Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 112258
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
258 PM PST THU FEB 11 2016

.SYNOPSIS...A MILD AND MOIST SOUTHWEST FLOW PATTERN TO NORTHWEST
OREGON AND SOUTHWEST WASHINGTON THROUGH FRIDAY. A COLD FRONT WILL
THEN BRING COOLER TEMPERATURES AND LOWER SNOW LEVELS TO BELOW THE
CASCADES PASSES FRIDAY NIGHT AND SATURDAY. A WARM FRONT WILL SPREAD
STEADIER RAIN AND PRODUCE RISING SNOW LEVELS LATE SATURDAY AND
SUNDAY. ADDITIONAL UNSETTLED WEATHER WILL PRODUCE MORE VALLEY RAIN
AND MOUNTAIN SNOW NEXT WEEK.

&&

.SHORT TERM...TODAY THROUGH SUNDAY...A MILD AND MOIST SOUTHWESTERLY
FLOW PATTERN WILL BRING OFF AND ON LIGHT SHOWERS FOR THE REMAINDER OF
THIS AFTERNOON...PARTICULARLY NORTH OF A LINE EXTENDING BETWEEN
TILLAMOOK AND MOUNT HOOD. THERE IS EVEN ENOUGH ELEVATED INSTABILITY
THAT A LIGHTNING STRIKE OR TWO CANNOT BE RULED OUT AS THE REMAINING
SHOWERS LIFT NORTHWARD ACROSS THE AREA. LATEST VISIBLE SATELLITE
IMAGERY ALSO REVEALS CLEARER SKIES ARE BEGINNING TO WORK THEIR WAY
NORTHWARD INTO LANE COUNTY THIS AFTERNOON. THIS SHOULD PRODUCE A
BREAK IN THE WET WEATHER AND CLOUDS TONIGHT...PARTICULARLY SOUTH AND
EAST OF PORTLAND. POPS WERE SPLIT INTO 3 HOURLY GRIDS TO TRY AND SHOW
TRENDS IN RAIN CHANCES DURING THE OVERNIGHT HOURS.

A SURFACE LOW PRESSURE IS CURRENTLY MOVING NORTHWARD ALONG 140W OFF
THE PACIFIC NORTHWEST COAST. AN ATTENDANT COLD FRONT CURRENTLY NEAR
130W WILL PUSH EASTWARD INTO THE REGION EARLY FRIDAY. THIS WILL
BRING A PERIOD OF RAIN FRIDAY MORNING...AND ALLOW SNOW LEVELS TO
LOWER TO NEAR 4500-5000 FT FRIDAY AFTERNOON. THE SHORTWAVE TROUGH
RESPONSIBLE FOR THE LOW PRESSURE SYSTEM WILL LAG A BIT AND SKIRT OUR
NORTHERN ZONES FRIDAY NIGHT. THIS SHOULD PRODUCE AN UPTICK IN SHOWER
ACTIVITY AND ALLOW SNOW LEVELS TO LOWER FURTHER...GENERALLY INTO THE
3500-4000 FT RANGE. SNOWFALL AMOUNTS WILL LIKELY BE GREATEST ACROSS
THE SOUTH WASHINGTON CASCADES WHERE 1 TO 4 INCHES OF SNOW APPEAR
LIKELY. FARTHER SOUTH...EVEN AN INCH OF NEW SNOW FRIDAY NIGHT MIGHT
BE A STRETCH IN THE LANE COUNTY CASCADES.

ANY REMAINING SHOWERS SHOULD COME TO AN END FAIRLY QUICKLY SATURDAY
MORNING AS WEAK SHORTWAVE RIDGING TEMPORARILY SHIFTS EASTWARD ACROSS
THE REGION. HOWEVER...THE BREAK IN THE WET WEATHER WILL BE SHORT
LIVED AS A STRONG WARM FRONT WILL SPREAD CLOUDS AND STEADY RAIN INTO
THE REGION SATURDAY AFTERNOON/EVENING...AND LIKELY CONTINUE TO BRING
RAIN TO THE AREA FOR MUCH OF SUNDAY. COLDER AIR WILL LIKELY BE SLOW
TO PUSH OUT OF THE CASCADES SATURDAY NIGHT. GIVEN MODEL QPF...THERE
APPEARS A GOOD CHANCE THAT PORTIONS OF THE SOUTH WASHINGTON CASCADES
AND PERHAPS THE NORTH OREGON CASCADES ABOVE 4000-5000 FT WILL SEE
ENOUGH SNOW...SOMEWHERE ON THE ORDER OF 4 TO 8 INCHES...TO RESULT IN
WINTER WX ADVISORIES SATURDAY NIGHT. HOWEVER...IMPACTS TO TRAVEL
SHOULD BE SHORT LIVED AS SNOW LEVELS SHOULD RISE TO 7000 FT OR HIGHER
ON SUNDAY. /NEUMAN

