Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 221703
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1002 AM PDT MON SEP 22 2014

.SYNOPSIS...LOW MARINE CLOUDS EXTEND WELL INLAND THIS MORNING AS A
COLD FRONT APPROACHES THE COAST. THE FRONT WILL SPREAD LIGHT RAIN
ACROSS THE AREA TONIGHT THROUGH TUESDAY MORNING. A STRONGER AND
SLOWER MOVING FRONT WILL BRING MORE SUBSTANTIAL RAIN TUESDAY NIGHT
THROUGH WEDNESDAY AFTERNOON. AN UPPER TROUGH WILL SUPPORT COOL AND
SHOWERY WEATHER THROUGH FRIDAY.

&&

.UPDATE...FEW CHANGES WERE MADE TO THE OVERALL FORECAST PACKAGE THIS
MORNING. MAIN CHANGES WERE TO COOL THINGS DOWN A TAD FOR TODAY AND
TUESDAY MAINLY DUE TO THE EXTENSIVE CLOUD COVER. VISIBLE SATELLITE
IMAGERY SHOWS PLENTY OF LOW CLOUDS EXTENDING INTO THE LOWER CASCADE
VALLEYS...WITH A MID-LEVEL DECK ABOVE. THE HIGHER CLOUDS ABOVE THE
STRATUS WILL DELAY THE BURNOFF OF THE LOWER STRATUS...BUT SOME
SUNBREAKS ARE LIKELY BY LATE AFTERNOON. BY THEN THE SUN ANGLE WILL
ALREADY BE GETTING LOWER IN THE SKY...SO NOT MUCH OPPORTUNITY FOR
SIGNIFICANT WARMING. TIMING OF RAIN ASSOCIATED WITH THE FRONT REMAINS
CONSISTENT WITH WHAT WAS MENTIONED IN THE PREVIOUS DISCUSSION BELOW.


ENJOY THE LAST FEW HOURS OF SUMMER...THE AUTUMNAL EQUINOX OCCURS AT
729 PM PDT THIS EVENING.  WEAGLE

/PREV DISC ISSUED 314 AM PDT MON SEP 22 2014/

.SHORT TERM...TODAY THROUGH WEDNESDAY...RADAR IMAGERY SHOWS SOME
SHOWERS OVER THE NORTHERN OREGON CASCADES...NEAR MOUNT HOOD...MOVING
NORTHWARD INTO THE SW WASHINGTON CASCADES EARLY THIS MORNING. THERE
WAS SOME BRIEF DRIZZLE ALONG THE COAST OVERNIGHT...BUT THE CLOUD
BASES HAVE LIFTED WITH THE MARINE STRATUS QUICKLY MOVING INLAND. LOW
CLOUDS HAVE FILLED IN MOST OF THE WILLAMETTE VALLEY AS OF 230 AM THIS
MORNING.

SATELLITE IMAGERY SHOWS A FRONT AROUND 160 MILES OFF OF THE OREGON
AND WASHINGTON COAST. THE FRONT APPEARS TO BE MOVING SLIGHTLY FASTER
THAN THE MODELS INDICATE...AND THE COAST MAY SEE SOME MORE DRIZZLE OR
LIGHT RAIN THIS MORNING. OTHERWISE...THE MAIN RAIN BAND SHOULD REMAIN
OFFSHORE TODAY. ISOLATED SHOWERS OR THUNDERSTORMS MAY DEVELOP OVER
THE CASCADES AGAIN THIS AFTERNOON.

THE FRONT WILL PUSH INLAND TONIGHT AND SPREAD WIDESPREAD RAIN ACROSS
NW OREGON AND SW WASHINGTON THROUGH TUESDAY MORNING. THE
COAST...COAST RANGE AND WASHINGTON CASCADES CAN EXPECT AROUND A
QUARTER OF AN INCH OF RAIN BY NOON TUESDAY...WHEREAS OTHER AREAS LESS
THAN 0.20 INCH AND LESS THAN 0.10 INCH FOR THE INLAND AREAS OF LANE
COUNTY. THE RAIN WILL TURN TO SHOWERS TUESDAY AFTERNOON.

A STRONGER FRONT WILL BRING MORE SUBSTANTIAL RAIN TUESDAY NIGHT
THROUGH WEDNESDAY. THIS FRONT WILL MOVE MORE SLOWLY AND RAINFALL
TOTALS WILL LIKELY BE MUCH HIGHER. THE CURRENT FORECAST IS FOR 1 TO
1.5 INCHES OF RAIN FOR THE COAST AND COAST RANGE...0.75 TO 1 INCH FOR
THE CASCADES AND CASCADES FOOTHILLS...AND 0.5 TO 0.75 INCH FOR THE
WILLAMETTE VALLEY FROM TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON.
SOME GUSTY SOUTH WINDS WILL ACCOMPANY THIS FRONT...MAINLY FOR THE
COAST WHERE 40-50 MPH WINDS IS EXPECTED FOR THE BEACHES AND
HEADLANDS.

