Area Forecast Discussion
Issued by NWS Portland, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KPQR 120448 CCA
AFDPQR

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

.SYNOPSIS...A MILD AND MOIST SOUTHWEST FLOW PATTERN INTO NORTHWEST
OREGON AND SOUTHWEST WASHINGTON WILL INTO 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...RADAR SHOWED MOST OF THE PRECIPITATION OVERRUNNING A
WARM FRONT THIS EVENING HAD LIFTED N INTO WA....LEAVING MOST OF THE
INTERIOR OF NW OREGON DRY LATE THIS EVENING. A COLD FRONT OFF THE
COAST WAS POISED TO PUSH INLAND...ACCORDING TO MOST MODELS FRI
MORNING. ON SATELLITE THE COLD FRONT APPEARED TO LACK DEEP MOISTURE
THIS EVENING AS EVIDENCED BY A LACK OF COLD TOPPED CLOUDS...BUT A
WAVE MOVING UP OFF THE S OREGON COAST SUGGESTED AT LEAST A SMALL
CHANCE FOR SOME RAIN TO MOVE BACK IN LATER TONIGHT...SO WILL NEED TO
KEEP A MENTION FOR THE POSSIBILITY OF SOME LIGHT RAIN LATE DOWN THE
S INTERIOR....BUT WITH THE BETTER CHANCES FOR RAIN REMAINING NEAR
THE COAST.

REMAINDER OF SHORT TERM DISCUSSION UNCHANGED... 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...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS. 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...CIGS AND VIS IN THE CENTRAL AND SOUTH VALLEY HAVE
DROPPED TO MOSTLY IFR THIS EVENING AND EXPECT THAT TO CONTINUE
TONIGHT. WINDS OUT OF THE EAST IN THE NORTH VALLEY SHOULD KEEP VFR
CONDITIONS IN PLACE NEAR THE GORGE BUT EXPECT CONDITIONS FROM KHIO
NORTH AND WEST TO BE MOSTLY IFR TONIGHT. THE COAST WILL LIKELY
HAVE MVFR CIGS OR VIS THROUGH FRIDAY MORNING. EXPECT MVFR VSBYS
AND POSSIBLY MVFR CIGS WITH A WEAK FRONT FRIDAY MORNING...THEN
RISING TO VFR IN THE AFTERNOON.

KPDX AND APPROACHES...VFR CONDITIONS WITH RAIN AND MID TO HIGH
CLOUDS. GUSTY WINDS OUT OF THE EAST NEAR THE COLUMBIA RIVER GORGE
AND AROUND KTTD. BOWEN

&&

.MARINE...THE BUILDING LONG-PERIOD NW SWELL WILL DOMINATE THE
WATERS 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...HOWEVER THERE IS STILL
SOME CONCERN THAT AREAS WITHIN 10 NM WILL NOT SEE FREQUENT GUSTS
ABOVE 20 KT. BEST CHANCE FOR INCREASED GUSTS WILL BE LATER
TONIGHT WHEN THE FRONT NEARS. THERE IS A CHANCE FOR GALE FORCE
GUSTS LATE IN THE WEEKEND. BOWEN/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 CASCADE HEAD OR FROM 10 TO 60 NM-
     WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.

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

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 AM PST FRIDAY FOR COASTAL
     WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 10 NM-
     COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST
     SATURDAY.

&&

$$

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.


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.