148
FXUS66 KMFR 141057
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
257 AM PST SUN DEC 14 2025
DISCUSSION
SATELLITE IMAGERY THIS MORNING SHOWS AN EXTENSIVE
AREA OF LOW CLOUDS ENTRENCHED ALONG THE COAST, WITH FOG AND LOW
STRATUS FILLING THE VALLEYS WEST OF THE CASCADES ONCE AGAIN.
HIGHER CLOUDS ARE STREAMING OVERHEAD, AND THESE ARE THE FIRST
SIGNS OF A FRONT WHAT WILL ATTEMPT TO PASS ONSHORE LATER TODAY.
ATTEMPT IS THE CORRECT WORD HERE, AS THE FRONT WILL WASH OUT AND
DISSIPATE AS IT MOVES ONSHORE, SO SOME LIGHT SHOWERS OR DRIZZLE IS
POSSIBLE ALONG THE IMMEDIATE COAST AND PERHAPS ON THE WESTERN
SLOPES OF THE COASTAL RANGES, BUT OTHERWISE PRECIPITATION WILL
REMAIN MOSTLY OFFSHORE.
AHEAD OF THIS FRONT, THE LOW CLOUDS AND FOG IN THE WEST SIDE
VALLEYS COULD BECOME DENSE IN PLACES, ESPECIALLY AROUND SUNRISE,
AND WILL BE SLOW TO ERODE/LIFT, WHICH WILL KEEP AFTERNOON
TEMPERATURES IN CHECK AGAIN TODAY. IT'S NOT OUT OF THE QUESTION
THAT FOG AND LOW STRATUS IN SOME VALLEYS WILL PERSIST ALL THE WAY
THROUGH THE AFTERNOON AS WELL, AND NEVER CLEAR BEFORE SETTLING
SOLIDLY IN AGAIN TONIGHT. HOWEVER, THE DYING FRONT MY STIR THE
ATMOSPHERE UP ENOUGH TO ERODE CLOUDS OUT FROM SOME OF THE VALLEYS
THAT HAVE NOT SEEN SUNSHINE IN SEVERAL DAYS.
A SECOND FRONT THEN ARRIVES QUICKLY ON THE HEELS OF THE
DISSIPATING ONE, ARRIVING TONIGHT INTO MONDAY WITH RAIN AND GUSTY
WINDS. THIS WILL BE A WARM SYSTEM, AND SNOW LEVELS WILL BE RATHER
HIGH, CLOSE TO 10000 FT, SO NO WINTER IMPACTS ARE EXPECTED. SOME
MODERATE RAINFALL AMOUNTS ARE FORECAST THROUGH THE DAY MONDAY,
MAINLY ALONG THE COAST AND WEST OF THE CASCADES. LIGHTER AMOUNTS
ARE EXPECTED TO THE EAST.
ANOTHER POTENT FRONT WITH PLENTY OF WIND AND PRECIPITATION
ARRIVES LATE TUESDAY, AND THIS ONE WILL BE A MUCH MORE IMPRESSIVE
SYSTEM. MODEL FORECAST SURFACE PRESSURE GRADIENTS HAVE TRENDED
STRONGER IN THE LATEST RUNS, AND WITH 700 MB WINDS OF 60 TO 70
KTS, THERE IS GROWING CONCERN FOR STRONG WINDS, ESPECIALLY ALONG
THE COAST AND ACROSS THE EAST SIDE, WHERE HIGH WIND HEADLINES MAY
BE NECESSARY, ESPECIALLY IF THE OFFSHORE SURFACE LOW SHOWS SIGNS
OF RAPIDLY DEEPENING. THERE IS ALSO HEALTHY MOISTURE INFLOW, SO
MODERATE TO HEAVY RAINFALL AMOUNTS ARE LIKELY AS WELL, ALTHOUGH
LOCAL DRAINAGES ARE LOWER THAN NORMAL AND THERE IS VERY LITTLE
SNOWPACK TO MELT, SO RIVER OR STREAM FLOODING CHANCES ARE LOW.
THE PASSING FRONT WILL INTRODUCE COLDER AIR, LOWERING SNOW
LEVELS TO BELOW 4000 FEET BY WEDNESDAY MORNING. THESE LOWER SNOW
LEVELS ARE NOT EXPECTED UNTIL AFTER THE FRONT HAS PASSED, MEANING
THAT THE MAIN SURGE OF PRECIPITATION WILL HAVE PASSED, AND POST
FRONTAL SHOWERS WILL DOMINATE. THIS WILL LIMIT WINTER WEATHER
IMPACTS, THOUGH 2 TO 4 INCHES OF SNOW ARE EXPECTED TO FALL ON THE
CASCADE PASSES THROUGHOUT THE DAY WEDNESDAY.