HEAVY RAIN MAY POSE A THREAT FOR DEBRIS FLOW IN AREAS AFFECTED BY THE
LOCAL WILDFIRES. WILL CONTINUE TO MONITOR THIS POSSIBILITY AND OF
COURSE PASS ALONG MORE INFORMATION AS WE LEARN THE SEVERITY OF THESE
BURN SCARS. TJ

.LONG TERM...AFTER OUR SLOW-MOVING FRONT CLEARS THE REGION WEDNESDAY
EVENING...MODELS SHOW DECENT AGREEMENT THAT AN UPPER LEVEL TROUGH
WILL SETTLE OVER THE PACIFIC NORTHWEST. THIS WILL MEAN COOL AND
UNSETTLED WEATHER WITH PLENTY OF SHOWERS AROUND FOR THE REST OF THE
WEEK. IT MAY TAKE UNTIL NEXT WEEKEND FOR TEMPS TO REBOUND BACK TO
NORMAL...THOUGH BEYOND FRIDAY MODELS HAVE ALL SORTS OF DIFFERENT
IDEAS OF HOW TO HANDLE OUR PATTERN. BEST GUESS IS THAT SOME FLAT
RIDGING WILL ATTEMPT TO RETURN BY THE WEEKEND...FOLLOWED BY SOME
FRONTAL SYSTEMS ATTEMPTING TO CLIP THE PAC NW BY EARLY NEXT WEEK.
THIS BASED MORE ON PATTERN RECOGNITION THAN ANYTHING ELSE...SO
CONFIDENCE IN ANY PARTICULAR SOLUTION IS RATHER LOW STARTING NEXT
WEEKEND.  WEAGLE

&&

.AVIATION...STRATUS REMAINS ACROSS MOST OF THE REGION THIS MORNING
WITH CIGS BETWEEN 2000-3000 FT. MODEL SOUNDINGS SUGGEST A FAIRLY
SHALLOW LAYER...SO EXPECT THE INTERIOR TAF SITES TO BECOME VFR BY
MIDDAY WITH ABUNDANT MID-HIGH CLOUDS AHEAD OF WEAKENING FRONTAL
SYSTEM. SOME SHOWERS WITH SLIGHT CHANCE OF THUNDERSTORMS OVER THE
CASCADES AGAIN THIS AFTERNOON AND EVENING. COASTAL AREAS LIKELY
REMAIN UNDER MVFR CIGS THROUGH TONIGHT...WITH POTENTIAL FOR CIGS
TO INCREASE TO AROUND 3500 FT FOR A FEW HOURS...WITH RAIN ARRIVING
THIS EVENING. SOME LIGHT RAIN SPREADS INLAND LATER IN THE EVENING
AND OVERNIGHT BUT VFR CONDITIONS SHOULD PREVAIL THROUGH 12Z
TONIGHT.

KPDX AND APPROACHES...EXPECT CIGS 2500-3000 FT THROUGH 19Z...THEN
BECOMING SCATTERED. VFR CONTINUES THROUGH 12Z TUE WITH INCREASING
MID AND HIGH CLOUDS AHEAD OF FRONTAL SYSTEM AND INCREASING RAIN
CHANCES AFT 03Z TUE.

&&

.MARINE...SOUTH WINDS CONTINUE BELOW ADVISORY LEVELS TODAY AS A
WEAKENING FRONT MOVES ACROSS THE WATERS TODAY. THE OUTER WATERS
MAY HAVE A FEW OCCASIONAL GUSTS TO 25 KT THIS AFTERNOON...BUT DO
NOT EXPECT THEM TO BE WIDESPREAD OR FREQUENT ENOUGH TO WARRANT AN
ADVISORY. THIS WEAK FRONT WILL BRING SOME RAIN TO THE WATERS...AND
PERHAPS A THUNDERSTORM TO OUR NORTHERN OUTER WATERS...THOUGH THE
OPC LIGHTNING DENSITY PRODUCT DEPICTS DECREASING LIGHTNING THIS
MORNING.

A STRONGER FRONT APPROACHES THE REGION TUE WITH INCREASING
WINDS...POTENTIALLY BRINGING SOME GALE FORCE WINDS LATE TUE
AFTERNOON OR EVENING ALONG WITH THE POTENTIAL FOR A COASTAL JET
TO DEVELOP. WINDS LIKELY EASE A LITTLE WED MORNING...BUT PROBABLY
REMAIN IN SMALL CRAFT RANGE THROUGH FRI WHEN THE ASSOCIATED LOW
PRES WEAKENS OFF THE SOUTH B.C. COAST.

SEAS REMAIN 7 FT OR LESS THROUGH EARLY TUE...BUT INCREASE ABOVE 10
FT TUE NIGHT. EXPECT SEAS TO PEAK NEAR 15 FT LATE WED NIGHT...AND
DROP BELOW 10 FT ON FRI.  CULLEN

&&

.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 AS THE FORECAST AREA.



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