663
FXUS66 KMFR 091720
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
920 AM PST TUE DEC 9 2025
..NEW AVIATION SECTION
AVIATION (18Z TAFS)
SHOWERS WILL BE AROUND THE COAST AND PARTS OF THE UMPQUA BASIN
THROUGH THIS CYCLE. KOTH IS LIKELY THE MAIN TERMINAL TO EXPERIENCE
ANY RAINFALL, BUT WE CANNOT COMPLETELY RULE OUT KRBG AS WELL.
OTHERWISE, A COMBINATION OF MVFR TO IFR/LIFR CONDITIONS WILL
PERSIST THROUGH MOST OF THIS CYCLE WITH INTERMITTENT VFR
CONDITIONS. OVERNIGHT INTO WEDNESDAY MORNING WE ARE EXPECTING LOW
CLOUDS/FOG TO BE PRESENT, SO CONFIDENCE IS HIGH (50%-70%) FOR AT
LEAST IFR CONDITIONS OVERNIGHT.
-GUERRERO
PREV DISCUSSION
/ISSUED 323 AM PST TUE DEC 9 2025/
DISCUSSION...UPDATED AVIATION SECTION...
AVIATION...09/12Z TAFS...A FRONT REMAINS AIMED AT THE OREGON COAST
JUST NORTH OF NORTH BEND. THIS IS BRINGING GUSTY WINDS TO THE COAST
AND A VARIETY OF CEILING CONDITIONS ACROSS THE REGION. ALONG THE
COAST AND JUST OFFSHORE, IFR AND LIFR CEILINGS ARE EXPECTED TO
PREVAIL THROUGH THE TAF PERIOD, WITH VISIBILITY ALSO LOWERING THIS
MORNING AS THE FRONT SLOWLY SAGS SOUTH. VFR CONDITIONS GENERALLY
PREVAIL ACROSS THE REGION, BUT LIFR CONDITIONS ARE SPOTTED IN THE
ROGUE/ILLINOIS/APPLEGATE VALLEYS, AND THESE LOWER CONDITIONS WILL
PREVAIL THROUGH THIS MORNING. IN THE UMPQUA BASIN, THE PROXIMITY OF
THE FRONT COULD LIMIT FOG DEVELOPMENT THERE, AND VFR CONDITIONS ARE
CURRENTLY PRESENT, BUT HAVE ADDED MVFR CEILINGS WHEN THE SUN COMES.
MEANWHILE, STRONG WINDS ALOFT WILL PERSIST NEAR THE CASCADES AND
OVER THE EAST SIDE IN OREGON (NORTH OF HIGHWAY 140) TODAY WHERE
HIGHER TERRAIN COULD EXPERIENCE GUSTS IN EXCESS OF 50 MPH. THIS
COULD LEAD TO SOME LOW-LEVEL WIND SHEAR OVER THERE (NE OF KLAMATH
FALLS) SINCE A LOW-LEVEL INVERSION PROBABLY DOESN'T ALLOW THESE
WINDS TO MIX ALL THE WAY TO THE SURFACE IN SOME VALLEYS. EVEN SO,
VERTICAL MIXING MAY IMPROVE TODAY TO ALLOW SURFACE WIND GUSTS TO 50
MPH FROM AROUND SUMMER LAKE EASTWARD.
PREV DISCUSSION... /ISSUED 235 AM PST TUE DEC 9 2025/
DISCUSSION...SATELLITE AND OBSERVATIONS SHOW THAT LOW CLOUDS ARE
DEVELOPING ACROSS SOME WEST SIDE VALLEYS, INCLUDING THE ROGUE
VALLEY. HEAVIER CLOUD COVER IS PREVENTING FOG DEVELOPMENT IN MORE
EAST SIDE SPOTS, INCLUDING KLAMATH FALLS FOR NOW. RADAR HAS A FEW
SHOWERS PASSING IN FAR NORTHERN COOS AND DOUGLAS COUNTIES AS THEY
MOVE EAST TONIGHT. THROUGH THE MORNING, THESE SHOWERS ARE FORECAST
TO REACH ~0.25"- 0.50" NEAR THE DOUGLAS/LANE COUNTY BORDER. SNOW
LEVELS IN THE AFFECTED AREAS ARE ABOVE 8,000 FEET TONIGHT.
