN THROUGH THE END OF THE WEEK. AND
WHILE A MORE ACTIVE PATTERN MAY DEVELOP LATE IN THE WEEKEND OR
EARLY NEXT WEEK...NO SIGNIFCANT STORMS APPEAR TO IMPACT THE WATERS
THROUGH THE MIDDLE OF NEXT WEEK.   CULLEN
&&

.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.


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.