238
FXUS66 KPQR 190015
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
415 PM PST TUE FEB 18 2025
SYNOPSIS
LIGHT RAIN RETURNS THIS EVENING AS A FRONTAL SYSTEM
PUSHES ACROSS THE REGION THROUGH WEDNESDAY. BREEZY WINDS LIKELY
WEDNESDAY, WITH GUSTS UP TO 50 MPH ALONG THE COAST AND UP TO 40
MPH INLAND. ANOTHER ROUND OF SNOW EXPECTED FOR THE CASCADES
THROUGH WED NIGHT, WITH 4 TO 8 INCHES OF SNOW EXPECTED AT PASS
LEVEL. THEN, TRENDING DRIER AND SLIGHTLY WARMER THURSDAY INTO
FRIDAY. LATER SATURDAY, POTENTIAL FOR HEAVIER RAIN RETURNS
THROUGH EARLY NEXT WEEK AS A MODERATE ATMOSPHERIC RIVER TAKES
AIM AT THE PACIFIC NW.
SHORT TERM...NOW THROUGH WEDNESDAY NIGHT
WATER VAPOR
SATELLITE IMAGERY THIS AFTERNOON SHOWS AN AMPLIFIED UPPER LEVEL
PATTERN SHIFTING EAST ACROSS THE PACIFIC TOWARD PACIFIC NW. WE
SEE TO SOME EXTENT A BAROCLINIC LEAF DEVELOPING DOWNSTREAM OF A
PV ANOMALY AT THE BASE OF THE UPPER LEVEL TROUGH. A WEAK SURFACE
LOW WILL LIKELY DEVELOP TONIGHT AS THE WEATHER SYSTEM
APPROACHES THE REGION. THIS LOW MOVES NORTH TOWARD VANCOUVER
ISLAND WHILE A WARM FRONT LIFTS ACROSS THE AREA, WITH LIGHT RAIN
THROUGH THIS EVENING. THE MAIN UNCERTAINTY COMES WITH THE
POTENTIAL OF A SECONDARY, COMPACT SURFACE LOW DEVELOPING NEAR
THE OREGON COAST WEDNESDAY MORNING. THIS WOULD BRING THE
POTENTIAL FOR MORE IMPACTFUL SOUTH TO SOUTHWESTERLY WINDS.
FORTUNATELY, THE LATEST MODEL RUNS HAVE BEEN TRENDING AWAY FROM
THIS SOLUTION. STILL, WILL LIKELY SEE WINDS INCREASING WEDNESDAY
MORNING. THE HREF SHOWS SOUTHERLY WINDS WITH GUSTS UP TO 40-50
MPH ALONG THE COAST BECOMING WESTERLY BY THE AFTERNOON. AND
ALTHOUGH THERE IS STILL POTENTIAL FOR A LOW TO SPIN UP QUICKLY
NEAR THE COAST, THE PROBABILITY OF EXCEEDING 60 MPH IS QUITE
LOW, AROUND 10%. BREEZY SOUTHERLY WINDS LIKELY THROUGH THE
WILLAMETTE VALLEY AS WELL MID-DAY WEDNESDAY, WITH GUSTS UP TO
30-40 MPH. THOSE IN THE COLUMBIA RIVER GORGE AND EAST
PORTLAND/VANCOUVER METRO WILL ALSO NOTICE THE EASTERLY WINDS
PICK-UP WED MORNING AS THE KTTD-KDLS PRESSURE GRADIENT INCREASES
TO AROUND -7 TO -8 MB.