THE ACTIVE WEATHER WILL CONTINUE, WITH ADDITIONAL FRONTS PASSING
THROUGH THE AREA EVERY OTHER DAY OR SO ALL THE WAY INTO EARLY
NEXT WEEK. EACH SYSTEM WILL HAVE A CHANCE TO PRODUCE GUSTY WINDS
AND PLENTY OF RAIN AND MOUNTAIN SNOW, BUT DETAILS ON EACH SYSTEM
ARE UNCERTAIN GIVEN THE WIDE RANGES IN THE ENSEMBLE SUITES. THAT
BEING SAID, THE MODELS ARE TRENDING TOWARDS ANOTHER STRONG SYSTEM
THURSDAY, WHICH COULD BE SIMILAR IN TERMS OF STRENGTH TO THE
PREVIOUS EVENT. IT SHOULD ALSO BE MENTIONED THAT WHILE MOST
SOLUTIONS KEEP SNOW LEVELS ABOVE THE VALLEY FLOORS, THERE ARE A
FEW ENSEMBLE MEMBERS DEPICTING LOW ELEVATION SNOW EARLY TO MIDDLE
NEXT WEEK, PERHAPS IN TIME FOR CHRISTMAS? WE WILL KEEP AN EYE ON
MODEL TRENDS AND UPDATE AS NECESSARY. -BPN
AVIATION...14/12Z TAFS
AREAS OF LOW STRATUS AND FOG ARE PRESENT
IN VALLEYS WEST OF THE CASCADES, RESULTING IN IFR/LIFR CONDITIONS AT
MEDFORD, GRANTS PASS, ROSEBURG, AND MONTAGUE. OVERNIGHT, IFR/LIFR IS
ALSO EXPECTED TO DEVELOP IN THE KLAMATH BASIN, INCLUDING KLAMATH
FALLS. THESE CONDITIONS WILL PERSIST THROUGH 18-20Z SUNDAY. SOME
AREAS, SUCH AS MEDFORD AND GRANTS PASS MAY SEE LITTLE OR NO
CLEARING, AND JUST SEE CEILINGS LIFT HIGHER LATE IN THE AFTERNOON TO
IFR/MVFR AND PERSIST INTO THE EVENING.
ALONG THE COAST AND JUST OFFSHORE, MARINE STRATUS REMAINS
ENTRENCHED, PRODUCING IFR/LIFR FROM GOLD BEACH SOUTH TODAY. THESE
CEILINGS ARE EXPECTED TO PERSIST INTO LATE SUNDAY MORNING. TONIGHT,
A FRONT APPROACHES THE COAST, WHICH WILL LIFT CEILINGS A BIT ALONG
THE NORTH COAST AND MAY PRODUCE SOME LIGHT DRIZZLE. -BPN
MARINE...UPDATED 200 AM PST SUNDAY, DECEMBER 14, 2025
RELATIVELY
CALM CONDITIONS IN LOW CLOUDS THIS MORNING WILL DETERIORATE THROUGH
TODAY AS A FRONT APPROACHES THE REGION. INCREASING SOUTH WINDS
AND STEEPENING SEAS WILL PRODUCE CONDITIONS HAZARDOUS TO SMALL
CRAFT BY THIS AFTERNOON.
WORSENING CONDITIONS ARE EXPECTED OVERNIGHT INTO MONDAY AS LOW
PRESSURE DEEPENS OVER THE NORTH PACIFIC AND A COLD FRONT SWINGS
THROUGH THE WATERS. THIS FRONT IS EXPECTED TO BRING SOUTHERLY GALES
TO AREAS NORTH OF CAPE BLANCO AND BEYOND 5 NM FROM SHORE LATE SUNDAY
NIGHT THROUGH MONDAY AFTERNOON WITH VERY STEEP AND HAZARDOUS SEAS
EXPECTED FOR ALL OTHER AREAS. WINDS EASE MONDAY AFTERNOON, BUT
WESTERLY SWELL BUILDS (10-12 FT @ 12 SECONDS) BEHIND THE FRONT WHICH
WILL MAINTAIN STEEP SEAS INTO MID-WEEK. ADDITIONAL FRONTAL SYSTEMS
WILL MAINTAIN ACTIVE WEATHER THROUGH THE WEEK WITH GALES POSSIBLE
AGAIN ON TUESDAY AND THURSDAY, ALONG WITH CONTINUED STEEP TO, AT
TIMES, VERY STEEP AND HAZARDOUS SEAS. -BPN/BR-Y
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 1 PM THIS
AFTERNOON TO 1 AM PST MONDAY FOR PZZ350-356-370-376.
HAZARDOUS SEAS WARNING FROM 1 AM TO 4 PM PST MONDAY FOR PZZ350-
356-370-376.
GALE WARNING FROM 1 AM TO 4 PM PST MONDAY FOR PZZ350-370.
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