Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 041017
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
315 AM PDT TUE AUG  4 2015

.SYNOPSIS...AN UPPER TROUGH WILL SETTLE INTO THE AREA TODAY AND WED
WITH WEAK RIDGING RETURNING THU AND FRI FOLLOWED BY A DEEPER TROUGH
FOR THE WEEKEND. TEMPERATURES WILL REMAIN NEAR NORMAL THROUGH THE
WEEK. THERE COULD BE SOME SHOWERS REACHING SOUTHWEST WASHINGTON OVER
THE WEEKEND.

&&

.SHORT TERM...ONSHORE FLOW CONTINUES THIS MORNING AS HIGH PRES OVER
THE NE PACIFIC CONTINUES. REMNANTS OF A COLD FRONT IS NOT BRINGING AS
MUCH CLOUDS AS EARLIER EXPECTED OVER THE COASTAL WATERS BUT THERE IS
SOME CLOUDS DEVELOPING OVER THE COASTAL STRIP AND LOWER COLUMBIA
RIVER AS FAR AS KELSO. IT DOES NOT APPEAR THE CLOUDS WILL MAKE IT
INTO THE WILLAMETTE VALLEY TODAY. HOWEVER IT APPEARS THAT AN UPPER
TROUGH OVER WESTERN B.C. WILL SAG FURTHER INTO THE PACNW TODAY AND
TONIGHT.  THIS SHOULD INCREASE...OR AT LEAST MAINTAIN WHAT CLOUDS
HAVE DEVELOPED OVER THE SOUTH WA AND NORTH OREGON COASTAL AREAS.
THE UPPER TROUGH WILL LINGER THROUGH WEDNESDAY WITH MORE
NORTHWEST ONSHORE FLOW AND MORE MORNING LOW CLOUDS ESPECIALLY
NORTH...POSSIBLY EVEN WORKING THEIR WAY MORE SOUTHWARD IN THE
WILLAMETTE VALLEY. THE MODELS SHOW A WEAK PIECE OF ENERGY ROTATING
AROUND THE BASE OF THE UPPER TROUGH AND THROUGH WESTERN WASHINGTON
LATE TUESDAY NIGHT AND WEDNESDAY. SOME DRIZZLE ON THE NORTH COAST
LOOKS REASONABLE IN THIS CASE.

HIGH TEMPS INLAND WILL BE NEAR SEASONAL NORMALS THROUGH THE WEEK WITH
WED BEING THE COOLEST DAY OF THE WORK WEEK. BUT THE TROUGH MOVES EAST
WED NIGHT AND THU. THIS WILL ALLOW THURSDAY TO BE A WARMER DAY WITH
MORE SUNSHINE AND MORNING LOW CLOUDS LIMITED TO THE  NORTHERN ZONES.

.LONG TERM...BROAD UPPER-LEVEL TROUGH AND CONTINUED ONSHORE FLOW
SHOULD KEEP TEMPERATURES OUT OF THE 90S LATE THIS WEEK INTO THE
WEEKEND...BUT WEAKENING ONSHORE FLOW AND WINDS BECOMING MORE
SOUTHERLY ON FRIDAY WILL ALLOW TEMPERATURES TO BE A BIT WARMER ON
FRIDAY THAN EARLIER IN THE WEEK. SOUTHERLY FLOW ALSO INTRODUCES A
CHANCE FOR THUNDERSTORMS IN THE OREGON CASCADES...MAINLY ALONG THE
CREST. THE SHIFT TO MORE SOUTHERLY WINDS OCCURS AHEAD OF A UPPER
LEVEL LOW DIGGING DOWN OUT OF ALASKA OVER THE WEEKEND... BRINGING A
CHANCE FOR SHOWERS SATURDAY AND SUNDAY. THERE IS SOME DISAGREEMENT
BETWEEN THE MODELS ON TIMING AND AMOUNT OF RAIN WITH OF THIS
SYSTEM...CREATING UNCERTAINTY WHICH SHOULD BECOME RESOLVED AS WE
APPROACH THIS WEEKEND. HAVE KEPT TEMPERATURES A BIT CLOSER TO
CLIMATOLOGY ON SATURDAY AND SUNDAY...BUT IF SYSTEM PLAYS OUT AS
FORECAST RIGHT NOW TEMPERATURES WILL LIKELY BE A BIT COOLER THAN
CURRENTLY FORECAST. -MCCOY

