083
FXUS66 KMFR 051226
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
426 AM PST MON JAN 5 2026
DISCUSSION
UPDATED AVIATION DISCUSSION FOR 12Z TAFS.
AVIATION...05/12Z TAFS
LOW PRESSURE WILL MOVE INLAND ACROSS
NORCAL TODAY. THIS WILL BRING WIDESPREAD LIGHT TO MODERATE
PRECIPITATION MAINLY SOUTH AND EAST OF A LINE FROM BROOKINGS TO
ROSEBURG, FOCUSED ON THE CASCADES AND SISKIYOUS THIS MORNING. THESE
AREAS WILL HAVE WIDESPREAD MVFR WITH HIGHER TERRAIN OBSCURED AND
AREAS OF IFR. FREEZING LEVELS WILL BE IN THE 3000-4000 FOOT RANGE.
CONDITIONS NW OF THESE AREAS WILL HAVE A MIX OF MVFR/VFR, THOUGH IFR
IS CURRENTLY IMPACTING ROSEBURG AND PROBABLY WILL CONTINUE
THROUGH THE MORNING HOURS. SOME IMPROVEMENT TO VFR/MVFR IS
EXPECTED THIS AFTERNOON AS THE LOW MOVES FARTHER INLAND AND
PRECIPITATION GOES WITH IT. BUT, WE EXPECT A RETURN OF MVFR/IFR
OVERNIGHT INTO TUESDAY MORNING. AREAS OF LIFR ARE POSSIBLE AT
ROSEBURG AND MEDFORD. -SPILDE
PREV DISCUSSION
/ISSUED 314 AM PST MON JAN 5 2026/
DISCUSSION...SATELLITE IMAGERY IS SHOWING LOW PRESSURE SPINNING
NEAR THE NORCAL COAST THIS MORNING. THIS WILL MOVE INLAND TODAY.
MODEL GUIDANCE EARLY THIS MORNING IS SHOWING A DEFORMATION AXIS
SETTING UP TO THE NORTH OF THE LOW AND THIS WILL MOVE ACROSS SW
OREGON AND NORCAL DURING THE MORNING RUSH. AT THE SAME TIME, SNOW
LEVELS WILL CONTINUE TO DROP TO AROUND 3500-4000 FEET AND THIS
WILL CAUSE SOME SNOW OVER THE PASSES, INCLUDING AT SISKIYOU SUMMIT
ON I-5. WEB CAMS AT THIS EARLY HOUR ARE SHOWING ROADS BECOMING
SNOW COVERED ALONG HIGHWAY 97 NORTH OF KLAMATH FALLS AND ALSO OVER
THE PASSES EAST OF KLAMATH FALLS. WE ISSUED WINTER WEATHER
ADVISORIES FOR THIS MORNING FOR ALL THOSE AREAS THROUGH NOON PST.
IT'S BEEN RAINING AT KLAMATH FALLS, BUT IT'LL TURN TO SNOW THIS
MORNING THERE TOO. THERE COULD BE AN INCH OR SO, SO WATCH FOR
SLICK SPOTS ON ROADWAYS THERE DURING THE MORNING COMMUTE. WITH
SNOW LEVELS DROPPING, WE ADJUSTED THE WINTER STORM WARNING FOR
THE NORCAL MOUNTAINS TO ABOVE 4000 FEET, WHICH CONTINUES THROUGH 4
PM PST. HOWEVER, SOME OF THE HI-RES GUIDANCE IS SHOWING HEAVIER
PRECIPITATION RATES DEVELOPING BETWEEN 4 AND 10 AM, AND THAT COULD
CAUSE SNOW LEVELS TO DROP EVEN MORE (DOWN TO AROUND 3500 FEET
AROUND MT. SHASTA CITY). A FEW INCHES ARE POSSIBLE THERE AND THIS
COULD CAUSE PROBLEMS ON I-5, IF THIS WERE TO OCCUR. MEANWHILE, A
COLD RAIN WILL GRADUALLY END FROM NW TO SE FOR OTHER AREAS WEST OF
THE CASCADES, INCLUDING HERE IN MEDFORD. THIS WHOLE SYSTEM WILL
PUSH TO THE SOUTH AND EAST OF THE AREA TONIGHT AND MOST AREAS WILL
GET A BREAK.
