516
FXUS66 KPQR 171139
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
339 AM PST MON FEB 17 2025
SYNOPSIS
A LOW PRESSURE SYSTEM MAINTAINS WIDESPREAD RAIN AND CASCADE
SNOW TODAY. HEAVY SNOW AND HAZARDOUS TRAVEL IS EXPECTED FOR THE
CASCADE PASSES THROUGH THIS AFTERNOON. MILDER TEMPERATURES
CONTINUE THROUGH THE WEEK, WITH ANOTHER WEATHER SYSTEM ARRIVING
LATER TUESDAY INTO WEDNESDAY. LIKELY TRENDING DRIER AND WARMER
LATER THIS WEEK, BUT POTENTIAL FOR HEAVIER RAIN RETURNS FOR THE
WEEKEND.
SHORT TERM...NOW THROUGH WEDNESDAY NIGHT
MOIST ONSHORE FLOW
CONTINUES TO MAINTAIN RAIN SHOWERS OVER THE AREA AND ACCUMULATING
SNOW IN THE CASCADES. WITH SNOW LEVELS AROUND 3500-4000 FT
TODAY, EXPECT AN ADDITIONAL ABOUT 0.5 TO 1 FT MORE OF SNOW
WITHIN THE CASCADES UNTIL THIS EVENING. AIDED BY A SHORTWAVE
TROUGH MOVING OVER THE REGION TODAY, EXPECT SNOWFALL RATES OF
0.5 TO 1.0 INCH PER HOUR AT TIMES UNTIL THIS EVENING FOR THE
CASCADE PASSES. AS A RESULT, WILL MAINTAIN THE WINTER STORM
WARNING FOR THE SW WASHINGTON AND NW OREGON CASCADES UNTIL
4 PM THIS AFTERNOON. THOSE TRAVELING THROUGH THE CASCADES
SHOULD PREPARE FOR WINTER WEATHER AND REFER TO ODOT/WSDOT FOR
THE LATEST ROAD CONDITIONS AND RESTRICTIONS.
FURTHERMORE, THE UPPER HOOD RIVER VALLEY WILL LIKELY SEE SOME
FREEZING RAIN ACCUMULATION AROUND 0.05 TO 0.10 INCH THIS MORNING
UNTIL 10 AM, SPECIFICALLY FOR AREAS ABOVE 1000 FT IN ELEVATION.
WITH EXPECTED ACCUMULATIONS AND CONCERN FOR SLIPPERY ROADS AND
SIDEWALKS, HAVE ISSUED A WINTER WEATHER ADVISORY UNTIL 10 AM
THIS MORNING FOR AREAS ABOVE 1000 FT, SUCH AS PARKDALE.
FOR AREAS WEST OF THE CASCADES, EXPECT RAINY WEATHER TO CONTINUE
TODAY, BECOMING SHOWERY BY THE EVENING AND DISSIPATING OVERNIGHT
INTO EARLY TUESDAY MORNING. EXPECT AN ADDITIONAL 0.25 INCH OF
RAIN ALONG THE COAST AND WITHIN THE WILLAMETTE VALLEY UNTIL 10
PM TONIGHT. AS FOR THE COAST RANGE AND CASCADE FOOTHILLS, AN
ADDITIONAL 0.50 TO 0.75 INCH OF RAINFALL IS EXPECTED. ALTHOUGH
RIVERS ARE ON THE RISE, THERE ARE STILL NO HYDRO IMPACTS
EXPECTED. COULD SEE SOME PATCHY FOG OR LOW STRATUS EARLY TUESDAY
MORNING AS SHOWERS AND CLOUD COVER DISSIPATES. BY TUESDAY
AFTERNOON, OFFSHORE WINDS WILL INCREASE AND TEMPERATURES WILL
INCREASE INTO THE LOW 50S.
ANOTHER FRONTAL SYSTEM WILL ARRIVE BETWEEN TUESDAY AFTERNOON AND
EVENING, PUSHING SNOW LEVELS BACK TO OVER 5000 FT AND BRINGING
SNOW TO THE CASCADES AND WIDESPREAD RAIN WEST OF THE CASCADES.
