Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 022145
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
245 PM PDT MON MAY  2 2016

.SYNOPSIS...SHOWERS AND MAYBE A FEW EVENING THUNDERSTORMS TODAY AND
AGAIN POSSIBLY ON TUE. OTHERWISE...WILL SEE RETURN TO INCREASED
ONSHORE FLOW AND THREAT OF SHOWERS FOR TUE AND WED. UNSETTLED WEATHER
CONTINUES THU AND FRI. THEN...LIKE PAST WEEKENDS...WARM AND DRY
CONDITIONS AS HIGH PRES BUILDS OVER THE REGION.
&&

.SHORT TERM...(TONIGHT THROUGH THUR). UPPER LOW PRES OFF THE CALIF
COAST IS MAINTAINING S TO SE FLOW ACROSS THE REGION TODAY THROUGH
TUE. WEAK DISTURBANCES OVER NW CALIF WILL LIFT N THIS EVENING.
ALREADY HAVE QUITE A BIT OF SHOWERS AND ISOLATED THUNDERSTORMS OVER
NE CALIF INTO SOUTH CENTRAL OREGON. THIS ACTIVITY WILL DRIFT N/NW
THIS EVENING...WITH NEWER SHOWERS DEVELOPING OVER THE OREGON CASCADES
AND COAST RANGE. MODELS CONTINUE TO SHOW BEST THREAT OF SHOWERS
EXTENDING FROM CENTRAL CASCADES NORTHWESTWARD INTO THE COAST RANGE
LATER THIS EVENING. SUSPECT THIS WILL SEE SHOWERS DEVELOP OVER THE
CASCADES...THEN SEE SHOWERS POP OVER THE COAST RANGE LATER THIS
EVENING. OF INTEREST WILL BE THE THERMAL TROUGH...WHICH IS NOW SLOWLY
MOVING INLAND AWAY FROM THE COAST AND INTO THE COAST RANGE. AS
SUCH...THIS MAY ACT MUCH LIKE A COLD FRONT...AND ENHANCE THE LIFTING
AND RESULTANT SHOWERS OVER THE COAST RANGE THIS EVENING. STILL CAN
NOT ELIMINATE THE THUNDERSTORM THREAT FOR MOST AREAS AWAY THE
CASCADES...SO WILL MAINTAIN A SLIGHT CHANCE THIS EVENING.

OTHERWISE...RATHER PLEASANT EVENING FOR MOST AREAS. LOW CLOUDS NOW
STREAMING NORTHWARD ALONG THE S OREGON COAST. AT 2 PM...LEADING EDGE
WAS ABOUT 10 MILES OFFSHORE FROM FLORENCE. THESE LOW CLOUDS SHOULD
INCREASE ALONG THE COASTAL AREAS UP TO LINCOLN CITY THROUGH 8 PM...
WITH LOW CLOUDS SPREADING FARTHER NORTH LATER THIS EVENING. WHILE
ONSHORE GRADIENT IS NOT ALL THAT IMPRESSIVE OVERNIGHT INTO EARLY
TUE...SO WOULD EXPECT MARINE LAYER TO REMAIN SOMEWHAT SHALLOW...WITH
LITTLE IF ANY PUSH INLAND PAST THE COAST RANGE.

AS DAY PROGRESSES ON TUE...AND THE MAIN UPPER TROUGH THAT SITS
FARTHER OFFSHORE DRAWS CLOSER...THE ONSHORE FLOW WILL INCREASE. THIS
WILL ALLOW FOR INCREASING CLOUDS ON TUE. STILL DECENT SOUTHERLY FLOW
ALOFT...SO WILL KEEP CHANCE OF SHOWERS FOR THE REGION. BUT
INSTABILITY NOT LOOKING SO GOOD. STILL...WILL KEEP SOME MINOR THREAT
OF THUNDERSTORMS NEAR THE CASCADES CREST FOR THE AFTERNOON.