THE NEXT DISTURBANCE WILL MOVE INTO WASHINGTON AND NW OREGON
TUESDAY MORNING. MOST OF OUR AREA WILL START OUT DRY (ASIDE FROM
SOME SNOW SHOWERS IN THE MOUNTAINS), BUT PRECIPITATION WILL
GRADUALLY INCREASE DUE TO OROGRAPHIC ENHANCEMENT OVER THE
CASCADES TUESDAY AFTERNOON. RAIN/SNOW WILL SETTLE SOUTHWARD
ACROSS MOST OF THE WEST SIDE TUESDAY NIGHT INTO WEDNESDAY. SNOW
LEVELS WILL BE GENERALLY AROUND 4000 FEET, BUT WILL BE A BIT LOWER
(DOWN TO AS LOW AS 3000 FEET ACROSS THE NORTH - NORTHERN DOUGLAS
COUNTY). SNOW WILL PICK UP ACROSS THE CASCADES AND THE CASCADE
FOOTHILLS DURING THIS TIME. WHILE THERE COULD BE A BRIEF BREAK
DURING WEDNESDAY MORNING, ANOTHER FRONTAL SYSTEM WILL MOVE IN FROM
THE NW RE-ENERGIZING SNOW OVER THE CASCADES/FOOTHILLS DURING THE
AFTERNOON AND AT NIGHT. SNOW AMOUNTS OF 1-2 FEET SEEM LIKELY, WITH
SOME WIND (40 MPH) AND LOW VISIBILITY CONDITIONS. AS SUCH, WE'VE
ISSUED A WINTER STORM WATCH WHICH WILL BE IN EFFECT FROM LATE
TUESDAY MORNING THROUGH THURSDAY MORNING. WE MAY ALSO NEED
ADVISORIES IN OTHER AREAS, LIKE THE HIGHWAY 97 CORRIDOR NORTH OF
KLAMATH FALLS (CHILOQUIN TO CHEMULT, CRESCENT AND LA PINE). WITH
THE FLOW ALOFT MOSTLY FROM THE WNW, WE EXPECT ONLY MINOR WINTER
IMPACTS FARTHER SOUTH IN NORCAL WITH THIS EVENT. EVEN SO, SNOW
LEVELS DROP TO THEIR LOWEST LEVELS OF THE SEASON WEDNESDAY NIGHT
INTO THURSDAY, DOWN TO 2000-2500 FEET AND EVEN SOME OF THE
GUIDANCE IS SHOWING A 40-60% CHANCE OF AT LEAST SOME WET SNOW
MIXING IN HERE AROUND THE VALLEY. THIS IS MOST LIKELY UP AROUND
EAST MEDFORD, JACKSONVILLE, AND IN ASHLAND.
ONCE WE GET PAST THAT, MODEL GUIDANCE IS IN PRETTY GOOD AGREEMENT
SHOWING A DRY PERIOD FRIDAY INTO NEXT WEEKEND WITH SOME COLD
NIGHTS, ESPECIALLY WHERE THERE'S FRESH SNOW COVER. WITH
STRENGTHENING INVERSIONS, THIS COULD CAUSE SOME FOG/FREEZING FOG
IN THE WEST SIDE VALLEYS ALONG WITH ANOTHER PERIOD OF AIR
STAGNATION. -SPILDE
AVIATION...05/06Z TAFS...A FRONT IS MOVING ACROSS THE AREA TONIGHT
AND MONDAY MORNING. EXPECT AREAS OF MVFR ALONG THE COAST WITH
SHOWERS. INLAND, EXPECT WIDESPREAD MVFR TO DEVELOP ALONG WITH LOCAL
IFR AND TERRAIN OBSCURATIONS. FREEZING LEVELS OF 3500-4000 FT MSL
ARE EXPECTED. SOME AREAS WEST OF THE CASCADES MAY SEE CONDITIONS
LOWER TO IFR/LIFR IN LOW STRATUS MONDAY MORNING. THE NATIONAL BLEND
OF MODELS SHOWS A 25-35% CHANCE FOR IFR/LIFR AT MEDFORD AND 20-30%
CHANCE AT ROSEBURG. SHOWERS ARE EXPECTED BEHIND THE FRONT LATE
MONDAY MORNING AND AFTERNOON AND WILL SEE GRADUAL IMPROVEMENT DURING
THE DAY. ALONG THE COAST, EXPECT CONDITIONS TO IMPROVE TO VFR BY
LATE 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, EXCEPT FOR CONTINUED MVFR ACROSS PORTIONS OF NORTHERN
CALIFORNIA AND EAST OF THE CASCADES. MVFR/IFR IS THEN EXPECTED TO
REDEVELOP IN VALLEYS WEST OF THE CASCADES MONDAY EVENING AND NIGHT.
MARINE...UPDATED 300 AM PST MONDAY, JANUARY 5, 2026...WINDS BECOME
NORTH TODAY AND COULD BE GUSTY THIS AFTERNOON SOUTH OF CAPE
BLANCO. CHOPPY SEAS MAY APPROACH SMALL CRAFT ADVISORY LEVELS THERE
DURING THE EVENING BEFORE SUBSIDING. ANOTHER FRONT PASSES TUESDAY
WITH A BRIEF PERIOD OF GUSTY SOUTH WINDS AND STEEP SEAS. THIS IS
FOLLOWED BY LONG PERIOD SWELL TUESDAY NIGHT AND BUILDING AND
STEEPENING SEAS WEDNESDAY INTO THURSDAY. -SPILDE
BEACH HAZARDS/HIGH SURF...UPDATED 300 AM PST MONDAY, JANUARY 5,
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. WE'LL
CONTINUE TO MONITOR FOR POSSIBLE BEACH HAZARD AND/OR HIGH SURF
PRODUCTS. -SPILDE/BPN
MFR WATCHES/WARNINGS/ADVISORIES
OR...WINTER STORM WATCH FROM TUESDAY MORNING THROUGH THURSDAY MORNING
FOR ORZ025-027-028.
WINTER WEATHER ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR
ORZ027>030.
CA...WINTER STORM WARNING UNTIL 4 PM PST THIS AFTERNOON FOR CAZ080-
082-083.
PACIFIC COASTAL WATERS...NONE.
MAS
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