PRECIPITATION RATES WILL LIKELY INCREASE ON WEDNESDAY AS THE UPPER
TROUGH PUSHES AN OCCLUDING FRONT ACROSS THE REGION. SNOW LEVELS
ABOVE 5000 FT WEDNESDAY MORNING WILL GRADUALLY FALL TO AROUND 3500-
4000 FT BY WEDNESDAY EVENING. THE HIGHER CASCADES ARE EXPECTED TO
PICK UP ANOTHER ROUND OF SNOW, WITH AROUND 4 TO 8 INCHES OF SNOW
LIKELY AT PASS LEVEL, THEREFORE HAVE ISSUED A WINTER WEATHER
ADVISORY FOR THE CASCADES. HEAVIEST SNOWFALL RATES EXPECTED BETWEEN
8 AM AND 4 PM ON WEDNESDAY.
THE UPPER HOOD RIVER VALLEY WILL POTENTIALLY SEE A MIX OF WINTRY
WEATHER TONIGHT INTO EARLY WED MORNING. PROBABILITIES HAVE DECREASED
AS FORECASTED TEMPERATURES MARGINALLY FALL TO BELOW FREEZING. BUT
THERE REMAINS A LOW CHANCE (10-30%) OF AREAS ABOVE 1000 FT TO SEE A
FREEZING RAIN WITH ICE ACCUMULATIONS UP TO A TENTH AN INCH OR SNOW
UP TO A HALF INCH. /DH
LONG TERM...THURSDAY THROUGH TUESDAY
MODELS AND THEIR ENSEMBLES
REMAIN IN GOOD AGREEMENT OF UPPER LEVEL RIDGING BUILDING OVER THE
REGION LATER THIS WEEK. EXPECT A MOSTLY DRY DAY ON THURSDAY. BUT
WITH CLOUDS, TEMPERATURES ONLY WARM INTO THE LOWER 50S. MOST
CLUSTERS KEEP THE AREA DRY ON FRIDAY, ALTHOUGH THERE IS AROUND A 40%
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.
LIGHT RAIN SHOWERS LATE FRIDAY INTO SATURDAY TURNS TO HEAVIER RAIN
LATER IN THE WEEKEND AS THE NEXT WEATHER SYSTEM WILL LIKELY BE
ASSOCIATED WITH A MODERATE ATMOSPHERIC RIVER, POTENTIALLY PERSISTING
THROUGH MONDAY. BOTH THE GEFS AND THE EUROPEAN ENSEMBLE SUGGESTS
MEAN PWAT AMOUNTS OF AROUND 1.1-1.2 INCH NOW. UNCERTAINTY REMAINS
WITH WHERE THE BAND OF HEAVIER MOISTURE SETS UP. THE HIGHEST CHANCES
OF IVT VALUES > 500 KG/M/S (OF AROUND 70-90%) HAVE SHIFTED SLIGHTLY
SOUTHWARD, ACCORDING TO THE CW3E IVT LANDFALL TOOL, TO MUCH OF THE
CENTRAL AND NORTHERN OREGON COAST. ALTHOUGH LATEST HEFS FORECASTS
SHOW A 5-15% CHANCE OF LOCAL TRIBUTARY RIVERS REACHING MINOR FLOOD
STAGE, WILL NEED TO MONITOR THE FLASHIER RIVERS AS WE GET CLOSER TO
SUNDAY. /DH
AVIATION
AN APPROACHING FRONTAL SYSTEM WILL SEE CONTINUED
OVERCAST SKIES AND RAIN SPREADING FROM SOUTHWEST TO NORTHEAST,
BRINGING MIXED VFR/MVFR CONDITIONS. RAIN HAS ALREADY BEGUN AT
ONP/EUG AND IS EXPECTED BY 03Z WED AT MOST OTHER TERMINALS,
ALTHOUGH VSBYS MAY REMAIN 6SM OR GREATER DURING LIGHT SHOWERS.
EAST TO SOUTHEAST WINDS AT GENERALLY 5-10 KT WILL CONTINUE
THROUGH THE WARM FRONTAL PASSAGE.
BY 04-08Z WED, COVERAGE OF RAIN WILL DECREASE TO INTERMITTENT
SHOWERS AND CONTINUED VFR CONDITIONS. AS THE SURFACE PRESSURE
GRADIENT TIGHTENS AHEAD OF THE APPROACHING COLD FRONT, OFFSHORE
WINDS WILL INCREASE TO 8-12 KT, HOWEVER PDX/TTD MAY SEE SPEEDS OF
15-20 KT AND GUSTS OF 25-30 KT DUE TO COLUMBIA GORGE OUTFLOW.
PERIODS OF LOW-LEVEL WIND SHEAR ARE EXPECTED INITIALLY ALONG THE
COAST AT AST/ONP AFTER 08-10Z WED, AND SUBSEQUENTLY ACROSS THE
CENTRAL/SOUTHERN WILLAMETTE VALLEY AT EUG/SLE/UAO AFTER 12-14Z WED
AS WINDS AT 2 KFT INCREASE OUT OF THE SOUTH TO SOUTH-SOUTHWEST TO
35-45 KT. SCATTERED TO NUMEROUS SHOWERS RETURN AFTER 12-14Z WED
AS THE COLD FRONT NEARS FROM THE WEST, WITH WINDS TURNING ABRUPTLY
OUT OF THE SOUTHWEST FOLLOWING THE FRONTAL PASSAGE AROUND 18-22Z
WED. INLAND TERMINALS WILL SEE CONTINUED WINDS AT 10-15 KT, WHILE
SOUTHWEST WINDS OF 10-15 KT GUST TO 25-30 KT ALONG THE COAST.