UPPER TROUGH WILL PUSH INTO THE PAC NW WED AND THU WED... WITH
MODERATE TO STRONG ONSHORE FLOW. WILL SEE MUCH COOLER CONDITIONS WITH
LOTS OF CLOUDS ACROSS THE REGION. WITH UPPER TROUGH OVER THE
REGION...BUT ANOTHER CUT OFF LOW LIKELY TO FORM OFF CALIF ON THU.
OVERALL...WED AND THU WILL BE RATHER CLOUDY WITH PLENTY OF SHOWERS
FOR THE REGION...ESPECIALLY OVER THE COAST RANGE AND THE CASCADES.
NOT MUCH THREAT OF THUNDER DUE TO LOT OF CLOUD COVER.WILL KEEP SLIGHT
CHANCE OF THUNDERSTORMS NEAR THE CASCADES CREST FOR WED
AFTERNOON/EVENING.ROCKEY.

.LONG TERM...THURSDAY NIGHT THROUGH MONDAY.  MODELS REMAIN IN FAIR
AGREEMENT THROUGH THE EXTENDED PERIOD AS THE UPPER LEVEL LOW
CONTINUES TO ADVANCE INTO THE GREAT BASIN WHILE AN UPPER RIDGE
BEGINS TO NOSE INTO THE PACIFIC NORTHWEST FROM THE NORTHEAST
PACIFIC. THIS WILL BRING AN END TO THE SHOWER CHANCES FOR MUCH OF
THE AREA ON FRIDAY...THOUGH WILL MAINTAIN A SLIGHT CHANCE FOR
SHOWERS OVER THE SOUTHERN PORTIONS OF THE CASCADE ZONES.
TEMPERATURES WILL WARM INTO THE WEEKEND BACK ABOVE SEASONAL NORMS
AS HEIGHTS RISE AND THE AIR MASS WARMS.   CULLEN
&&
.AVIATION...VFR CONDITIONS INLAND THROUGH TUESDAY WITH WINDS
SWITCHING ONSHORE. ALONG THE COAST...MARINE STRATUS CURRENTLY
MOVING NORTH FROM THE NORTHERN CALIFORNIA COAST WILL LIKELY ARRIVE
BETWEEN 01Z AND 08Z TUESDAY AND BRING A PERIOD OF IFR CONDITIONS
AND POSSIBLY BREEZY WINDS OUT OF THE SOUTH. THERE IS A SLIGHT
CHANCE OF THUNDERSTORMS THROUGH ABOUT 09Z TUE WITH THE BEST
CHANCES OVER THE MOUNTAINS BUT WITH A SMALL CHANCE ELSEWHERE.

KPDX AND APPROACHES...VFR CONDITIONS THROUGH TUESDAY AS TURNS
ONSHORE. ANY THUNDERSTORMS THAT DEVELOP WILL MOST LIKELY REMAIN
AWAY FROM KPDX.
&&

.MARINE...A SOUTHERLY WIND REVERSAL IS WORKING ITS WAY NORTH
ALONG THE COAST. MODELS HAVE BACK OFF WINDS WITH THE REVERSAL SO
DO NOT EXPECT SIGNIFICANT INCREASE IN WINDS OVER THE WATERS. A
WESTERLY SWELL HAS PUSHED SEAS TO AROUND 8 FT BUT SHOULD RELAX
TO 6 TO 7 FT TUESDAY.

HIGH PRESSURE BUILDING BACK INTO THE NORTHEAST PACIFIC SHOULD
BRING NORTHERLY WINDS BACK ON TUESDAY. STARTING TUESDAY
NIGHT...PERIODS OF GUSTY 25 TO 30 KT NORTHERLY WINDS ARE ON TAP
DURING...PARTICULARLY ACROSS THE CENTRAL OREGON WATERS. WHILE
SEAS SHOULD GENERALLY REMAIN UNDER 10 FT...EXPECT SEAS TO BECOME
ESPECIALLY STEEP AND HAZARDOUS DURING THE SECOND HALF OF THE WEEK
AS FRESH SWELL/WIND WAVE DOMINATE DUE TO PERIODS OF NORTH-
NORTHWESTERLY GALES OFF VANCOUVER ISLAND. BOWEN

&&

.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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