311
FXUS66 KMFR 022159
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
159 PM PST TUE DEC 2 2025
DISCUSSION
KEY POINTS:
* OVERALL, MINIMAL WEATHER IMPACTS THROUGH THIS WEEK
* BY FAR AND LARGE, MOSTLY DRY CONDITIONS EXPECTED THROUGH FRI
* NEXT WIDESPREAD CHANCE FOR PRECIPITATION IS MAINLY SATURDAY
- COULD BE AS EARLY AS FRIDAY
- VERY HIGH SNOW LEVELS (6,000FT+)
* MORNING FOG FOR WESTSIDE VALLEYS/LOW LYING AREAS WED. MORNING
* SIGNS POINTING TOWARDS ACTIVE WEATHER AROUND DEC 9TH-12TH
- HEAVY RAIN (WEST OF CASCADES) AND HEAVY SNOW (CASCADES)
* KING TIDES ARE THIS WEEKEND, BUT NOT EXPECTING IMPACTS/HAZARDS
FURTHER DETAILS:
AN UPPER LEVEL RIDGE HAS SHIFTED WESTWARD TO ALLOW MERIDIONAL FLOW
TODAY. THERE WILL BE AN AREA PVA SPREADING THROUGH THE REGION, BUT
BY FAR AND LARGE WE ARE NOT EXPECTING MUCH--IF ANY--PRECIPITATION.
THE MOISTURE IS LACKING IN THIS SCENARIO, AND THE MAIN IMPACT HERE
IS THE COOLER AIRMASS ADVECTING IN FROM CANADA THROUGH THURSDAY. FOG
AND/OR FREEZING FOG FOR WESTSIDE AREAS MAY COME TO FRUITION TOMORROW
(WED) MORNING WHICH COULD LEAD TO ICE ACCUMULATION ON ELEVATED
SURFACES. NOT EXPECTING THIS ON THE ROADS BUT SOME VERY ISOLATED
BRIDGES COULD BE IMPACTED, SO PLAN FOR A LITTLE EXTRA COMMUTE TIME
TOMORROW AND TIME TO HEAT THOSE VEHICLES UP.
OVERALL, DETERMINISTIC/ENSEMBLE GUIDANCE ARE IN FAIRLY GOOD
AGREEMENT WITH THE GENERAL PATTERN THIS WEEK. WE DO START TO SEE
SOME MINOR DISCREPANCIES THURSDAY NIGHT (PREVIOUSLY THIS WAS FRIDAY)
WHERE SOME GUIDANCE BRINGS IN VERY LIGHT QPF. HOWEVER, THIS MAY END
UP BEING CLOUDS WITHOUT QPF. REGARDLESS, THE IMPACTS LOOK TO BE
MINIMAL IN ANY SOLUTION AS PRECIPITATION WOULD BE VERY LIGHT
THURS/FRI. THE MUCH BETTER AND MORE WIDESPREAD CHANCES STARTS FRIDAY
NIGHT/SATURDAY AND CONTINUES THROUGH SUNDAY MORNING. THE RESULT WILL
BE RAINFALL FOR MOST AREAS AS SNOW LEVELS ARE 6K+ FEET. FOR
PERSPECTIVE, SEVERAL ENSEMBLE MEMBERS (BOTH GFS AND EURO) HAVE NO
SNOW ACCUMULATION FOR CRATER LAKE. IN TYPICAL FASHION, COASTAL AREAS
WILL SEE THE HIGHEST 48HR QPF AMOUNTS, BUT THE UMPQUA BASIN AND THE
CASCADES WILL ALSO BE ON THIS LIST OF HIGHER QPF AMOUNTS. CRATER
LAKE COULD END UP WITH AN INCH OF RAINFALL OVER 48 HOURS GIVEN THE
HIGH SNOW LEVELS. AT THIS TIME, FLOODING ANYWHERE IS UNLIKELY, BUT
NUISANCE TYPE FLOODING WITH PONDING ON ROADWAYS WILL LIKELY OCCUR.
ADDITIONALLY, THERE MAY BE ISOLATED FLOOD PRONE AREAS THAT HAVE POOR
DRAINAGE THAT COULD SEE FURTHER NUISANCE TYPE FLOODING. THAT BEING
SAID, NOT SEEING ANY NOTABLE RIVER RISES WITH THIS SYSTEM, AND WE
ARE NOT EXPECTING WIDESPREAD FLOODING.
LOOKING AHEAD, CLUSTER ANALYSIS FOR 500MB ANOMALIES IS SPLIT SHOWING
A POTENTIAL TROUGH IN THE AREA DEC 9TH-12TH WHICH COULD LEAD TO A
SLIGHT RISK OF BOTH HEAVY RAINFALL AND A HEAVY SNOWFALL, BUT GIVEN
THE SPLIT THERE IS A LOT OF UNCERTAINTY. ADDITIONALLY, THIS IS
PRETTY FAR OUT AND A LOT COULD CHANGE, BUT WE ARE WATCHING THIS TIME
PERIOD FOR POTENTIAL ACTIVE WEATHER. SOON, WE WILL BE ABLE TO NARROW
DOWN THE TIMING, IMPACTS, AND OVERALL HAZARDS. FOR NOW, WE WILL WAIT
FOR NEW DATA AND CONTINUE TO MONITOR.
AVIATION...(18Z TAFS)
CONDITIONS ARE EXPECTED TO IMPROVE LATER
THIS MORNING/EARLY AFTERNOON WITH VFR CONDITIONS EXPECTED THROUGH
THE AFTERNOON AND PARTS OF THE EVENING PERIOD. VALLEY FOG AND LOW
CLOUDS ARE EXPECTED TO REDEVELOP TONIGHT WHICH WOULD IMPACT BOTH
KMFR AND KRBG. SOME UNCERTAINLY HERE, BUT IFR CONDITIONS ARE
LIKELY OVERNIGHT FOR BOTH KRBG AND KMFR. HOWEVER, LIFR CONDITIONS
HAVE AT LEAST A 55% CHANCE OVERNIGHT FOR THESE TWO TERMINALS.
OTHERWISE, EXPECTING HIGH CLOUDS THROUGH THE SECOND HALF OF THIS
CYCLE WITH GENERALLY LIGHT WIND SPEEDS. HOWEVER, KLMT WILL HAVE
SOME BREEZY (AT TIMES) CONDITIONS THIS AFTERNOON.
-GUERRERO
MARINE...UPDATED 200 PM PST TUESDAY, DECEMBER 2, 2025
BREEZY TO GUSTY
NORTHERLY WINDS WILL CONTINUE THROUGH THURSDAY MORNING, WITH WINDS
REACHING SMALL CRAFT ADVISORY LEVELS FROM PORT ORFORD SOUTHWARD.
ADDITIONALLY, LONG PERIOD WEST SWELL IS PEAKING TODAY (8 TO 9 FEET
AT 16 SECONDS AND COMBINED SEAS OF 8 TO 11 FEET) AND WILL PERSIST
TONIGHT AND WEDNESDAY. ADDITIONALLY, SOME AREAS SOUTH OF GOLD BEACH
MAY SEE BRIEF HAZARDOUS SEAS LATE TONIGHT INTO WEDNESDAY. CONDITIONS
ARE EXPECTED TO IMPROVE BY LATE THURSDAY. FRIDAY INTO THE WEEKEND,
SOUTH WINDS WILL DEVELOP AS A FRONTAL SYSTEM MOVES INTO THE AREA AND
SEAS WILL INCREASE.
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 4 PM PST
WEDNESDAY FOR PZZ356-376.
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