Area Forecast Discussion
Issued by NWS Portland, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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

000
FXUS66 KPQR 060420
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
900 PM PDT THU MAY  5 2016

.SYNOPSIS...HIGH PRESSURE BUILDING ACROSS THE REGION TONIGHT WILL
BRING WELL ABOVE AVERAGE TEMPERATURES AND PLENTY OF SUNSHINE FRIDAY
AND SATURDAY. A WEAK FRONT WILL BRING MARINE CLOUDS AND AREAS OF
DRIZZLE AND LIGHT SHOWERS SATURDAY EVENING TO THE COAST AND SATURDAY
NIGHT AND SUNDAY MORNING TO INTERIOR LOCATIONS. EXPECT TEMPERATURES
TO DROP MUCH CLOSER TO AVERAGE SUNDAY AND MONDAY. HIGH PRESSURE
PUSHING BACK OVER THE REGION NEXT WEEK WILL BRING ANOTHER ROUND OF
UNSEASONABLY WARM WEATHER.

&&

.SHORT TERM...TONIGHT THROUGH SUNDAY...A LARGE UPPER LEVEL LOW
PRESSURE SYSTEM CONTINUES TO SLOWLY SHIFT WESTWARD INTO CALIFORNIA.
THIS HAS RESULTED IN THE SOUTHERLY FLOW OVER THE REGION YESTERDAY TO
GIVE WAY TO NORTHEASTERLY TO EASTERLY WINDS UP TO 500MB PER THE 00Z
KSLE SOUNDING. MOISTURE AND INSTABILITY GENERALLY PRESENT EAST OF
THE CASCADES HAVE RESULTED IN A FEW SHOWERS AND VERY ISOLATED
THUNDERSTORMS ALONG THE CASCADE CREST THIS EVENING. SO FAR THESE
STORMS HAVE DISSIPATED QUICKLY AS THEY MOVE WEST OF THE CREST INTO A
DRIER AND MORE STABLE ENVIRONMENT. EXPECT THIS TREND TO CONTINUE
OVERNIGHT FOR ANY REMAINING SHOWERS THAT MOVE WESTWARD TOWARDS THE
CASCADE CREST.

UPPER LEVEL HIGH PRESSURE WILL BUILD INTO THE PACIFIC NORTHWEST
FRIDAY AND EARLY SATURDAY AND BRING ANOTHER ROUND OF SUNSHINE AND 80S
TO INTERIOR VALLEY LOCATIONS. AN EXCEPTION TO THIS IDEA MAY BE ACROSS
FAR EASTERN LANE COUNTY LATE FRIDAY AFTERNOON AND EARLY EVENING WHERE
A SHOWER OR THUNDERSTORM COULD BRIEFLY PUSH WESTWARD OVER THE
CASCADE CREST...BUT IT SHOULD BE NOTED THAT MODELS HAVE TRENDED AWAY
FROM THIS IDEA SO ODDS OF ANYTHING OF NOTE...ARE LOOKING LESS AND
LESS LIKELY.

SURFACE HIGH PRESSURE IN THE NORTHEAST PACIFIC AND LOW PRESSURE OVER
NORTHERN CALIFORNIA WILL PRODUCE BREEZY NORTHERLY WINDS ALONG THE
COAST FRIDAY AND SATURDAY. THIS SHOULD PRODUCE FAVORABLE UPWELLING
CONDITIONS AND MAY ALLOW SOME PATCHY STRATUS TO DEVELOP NEAR THE
CENTRAL OREGON COAST TONIGHT AND PERHAPS EXPANDING FARTHER NORTHWARD
LATE FRIDAY NIGHT AND EARLY SATURDAY MORNING. IN ADDITION...CANNOT
RULE OUT A FEW OF THE SHELTERED BAYS SEEING SOME SHALLOW FOG TOWARDS
SUNRISE EACH MORNING TOO.

A WEAK FRONT STILL APPEARS ON TRACK TO IMPACT NORTHWEST OREGON AND
SOUTHWEST WASHINGTON SATURDAY NIGHT. THIS SYSTEM WILL MAINLY BRING
CONSIDERABLY COOLER TEMPERATURES SUNDAY...AND AN INCREASE IN MARINE
CLOUDS AND A CHANCE OF DRIZZLE AND/OR LIGHT SHOWERS SATURDAY NIGHT
AND SUNDAY. AS SUCH...EXPECT MARINE CLOUDS TO CONSOLIDATE OFFSHORE
SATURDAY AND PUSH INTO THE COAST DURING THE LATE AFTERNOON OR
EVENING HOURS. A SURGE OF BREEZY WEST WINDS SHOULD PUSH UP THE
COLUMBIA RIVER AND THROUGH THE COAST RANGE GAPS SATURDAY EVENING.
GIVEN THE LOW LEVEL FLOW WILL BE SOMEWHAT WESTERLY ALONG THE NORTH
COAST...AREAS OF DRIZZLE SHOULD DEVELOP SATURDAY
NIGHT...PARTICULARLY NORTH OF NEWPORT AND/OR TILLAMOOK. AS THE FRONT
PUSHES INLAND...THERE IS A DECENT CHANCE A FEW LIGHT SHOWERS OR
AREAS OF DRIZZLE WILL DEVELOP IN THE WILLAMETTE VALLEY...
PARTICULARLY NEAR THE CASCADE FOOTHILLS LATE SATURDAY NIGHT OR EARLY
SUNDAY MORNING. MODEL SOUNDINGS INDICATE THERE MAY BE ENOUGH
DESTABILIZATION OF THE LOWER ATMOSPHERE TO ALLOW A FEW SHALLOW
SHOWERS TO LINGER INTO THE EARLY AFTERNOON HOURS ON SUNDAY...BUT
OVERALL THE AFTERNOON SHOULD END UP DRIER WITH AT LEAST SOME
SUN BREAKS DEVELOPING.

