516
FXUS66 KPQR 172245
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
245 PM PST MON FEB 17 2025
SYNOPSIS
DECREASING SHOWERS THROUGH THIS EVENING, THEN WILL SEE A
BRIEF BREAK IN THE ACTIVE WEATHER PATTERN THROUGH AT LEAST TUESDAY
MORNING. LIGHT RAIN RETURNS LATER TUESDAY AS ANOTHER WEATHER SYSTEM
PUSHES ACROSS THE REGION THROUGH WEDNESDAY. BREEZY WINDS ALSO
POSSIBLE ON WEDNESDAY. THEN, LIKELY TRENDING DRIER AND WARMER LATER
THIS WEEK, INTO THE WEEKEND. BUT, THE POTENTIAL FOR HEAVIER RAIN
RETURNS LATER SATURDAY THROUGH EARLY NEXT WEEK AS AN ATMOSPHERIC
RIVER TAKES AIM AT THE PACIFIC NW.
SHORT TERM...NOW THROUGH WEDNESDAY NIGHT
SHOWERS CONTINUE THROUGH
THIS EVENING AS AN UPPER SHORTWAVE TROUGH DROPS ACROSS THE PACIFIC
NW TOWARD THE GREAT BASIN REGION TONIGHT. WITH SNOW LEVELS AROUND
4000 FT, CASCADE PASSES ARE SEEING TEMPERATURES AROUND 31-34 DEG.
WILL ALLOW THE WINTER STORM WARNING TO EXPIRE AT 4 PM THIS
AFTERNOON, WITH UP TO 2 INCHES OF SNOW POSSIBLE THROUGH THIS
EVENING. SHOWERS EXPECTED TO DISSIPATE ACROSS THE AREA TONIGHT WITH
DRY CONDITIONS PERSISTING THROUGH TUESDAY MORNING. HIGH PRESSURE WILL
LIKELY MAINTAIN CLOUDY CONDITIONS WITH SOME MORNING FOG AS A
SHORTWAVE UPPER RIDGE PASSES OVER THE REGION PROMOTING STABLE
CONDITIONS.
THE NEXT WEATHER SYSTEM QUICKLY APPROACHES AS A DIGGING UPPER TROUGH
APPROACHES THE WEST COAST ON TUESDAY. A WARM FRONT WILL PUSH LIGHT
PRECIPITATION ONSHORE BY TUESDAY AFTERNOON, SPREADING INLAND LATER
IN THE DAY THROUGH TUESDAY NIGHT. WITH THE DIGGING TROUGH, MODELS
ARE SUGGESTING THE LIKELIHOOD OF A COMPACT SURFACE LOW SPINNING UP
OFFSHORE NEAR THE OREGON COAST, ALTHOUGH NOT ALL ARE IN AGREEMENT.
AT THE MOMENT, DOES NOT LOOK TOO IMPACTFUL, BUT COULD BRING SOME
BREEZY WINDS SOMEWHERE ALONG THE COAST ON WEDNESDAY MORNING. NBM
GUIDANCE SUGGESTS THERE IS A 20-40% CHANCE OF WIND GUSTS EXCEEDING
50 MPH, HIGHEST PROBS BETWEEN TILLAMOOK AND NEWPORT. CHANCES FOR
WIND GUSTS EXCEEDING 60 MPH ARE MUCH LOWER (LESS THAN 10%). IN THIS
SCENARIO, THE STRONGEST WINDS WOULD LIKELY BE ASSOCIATED WITH A
WESTERLY STING JET AS THE LOW NEARS THE SHORE. ELSEWHERE, OFFSHORE
WINDS ARE EXPECTED TO INCREASE TUESDAY NIGHT INTO WEDNESDAY WITH
BREEZY EASTERLY WINDS RETURNING TO THE WEST COLUMBIA RIVER GORGE AND
EASTERN PORTLAND/VANCOUVER METRO. LATEST NAM/GFS GUIDANCE SUGGESTS
THE PRESSURE GRADIENT BETWEEN KTTD-KDLS INCREASES TO AROUND -6 TO -8
MB. ALSO, WATCHING TO SEE HOW THE LOW PROGRESSES FOR THE POTENTIAL
OF BREEZY SOUTHERLY WINDS THROUGH THE WILLAMETTE VALLEY LATER
WEDNESDAY. CURRENTLY A 30-40% CHANCE OF WIND GUSTS EXCEEDING 35 MPH,
BUT GENERALLY LESS THAN 10% CHANCE OF ADVISORY LEVEL WIND GUSTS OF
45 MPH.
PRECIPITATION RATES LIKELY INCREASE ON WEDNESDAY AS THE UPPER TROUGH
PUSHES AN OCCLUDING FRONT ACROSS THE REGION. SNOW LEVELS STARTING
OUT HIGHER, AROUND 4500-5000 FT WED MORNING, GRADUALLY FALLING TO
AROUND 4000 FT BY WED EVENING, WILL LIKELY LIMIT SNOWFALL AMOUNTS
THROUGH THE CASCADE PASSES. LATEST PROBS SHOW AROUND 40-50% CHANCE
OF 6 INCHES OF SNOWFALL ABOVE 4000 FT THROUGH WED NIGHT.
