573
FXUS66 KPQR 071720 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
920 AM PST SAT FEB 7 2026
UPDATED AVIATION DISCUSSION
SYNOPSIS
A FRONTAL SYSTEM WILL BRING WIDESPREAD RAINFALL TO
THE PACIFIC NORTHWEST THIS WEEKEND, ALTHOUGH SNOW LEVELS REMAIN
ABOVE THE CASCADE PASSES THROUGH SUNDAY. COOLER AND SHOWERY
WEATHER THEN CONTINUES SUNDAY NIGHT INTO EARLY NEXT WEEK, WITH
LIGHT SNOW ACCUMULATIONS AT PASS-LEVEL. A DRIER PATTERN RETURNS
MIDWEEK BEFORE RAIN CHANCES INCREASE LATE IN THE WEEK.
SHORT TERM...NOW THROUGH SUNDAY NIGHT
UPPER-LEVEL RIDGING
CONTINUES TO DE-AMPLIFY AND SHIFT EASTWARD AS MEAN TROUGHING
RETURNS TO THE PACIFIC NORTHWEST INTO EARLY NEXT WEEK. A FRONTAL
SYSTEM AND ASSOCIATED WEAK TO MODERATE ATMOSPHERIC RIVER WILL
MOVE ONSHORE AND BRING WIDESPREAD RAINFALL TO THE REGION TODAY
THROUGH MUCH OF SUNDAY. LATEST SATELLITE IMAGERY DEPICTS CLOUDS
ASSOCIATED WITH THIS SYSTEM ALREADY REACHING EASTWARD TO THE
CASCADES EARLY THIS MORNING, WITH THIS CLOUD COVER ACTING TO
MAINTAIN MILDER TEMPERATURES AND MINIMIZE CHANCES FOR FOG AND
FROST THROUGH THE REMAINDER OF THE OVERNIGHT PERIOD AND INTO
THIS MORNING. NEAR-TERM GUIDANCE SHOWS RAINFALL ONSET IN THE
MORNING ALONG THE COAST, BEFORE REACHING INLAND TO THE I-5
CORRIDOR BY MIDDAY FROM THE COWLITZ VALLEY SOUTH THROUGH THE
PORTLAND AREA, AND THROUGH THE AFTERNOON FOR MUCH OF THE
WILLAMETTE VALLEY. MILD SOUTHWESTERLY FLOW ALOFT WILL KEEP SNOW
LEVELS ABOVE 6000-7000 FT, YIELDING ALL RAIN AT THE CASCADE
PASSES THROUGH AT LEAST TONIGHT.
SHORT-RANGE GUIDANCE CONTINUES TO SUPPORT THE DEVELOPMENT OF A
SECONDARY AREA OF LOW PRESSURE OFFSHORE ALONG THE BOUNDARY AS
THE FRONT MOVES INLAND, A FEATURE WHICH TENDS TO STALL THE
PROGRESSION OF THE FRONT AS THE FORWARD MOTION OF THE OVERALL
PATTERN AND THE RELATIVE MOTION OF THE BOUNDARY BRIEFLY ACTING
AS A WARM FRONT AHEAD OF THE INCIPIENT LOW OFFSET ONE ANOTHER.
A STALLED BOUNDARY WOULD LOCALLY INCREASE THE DURATION OF
HEAVIER RAIN RATES AND OBSERVED RAINFALL, HOWEVER GIVEN VERY
DRY ANTECEDENT CONDITIONS THROUGH JANUARY ACROSS THE REGION,
EVEN HIGHER-END RAINFALL TOTALS PRESENT ONLY A LIMITED RISK FOR
URBAN AND OTHER POOR-DRAINIAGE FLOODING, AND MORE WIDESPREAD
AREAL OR RIVER FLOODING REMAINS VERY UNLIKELY.
AS CONSENSUS IN A LONGER DURATION OF RAIN HAS BUILT, FORECAST
TOTALS HAVE INCREASED. BY THE TIME RAIN DIMINISHES IN COVERAGE
SUNDAY NIGHT, THERE IS HIGH CONFIDENCE (75-95% LIKELIHOOD) OF AT
LEAST ONE INCH OF RAINFALL ACROSS THE REGION. RAIN AMOUNTS WILL
BE HIGHEST IN AREAS OF TERRAIN, WITH ROUGHLY 15-35% CHANCES OF
TOTALS EXCEEDING THREE INCHES IN THE COAST RANGE AND CASCADES.
VALLEY LOCALES WILL SEE RELATIVELY LOWER TOTALS, WITH 10-40%
CHANCES OF EXCEEDING TWO INCHES ALONG THE I-5 CORRIDOR. -36
LONG TERM...MONDAY THROUGH FRIDAY
BEHIND THE DEPARTING
BOUNDARY, SNOW LEVELS WILL FALL TO 3000-3500 FT SUNDAY NIGHT
INTO MONDAY, ALLOWING FOR SNOW TO BEGIN ACCUMULATING AT PASS-
LEVEL IN THE CASCADES. BY THIS TIME, PRECIPITATION AMOUNTS WILL
BE MUCH LOWER, SO FORECAST SNOW AMOUNTS ARE VERY LIKELY (85-90%
CHANCE) TO REMAIN BELOW SIX INCHES. LINGERING RAIN AND MOUNTAIN
SNOW SHOWERS ARE EXPECTED TO CONTINUE INTO MONDAY NIGHT BEFORE
DIMINISHING.
