873
FXUS66 KMFR 042356
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
356 PM PST SUN JAN 4 2026
UPDATE
AVIATION DISCUSSION UPDATED.
AVIATION...05/00Z TAFS
A FRONT IS APPROACHING THE AREA
MOVING ONSHORE WILL GRADUALLY MOVE INLAND ACROSS THE AREA TONIGHT
AND MONDAY MORNING. EXPECT VFR CONDITIONS ACROSS THE REGION TO DROP
TO MVFR WITH LOCALIZED IFR IN PRECIPITATION AS THE FRONT PASSES
THROUGH THIS EVENING AND TONIGHT, ALONG WITH INCREASING AREAS OF
TERRAIN OBSCURATION. FREEZING LEVELS OF 4000-4500 FT THIS AFTERNOON
WILL LOWER TO 3500-4000 FT MSL BEHIND THE FRONT. SOME AREAS WEST OF
THE CASCADES MAY SEE CONDITIONS LOWER TO IFR/LIFR IN LOW STRATUS
MONDAY MORNING, WITH THE NATIONAL BLEND OF MODELS SHOWING AT 25-35%
CHANCE AT MEDFORD AND 20-30% CHANCE AT ROSEBURG. SHOWERS ARE
EXPECTED BEHIND THE DEPARTING FRONT LATE MONDAY MORNING AND
AFTERNOON. ALONG THE COAST, EXPECT CONDITIONS TO IMPROVE TO VFR
MONDAY MORNING, EXCEPT FOR SOME LOCAL MVFR CEILINGS WHICH MAY
CONTINUE ALONG THE SOUTHERN CURRY COAST INTO THE AFTERNOON. INLAND,
EXPECT MOST AREAS TO IMPROVE TO VFR IN THE MID TO LATE AFTERNOON ON
MONDAY.
PREV DISCUSSION
/ISSUED 253 PM PST SUN JAN 4 2026/
DISCUSSION...A PERSISTING UPPER TROUGH WILL GUIDE WEATHER
ACROSS NORTHERN CALIFORNIA AND SOUTHERN OREGON INTO MONDAY. FOR THIS
EVENING, A WEAK COLD FRONT WILL HELP TO PUSH ANOTHER ROUND OF LIGHT
TO MODERATE PRECIPITATION ACROSS THE AREA. COLD AIR BEHIND THE FRONT
WILL LOWER SNOW LEVELS TO 3500-4000 FEET BY MONDAY MORNING. WITH
PRECIPITATION CONTINUING THROUGH THE DAY MONDAY, ADDITIONAL SNOWFALL
IS EXPECTED FOR CASCADES PASSES AND SAWYERS BAR ROAD WEST OF ETNA
TONIGHT THROUGH MONDAY MORNING. 1 TO 2 INCHES MAY REACH INTERSTATE 5
AT SIKIYOU SUMMIT OR BETWEEN WEED AND DUNSMUIR AS WELL AS ON HIGHWAY
89 AND 97. WITH LIMITED SNOWFALL, ROAD WARMTH, AND LINGERING WATER
ON ROAD SURFACES, HIGHWAY SNOW ACCUMULATION MAY BE LIMITED BUT
SLIPPERY CONDITIONS MAY DEVELOP WHERE SNOW SHOWERS FALL.
THE UPPER TROUGH SPLITS ON MONDAY, SENDING A CUTOFF LOW TO THE
SOUTH. THIS WILL BRING A BRIEF PAUSE IN ACTIVITY ON TUESDAY MORNING,
WITH SLIGHT CHANCES OF ISOLATED SHOWERS PERSISTING. A COLD FRONT
BRINGS AFTERNOON SHOWERS TO THE COAST AND THE CASCADES, THEN
PRECIPITATION MOVES INLAND THROUGH WEDNESDAY AND THURSDAY. WHILE
COASTAL AND LOW-LYING AREAS WILL SEE LIGHT TO MODERATE ACTIVITY AT
MOST, SNOWFALL OVER THE CASCADES REMAINS A CONCERN THROUGH MIDWEEK.
FORECAST AMOUNTS REMAIN AT 8 TO 16 INCHES BETWEEN 4500 AND 5500
FEET, WHICH WOULD INCLUDE CASCADES PASSES AND WILLAMETTE PASS.
ACCUMULATION COULD REACH 16 TO 24 INCHES OVER PEAKS AND RIDGELINES.