.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...THE PROGRESSIVE WEATHER
PATTERN WILL PERSIST INTO NEXT WEEK. MODELS CONTINUE TO SHOW A FLAT
UPPER LEVEL RIDGE MOVING OVER THE PAC NW EARLY NEXT WEEK. THIS COULD
BRING A BRIEF BREAK FROM THE RAIN MONDAY...BUT WILL MAINTAIN SOME
CHANCE POPS IN THE FORECAST DUE TO LINGERING INSTABILITY. A WEAK
SHORTWAVE DISTURBANCE LOOKS TO RIDE OVER THE TOP OF THE RIDGE ON
TUESDAY AND WILL LIKELY PUSH ANOTHER FRONT ACROSS THE REGION LATE
TUESDAY/EARLY WEDNESDAY BRINGING MORE RAIN. CASCADE SNOW LOOKS TO
RETURN WEDNESDAY AFTERNOON WITH SNOW LEVELS LOWERING TO AROUND 3500
FT. UNSETTLED WEATHER AND LOWERING SNOW LEVELS CONTINUE INTO
THURSDAY AS THE BASE OF THE TROUGH MOVES ACROSS THE FORECAST AREA.
MONDAY WILL LIKELY BE THE WARMEST DAY...WITH TEMPS TRENDING COOLER
EARLY NEXT WEEK. /64

&&

.AVIATION...MOSTLY VFR CONDITIONS TONIGHT WITH CIGS RANGING
BETWEEN 5K AND 9K. THE COAST WILL LIKELY HAVE MVFR CIGS THIS
EVENING...AND THEN AGAIN FRIDAY MORNING. COULD SEE BRIEF FOG AT
KHIO OR KSPB OVERNIGHT...BUT VFR SHOULD OVERALL DOMINATE. EXPECT
MVFR VSBYS AND POSSIBLY MVFR CIGS WITH A WEAK FRONT FRIDAY
MORNING.

KPDX AND APPROACHES...VFR CONDITIONS WITH RAIN AND HIGH CLOUDS. TJ

&&

.MARINE...A MIXED SWELL CONTINUES OVER THE WATERS THIS EVENING WITH
A BUILDING LONG-PERIOD NW SWELL AND A SUBSIDING 11 SEC W SWELL.
THE BUILDING LONG-PERIOD NW SWELL WILL DOMINATE THE WATERS LATE
TONIGHT AND PEAK AROUND 14 FT BY FRIDAY MORNING. SEAS WILL STAY ABOVE
10 FT THROUGH THE WEEKEND. A LOW-END SMALL CRAFT ADVISORY FOR WINDS
CONTINUES TONIGHT. THERE IS STILL SOME CONCERN THAT AREAS WITHIN 10
NM WILL NOT SEE FREQUENT GUSTS ABOVE 20 KT. 30 AM THIS MORNING...AND
TO 14 FT WITH BREAKERS LIKELY DURING THE STRONG EBB AROUND 645 PM
TONIGHT.HAVE DELAYED THE START TIME OF THE ADVISORY IN THE INNER
WATERS UNTIL LATE TONIGHT AS THINK THE BEST CHANCE FOR INCREASED
GUSTS WILL BE WHEN THE FRONT NEARS. THERE IS A CHANCE FOR GALE FORCE
GUSTS LATE IN THE WEEKEND. TJ

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 AM PST FRIDAY FOR WATERS
     FROM CAPE SHOALWATER WA TO FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 AM PST SATURDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT
     60 NM.

     SMALL CRAFT ADVISORY FOR WINDS FROM 9 PM TONIGHT TO 4 AM PST
     FRIDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR
     OUT 10 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 4 PM
     THIS AFTERNOON TO 4 PM PST FRIDAY.

&&

$$

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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