343
FXUS66 KMFR 092222
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
222 PM PST TUE DEC 9 2025
DISCUSSION (TODAY THROUGH MONDAY)
KEY POINTS:
* OVERALL, MINIMAL WEATHER IMPACTS THROUGH THIS WEEKEND
* MOSTLY LIGHT RAINFALL CHANCES EXPECTED THROUGH WEDNESDAY
- NO SNOW EXPECTED
* NEXT WIDESPREAD CHANCE FOR PRECIPITATION IS EARLY NEXT WEEK
- COULD BE AS EARLY AS SUNDAY
- SNOW: SNOW LEVELS ARE HIGH 6,000+ FT
- LITTLE TO NO SNOW ACCUMULATION EXPECTED
- RAIN: MAINLY FOR COASTAL AREAS, CASCADES, & UMPQUA BASIN
- HIGHEST CHANCES FOR ACCUMULATION OF AT LEAST 0.25"/24HRS
- WIND: ADVISORY LEVEL WIND SPEEDS POSSIBLE EARLY NEXT WEEK
- MAINLY EASTSIDE AREAS AND SHASTA VALLEY
FURTHER DETAILS:
OUR WEATHER ACROSS THE PACNW IS BEING DICTATED BY AN AREA OF LOW
PRESSURE OVER THE GULF OF ALASKA AND HIGH PRESSURE OFF THE COAST OF
CALIFORNIA. THIS IS ALLOWING FOR A LARGE SWATH OF MOISTURE ADVECTION
INTO THE REGION BETWEEN THESE TWO FEATURES. BY FAR AND LARGE, NEARLY
ALL THE WEATHER IMPACTS WILL BE NORTH OF OUR FORECAST AREA. IN OTHER
WORDS, WE ARE ONLY EXPECTING LIGHT RAINFALL THROUGH WEDNESDAY GIVEN
THE STRENGTH AND PLACEMENT OF THE HIGH PRESSURE. ADDITIONALLY, WE
WILL HAVE WIND ADVISORY CONDITIONS OVER PARTS OF THE EASTSIDE
THROUGH THIS EVENING. EVENTUALLY, THE RIDGE OF HIGH PRESSURE DOES
BREAK DOWN, AND THE ORIENTATION SHIFTS TO ALLOW THIS MOISTURE
PLUME TO GO FARTHER NORTH INTO CANADA THURSDAY THROUGH SUNDAY.
THROUGH THIS STRETCH, WE ARE EXPECTING DRY CONDITIONS ACROSS THE
FORECAST AREA. THERE IS SOME UNCERTAINTY ON THE NEXT POTENTIAL
AREA OF LOW PRESSURE IMPACTING THE REGION, AND IT COULD BE AS
EARLY AS SUNDAY. DETERMINISTIC AND ENSEMBLE MEMBERS HAVE A STRONG
SIGNAL FOR RAINFALL CHANCES INCREASING BY MONDAY. SNOW LEVELS ARE
REALLY HIGH EARLY NEXT WEEK, AND AT THIS TIME VERY LITTLE SNOWFALL
IS ANTICIPATED. CLUSTER ANALYSIS SHOWS A SPLIT WITH 5000MB
HEIGHTS EARLY NEXT WEEK. THIS DOESN'T LEAD TO HIGH CONFIDENCE WITH
SOME OF THE EXACT DETAILS, BUT AT THIS TIME THERE ISN'T A LOT OF
CONFIDENCE FOR IMPACTFUL WEATHER THROUGH EARLY NEXT WEEK. THE
PROBABILITY FOR AT LEAST 2.0" OF SNOW OVER 24 HOURS IS ONLY AROUND
20% MON/TUES FOR AREAS IN/AROUND CRATER LAKE. IN FACT, MOST
ENSEMBLE MEMBERS HAVE ZERO SNOWFALL AT CRATER LAKE THROUGH EARLY
NEXT WEEK. WE ARE GOING TO NEED THE PATTERN TO SHIFT IN A WAY THAT
ALLOWS COLDER ARCTIC/CANADIAN AIR TO ADVECT INTO THE REGION, BUT
THIS DOESN'T LOOK PROMISING THROUGH NEXT WEEK. FOR PERSPECTIVE,
THE LATEST CRATER LAKE HAS HAD ZERO SNOW DEPTH WAS DECEMBER 26TH,
1976. RECORD KEEPING BEGAN IN 1919 FOR CRATER LAKE, AND WE HAVE
ONLY HAD 9 YEARS WHERE WE WENT INTO DECEMBER FOR THE LAST SNOW
DEPTH OF ZERO. THIS WILL BE THE 10TH YEAR, AND WILL LIKELY RANK AT
LEAST 3RD LATEST EVER. IN 1958, WE WENT UNTIL DECEMBER 20TH, AND
IN 2008 WE WENT UNTIL DECEMBER 11TH.
-GUERRERO
AVIATION (00Z TAFS)
RAIN SHOWERS ARE STILL EXPECTED THROUGH EARLY PARTS OF THIS TAF
CYCLE WHICH WILL MAINLY IMPACT KOTH, BUT THERE WILL BE SHOWERS
AROUND KRBG AND KMFR AS WELL. OVERALL, THIS WILL BE MOSTLY A MVFR
TO IFR/LIFR TAF CYCLE AS CEILINGS REDUCE OVERNIGHT IN ADDITION TO
VISIBILITIES. HIGH CONFIDENCE (50%-70%) FOR IFR/LIFR CONDITIONS
OVERNIGHT. THE ONE CAVEAT IS KLMT WHICH WILL HAVE THE HIGHEST
UNCERTAINTY FOR IFR/LIFR, BUT OVERALL CONDITIONS WILL DETERIORATE
OVERNIGHT ACROSS THE AREA WITH FOG/LOW CLOUDS.
-GUERRERO
MARINE...UPDATED 230 PM PST TUESDAY, DECEMBER 9, 2025
GUSTY
SOUTH WINDS AND STEEP WIND WAVES COMBINED WITH WESTERLY SWELL WILL
MAINTAIN CONDITIONS HAZARDOUS TO SMALL CRAFT THROUGH THIS EVENING.
WINDS SUBSIDE TONIGHT, BUT WEST SWELL PERSISTS INTO WEDNESDAY,
ESPECIALLY NORTH OF CAPE BLANCO AND HIGH STEEP WILL CONTINUE TO POSE
A THREAT TO SMALLER CRAFTS. CONDITIONS IMPROVE FOR THE LATTER HALF
OF THE WEEK AS HIGH PRESSURE BUILDS OVER THE REGION. EXPECTING
SHOWERS OVER THE WATERS THROUGH MID-WEEK AS WELL WHICH COULD FURTHER
REDUCE VISIBILITIES (FOG/LOW CLOUDS EXPECTED AS WELL) OVER THE NEXT
COUPLE DAYS.
-SMITH
MFR WATCHES/WARNINGS/ADVISORIES
OR...WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR ORZ030-031.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 1 AM PST
WEDNESDAY FOR PZZ356-376.
SMALL CRAFT ADVISORY UNTIL 10 AM PST WEDNESDAY FOR PZZ350-370.
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