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AREA FORECAST DISCUSSION 
NATIONAL WEATHER SERVICE PORTLAND OR 
130 PM PST FRI MAR 6 2015

.SYNOPSIS...AN UPPER LEVEL RIDGE OF HIGH PRES WILL REMAIN OVER THE 
REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THIS WILL 
MAINTAIN A DRY AND WARMER THAN NORMAL WEATHER PATTERN. AROUND MID 
WEEK NEXT WEEK A CHANCE FOR RAIN RETURNS AS A PACIFIC SYSTEM IS 
EXPECTED TO BREAK THROUGH THE RIDGE.
&&

.SHORT TERM...THE STRONG UPPER RIDGE...SEEN IN WATER VAPOR PICTURES 
JUST OFFSHORE EARLY THIS AFTERNOON...IS EXPECTED THE REMAIN THROUGH 
THE WEEKEND AND INTO EARLY NEXT WEEK. MODELS AGREE ON TURNING THE 
LOW LEVEL FLOW AROUND TO A MORE NORTHERLY DIRECTION TONIGHT AND 
SAT...RESULTING IN CONTINUED DRY AND RELATIVELY MILD CONDITIONS THAT 
WILL LAST THROUGH SUN. 

A SURFACE HIGH CENTERED OFF THE COAST OF WA AND VANCOUVER ISLAND 
OVER THE WEEKEND IS EXPECTED TO SINK S SOME MON AS A SHORTWAVE 
RIDING OVER THE TOP OF THE RIDGE FLATTENS IT. THIS WILL TURN THE LOW 
LEVEL FLOW LIGHTLY ONSHORE ACROSS AT LEAST THE N PART OF THE 
FORECAST AREA MON MODERATING TEMPS A BIT MAINLY ALONG THE COAST. GFS 
AND NAM MODEL SOUNDINGS INDICATE SOME SHALLOW MOISTURE ALONG THE 
COAST MON WITH THE ONSHORE FLOW...WHICH MAY RESULT IN SOME PATCHY 
LOW CLOUDS ALONG THE COAST.
&&

.LONG TERM...MONDAY NIGHT THROUGH THURSDAY...FORECAST MODELS REMAIN 
IN FAIR AGREEMENT THAT THE PERSISTENT UPPER RIDGE WILL BREAK DOWN 
AND SLIDE EASTWARD EARLY NEXT WEEK. THIS WILL BRING A TRANSITION TO 
MORE NORMAL MARCH WEATHER AND A RETURN OF SOME PRECIPITATION. WHILE 
THE MODELS CONTINUE TO STRUGGLE A BIT WITH THE PRECISE HANDLING OF 
THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT AS IT MOVES 
ONSHORE...THIS SEEMS TO BE A HIGH POP AND LOW-MODERATE QPF EVENT 
WITH RAINFALL ACCUMULATIONS AROUND A HALF TO THREE QUARTERS OF AN 
INCH AT MOST. THE SYSTEM WILL BE FAIRLY WARM SO WHILE SNOW LEVELS 
MAY FALL ENOUGH TO ADD SOME SNOWFALL TO THE HIGHER CASCADE 
LOCATIONS...EXPECT ONLY RAIN BELOW AROUND 6000 FT OR SO AND NO 
SIGNIFICANT ADDITION TO THE MEAGER CASCADE SNOWPACK THIS WINTER. 
CULLEN
&&

.AVIATION...VFR NEXT 24 HRS. PATCHY FOG RETURNS IN THE SOUTH
WILLAMETTE VALLEY AFTER 06Z SAT...PRIMARILY IMPACTING KEUG. SOME
LOCAL FOG POSSIBLE ALONG THE SOUTH OR COAST AND ALONG THE COLUMBIA
RIVER OVERNIGHT.

KPDX AND APPROACHES...VFR PREVAILING NEXT 24 HOURS. /27

&&

.MARINE...WITH HIGH PRESSURE PREVAILING OVER THE WATERS THROUGH
THE WEEKEND...EXPECT BENIGN CONDITIONS FOR THE COASTAL WATERS.
LIGHT SOUTHERLY WINDS WILL TRANSITION TO NORTHERLY FOR THE
WEEKEND WITH 15 TO 20 KT GUSTS OVER THE OFFSHORE WATERS SAT NIGHT
AND SUN. A CLOSED UPPER LOW OVER THE CENTRAL PAC MON DRIFTS CLOSER
TO THE CALIFORNIA AND S OREGON COAST TUE AND WED.

SEAS HOLDING IN THE 3 TO 5 FOOT RANGE THROUGH THE 5-DAY FORECAST
PERIOD. SPECTRAL ANALYSIS SUGGESTS THERE WILL BE MULTIPLE 2 OR 3
FOOT COMPONENTS THROUGH TONIGHT...PRIMARILY FROM THE WNW AND SSW.
GUIDANCE HAS COME DOWN ON SEAS IN THE EXTENDED PERIOD AROUND NEXT
WEDNESDAY...AND NOW SHOWS 10 TO 11 FEET WHICH SEEMS MORE
REASONABLE THAN THE TEENS IT WAS SHOWING EARLIER. TUESDAY NIGHT
AND INTO WEDNESDAY APPEARS TO BE THE NEXT CHANCE FOR ANY
SIGNIFICANT WINDS OR SEAS. 

&&

.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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