THIS AMOUNT OF SNOW REPRESENTS ADVISORY-LEVEL WINTER WEATHER FOR THE
CASCADES THROUGH MUCH OF WEDNESDAY, BUT FORECAST SNOW LEVELS HAVE
BEEN TRENDING UPWARDS THROUGH RECENT MODEL RUNS. WHILE THIS DOESN'T
CHANGE THAT SNOW OVER THE CASCADES LOOKS TO BE THE MAIN IMPACT OF
THE MIDWEEK FRONT, THE TIMING AND AMOUNTS COULD CHANGE. SNOWFALL IS
EXPECTED EAST OF THE CASCADES AS WELL, WITH 4 TO 8 INCHES FORECAST
FOR EASTERN CASCADES FOOTHILLS AND 3 TO 6 INCHES FOR EAST SIDE
TERRAIN. BASIN FLOORS ARE EXPECTED TO SEE AN INCH OR LESS. WEST OF
THE CASCADES, THE LOWEST FORECAST SNOW LEVELS ARE UP TO 2500 FEET
AND THAT'S ON THURSDAY MORNING WHEN PRECIPITATION IS CLEARING OUT.
WITH THIS FORECAST, INTERSTATE 5 AT SISKIYOU SUMMIT WOULD SEE AN
INCH OF SNOWFALL AT MOST AND A FEW STRAY SNOW SHOWERS WOULD BE
POSSIBLE AROUND THE MOUNT SHASTA REGION.
BEHIND THE MIDWEEK FRONT, EXPECTATIONS FOR A PERIOD OF STABLE
WEATHER REMAIN AS ACTIVITY TRAILS OFF THROUGH THURSDAY AND A PACIFIC
RIDGE REMAINS IN DETERMINISTIC IMAGERY. SOME GFS ENSEMBLE MEMBERS
SHOW UPPER TROUGHS BRIEFLY FLATTENING THE RIDGE. NBM GUIDANCE KEEPS
COASTAL PRECIPITATION CHANCES AT 10-20% AT THE HIGHEST AND SINGLE
DIGIT CHANCES INLAND FOR FRIDAY THROUGH SUNDAY. -TAD
MARINE...UPDATED 200 PM PST SUNDAY, JANUARY 4, 2026...WITH THE
PASSAGE OF THE FRONT, WINDS HAVE DIMINISHED AND SEAS WILL GRADUALLY
LOWER THROUGH TONIGHT. IMPROVED CONDITIONS ARE EXPECTED MONDAY INTO
TUESDAY WITH A MIX OF NORTHWEST SWELL AND LINGERING FRESH SOUTH
SWELL. ANOTHER FRONT PASSES TUESDAY WITH A BRIEF PERIOD OF GUSTY
SOUTH WINDS AND STEEP SEAS, FOLLOWED BY LONG PERIOD SWELL
ARRIVING TUESDAY NIGHT, AND BUILDING AND STEEPENING WEDNESDAY INTO
THURSDAY.
-BPN
BEACH HAZARDS/HIGH SURF...UPDATED 200 PM PST SUNDAY, JANUARY 4,
2026...LONG PERIOD SWELL, ORIGINATING FROM A STORM ALONG THE
ALEUTIAN ISLANDS, IS FORECAST TO ARRIVE IN THE SOUTHERN OREGON
WATERS TUESDAY NIGHT, THEN BUILD WEDNESDAY INTO THURSDAY. EARLY
INDICATIONS ARE SHOWING THE SWELL ARRIVING AT 3-6 FEET AT 20-25
SECONDS, WHICH INITIALLY POSES A RISK FOR SNEAKER WAVES TUESDAY
NIGHT INTO WEDNESDAY. THEN, AS THE SWELL BUILDS TO 13-18 FEET, HIGH
SURF RISK INCREASES WEDNESDAY AFTERNOON INTO THURSDAY. IT'S STILL
SEVERAL DAYS AWAY, SO WE'LL CONTINUE TO MONITOR FOR POSSIBLE BEACH
HAZARD AND/OR HIGH SURF PRODUCTS. -SPILDE/BPN
MFR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY UNTIL 4 PM PST MONDAY FOR ORZ027.
CA...WINTER STORM WARNING UNTIL 4 PM PST MONDAY FOR CAZ080-082-083.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 10 PM PST THIS
EVENING FOR PZZ350-356-370-376.
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