THE MAJORITY OF ENSEMBLE MEMBERS FAVOR A DRY BREAK TUESDAY
THROUGH THURSDAY AS THE FLOW ALOFT WEAKENS AND UPPER-LEVEL
HEIGHTS RISE MODESTLY OVERHEAD. A COOLER, MORE SEASONABLE
AIRMASS NONETHELESS LOOKS TO REMAIN IN PLACE THROUGH MUCH OF THE
WORKWEEK. FORECAST CONFIDENCE THEN DECREASES LATE IN THE WEEK
AS CHANCES INCREASE FOR UPPER-LEVEL TROUGHING AND ADDITIONAL
PRECIPITATION RETURNS TO THE REGION. -36
AVIATION
A INCOMING SYSTEM WILL BRING DETERIORATING FLYING
CONDITIONS AND WIDESPREAD RAIN ACROSS THE AIRSPACE THROUGH THE
TAF PERIOD. EXPECT A MIXTURE OF MVFR/IFR CONDITIONS ALONG THE
COAST, WITH AROUND A 20% CHANCE FOR PERIODS OF LIFR CONDITIONS.
THE CURRENT VFR FLYING CONDITIONS INLAND WILL PERSIST THROUGH
AROUND 00Z SUNDAY, AFTERWARDS CONDITIONS ARE EXPECTED TO BECOME
PREDOMINATELY MVFR THROUGH AT LEAST THE REMAINDER OF THE TAF
PERIOD. AROUND 04Z-06Z SUNDAY, THERE IS A 20-40% CHANCE FOR
IFR CONDITIONS TO DEVELOP FOR INLAND LOCATIONS. OVERALL, EXPECT
LOWERED FLIGHT CONDITIONS TO CONTINUE TO DEVELOP THROUGH THE TAF
PERIOD WITH PREDOMINATELY MVFR EXPECTED ACROSS THE AIRSPACE WITH
INTERMITTENT IFR/LIFR CONDITIONS.
THE CURRENT EASTERLY WINDS AROUND 10-15 KT WILL CONTINUE IN THE
PORTLAND AREA, WITH GUSTS TO 20 KT AT KTTD. AFTER THE FRONTAL
PASSAGE, SOUTHERLY FLOW WILL DEVELOP FOR INLAND LOCATIONS.
SOUTHERLY FLOW IS ALREADY IN ALONG THE COAST, WITH GUSTS UP TO 30
KT EXPECTED THROUGH AROUND 00Z SUNDAY. LOW-LEVEL WIND SHEAR UP TO
50 KT OUT OF THE SOUTH-SOUTHWEST ALONG THE COAST AND KTTD ARE
LIKELY AS THE FRONTAL BOUNDARY PASSES THROUGH THE LATE MORNING FOR
COASTAL LOCATIONS AND FROM THE AFTERNOON THROUGH THE EARLY
EVENING FOR KTTD.
KPDX AND APPROACHES...VFR CONDITIONS, EAST WINDS AND RAIN
CONTINUE THROUGH THIS MORNING. WINDS EXPECTED TO BECOME MORE
SOUTHERLY AT 5-10 KT OVER THE NEXT FEW HOURS AS A FRONTAL PASSAGE
IS EXPECTED. ALONG WITH THE FRONTAL PASSAGE, FLIGHT CONDITIONS ARE
EXPECTED TO FALL TOWARDS MVFR AROUND 00Z SUNDAY. THESE LOWERED
FLIGHT CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE REMAINDER
OF THE TAF PERIOD. AROUND 05Z SUNDAY AND THROUGH THE REMAINDER OF
THE TAF PERIOD, THERE IS A 10-25% CHANCE FOR IFR CONDITIONS TO
DEVELOP AT OR NEAR THE TERMINAL. /42
MARINE
HIGH PRESSURE CONTINUES TO SHIFT INLAND WHILE A
FRONTAL SYSTEM TRAVERSES THE WATERS AND MOVE ONSHORE THROUGH
MUCH OF THE WEEKEND. AS THE FRONTAL BOUNDARY NEARS THE COAST, A
TIGHTENING PRESSURE GRADIENT WILL SEE SOUTHERLY WINDS RISE TO
20-30 KT THIS MORNING. CHANCES ARE HIGH (70-90%) FOR AT LEAST
ISOLATED AND INTERMITTENT GALE-FORCE GUSTS OF 35-40 KT, BUT
CONFIDENCE IS LOWER (10-40% CHANCE) FOR MORE FREQUENT OR
PERSISTENT GUSTS. GALE-FORCE GUSTS ARE MOST LIKELY TO OCCUR
BEYOND 20 NM FROM 6 AM UNTIL NOON TODAY DURING THE FRONTAL
PASSAGE, HOWEVER THESE GUSTS ARE EXPECTED TO BE TOO BRIEF AND
ISOLATED TO WARRANT A GALE WARNING, THEREFORE A SMALL CRAFT
ADVISORY REMAINS IN EFFECT ACROSS THE WATERS.
A PERSISTENT SOUTHWESTERLY TO WESTERLY SWELL OF 8-10 FT AT 11-14
SECONDS WILL CONTINUE INTO EARLY NEXT WEEK. SEAS PEAK BEHIND THE
FRONTAL PASSAGE THIS AFTERNOON, MOST LIKELY AT 10-13 FT, AND WITH
LESS THAN A 10% CHANCE OF EXCEEDING 15 FT, BEFORE FALLING BELOW 10
FT ON SUNDAY MORNING. SEAS OF 8-10 FT THEN PERSIST INTO TUESDAY
BEFORE EASING BELOW 8 FT THROUGH MIDWEEK. FURTHER ACTIVE WEATHER
IS POSSIBLE TO END THE WORKWEEK, BUT CONFIDENCE IN FORECAST
DETAILS REMAINS LOW AT THIS TIME. -36
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 1 AM PST SUNDAY FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 4 AM PST SUNDAY FOR PZZ251>253-
271>273.
WWW.WEATHER.GOV/PORTLAND
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