359
FXUS66 KMFR 050550
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
950 PM PST THU DEC 4 2025
..UPDATED MARINE DISCUSSION AND AVIATION DISCUSSION FOR 06Z TAFS
DISCUSSION
THE BATTLE ZONE BETWEEN DRY AND WET WILL BE SW
OREGON AND NORTHERN CALIFORNIA FOR AT LEAST THE NEXT WEEK. MODEL
GUIDANCE IS NEAR UNANIMOUS IN SHOWING A STRONG, MOIST UPPER LEVEL
JET AND ARS DIRECTED INTO BRITISH COLUMBIA AND PORTIONS OF THE
PACNW (ESPECIALLY NORTHERN OREGON AND WASHINGTON) THROUGH NEXT
THURSDAY. BUT, STRONG HIGH PRESSURE ALOFT CURRENTLY SITUATED
BETWEEN 30 AND 40N AND AROUND 140W WILL GRADUALLY DRIFT ESE DURING
THIS TIME PERIOD AND WILL SERVE TO DEFLECT MOST OF THE HEAVIEST
PRECIPITATION ASSOCIATED WITH THE JET TO OUR NORTH. AT TIMES,
HOWEVER, SHORTWAVE DISTURBANCES WILL ALLOW FOR FRONTAL SYSTEMS TO
WAG TO THE SOUTH AND BRING SOME RAIN TO OUR AREA. WITH THE MAIN
ACTIVITY/FRONTS REMAINING TO THE NORTH, THIS SHOULD ALSO KEEP
TEMPERATURES ABOVE NORMAL FOR EARLY DECEMBER AND SNOWFALL WILL BE
LIMITED IN THE MOUNTAINS.
ONE SUCH SYSTEM IS EXPECTED TO COME OVER THE TOP THE OFFSHORE
RIDGE ON FRIDAY, WITH A SLUG OF MODERATE TO PERHAPS BRIEFLY HEAVY
PRECIPITATION FOCUSED IN COOS AND DOUGLAS COUNTIES, ESPECIALLY THE
COAST AND COAST RANGES, BUT ALSO THE CASCADES AND ADJACENT WEST
SIDE FOOTHILLS. SNOW LEVELS ARE UP AROUND 9000 FEET FRIDAY, SO
PRECIPITATION WILL BE RAIN, EVEN AT THE HIGHER MOUNTAINS. MOST
LIKELY RAIN AMOUNTS IN THOSE AREAS WILL BE 0.50-1.50 INCHES,
PERHAPS SLIGHTLY HIGHER IN AREAS OF HIGHER OROGRAPHIC ENHANCEMENT
(NNW-FACING SLOPES OF CASCADES). BUT, THIS ISN'T THE TYPE OF FLOW
THAT BRINGS A LOT OF RAIN TO THE ROGUE/ILLINOIS VALLEYS, SO
AMOUNTS DROP OFF SIGNIFICANTLY, TO AROUND 0.10-0.25 OF AN INCH.
SOUTH AND EAST OF THE CASCADES, SOME PLACES WON'T MEASURE ANY
RAINFALL, BUT A FEW HUNDREDTHS HERE AND THERE WILL BE THE GENERAL
RULE, AGAIN ASIDE FROM ANY NNW-FACING TERRAIN ENHANCEMENT. MODELS
ARE SHOWING A MID-LEVEL JET OF 45-50 KT AROUND 700 MB LATE FRIDAY
AFTERNOON/NIGHT AND THIS COULD BRING GUSTS UP TO 45 MPH OVER THE
HIGHER TERRAIN AND THE EAST SIDE (SUMMER LAKE REGION) THEN. WE
DON'T THINK THIS WILL AFFECT A LARGE AREA, SO WE AREN'T PUTTING UP
A WIND ADVISORY, BUT HUNTERS OR OTHERS VENTURING INTO THE
MOUNTAINS SHOULD BE AWARE OF POTENTIALLY GUSTY WINDS. GRADUALLY,
SNOW LEVELS FALL TO 5500-6000 FEET BY SATURDAY MORNING, BUT
PRECIPITATION SHOULD BE TAPERING OFF OR ENDING BY THEN. SOME LIGHT
RAIN/DRIZZLE HAS THE HIGHEST PROBABILITY OF PERSISTING ALONG THE
COAST AND INTO THE UMPQUA BASIN DURING SATURDAY.
AFTER A BREAK SATURDAY/SATURDAY NIGHT, THE NEXT DISTURBANCE WILL
MOVE OVER THE TOP AND INTO WA/OR SUNDAY. THIS WILL BRING A RENEWED
RISK OF MODERATE PRECIPITATION ACROSS N&W SECTIONS OF THE CWA,
ONCE AGAIN WITH MOST, IF NOT ALL, PRECIPITATION STAYING TO THE
NORTH OF THE OR/CA BORDER. WE DON'T CURRENTLY PREDICT ANY
MEASURABLE RAINFALL HERE IN MEDFORD, BUT THERE COULD BE A
0.10-0.30 OF AN INCH FROM THE COAST TO THE UMPQUA DIVIDE/CASCADES.