ADDITIONALLY, GUIDANCE CONTINUES TO SUGGEST A MODERATE CHANCE OF A
MIX OF WINTRY WEATHER RETURNING TO THE UPPER HOOD RIVER VALLEY WED
MORNING, WITH AROUND A 30-40% CHANCE OF 1 INCH OF SNOW ABOVE 500 FT,
AND UP TO A TENTH INCH OF ICE NEAR PARKDALE. /DH
LONG TERM...THURSDAY THROUGH MONDAY
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 AND
EARLY NEXT WEEK. 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 OF AROUND 1.0-1.1 INCH, WHILE THE GEFS SHOWS
SLIGHTLY LOWER AVERAGE PWAT AMOUNTS OF AROUND 0.9 INCH. UNCERTAINTY
REMAINS WITH WHERE THE BAND OF HEAVIER MOISTURE SETS UP, ALTHOUGH
THE HIGHEST CHANCES ARE NEAR 45N ACCORDING TO THE CW3E IVT LANDFALL
TOOL. ALTHOUGH LATEST HEFS FORECASTS SHOW A 10% OR LESS CHANCE OF
REACHING MINOR FLOOD STAGE, WILL NEED TO MONITOR THE FLASHIER RIVERS
AS WE GET CLOSER TO SUNDAY, INCLUDING THE GRAYS RIVER. /DH
AVIATION
POST-FRONTAL SHOWERS WILL CONTINUE TO DECREASE ACROSS
THE AREA THIS EVENING ALLOWING FOR IMPROVING FLIGHT CONDITIONS
INLAND. COASTAL AREAS ARE HOLDING ON TO IFR CEILINGS THIS EVENING,
AND WILL BOUNCE BETWEEN MVFR AND IFR TONIGHT. CALM WINDS AND
LINGERING SURFACE MOISTURE WILL LIKELY LEAD TO FOG AND LOW CLOUDS
(IFR) FOR AREAS THAT SEE CLEARING SKIES TONIGHT INTO TUESDAY
MORNING. THERE IS AROUND A 30-50% CHANCE OF IFR FOR THE
WILLAMETTE VALLEY TONIGHT WITH HIGHER CHANCES (~90%) FOR IFR ALONG
THE COAST. EXPECT MOSTLY VFR CONDITIONS AFTER 18Z TUESDAY. HIGH
CLOUDS WILL INCREASE TUESDAY AFTERNOON AS THE NEXT FRONT
APPROACHES FROM THE SW.
PDX AND APPROACHES...MOSTLY VFR CONDITIONS EXPECTED THIS EVENING
WITH MVFR CIGS WITH ANY LINGERING SHOWERS. THERE IS A 50% CHANCE
FOR IFR CONDITIONS AFTER 2 AM TUESDAY MORNING. FLIGHT CONDITIONS
SHOULD IMPROVE TO MVFR LATE TUESDAY MORNING, THEN VFR LATE TUESDAY
AFTERNOON. ~TJ
MARINE
SEAS WILL GRADUALLY SUBSIDE TONIGHT, BUT REMAIN ABOVE 10
FEET CONTINUING THE SMALL CRAFT ADVISORY. SOUTH WINDS WILL
INCREASE TUESDAY AFTERNOON AND NIGHT AHEAD OF THE NEXT FRONTAL
SYSTEM. THE LATEST MODEL RUNS ARE BEGINNING TO COME INTO
ALIGNMENT ON THE TRACK OF THE ASSOCIATED SURFACE LOW. IF THIS
MODEL TREND CONTINUES WITH THE 00Z MODEL RUNS, THEN THE FORECAST
CONFIDENCE ON THE TIMING AND LOCATION OF GALE FORCE WINDS WILL
INCREASE ALLOWING FOR UPDATES TO THE CURRENT GALE WATCH. A
COMBINATION OF WIND WAVE, FRESH SWELL, AND OPEN-OCEAN SWELL WILL
RESULT IN SEAS BUILDING TO 14 TO 17 FEET WEDNESDAY AFTERNOON.
ANOTHER FRONTAL SYSTEM WILL BRING THE POTENTIAL FOR ANOTHER ROUND
OF GALES AND ELEVATED SEAS OVER THE WEEKEND. ~TJ
PQR WATCHES/WARNINGS/ADVISORIES
OR...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
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page