738
FXUS66 KPQR 051315 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
ISSUED BY NATIONAL WEATHER SERVICE SEATTLE WA
515 AM PST MON JAN 5 2026
SYNOPSIS
DRY CONDITIONS TODAY AS WEAK RIDGING MOVES OVERHEAD.
THIS BREAK IS SHORT-LIVED AS BACK-TO-BACK SYSTEMS ARRIVE TUESDAY
TO WEDNESDAY. THIS WILL BRING ONE TO TWO FEET OF SNOW ACROSS THE
CASCADES, INCLUDING THE PASSES. THOSE TRAVELING THROUGH THE
CASCADES SHOULD TAKE EXTRA PRECAUTIONS. MEANWHILE, THE LOWLANDS
WILL RECEIVE WIDESPREAD RAIN. GUIDANCE SUGGESTS THAT HIGH
PRESSURE WILL RETURN DRIER WEATHER BY THE END OF THE WEEK.
SHORT TERM
NOW THROUGH WEDNESDAY NIGHT…RADAR IMAGERY AS OF
EARLY MONDAY MORNING DEPICTS DECREASING SHOWERS ACROSS NORTHWEST
OREGON AND SOUTHWEST WASHINGTON AS A WEAK LOW PRESSURE SYSTEM
EXITS THE REGION. ANY LINGERING SHOWERS ARE MAINLY CONFINED TO
THE COAST, COAST RANGE, AND CASCADES. DRY WEATHER RETURNS TODAY
WITH INCREASING CLOUD BREAKS AS TRANSIENT, WEAK RIDGING MOVES
OVERHEAD. CLOUD COVER INCREASES TONIGHT AS THE NEXT SYSTEM
APPROACHES, THOUGH THERE MAY BE ENOUGH CLEARING IN THE EVENING
FOR SOME PATCHY FOG DEVELOPMENT AND LOW VISIBILITY IMPACTS,
ESPECIALLY FOR OUR TYPICALLY FOGGY LOCATIONS LIKE THE TUALATIN
VALLEY AND THE SOUTHERN WILLAMETTE VALLEY.
TUESDAY TO WEDNESDAY, TWO ROBUST, BACK-TO-BACK WEATHER SYSTEMS
WILL MOVE IN FROM THE NORTHWEST. SNOW LEVELS WILL BE AROUND
2000-3500 FEET, SO THE MAIN IMPACTS FROM THESE SYSTEMS WILL BE
HEAVY SNOW ACROSS THE CASCADES, INCLUDING OUR MAIN PASSES SUCH
AS HWY 26 AT GOVERNMENT CAMP, SANTIAM PASS, AND WILLAMETTE PASS.
A WINTER STORM WARNING HAS BEEN ISSUED ACROSS THE SOUTH
WASHINGTON CASCADES AND THE NORTHERN AND CENTRAL CASCADES OF
OREGON FROM 4 AM TUESDAY TO 4 PM THURSDAY, WHERE SNOW
ACCUMULATIONS OF ONE TO TWO FEET ARE EXPECTED. THE HEAVIEST SNOW
WILL FALL TUESDAY AFTERNOON AND EVENING (FIRST SYSTEM) AS WELL
AS WEDNESDAY AFTERNOON AND EVENING (SECOND SYSTEM), WITH LIGHTER
SNOW IN-BETWEEN. CHANCES FOR SNOW AMOUNTS EXCEEDING 2 FEET IN A
48 HOUR PERIOD FROM 4 AM TUESDAY TO 4 AM THURSDAY ARE AROUND
25-45%. IF YOU PLAN TO TRAVEL THROUGH THE CASCADES THIS WEEK,
MAKE SURE TO CHECK THE LATEST WEATHER FORECAST AND REFER TO
ODOT/WSDOT FOR TRAVEL RESTRICTIONS. IF YOU MUST TRAVEL, USE
EXTRA CAUTION AND PACK AND EMERGENCY KIT.
FOR EVERYWHERE ELSE BELOW 2000 FEET, TUESDAY AND WEDNESDAY WILL
BE A SOAKER WITH WIDESPREAD RAIN AND MINIMAL HYDRO CONCERNS.
COLDER AIR ALOFT WILL ALSO BRING INCREASED INSTABILITY,
ESPECIALLY ALONG THE COAST. THEREFORE, THERE IS A 15-20% CHANCE
FOR THUNDERSTORMS ALONG THE COAST TUESDAY AFTERNOON AND
WEDNESDAY AFTERNOON. ANY PASSING THUNDERSTORMS MAY BRING
LIGHTNING, HEAVY RAIN, ERRATIC GUSTY WINDS, AND/OR SMALL HAIL.
