994
FXUS66 KPQR 060320 AAB
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
719 PM PST MON JAN 5 2026
UPDATED MARINE DISCUSSION.
SYNOPSIS
A BRIEF PERIOD OF DRY AND RELATIVELY QUIET WEATHER
CONTINUES THIS AFTERNOON AS WEAK UPPER-LEVEL RIDGING CROSSES THE
PACIFIC NORTHWEST. THIS PAUSE WILL BE SHORT-LIVED, WITH AN
ACTIVE PATTERN RETURNING TUESDAY THROUGH WEDNESDAY AS SUCCESSIVE
SYSTEMS MOVE INLAND. SIGNIFICANT SNOWFALL IS EXPECTED IN THE
CASCADES, INCLUDING THE PASSES, WHILE WIDESPREAD RAIN IMPACTS
THE LOWLANDS. GUSTY WINDS WILL ALSO PERSIST THROUGH TUESDAY AND
WEDNESDAY. A TRANSITION TOWARD DRIER CONDITIONS BECOMES MORE
LIKELY LATE IN THE WEEK AS HIGH PRESSURE ATTEMPTS TO REESTABLISH
ITSELF OVER THE REGION.
UPDATE
AREAS OF DENSE FOG ARE OCCURRING ALONG PORTIONS OF THE I-5
CORRIDOR FROM SALEM TO WOODBURN. FOG IS ALSO OCCURRING IN PORTIONS OF
STAYTON, MARION, JEFFERSON, TURNER, AND AUMSVILLE. A DENSE FOG
ADVISORY HAS BEEN ISSUED FOR THESE LOCATIONS, WHICH IS IN EFFECT
UNTIL 7 AM TUESDAY. NOTE FOG MAY SPREAD FURTHER TO THE SOUTH INTO
ALBANY, CORVALLIS, EUGENE-SPRINGFIELD, HARRISBURG AND OTHER NEARBY
TOWNS LATER THIS EVENING. FOG WILL LIKELY SPREAD INTO THE MCMINNVILLE
AREA AS WELL. REGARDLESS OF HOW WIDESPREAD FOG BECOMES, EXPECT FOG TO
LIFT BY 7 AM TUESDAY AS SOUTHERLY WINDS BEGIN TO INCREASE AHEAD OF AN
INCOMING FRONTAL BOUNDARY. HIGH CLOUDS WILL ALSO BE ON THE INCREASE
TONIGHT AS THIS FRONT APPROACHES. -23
SHORT TERM...NOW THROUGH WEDNESDAY NIGHT
SHOWERS HAVE
DIMINISHED ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON THIS
AFTERNOON AS THE DEPARTING LOW PRESSURE SYSTEM SHIFTS FARTHER
EAST. RESIDUAL PRECIPITATION REMAINS LIMITED TO FAVORED TERRAIN,
PRIMARILY THE CASCADES AS OF 2 PM. ELSEWHERE, DRY CONDITIONS
PREVAIL WITH INTERMITTENT BREAKS IN CLOUD COVER AS WEAK RIDGING
TEMPORARILY SUPPRESSES PRECIPITATION. TEMPERATURES REMAIN
SEASONABLE, AND WINDS ARE GENERALLY LIGHT. CLOUD COVER INCREASES
THIS EVENING AND OVERNIGHT AHEAD OF THE NEXT APPROACHING
SYSTEM. ANY CLEARING THAT OCCURS EARLY TONIGHT MAY ALLOW FOR
LOCALIZED FOG DEVELOPMENT, PARTICULARLY IN THE SOUTHERN
WILLAMETTE VALLEY AND OTHER FOG-PRONE INTERIOR VALLEYS.
VISIBILITY REDUCTIONS MAY BE BRIEF BUT COULD IMPACT LATE-NIGHT
AND EARLY-MORNING TRAVEL.