FROM TUESDAY NIGHT INTO WEDNESDAY MORNING, THERE IS AROUND A
30-50% CHANCE FOR A WINTRY MIX OF SNOW/SLEET RETURNING TO THE
UPPER HOOD RIVER VALLEY AS TEMPERATURES ARE FORECAST TO COOL TO
AROUND 30-34 DEGREES. ADDITIONALLY, NBM DOES SUGGEST A 10-20%
CHANCE OF 0.5 INCH OR MORE OF SNOW EARLY WEDNESDAY MORNING FOR
AREAS WITHIN THE UPPER HOOD RIVER VALLEY, SUCH AS ODELL AND
PARKDALE.
THIS TUESDAY INTO WEDNESDAY WEATHER SYSTEM WILL NEED TO BE
MONITORED AS THERE IS A POTENTIAL FOR A STRONGER LOW SPINNING UP
NEAR THE COASTLINE AND MOVING NORTHEAST INTO THE REGION. LATEST
MODELS SUGGEST THIS LOW TO DEEPEN TO AROUND 995 MB, BRINGING A
10-20% CHANCE OF WIND GUSTS UP TO 50 MPH ALONG THE COAST.
INLAND, MORE RAIN AND CASCADE SNOW IS EXPECTED UNTIL EARLY
THURSDAY MORNING. ~HALL
LONG TERM...THURSDAY THROUGH SUNDAY
MODELS AND THEIR ENSEMBLES
ARE IN GOOD AGREEMENT LATER THIS WEEK OF UPPER LEVEL RIDGING
BUILDING OVER THE REGION. MOST CLUSTERS KEEP THE AREA DRY MUCH OF
THURSDAY AND FRIDAY, ALTHOUGH THERE IS AROUND A 20-30% CHANCE
THAT A FRONT IS ABLE TO PUSH RAIN BACK INTO SOUTHWEST WASHINGTON
AND FAR NW OREGON BY FRIDAY AFTERNOON. TEMPERATURES ARE LIKELY
TO CONTINUE THE GRADUAL WARMING TREND INTO THE MID TO UPPER 50S
INTO THE WEEKEND. THE NEXT WEATHER SYSTEM THAT BRINGS MORE RAIN
TO THE PACIFIC NW OVER THE WEEKEND WILL LIKELY BE ASSOCIATED
WITH A WEAK TO MODERATE ATMOSPHERIC RIVER. THE EUROPEAN ENSEMBLE
SUGGESTS AVERAGE PWAT AMOUNTS AROUND 1 INCH, WITH SOME MEMBERS
SHOWING UP TO 2 INCHES WITHIN 24 HOURS POSSIBLE. THE GFS
ENSEMBLE SHOWS SLIGHTLY LOWER AVERAGE PWAT AMOUNTS AROUND 0.75
INCH, WITH SOME MEMBERS SHOWING UP TO 1.5 INCHES WITHIN 24 HOURS
POSSIBLE. UNCERTAINTY WITH WHERE THE BAND OF HEAVIER MOISTURE
SETS UP LEADS TO THIS VARIATION OF EXPECTED TOTAL PRECIPITATION.
~HALL/DH
AVIATION
SATELLITE, RADAR, AND SURFACE OBSERVATIONS AS OF 11Z
MON DEPICT SHOWERS CONTINUING ACROSS THE AREA AS A WEAK TROUGH
MOVES THROUGH, BRINGING A MIX OF MVFR AND VFR CIGS. EXPECT THIS
TREND TO CONTINUE THROUGH AT LEAST THIS MORNING, BEFORE SHOWERS
BEGIN DECREASING IN THE AFTERNOON. AFTER 21Z TUE, WILLAMETTE
VALLEY TERMINALS COULD IMPROVE MORE TO VFR, HOWEVER THERE COULD
STILL BE SOME SPORADIC MVFR CIGS (20-40% CHANCE).