&&

.AVIATION...A STABLE LOW LEVEL NORTHWESTERLY FLOW PATTERN
CONTINUES EARLY TODAY. SATELLITE IMAGERY REVEALS MVFR CIGS ALONG
THE N OREGON COAST...BUT ONLY A FEW LOCAL POCKETS ALONG THE REST
OF THE COASTAL AREAS. WITH NEARLY ZERO T/TD SPREAD AND CALM WINDS
AT KONP...WOULD NOT BE SURPRISED TO SEE SOME ADDITIONAL
DEVELOPMENT OR ENHANCEMENT OF MVFR CIGS ALONG REMAINDER OF COAST
THROUGH OVERNIGHT PERIOD. WITH ONLY A LITTLE OFFSHORE STRATUS AND
LIMITED MVFR CIGS AROUND KKLS...CONFIDENCE IS SOMEWHAT LOW IN
SEEING SIGNIFICANT DEVELOPMENT OF LOWER MVFR CIGS FOR THE PORTLAND
METRO AREA. IF ANY DOES DEVELOP...IT WILL LIKELY BE LIMITED TO
KTTD AND KPDX WITH THE REMAINING INTERIOR TAF SITES REMAINING VFR.
COASTAL AREAS LIKELY SEE A FEW HOURS OF CIGS SCATTERING THIS
AFTERNOON...BUT EXPECT WIDESPREAD MVFR TO IFR CIGS AFT 06Z WED FOR
THE COAST.


KPDX AND APPROACHES...A STABLE NORTHWESTERLY FLOW PATTERN WILL
BRING PRIMARILY VFR CONDITIONS THROUGH 06Z WEDNESDAY. THERE IS A
CHANCE FOR A BRIEF PERIOD OF MVFR CIGS DEVELOPING OVER THE
TERMINAL TUESDAY MORNING...MOST LIKELY BETWEEN 13Z AND 17Z
TUESDAY...BUT GIVEN LACK OF DEVELOPMENT AND ONSHORE PUSH TO THIS
POINT...CONFIDENCE IS SOMEWHAT LOW THAT THIS WILL DEVELOP.

&&

.MARINE...HIGH PRESSURE CONTINUES OVER THE NORTHEAST PACIFIC AND
MAINTAINS THE TYPICAL SUMMERTIME PATTERN OF NORTHERLY WINDS ALONG
THE COAST WITH OCCASIONAL STEEPER WIND DRIVEN SEAS FROM TIME TO
TIME THIS WEEK.

THE FIRST ROUND OF WINDS AND HIGHER SEAS SHOULD
ARRIVE TUESDAY AFTERNOON AND EVENING. SMALL CRAFT ADVISORIES FOR
WINDS AND HAZARDOUS SEAS REMAIN IN EFFECT FOR THE CENTRAL OREGON
WATERS. THE NEXT MAJOR UPTICK IN WINDS AND SEAS WILL LIKELY
ARRIVE THURSDAY AFTERNOON AND EVENING AS THERMAL LOW PRESSURE
TEMPORARILY STRENGTHENS OVER CALIFORNIA AND WE WILL LIKELY NEED
ANOTHER ROUND OF SMALL CRAFT ADVISORIES FOR THE CENTRAL OREGON
WATERS.

AN UPPER LEVEL TROUGH SHOULD SETTLE INTO THE PACIFIC NORTHWEST
OVER THE WEEKEND...AND A WEAK FRONT MAY BRIEFLY TURN WINDS
SOUTHERLY...BUT WINDS LOOK TO REMAIN RELATIVELY BENIGN.
OTHERWISE...WE MAY SEE NORTHERLY WINDS STRENGTHEN AS THERMAL LOW
PRESSURE OVER CALIFORNIA RETURNS LATE IN THE WEEKEND INTO EARLY
NEXT WEEK.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM THIS AFTERNOON TO 3 AM
     PDT WEDNESDAY FOR COASTAL WATERS FROM CASCADE HEAD OR TO
     FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM THIS
     AFTERNOON TO 3 AM PDT WEDNESDAY FOR COASTAL WATERS FROM
     CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

&&

$$

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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