BEGINNING TUESDAY, THE PATTERN TURNS MARKEDLY MORE ACTIVE AS TWO
WELL-ORGANIZED SYSTEMS ARRIVE IN CLOSE SUCCESSION FROM THE
NORTHWEST. SNOW LEVELS ARE EXPECTED TO REMAIN BETWEEN ROUGHLY
2000 AND 3500 FEET, PLACING THE CASCADES FIRMLY IN THE SNOW
ZONE. HEAVY SNOW IS ANTICIPATED ACROSS THE SOUTH WASHINGTON
CASCADES AND THE NORTHERN AND CENTRAL OREGON CASCADES, INCLUDING
MAJOR PASSES SUCH AS GOVERNMENT CAMP, SANTIAM PASS, AND
WILLAMETTE PASS. A WINTER STORM WARNING REMAINS IN EFFECT FROM 4
AM TUESDAY THROUGH 4 PM THURSDAY, WITH TOTAL ACCUMULATIONS OF
ONE TO TWO FEET LIKELY. THE MOST INTENSE SNOWFALL IS EXPECTED
DURING TWO PRIMARY WINDOWS: TUESDAY AFTERNOON INTO TUESDAY
NIGHT, FOLLOWED BY ANOTHER SURGE WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT. LIGHTER SNOWFALL IS EXPECTED BETWEEN THESE
PERIODS. PROBABILITIES FOR EXCEEDING TWO FEET OF SNOW DURING THE
WARNING PERIOD REMAIN IN THE 25-45% RANGE. FOR A MORE PRECISE
DAY BY DAY PROBABILITY, THERE IS A 15-25% CHANCE OF ONE FOOT OR
MORE ON TUESDAY AND A 35-45% CHANCE ON WEDNESDAY. TRAVEL THROUGH
THE CASCADES IS STRONGLY DISCOURAGED DURING PERIODS OF HEAVY
SNOW, AND TRAVELERS SHOULD BE PREPARED FOR RAPIDLY CHANGING
CONDITIONS.
ADDITIONALLY, THESE TWO ORGANIZED SYSTEMS WILL BRING GUSTY WINDS
TUESDAY AFTERNOON THROUGH WEDNESDAY. EXPECT WIND GUSTS UP TO 30
MPH INLAND, AND UP TO 40 MPH ALONG THE COAST AND IN THE CASCADE
PASSES. AS FOR THE HIGH CASCADES (OR ABOVE THE PASSES), EXPECT
GUSTS UP TO 40-50 MPH. WITH HEAVY AND DRY SNOW PAIRED WITH GUSTY
WINDS IN THE HIGH CASCADES ON TUESDAY NIGHT, BLOWING SNOW AND
SNOW DRIFTS WILL BE POSSIBLE. THESE CONDITIONS COULD RAPIDLY
REDUCE VISIBILITY AND OBSCURE TERRAIN FEATURES, INCREASING THE
RISK FOR BACKCOUNTRY AND HIGH-ELEVATION RECREATIONISTS. THOSE
RECREATING ABOVE PASS LEVEL SHOULD USE CAUTION, BE PREPARED FOR
RAPIDLY CHANGING CONDITIONS, AND CLOSELY MONITOR THE LATEST
FORECASTS AND AVALANCHE GUIDANCE. AWAY FROM THE MOUNTAINS,
WIDESPREAD RAIN IS EXPECTED TUESDAY AND WEDNESDAY, THOUGH
RAINFALL AMOUNTS ARE NOT ANTICIPATED TO POSE SIGNIFICANT
HYDROLOGIC CONCERNS. SPECIFICALLY, TUESDAY WILL SEE 0.3 TO 0.7
INCHES INLAND, 1.0 TO 1.5 INCHES ALONG THE COAST, AND 1 TO 2
INCHES IN ELEVATED TERRAIN. AS FOR WEDNESDAY, AROUND 0.5 INCHES
INLAND, 0.5 TO 1.0 INCHES ALONG THE COAST, AND 1.0 TO 1.5
INCHES IN ELEVATED TERRAIN. COLDER AIR ALOFT WILL INCREASE
INSTABILITY, PARTICULARLY ALONG THE COAST, WHERE THERE IS A
15-20% CHANCE OF THUNDERSTORMS DURING THE AFTERNOON AND EVENING
HOURS BOTH TUESDAY AND WEDNESDAY. ANY THUNDERSTORMS THAT DEVELOP
MAY PRODUCE BRIEF HEAVY RAIN, GUSTY AND ERRATIC WINDS, SMALL
HAIL, AND LIGHTNING. ~12
LONG TERM...THURSDAY THROUGH SUNDAY
RAIN TRANSITIONS INTO
POST-FRONTAL SHOWERS THURSDAY WITH LINGERING SNOW ACROSS THE
CASCADES. WILL NOTE THAT THERE IS A 10% CHANCE THAT SNOW LEVELS
DROP AS LOW AS 800-1000 FEET ON THURSDAY, ESPECIALLY OVER
SOUTHWEST WASHINGTON. ANY HEAVY SHOWERS THAT OCCUR MAY BRIEFLY
BRING SNOW LEVELS DOWN BELOW 1000 FEET, RESULTING IN BRIEF SNOW.
GIVEN THE ONSHORE FLOW AND MILDER TEMPERATURES, ANY SNOW THAT
FALLS WILL LIKELY NOT RESULT IN IMPACTFUL ACCUMULATIONS.
