Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 042152
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
200 PM PST WED MAR 4 2015

.SYNOPSIS...AN UPPER LEVEL RIDGE OF HIGH PRES WILL REMAIN THROUGH
THE WEEKEND MAINTAINING A DRY AND GENERALLY MILD WEATHER PATTERN.
THE UPPER RIDGE WILL WEAKEN EARLY NEXT WEEK AND A FRONT MAY BRING
RAIN TO THE REGION BY TUESDAY.
&&

.SHORT TERM...MODELS MAINTAIN A STRONG RIDGE OVER THE PACIFIC NW
THROUGH SAT FOR CONTINUED DRY WEATHER. MODEL CONSENSUS IS FOR THE
WEAK N OFFSHORE FLOW TO SWITCH AROUND TO A S FLOW ALONG THE COAST
FRI. FLOW HOWEVER APPEARS TO REMAIN WEAK...SO THE MAIN THREAT FOR
MARINE CLOUDS AND FOG SHOULD BE LIMITED TO NEAR THE COAST FRI NIGHT
INTO SAT MORNING. INLAND EXPECT SKIES TO REMAIN MOSTLY CLEAR THROUGH
THIS TIME. H8 TEMPS EXPECTED TO CREEP UP A COUPLE OF DEGREES EACH
DAY RESULTING IN GRADUALLY WARMING DAYTIME TEMPS THROUGH SAT FOR
INLAND AREAS. BY SAT AFTERNOON SFC WINDS EXPECTED TO VEER AROUND TO
THE N AGAIN...WHICH SHOULD ALLOW COASTAL AREAS TO SHAKE MOST OF THE
MARINE CLOUDS BY THE AFTERNOON.

.LONG TERM...ECMWF AND GEM MAINTAIN A STRONG UPPER RIDGE THROUGH MON
WITH OFFSHORE FLOW. 12Z GFS BROKE RANKS WITH OTHER MODELS IN DIGGING
A TROUGH AND COLD FRONT DOWN FROM THE NW MON...BUT A LOOK THROUGH
THE GFS ENSEMBLE MEMBERS INDICATED QUITE A BIT OF SPREAD IN THE
SOLUTIONS. GIVEN THE BETTER CONSISTENCY IN ECMWF/GEM SOLUTION PREFER
TO CONTINUE CLOSER TO THOSE MODELS. AFTER DRY AND MILD WEATHER SUN
AND MON...A SYSTEM EXPECTED IS EXPECTED TO EJECT OUT OF THE E
PACIFIC TROUGH WEAKENING THE RIDGE AND BRINGING CHANCES FOR RAIN FOR
TUE AND WED.
&&

.AVIATION...GENERALLY VFR CLR THROUGH THU AND BEYOND. VERY DIFFUSE
SURFACE THERMAL LOW SITUATED FROM THE N OREGON COAST RANGE TO THE
S OREGON COAST EARLY THIS AFTERNOON. THIS FEATURE WILL DRIFT BACK
TO THE COASTLINE TONIGHT FOR VERY LIGHT OFFSHORE FLOW. MAY BE
SOME PATCHY FOG TONIGHT...PRIMARILY ALONG THE S WA AND N OREGON
COAST NEAR THE BAYS.

KPDX AND APPROACHES...VFR CONTINUES UNDER DRY STABLE AIR MASS.
WEISHAAR.

&&

.MARINE...RATHER TRANQUIL MARINE CONDITIONS FOR THE NEXT FEW DAYS.
N WIND TO PEAK THIS EVENING...ESPECIALLY OVER THE SRN WATERS WITH
GUSTS TO 20 KT POSSIBLE. WIND DIMINISHES OVERNIGHT TONIGHT. NAM
MODEL STILL SUGGESTING A WIND REVERSAL OVER THE WATERS LATE THU
AND THU NIGHT. WEAK SURFACE GRADIENTS OVER THE WATERS DURING THE
WEEKEND AND FIRST PART OF NEXT WEEK. SIGNIFICANT MODEL DIFFERENCES
EARLY TO MID NEXT WEEK. HAVE LEANED TOWARD THE ECMWF FOR THE END
OF THE EXTENDED PERIOD.

SEAS HOLDING IN THE 3 TO 5 FOOT RANGE FOR THE NEXT FEW DAYS.
SPECTRAL ANALYSIS SUGGESTS THERE WILL BE MULTIPLE 1 OR 2 FOOT
COMPONENTS THROUGH AT LEAST FRI...PRIMARILY FROM THE WNW AND SSW.
WEISHAAR

&&

.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.


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