Willamette Aviation | NWS Forecast Discussion



000
FXUS66 KPQR 080314
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
815 PM PDT TUE SEP 7 2010

.SYNOPSIS...UNSETTLED WEATHER REMAINS THROUGH WED. A BRIEF BREAK
WITH CALMER WEATHER IS EXPECTED FOR THU AND FRI...BUT TEMPS REMAIN
BELOW NORMAL. UNSETTLED WEATHER RETURNS FOR THE WEEKEND.
&&

.SHORT TERM...RATHER ACTIVE LATE AFTERNOON AND EVENING...WITH VERY
HEAVY SHOWERS REPORTED IN MANY LOCALES INLAND. ONE AREA OF SHOWERS
IN PARTICULAR OVER SOUTHEAST CLARK COUNTY WAS PRODUCING RAIN OF 1 TO
1.5 INCHES PER HOUR. MOST LOCATIONS PICKING UP A GOOD 0.25 TO 0.50
INCH OF RAIN THIS EVENING. EVEN A FEW REPORTS OF THUNDER. AHH...TIS
THE SEASON OF CHANGES...IN THIS CASE...CHANGE TO EARLY FALL.

NOT MUCH CHANGE IN THE OVERNIGHT HOURS...EXCEPT SHOWERS WILL
GRADUALLY WEAKEN.

AN UPPER LOW IS FORECAST TO SLOWLY DROP SOUTHEAST INTO THE INTER
MOUNTAIN REGION BY THU AFTERNOON. AS THIS LOW SLOWLY PROGRESSES
INLAND WE WILL REMAIN IN A FAIRLY UNSTABLE AIR MASS WITH SOME
POTENTIAL FOR SHOWERS. THE FURTHER IT MOVES EAST THE LESS LIKELY ANY
POPS WILL BECOME AS A WEAK RIDGE BUILDS.              ROCKEY/WOLFE

.LONG TERM...MODELS ARE SHOWING WEAK UPPER LEVEL SHORTWAVE RIDGING
MOVING OFF TO THE EAST AT THE BEGINNING OF THE LONG TERM PERIOD ON
FRIDAY NIGHT. AN UPPER LEVEL LOW FROM THE GULF OF ALASKA WILL THEN
DROP DOWN INTO THE PAC NW OVER THE WEEKEND. THE MODELS ARE KEEPING
THIS LOW NORTH OF THE CWA...OVER BRITISH COLUMBIA AND WASHINGTON. SO
ANY PRECIP CHANCES IN MOIST ONSHORE FLOW SHOULD BE SPOTTY AND
CONFINED MAINLY TO THE FAR NORTH. MODEL SOLUTIONS BEGIN TO DIVERGE
BY THE END OF THE WEEKEND. HOWEVER...THERE IS GENERAL AGREEMENT THAT
ANOTHER UPPER LEVEL DISTURBANCE WILL APPROACH THE REGION SOMETIME ON
TUE OR WED. JFP
&&

.AVIATION...SHOWERS ON THE DECREASE THIS EVENING WITH MOST ACTIVE
SHOWERS ALONG THE I-5 CORRIDOR EAST TO THE CASCADES. MIX OF VFR
AND MVFR WITH MVFR BECOMING MORE WIDESPREAD LATER TONIGHT IN THE
COOL AND MOIST AIR MASS. LOCAL IFR CIGS AND VISIBILITIES IN AREAS
WITH ENOUGH CLEARING. SHOWERS RETURN WED AFTERNOON BUT EXPECTED TO
BE WEAKER THAN TODAY.

KPDX AND APPROACHES...SHOWER BAND PASSING EAST OF KPDX AS OF 03Z
AND IFR CIGS EXPECTED TO LIFT TO MVFR OR VFR. MVFR CEILINGS BECOME
MORE DOMINATE LATER TONIGHT...08Z-10Z...AS THE LOW LEVELS BECOME MORE
STABLE.
&&

.MARINE...A VERY WEAK LOW OVER THE SOUTHERN COASTAL WATERS WILL
SHIFT INLAND TONIGHT. HIGHER PRES WILL CONTINUE WELL OFFSHORE
THROUGH THE WEEK...WHILE A WEAK SURFACE TROUGH TENDS TO PERSIST
OVER THE WATERS. SHOULD NOT BE MUCH GRADIENT THIS WEEK SO WILL
KEEP WINDS BETWEEN 10 AND 15 KT. SEAS NOT A PROBLEM EITHER...WITH
WESTERLY SWELL REMAINING NEAR 6 FT OR LESS. COLUMBIA BAR CLOSE TO
ROUGH CONDITIONS DURING THE EBB CURRENTS.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.

&&

$$

MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND

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.
Weather information courtesy of NOAA and AviationWeather.gov