FRIDAY INTO THE WEEKEND DRIER WEATHER APPEARS TO RETURN AS
THE MAJORITY OF ENSEMBLE MEMBERS (80-90%) SUGGEST RIDGING
BEGINNING TO BUILD OVER THE NORTHEAST PACIFIC WITH INCREASING
500 MB HEIGHTS OVER THE PACIFIC NORTHWEST. ENSEMBLES PLACE THE
RIDGE AXIS JUST OFFSHORE ON FRIDAY, BUT BY THIS WEEKEND THE
AXIS SHIFTS OVERHEAD OF US. WILL NOTE THAT THERE IS A 15-25%
CHANCE THAT WE DON`T STAY DRY DUE TO RIDGE EITHER NOT BEING
AMPLIFIED ENOUGH OR THE RIDGE AXIS BEING PLACED TO THE EAST OF
US. SOME ENSEMBLES ARE SHOWING PRECIPITATION RIDING THE
NORTHWESTERN PERIPHERY OF THE RIDGE AND BRINGING CONTINUED
SHOWERY CONDITIONS TO THE PACIFIC NORTHWEST. ~12/10
AVIATION
HIGH PRESSURE BRIEFLY BUILDS OVER THE REGION TONIGHT,
BEFORE THE NEXT FRONT ARRIVES TO THE COAST BY TUESDAY MORNING.
SATELLITE AND SURFACE WEATHER OBSERVATIONS THIS AFTERNOON SHOW
SCATTERED CLOUDS WITH PREDOMINATELY VFR. EXPECT THESE CONDITIONS
TO CONTINUE THROUGH AT LEAST 12Z TUESDAY. INCREASING CLOUD BREAKS
THIS EVENING, THOUGH, MAY RESULT IN PATCHY FOG OVERNIGHT AFTER
06Z TUE. GUIDANCE SUGGESTS A 20-30% CHANCE FOR FOG LEADING TO VIS
REDUCTIONS TO IFR OR LOWER ACROSS THE TUALATIN VALLEY AND SOUTHERN
WILLAMETTE VALLEY. LOW CONFIDENCE FOR FOG TONIGHT AS THERE WILL
ALSO BE INCREASING CLOUD COVER AHEAD OF THE NEXT SYSTEM. CHANCES
FOR MVFR CIGS INCREASE AT THE NORTH OREGON COAST AFTER 13-14Z
TUESDAY AS RAIN ARRIVES. RAIN WILL SPREAD INLAND BY AROUND 16-18Z
TUESDAY WITH CHANCES FOR MVFR ALSO INCREASING TO AROUND 50-60%
AFTER 18Z FOR INLAND TERMINALS. LIGHT WINDS ARE EXPECTED TO
INCREASE OUT OF THE SOUTH WITH THE APPROACHING FRONT. PEAK WIND
GUSTS UP TO 35 KT AT THE COAST, AND TO AROUND 25 KT INLAND.
