497 
FXUS66 KPQR 041008
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR 
208 AM PST WED NOV 4 2015

.SYNOPSIS...A WEAK RIDGE OF HIGH PRES WILL MOVE ACROSS THE PACIFIC
NW TODAY BRINGING A SHORT PERIOD OF DRY WEATHER. THE NEXT
WEATHERMAKER WILL BE A MOIST TROUGH OF LOW PRES ALOFT MOVING ACROSS
THE REGION TONIGHT AND THU...BRINGING A GOOD CHANCE FOR RAIN TO THE
REGION. A WEAK WARM FRONT WILL LIFT N INTO WA THU NIGHT AS HIGH
PRESALOFT BUILDS IN FOR A DRY DAY FRI. ANOTHER SERIES OF FRONTS WILL
BRING SOME RAIN TO THE PACIFIC NORTHWEST THIS WEEKEND.
&&

.SHORT TERM...TEMPS EARLY THIS MORNING HAD ALREADY DROPPED INTO THE
30S AT MOST LOW ELEVATION LOCATIONS...AND WITH DEW POINTS IN THE LOW
TO MID 30S SUGGESTS MANY AREAS WILL SEE THEIR FROST THIS MORNING.
AREAS OF FOG WERE ALSO BEGINNING TO FORM IN SOME AREAS...AND WITH
DEW POINT DEPRESSIONS SMALL WITH LIGHT WINDS EXPECT MANY VALLEY
AREAS TO FILL IN WITH FOG DURING THE NEXT FEW HOURS.

A RATHER FLAT POSITIVE TILT RIDGE WAS EVIDENT OFFSHORE THIS MORNING
IN SATELLITE PICTURES. HIGH CLOUDS WERE BEGINNING TO SPILL IN OVER
THE TOP OF THE RIDGE INTO WESTERN WA AND EXTREME NW OREGON EARLY
THIS MORNING...AND WILL LIKELY SEE MORE HIGH CLOUDS SPREAD IN LATER
TODAY AS THE RIDGE MOVES SE ACROSS THE REGION.

MODELS REMAIN IN VERY GOOD AGREEMENT WITH THE SHORT WAVE EXPECTED TO
MOVE SE ACROSS THE REGION LATE TONIGHT AND EARLY THU. MODEL TIME
HEIGHT CROSS SECTIONS INDICATE DEEP MOISTURE TO MOVE ACROSS THE
REGION WITH THIS WAVE. IN ADDITION TO MODEST LIFT PROVIDED BY THE
SHORTWAVE...MODEL ISENTROPIC FIELDS ALSO INDICATE WEAK BUT DEEP
MOIST ISENTROPIC LIFT BETWEEN 285 TO 300K ISENTROPES. WHILE NOT
EXPECTED TO BE A HEAVY RAIN EVENT...MOISTURE AND LIFT APPEAR TO BE
ENOUGH TO JUSTIFY GOING WITH FAIRLY HIGH POPS...LIKELY OR BETTER...
FOR LATE TONIGHT AND EARLY THU. LOW LEVEL MOISTURE...BELOW 700
MB...IS SLOW TO CLEAR OUT LATER THU AND THU NIGHT. WEAK MOIST
ISENTROPIC LIFT REMAINS BELOW THE 290K ISENTROPE THROUGH THU
NIGHT...MAINLY ACROSS THE N PART OF THE FORECAST AREA IN AN AREA OF
WEAK WARM AIR ADVECTION UNDER A BUILDING RIDGE ALOFT. AGAIN ANY
PRECIPITATION LINGERING THROUGH THU NIGHT IS LIKELY TO BE ON THE
LIGHT SIDE...BUT GIVEN THE LOW LEVEL LIFT AND MOISTURE WILL UP POPS
A BIT MAINLY ACROSS THE N PART OF THE FORECAST AREA.

ANOTHER TRANSITORY RIDGE ALOFT MOVING ACROSS THE REGION FRI SHOULD
BRING A SHORT PERIOD OF DRY WEATHER BACK TO MOST AREAS...EXCEPT FOR
A LINGERING SLIGHT CHANCE FOR LIGHT RAIN IN THE S WA CASCADES IN THE
MORNING...AND A SLIGHT CHANCE FOR LIGHT RAIN REACHING THE S WA COAST
FRI AFTERNOON AHEAD OF THE NEXT FRONTAL SYSTEM.
 
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS. FRIDAY NIGHT
THROUGH TUESDAY...PROGRESSIVE PATTERN CONTINUES THROUGH THE WEEKEND
WITH RAIN MOVING BACK IN ON SATURDAY.
THIS SYSTEM WILL NOT BRING AS MUCH RAIN AS WE SAW LAST WEEKEND...BUT
MOST OF THE AREA COULD SEE A MODERATE AMOUNT OF RAIN. ANOTHER
SHORTWAVE MOVES IN BEHIND THE FRONT SUNDAY WHICH WILL BRING DOWN
SNOW LEVELS WITH MORE PRECIPITATION SUNDAY INTO MONDAY. THIS LOOKS
LIKELY TO BRING MORE SNOW DOWN TO THE CASCADE PASSES AND MAYBE EVEN
AS LOW AS HIGHER ELEVATIONS IN THE CASCADE FOOTHILLS. SHOWERY
CONDITIONS THROUGH MONDAY...WITH TUESDAY LOOKING DRIER AT THIS TIME.
-MCCOY
&& 

.AVIATION...VFR CONDITIONS EARLY THIS MORNING WILL GIVE WAY TO PLENTY
OF LIFR CONDITIONS IN THE VALLEYS OF NORTHWEST OREGON AND SOUTHWEST
WASHINGTON BETWEEN 11Z AND 17Z WEDNESDAY. IMPROVEMENT TO PREDOMINANTLY
VFR CONDITIONS SHOULD OCCUR AROUND MIDDAY. A WEAKENING FRONTAL SYSTEM
WILL BRING RAIN AND MVFR CIGS TO THE AREA AS WE APPROACH 12Z THURSDAY.

KPDX AND APPROACHES...VFR CONDITIONS EARLY THIS MORNING SHOULD
GIVE WAY TO LIFR/IFR CONDITIONS...PRIMARILY BETWEEN 12Z AND 16Z
WEDNESDAY BEFORE CONDITIONS IMPROVE MIDDAY. A WEAK FRONTAL STORM
SYSTEM WILL LIKELY BRING RAIN AND MVFR CONDITIONS TO THE AREA
BETWEEN 06Z AND 12Z THURSDAY. /NEUMAN

&&

.MARINE...EXPECT A FAIRLY BENIGN PERIOD OF WEATHER OVER THE
WATERS FOR THE NEXT FEW DAYS AS WEAK HIGH PRESSURE LINGERS OVER
THE NORTHEAST PACIFIC. A STRONGER FRONTAL STORM SYSTEM WILL THEN
ARRIVE LATE IN THE WEEK AND LIKELY BRING SOLID SMALL CRAFT
ADVISORY LEVEL WIND GUSTS OF 25 TO 30 KT TO THE WATERS LATE FRIDAY
INTO EARLY SATURDAY. A WESTERLY SWELL BETWEEN 10 AND 15 FT WILL
ALSO LIKELY PUSH INTO THE WATERS OVER THE WEEKEND AND PERSIST INTO
EARLY NEXT WEEK. /NEUMAN

&&

.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.