THE UPPER LEVEL TROUGH RESPONSIBLE FOR SENDING THE AFOREMENTIONED
FRONT INTO THE REGION WILL LAG AND PUSH ACROSS THE INTERIOR
NORTHWEST AS IT DIVES SOUTHEASTWARD SUNDAY NIGHT AND MONDAY. THIS
SHOULD BRING A REINFORCING SHOT OF COOLER TEMPERATURES AND ONSHORE
FLOW SUNDAY NIGHT SO A FEW SHOWERS COULD REAPPEAR DURING THIS TIME
FRAME...PARTICULARLY ACROSS THE HIGHER TERRAIN OF OUR MORE NORTHERN
ZONES. WILL LET MID SHIFT EVALUATE FURTHER. /NEUMAN


&&

.LONG TERM...PREVIOUS DISCUSSION BELOW...AS THE SYSTEM CURRENTLY
LOCATED AT 50N AND 160W LIFTS NORTHEASTWARD AND WEAKENS...IT WILL
SEND A WEAK FRONT TOWARDS THE PACIFIC COAST SATURDAY NIGHT AND INTO
SUNDAY MORNING. THIS WILL USHER IN A FAIRLY STRONG MARINE PUSH WITH
SOME DRIZZLE EXPECTED SUNDAY MORNING. THIS MARINE PUSH WILL ALSO
COOL TEMPERATURES BACK TO NEAR NORMAL SUNDAY AND MONDAY AFTER
TEMPERATURES SOAR OVER 15 DEGREES ABOVE NORMAL ON FRIDAY AND
SATURDAY. OFFSHORE FLOW TAKES OVER AGAIN BY NEXT TUESDAY WHICH WILL
LEAD TO AN EXTENDED PERIOD OF WELL ABOVE NORMAL TEMPERATURES AND
LITTLE PRECIPITATION NEXT WEEK. BENTLEY

&&

.AVIATION...MOSTLY VFR CONDITIONS TONIGHT AND FRIDAY. THE COAST
WILL LIKELY HAVE SOME MVFR CONDITIONS LATE TONIGHT INTO FRIDAY
MORNING. MVFR STRATUS MAY RETURN KCVO AND SOUTHWARD INCLUDING KEUG
BETWEEN 11 AND 17Z. NORTH WINDS WILL GUST AROUND 20-25KT IN THE
WILLAMETTE VALLEY AND ALONG THE CENTRAL OREGON COAST FRIDAY
AFTERNOON.

KPDX AND APPROACHES...VFR CONDITIONS TONIGHT AND FRIDAY. TJ

&&

.MARINE...HIGH PRESSURE OVER THE WATERS AND LOW PRESSURE TO THE
SOUTH WILL MAINTAIN NORTHERLY WINDS THE NEXT COUPLE OF DAYS. WIND
GUSTS UP TO 25 KT WILL PERSIST BEYOND 10 NM THROUGH AT LEAST
SATURDAY EVENING AND MAINTAIN A SMALL CRAFT ADVISORY. GUSTS WITHIN
10 NM WILL OCCASIONALLY BE AROUND 25 KT...MAINLY IN THE
AFTERNOONS. WIND DRIVEN SEAS WILL CONTINUE CHOPPY CONDITIONS WITH
SQUARED SEAS AT TIMES. A WEAK FRONT WILL MOVE ACROSS THE WATERS
SATURDAY NIGHT AND BRIEFLY WEAKEN THE SURFACE PRESSURE GRADIENT.
HIGH PRESSURE RETURNS SUNDAY FOR CONTINUED NORTH WINDS EARLY NEXT
WEEK. TJ

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT SATURDAY FOR
     WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR FROM 10 TO
     60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
     FLORENCE OR OUT 10 NM.WATERS FROM CAPE SHOALWATER WA TO
     CASCADE HEAD OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT THIS EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR
     OUT 10 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT SATURDAY
     FOR WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60
     NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 AM PDT FRIDAY FOR
     COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 3 AM TO
     7 AM PDT FRIDAY.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 4 PM TO
     7 PM PDT FRIDAY.
&&


$$

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.