THE UPPER LEVEL HIGH TO OUR SOUTHWEST OFF OF CENTRAL CALIFORNIA IS
STILL LOOKING TO BE ENOUGH TO KEEP MOST OF THE ACTIVITY NORTH NEAR
PORTLAND AND SEATTLE THIS WEEK. THE MAIN AREAS TO SEE RAINFALL FOR
THE NEXT FEW DAYS WILL BE THE SAME LOCATIONS TO SEE IT NOW. BETWEEN
THIS MORNING AND WEDNESDAY MORNING, VERY NORTHERN COOS AND DOUGLAS
COUNTIES, INCLUDING PARTS OF THE CASCADES, CAN EXPECT 0.30"-0.75",
WITH NEAR 1.25"-1.75" NEAR THE NORTHERNMOST PART OF DOUGLAS
COUNTY. MOST OF THE RAIN WILL FALL BETWEEN THIS MORNING AND INTO
THE EVENING. ALTHOUGH MOST OF THIS WILL BE OCCURRING IN A 12 HOUR
PERIOD, THERE IS A LOWER CONCERN FOR FLOODING WITH THIS COMPARED
TO AREAS NORTH OF US. EAST SIDE AND NORTHERN CALIFORNIA HAVE THE
LOWEST CHANCES FOR RAIN WITH LESS THAN .15" FROM CHEMULT TO FORT
ROCK BEING THE MOST TO EXPECT.
ALTHOUGH THE AREA WILL BE DRY, EAST SIDE WILL HAVE TO DEAL WITH
STRONGER WINDS BETWEEN NOW AND THIS AFTERNOON. A MID-LEVEL JET OF 50-
60 KT WITH SIMILAR SPEEDS AT 300 MB SHOW THAT STRONG WINDS ARE
FORECAST TO REACH THE SURFACE DURING THIS TIME WITH GUSTS NEAR 50
MPH. A WIND ADVISORY IS IN EFFECT THROUGH THIS EVENING, AND THIS
INCLUDES AREAS NEAR SILVER LAKE, SUMMER LAKE, AND PAISLEY. WIND
GUSTS NEAR 45 MPH HAVE ALREADY BEEN REPORTED AT SUMMER LAKE
EARLY THIS MORNING. PLEASE SEE THE NPWMFR FOR MORE INFORMATION.
GETTING INTO THE MIDDLE OF THE WEEK, THE HIGH PRESSURE TO OUR
SOUTHWEST TAKES CONTROL AND BRINGS DRIER CONDITIONS THROUGH AT LEAST
THE START OF NEXT WEEKEND. EARLIER MODELS WERE SHOWING A CONTINUED
CHANCE OF SHOWERS AT THE COAST THROUGH THE WORK WEEK, BUT THIS HAS
STARTED TO BACK OFF. THE EC HAS ALSO BACKED OFF ON WEEKEND RAIN
CHANCES, BUT IT IS STILL COMING IN EARLIER THAN THE GFS WITH A
MONDAY MORNING VS MONDAY AFTERNOON TIMEFRAME. EITHER WAY, THERE IS
SOME MORE AGREEMENT THAT EARLY NEXT WEEK COULD HAVE ACTIVE WEATHER
IN BOTH SOUTHERN OREGON AND NORTHERN CALIFORNIA. IN THE MEANTIME, WE
WILL BE WATCHING FOR HOW THE SYSTEM THE NEXT FEW DAYS MOVES THROUGH
AND WATCH FOR HOW THE MODELS HANDLE THE NEXT WEEK AFTER. -9
MARINE...UPDATED 200 AM PST TUESDAY, DECEMBER 9, 2025...GUSTY SOUTH
WINDS AND STEEP WIND WAVES COMBINED WITH WESTERLY SWELL WILL
MAINTAIN CONDITIONS HAZARDOUS TO SMALL CRAFT THROUGH AT LEAST TODAY.
WINDS SUBSIDE TONIGHT, BUT WEST SWELL PERSISTS INTO WEDNESDAY,
ESPECIALLY NORTH OF CAPE BLANCO. CONDITIONS IMPROVE FOR THE LATTER
HALF OF THE WEEK AS SWELL DOMINATED SEAS GRADUALLY LOWER. 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.
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.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page