-10
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 700-1000 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 (60-70%) 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 OF THE U.S. WEST COAST 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. -10
AVIATION
PREDOMINATELY VFR CONDITIONS TODAY AS HIGH PRESSURE
BUILDS OVERHEAD. SHOWERS WILL GRADUALLY DECREASE THIS MORNING
WITH CONDITIONS COMPLETELY DRYING OUT BY 15-18Z MON. WINDS
GENERALLY LIGHT AND VARIABLE AROUND 5 KT OR LESS. INCREASING
CLOUD BREAKS THIS EVENING MAY RESULT IN PATCHY FOG OVERNIGHT
AFTER 06Z TUE. GUIDANCE SUGGESTS A 20-30% CHANCE FOR FOG LEADING
TO VIS REDUCTIONS TO IFR/MVFR OR LOWER ACROSS THE TUALATIN
VALLEY (KHIO) AND SOUTHERN WILLAMETTE VALLEY (KEUG). LOW
CONFIDENCE FOR FOG TONIGHT AS THERE WILL ALSO BE INCREASING
CLOUD COVER TONIGHT AHEAD OF THE NEXT SYSTEM.
KPDX AND APPROACHES...VFR CONDITIONS PREVAIL THROUGH THE TAF
PERIOD AS HIGH PRESSURE BUILDS. VARIABLE WINDS UNDER 5 KT. -10
MARINE
HIGH PRESSURE BUILDS TODAY, RETURNING WEAK NORTHERLY
WINDS AND SEAS SUBSIDING TO 6-8 FEET AT 10-11 SEC THROUGH THIS
EVENING. TONIGHT, WINDS TURN MORE SOUTHERLY AHEAD OF THE NEXT
FRONT. THIS STRONG FRONT WILL MOVE THROUGH ON TUESDAY, RETURNING
AT LEAST WIDESPREAD SMALL CRAFT CONDITIONS AND A 70-90% CHANCE
FOR OCCASIONAL GALE FORCE WIND GUSTS OF 34 KT OR STRONGER. A
SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE WATERS NORTH OF
CAPE FOULWEATHER BEGINNING 10 PM TONIGHT THROUGH 10 AM TUESDAY.
A GALE WATCH HAS ALSO BEEN ISSUED FOLLOWING THIS SMALL CRAFT
ADVISORY FROM 10 AM-10 PM TUESDAY GIVEN THE POTENTIAL FOR GALE
FORCE WIND GUSTS. THERE IS STILL SOME UNCERTAINTY WHETHER OR NOT
WE’LL SEE WIDESPREAD GALE FORCE WIND GUSTS TO WARRANT A GALE
WARNING AT THIS POINT. FOR THE WATERS SOUTH OF CAPE FOULWEATHER,
THE SMALL CRAFT ADVISORY BEGINS 7 AM TUESDAY AND LASTS THROUGH
TUESDAY EVENING AS WINDS WILL NOT BE AS STRONG FURTHER SOUTH.
WEDNESDAY THROUGH THE END OF THE WEEK, A LONG PERIOD
NORTHWESTERLY SWELL WILL MOVE IN AND RETURN HAZARDOUS SEAS. SEAS
MOST LIKELY PEAK BETWEEN 17-19 FEET WEDNESDAY TO THURSDAY.
GUIDANCE SUGGESTS A 25-50% CHANCE FOR SEAS EXCEEDING 20 FEET FOR
THE WATERS BEYOND 20 NM, AND A 10-20% CHANCE FOR THE WATERS OUT
20 NM INCLUDING THE MAIN CHANNEL OF THE COLUMBIA RIVER BAR. -10
BEACH HAZARDS
A LONG-PERIOD NORTHWESTERLY SWELL WILL BRING A
HIGH THREAT FOR SNEAKER WAVES WEDNESDAY TO FRIDAY. DURING THIS
TIME, 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. -10
PQR WATCHES/WARNINGS/ADVISORIES
OR...WINTER STORM WARNING FROM 4 AM TUESDAY TO 4 PM PST THURSDAY
FOR ORZ126>128.
WA...WINTER STORM WARNING FROM 4 AM TUESDAY TO 4 PM PST THURSDAY
FOR WAZ211.
PZ...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PST THIS
EVENING FOR PZZ210.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM PST
TUESDAY FOR PZZ210-251-252-271-272.
GALE WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING FOR
PZZ251-252-271-272.
SMALL CRAFT ADVISORY FROM 7 AM TO 10 PM PST TUESDAY FOR PZZ253-
273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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