PDX AND APPROACHES...LARGELY LOW-VFR CIGS AT 4-5 KFT EXPECTED
THROUGH THE PERIOD WITH RAIN ARRIVING BY THIS EVENING. SOME
PERIODS OF MVFR CIGS/VSBYS CANNOT BE RULED OUT DURING STEADY LIGHT
RAIN, WITH AN IMPROVEMENT BACK TO VFR FAVORED AFTER 08Z WED. EAST
TO EAST-SOUTHEAST WINDS AT 6-12 KT EXPECTED INTO THIS EVENING,
INCREASING TO 10-15 KT OVERNIGHT AFTER 06Z WED. EAST-SOUTHEASTERLY
GUSTS OF 20-25 KT ARE POSSIBLE AFTER 08-10Z WED, FOLLOWED BY A
SHIFT TO SOUTH-SOUTHWESTERLY FLOW AT 10-15 KT BEHIND THE COLD
FRONTAL PASSAGE AFTER 21Z WED. -PICARD
MARINE
A FRONTAL SYSTEM MOVING ONSHORE THIS EVENING INTO
WEDNESDAY WILL BRING GUSTY WINDS AND BUILDING SEAS. GALE WARNINGS
HAVE BEEN EXPANDED TO INCLUDE ALL INNER WATERS SOUTH OF CAPE
FALCON AFTER 4 AM WEDNESDAY, IN ADDITION TO ALL OUTER WATERS
AS OF 4 PM TODAY. A STRONG COLD FRONT SWEEPING THROUGH THE REGION
WILL PRODUCE SOUTHERLY GUSTS OF 35 TO 45 KT, INITIALLY BEYOND
10NM, AND SUBSEQUENTLY TO NEAR-SHORE ZONES AS WINDS TURN OUT OF
THE SOUTH-SOUTHWEST. FURTHER GUSTS OF 35 TO 45 KT ARE EXPECTED AS
WINDS TURN OUT OF THE WEST BEHIND THE APPROACHING COLD FRONT.
A SMALL CRAFT ADVISORY IS IN EFFECT AS OF 4 PM TODAY FOR INNER
WATERS NORTH OF CAPE FALCON AND WITHIN THE COLUMBIA RIVER BAR. A
GALE WATCH HAS ADDITIONALLY BEEN ISSUED FOR INNER WATERS NORTH OF
CAPE FALCON AFTER 7 AM WEDNESDAY, WITH ISOLATED TO SCATTERED GUSTS
OF 35 KT POSSIBLE, MOST LIKELY BEHIND THE COLD FRONTAL PASSAGE AS
WINDS TURN OUT OF THE WEST. WITHIN THE COLUMBIA RIVER BAR, CHOPPY
SEAS GROWING TO 11 TO 13 FT ARE EXPECTED THROUGH WEDNESDAY DESPITE
MODEST EBB TIDES AS GUSTY SOUTHERLY WINDS TURN WESTERLY WEDNESDAY
AFTERNOON. THERE REMAINS SOME UNCERTAINTY IN THE STRENGTH OF WINDS
AS WELL AS RESULTANT WAVE HEIGHTS BEYOND WEDNESDAY AFTERNOON DUE
TO ASSOCIATED UNCERTAINTY IN THE LOCATION OF THE PARENT SURFACE
LOW.
FOLLOWING A QUIETER THURSDAY AND FRIDAY, ADDITIONAL GALES ARE
EXPECTED AS ANOTHER SURFACE LOW AND STRONG COLD FRONT TRACK ACROSS
THE NORTHEAST PACIFIC ON SATURDAY. IN FACT, THERE APPEARS TO BE A
40-50% CHANCE IN STORM-FORCE WINDS IN OUTER WATERS ON SATURDAY,
THOUGH THERE REMAINS UNCERTAINTY GIVEN THE LEAD TIME. -PICARD
PQR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY FROM 4 AM WEDNESDAY TO 4 AM PST
THURSDAY FOR ORZ126>128.
WA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 4 AM PST
THURSDAY FOR WAZ211.
PZ...SMALL CRAFT ADVISORY UNTIL 4 PM PST WEDNESDAY FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 7 AM PST WEDNESDAY FOR PZZ251.
GALE WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON
FOR PZZ251.
SMALL CRAFT ADVISORY UNTIL 4 AM PST WEDNESDAY FOR PZZ252-253.
GALE WARNING FROM 4 AM TO 4 PM PST WEDNESDAY FOR PZZ252-253.
GALE WARNING UNTIL 4 PM PST WEDNESDAY FOR PZZ271>273.
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