KPDX AND APPROACHES...PREDOMINATELY VFR EXPECTED THROUGH TUESDAY
MORNING, WITH SOME SCATTERED LOW CLOUDS IN THE AREA TODAY AND
TONIGHT. CIGS BEGIN TO LOWER AGAIN TUESDAY MORNING AS THE FRONT
APPROACHES WITH RAIN BECOMING LIKELY BY 18Z TUESDAY. CIGS LIKELY
LOWERING TO MVFR AFTER 18Z TUE. LIGHT WINDS TODAY, BECOMING
SOUTHERLY TUESDAY MORNING, WITH GUSTS UP TO 25 KT EARLY TUE
AFTERNOON. /DH
MARINE
HIGH PRESSURE OVER THE WATERS TODAY WILL MAINTAIN
RELATIVELY BENIGN CONDITIONS WITH SEAS OF AROUND 6 TO 7 FT. LIGHT
NORTHERLY WINDS BACK TO SOUTHWESTERLY OVERNIGHT AHEAD OF AN
APPROACHING FRONT. SOUTHWEST WINDS WILL INCREASE THROUGH TUESDAY
MORNING, WITH A PERIOD OF AROUND 4 HOURS OF GALE FORCE WIND GUSTS
EXPECTED, MOST LIKELY BETWEEN 7 AM AND 4 PM. HAVE ISSUED A GALE
WARNING FOR THE COASTAL WATERS NORTH OF CAPE FOULWEATHER, AS WELL
AS FOR THE COLUMBIA RIVER BAR, WITH WINDS EXPECTED TO PEAK AROUND
40 KT NEAR THE FRONTAL PASSAGE. FOR THE WATERS SOUTH OF CAPE
FOULWEATHER, THE SMALL CRAFT ADVISORY REMAINS IN EFFECT AFTER 7
AM TUESDAY AS WINDS ARE EXPECTED TO WEAKEN AS THE FRONT DROPS
FARTHER SOUTH. WIND DRIVEN SEAS ARE EXPECTED TO BUILD TO AROUND 10 TO
12 FT ON TUESDAY.
ONSHORE WESTERLY WINDS ARE EXPECTED TO GRADUALLY DECREASE BEHIND THE
FRONT THROUGH TUESDAY NIGHT, BEFORE ANOTHER STRONG FRONT
APPROACHES THE WATERS EARLY WEDNESDAY. WESTERLY WINDS BEHIND THIS
FRONT ARE EXPECTED TO INCREASE BY WEDNESDAY AFTERNOON, THOUGH CHANCES
FOR WIND GUSTS EXCEEDING 34 KT ARE LOWER, AROUND 30-40%. THERE IS
ALSO A SLIGHT CHANCE FOR THUNDERSTORMS ACROSS THE WATERS ON
WEDNESDAY. A LONG PERIOD NORTHWESTERLY SWELL WILL PUSH INTO THE
WATERS ON WEDNESDAY, WITH SEAS BECOMING STEEP AND HAZARDOUS, LIKELY
BUILDING TO AT LEAST 20 FT LATE WEDNESDAY. GUIDANCE SUGGESTS THERE IS
AROUND A 50-75% CHANCE OF SEAS EXCEEDING 20 FT BY WEDNESDAY NIGHT.
CHANCES FOR SEAS OF 25 FT OR HIGHER ARE LOW, RANGING BETWEEN 1-5%.
SEAS SLOWLY SUBSIDE ON THURSDAY, BUT ARE NOT LIKELY TO FALL BELOW 15
FT UNTIL THURSDAY NIGHT. -23/DH
BEACH HAZARDS
HIGH SURF CONDITIONS ARE EXPECTED TO OCCUR WEDNESDAY
AFTERNOON THROUGH THURSDAY AFTERNOON AS A NORTHWESTERLY SWELL
ARRIVES, BRINGING BREAKERS UP TO 25 FT WITHIN THE SURF ZONE. A
HIGH SURF ADVISORY HAS BEEN ISSUED TO COVER THIS THREAT.
DESTRUCTIVE WAVES MAY WASH OVER BEACHES, JETTIES, AND OTHER
STRUCTURES UNEXPECTEDLY. PEOPLE CAN BE SWEPT OFF ROCKS AND JETTIES
AND DROWN WHILE OBSERVING HIGH SURF. MINOR BEACH EROSION MAY
DAMAGE COASTAL PROPERTIES AND BUILDINGS. HIGHER THAN NORMAL WATER
RUN-UP IS EXPECTED ON BEACHES AND LOW-LYING SHORELINE.
ALTHOUGH HIGH SURF CONDITIONS EASE THURSDAY NIGHT INTO FRIDAY,
SNEAKER WAVES WILL REMAIN A THREAT. WAVES MAY RUN FURTHER UP THE
BEACH THAN NORMAL. THESE WAVES CAN EASILY CATCH PEOPLE OFF GUARD.
NEVER TURN YOUR BACK TO THE OCEAN. RAZOR CLAMMERS SHOULD USE EXTRA
CAUTION. -23
PQR WATCHES/WARNINGS/ADVISORIES
OR...HIGH SURF ADVISORY FROM 10 AM WEDNESDAY TO 4 PM PST THURSDAY FOR
ORZ101>103.
DENSE FOG ADVISORY UNTIL 7 AM PST TUESDAY FOR ORZ115.
WINTER STORM WARNING FROM 4 AM TUESDAY TO 4 PM PST THURSDAY FOR
ORZ126>128.
WA...HIGH SURF ADVISORY FROM 10 AM WEDNESDAY TO 4 PM PST THURSDAY FOR
WAZ201.
WINTER STORM WARNING FROM 4 AM TUESDAY TO 4 PM PST THURSDAY FOR
WAZ211.
PZ...SMALL CRAFT ADVISORY UNTIL 7 AM PST TUESDAY FOR PZZ210.
GALE WARNING FROM 7 AM TO 1 PM PST TUESDAY FOR PZZ210.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 AM PST TUESDAY
FOR PZZ251-252-271-272.
GALE WARNING FROM 7 AM TO 4 PM PST TUESDAY FOR PZZ251-252-271-
272.
SMALL CRAFT ADVISORY FROM 7 AM TUESDAY TO 4 AM PST WEDNESDAY FOR
PZZ253-273.
WWW.WEATHER.GOV/PORTLAND
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