THE PACIFIC FIRE HOSE WILL CONTINUE TO WAG BACK AND FORTH TUESDAY
THROUGH THURSDAY WITH MODELS SHOWING A WARM FRONT SHIFTING NORTH
OF THE AREA AND SNOW LEVELS ONCE AGAIN RISING ABOVE 8000 FEET. THE
FORCE FIELD STILL APPEARS TO BE THE OR/CA BORDER, WITH
PRECIPITATION REALLY STRUGGLING TO REACH INTO NORCAL DURING THE
STRETCH. RIGHT NOW, WE CAN EXPECT SOME MINOR RISES ON AREA CREEKS,
STREAMS AND RIVERS ACROSS N&W SECTIONS OF THE CWA (UP AROUND
ROSEBURG AND NORTH/WEST), BUT SINCE THEY'RE RUNNING LOW FOR THIS
TIME OF YEAR, WE DON'T EXPECT FLOODING. MOST SIGNIFICANT IMPACTS
FROM THE RAIN WILL BE TO OUR NORTH.
BEYOND THAT, MODEL CLUSTERS/ENSEMBLES ARE GENERALLY SPLIT BETWEEN
THE UPPER RIDGE MOVING ONSHORE INTO THE SW LATE NEXT WEEK AND THEN
INTO THE NATION'S MIDSECTION OVER THE WEEKEND OR UPPER RIDGING
HOLDING IN THE SW LONGER. IF THE PATTERN IS MORE PROGRESSIVE, UPPER
TROUGHING OVER THE NORTH PACIFIC/GULF OF ALASKA COULD HEAD IN OUR
DIRECTION FRI/SAT. RIGHT NOW, ABOUT 20-40% OF THE MEMBERSHIP SHOW
A COLDER SOLUTION WITH THE POTENTIAL FOR LOWER SNOW LEVELS.
HOWEVER, MORE LIKELY, SOME SEMBLANCE OF THE UPPER RIDGE REMAINS
OVER THE SW WITH A SHIFT IN THE STORM TRACK SLIGHTLY SOUTHWARD
WITH TIME. THIS IS LIKELY DUE TO SOME BLOCKING EXPECTED
DOWNSTREAM. THIS BRINGS BETTER ODDS FOR PRECIP HERE, BUT WITH
TEMPS REMAINING NEAR TO ABOVE NORMAL. CPC 8-14 DAY FORECAST IS
SHOWING THIS SCENARIO WITH BETTER ODDS FOR ABOVE NORMAL TEMPS
CONTINUING THROUGH WEEK 2, BUT ALSO A HIGHER PROBABILITY OF ABOVE
NORMAL PRECIP. SINCE THERE ARE MANY SCENARIOS AND PLENTY CAN
CHANGE BETWEEN NOW AND THEN, WE'D RECOMMEND CHECKING BACK FOR
UPDATES! -SPILDE
AVIATION...05/06Z TAFS
A WEAK FRONT IS BRINGING LIFR CEILINGS TO
THE COAST AND MVFR TO IFR CEILINGS FOR INLAND AREAS WEST OF THE
CASCADES. RAIN SHOWERS HAVE ALSO BROUGHT PERIODS OF LOWER
VISIBILITIES TO THE NORTH BEND TERMINAL. SHOWERS ARE EXPECTED TO
MOVE INLAND THROUGH THE NIGHT AND INTO SATURDAY MORNING, BRINGING
CHANCES OF LOWER CEILINGS AND VISIBILITIES AS WELL AS POSSIBLY
OBSCURING ELEVATED TERRAIN. EAST OF THE CASCADES, ONLY ISOLATED
SHOWERS AND VFR TO MVFR CEILINGS ARE EXPECTED.
CONDITIONS WEST OF THE CASCADES START TO IMPROVE LATE IN THE
AFTERNOON, BUT LOW LEVEL WIND SHEAR WILL DEVELOP OVER THE CASCADES
AND EAST SIDE TERRAIN NEAR 00Z. AT 1500-2000 FEET, WINDS OUT OF THE
WEST ARE FORECAST TO BE 40 TO 50 KTS OVER THESE AREAS. LOW LEVEL
SHEAR DOESN'T LOOK TO AFFECT ANY AREA TERMINALS, AND SHEAR LOOKS TO
DISSIPATE NEAR THE END OF THIS TAF PERIOD. -TAD
MARINE...UPDATED 800 PM PST THURSDAY, DECEMBER 4, 2025...WINDS WILL
TRANSITION TO SOUTH AND SOUTHWEST ON FRIDAY AHEAD OF ANOTHER FRONT.
ADVISORY STRENGTH WINDS ON FRIDAY WILL BE STRONGEST NEAR SHORE NORTH
OF CAPE BLANCO. THE COMBINATION OF WEST-NORTHWEST SWELL, RESIDUAL
NORTHERLY FRESH SWELL, AND SOUTHERLY WIND SEAS WILL RESULT IN STEEP,
CHAOTIC SEAS INTO THE WEEKEND. CONDITIONS REMAIN UNSETTLED THROUGH
THE FIRST PART OF NEXT WEEK, WITH SEVERAL FRONTS BRINGING PERIODS OF
GUSTY SOUTH WINDS AND A LIKELIHOOD OF HIGH AND STEEP SEAS.
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 4 PM THIS
AFTERNOON TO 4 PM PST SATURDAY FOR PZZ350-370.
SMALL CRAFT ADVISORY UNTIL 4 PM PST SATURDAY FOR PZZ356-376.
MAS/BPN
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