WINDS WILL GENERALLY BE SOUTHERLY TO SOUTHWESTERLY UNDER 10 KT
ACROSS ALL TERMINALS WITH GUSTS UP TO 20 KT ALONG THE COAST THIS
MORNING. LIGHT EASTERLY WINDS IN THE EASTERN PORTLAND METRO
CONTINUE THROUGH 18Z MON, BUT ARE FORECAST TO TURN MORE
SOUTHERLY BETWEEN 18-21Z MON.
PDX AND APPROACHES...SHOWERS AND LIGHT EASTERLY WINDS CONTINUE
THIS MORNING WITH A MIX OF MVFR/VFR CIGS THROUGHOUT THE TAF
PERIOD. SHOWERS DECREASE THIS AFTERNOON WITH WINDS TURNING MORE
SOUTHERLY AROUND 5-10 KT. -ALVIZ
MARINE
SOUTHWESTERLY WINDS WILL GRADUALLY WEAKEN TODAY, WITH
GUSTS FALLING BELOW 20 KT. HOWEVER, SEAS WILL INCREASE TODAY
AROUND 12 TO 14 FEET AT 15 SECONDS DUE TO AN INCOMING WESTERLY
SWELL. HIGH PRESSURE WILL CONTINUE THE BRIEF LULL IN WINDS MONDAY
NIGHT TO TUESDAY WITH SEAS SUBSIDING TO 9 TO 10 FEET AT 12
SECONDS.
ANOTHER FRONTAL SYSTEM ARRIVES TUESDAY NIGHT INTO WEDNESDAY
MORNING, BRINGING ANOTHER ROUND OF INCREASED WINDS AND BUILDING
SEAS. CONFIDENCE IS INCREASING FOR GALE FORCE SOUTHERLY WIND
GUSTS UP TO 40 KT IN THE OUTER WATERS (10 TO 60 NM OUT) AND UP TO
35 KT OVER THE INNER WATERS (OUT 10 NM). WILL NOTE THAT THERE IS
ALSO A 30-50% CHANCE FOR ISOLATED STORM FORCE WIND GUSTS UP TO 50
KT ACROSS THE OUTER WATERS. DUE TO GREATER CONFIDENCE IN GALE
FORCE GUSTS IN THE OUTER WATERS, A GALE WATCH HAS BEEN ISSUED FOR
THESE MARINE ZONES (PZZ271-273) BEGINNING 4 PM TUESDAY AND
LASTING THROUGH 10 AM WEDNESDAY. PREDOMINATELY WIND-DRIVEN SEAS
WILL ALSO BUILD DURING THIS TIME, AROUND 12 TO 15 FEET AT 14
SECONDS. -ALVIZ
BEACH HAZARDS
A WESTERLY SWELL OF 12-14 FT AT 15 SECONDS WILL
RESULT IN AN INCREASED THREAT FOR SNEAKER WAVES ALONG ALL COASTAL
BEACHES TODAY. THEREFORE, THE BEACH HAZARDS STATEMENT REMAINS IN
EFFECT THROUGH 4 PM MONDAY. BEACHGOERS SHOULD REMAIN VIGILANT FOR
WAVES OCCASIONALLY RUNNING UP MUCH FARTHER ONTO THE BEACH THAN
BACKGROUND WAVE CONDITIONS. STAY OFF OF ROCKS, JETTIES AND LOGS.
NEVER TURN YOUR BACK ON THE OCEAN. -ALVIZ/TK
PQR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY UNTIL 10 AM PST THIS MORNING FOR ORZ121.
WINTER STORM WARNING UNTIL 4 PM PST THIS AFTERNOON FOR
ORZ126>128.
WA...WINTER STORM WARNING UNTIL 4 PM PST THIS AFTERNOON FOR WAZ211.
PZ...SMALL CRAFT ADVISORY UNTIL 4 AM PST TUESDAY FOR PZZ210-251>253-
271>273.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
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