538
FXUS66 KMFR 211145
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
345 AM PST FRI FEB 21 2025
DISCUSSION
FOG HAS FORMED IN MANY AREA VALLEYS EARLY THIS
MORNING, AND THESE AREAS ARE LIKELY TO STICK AROUND FOR A FEW
HOURS PAST SUNRISE. MEANWHILE, HIGH LEVEL CLOUDS HAVE BEGUN TO
STREAM INTO THE REGION AHEAD OF THE NEXT FRONTAL SYSTEM
APPROACHING THE PACIFIC NORTHWEST. THESE HIGH CLOUDS TYPICALLY
LIMIT FOG, BUT ANY PERIODS OF CLEARING OR HOLES IN THE CLOUD DECK
COULD ALLOW FOR ADDITIONAL FORMATION OR SPREAD.
TODAY LOOKS TO REMAIN LARGELY UNEVENTFUL OTHER THAN INCREASING
CLOUDS, AS THE WEAK UPPER RIDGE FLATTENS, ALLOWING A WEAK FRONT TO
APPROACH THE OREGON COAST LATE TONIGHT INTO SATURDAY. THIS FIRST
FRONT WILL BE UNIMPACTFUL, GLANCING BY JUST TO OUR NORTH AND BRINGING
SOME SHOWERS TO THE COAST AND OVER HIGHER TERRAIN WEST OF AND
ALONG THE CASCADES. IN GENERAL, AREAS THAT MANAGE TO GET RAIN WILL
GET 0.1 INCHES OR LESS FROM THIS AFTERNOON TO SATURDAY MORNING,
AND SNOW LEVELS WILL REMAIN WELL ABOVE 5000 FEET.
MODELS HAVE TRENDED A BIT FARTHER SOUTH WITH THE PREFERRED STORM
TRACK LATER IN THE WEEKEND, NOW BRINGING SUSTAINED PRECIPITATION
CHANCES INTO THE AREA SATURDAY AFTERNOON TO TUESDAY MORNING AS AN
ATMOSPHERIC RIVER SETS UP AND PROVIDES PLENTY OF MOISTURE. IN
THIS TIMEFRAME, SATURDAY AFTERNOON-SUNDAY MORNING AND MONDAY
EVENING-TUESDAY MORNING WILL BE THE MAIN PERIODS OF INTEREST AS
FRONTS ARE EXPECTED TO SUPPORT ADDITIONAL LIFTING AND ENHANCE
PRECIPITATION. GUSTY WINDS ARE LIKELY ALONG THE OREGON COAST AND
OVER ELEVATED TERRAIN, AS WELL AS IN THE SHASTA VALLEY AND ACROSS
THE EAST SIDE; THE TYPICAL TROUBLE AREAS FOR WIND. FOR THE MOST
PART, WINDS WILL REMAIN BELOW ADVISORY LEVELS, BUT IT IS VERY
CLOSE, ESPECIALLY MONDAY.
THE SATURDAY FRONT LOOKS TO BE THE WETTEST PERIOD, WITH AREAS
SOUTH OF CAPE BLANCO FORECAST TO GET 2 TO 3 INCHES OF RAINFALL AND
AREAS TO THE NORTH GETTING 1 TO 1.5 INCHES. SNOW LEVELS OF 8000
FEET OR HIGHER MAKE SNOWFALL A NON-ISSUE FOR THIS FIRST FRONT.
FROM SUNDAY MORNING TO MONDAY MORNING, SHOWERS CONTINUE WITH
UPSLOPE FLOW BEING THE MAIN LIFTING MECHANISM. THE OREGON COAST
WILL STILL SEE THE MOST RAINFALL IN THIS PERIOD, WITH ANOTHER 1 TO
1.5 INCHES FORECAST FROM BROOKINGS TO REEDSPORT. IN GENERAL,
ACTIVITY LOOKS MORE SPORADIC IN THIS PERIOD. SNOW LEVELS REMAINING
OVER 6000 FEET WILL CONTINUE TO LIMIT SNOWFALL.
FOR THE MONDAY EVENING FRONT, MOISTURE INTO THE AREA DECREASES,
AND PRECIPITATION AMOUNTS WILL TREND LESS THAN THE PREVIOUS
FRONT. WHILE THIS WILL BE THE "DRIEST" PERIOD OF THE OVERALL
EVENT, SNOW LEVELS DROPPING TO 4000 FEET WITH THIS FRONT WILL MAKE
ACTIVITY OVER THE CASCADES WORTH CONSIDERING. ALSO, THIS IS THE
PERIOD WITH THE HIGHEST POTENTIAL FOR STRONG INLAND WINDS, WITH
MODELS DEPICTING A PEAK IN MFR-RDD SEA-LEVEL PRESSURE GRADIENTS
AND WELL ALIGNED MID LEVEL WINDS.
MID NEXT WEEK, ENSEMBLES FAVOR A HIGH PRESSURE RIDGE RETURNING TO
THE REGION WITH A PERIOD OF DRY AND STABLE WEATHER. WITH
LINGERING MOISTURE AT THE SURFACE, MORNING VALLEY FOG WILL BE A
CONSIDERATION. TEMPERATURES WEST OF THE CASCADES LOOK TO BE SAFELY
ABOVE FREEZING, WHILE TEMPERATURES EASTWARD ARE EXPECTED TO BE IN
THE MID 20S TO LOW 30S. -BPN
AVIATION...21/12Z TAFS
LIFR CONDITIONS ARE PRESENT AT BOTH
ROSEBURG/KLAMATH FALLS DUE TO FOG/FREEZING FOG WITH VISIBILITY
REDUCED TO 1/4 OF A MILE AND VERTICAL VISIBILITY OF 100-200 FT.
CURRENTLY, CONDITIONS ARE VFR AT MEDFORD, THOUGH GOES-18
NIGHTTIME MICROPHYSICS RGB SATELLITE IMAGERY SHOWS AREAS OF
LIFR FOG DEVELOPING NEARBY AND EXPECT THIS TO FILL IN THERE
IN THE NEXT HOUR OR SO. EXPECT THESE CONDITIONS TO LAST THROUGH 18-
19Z BEFORE VFR RETURNS LATE THIS MORNING/THIS AFTERNOON.
TONIGHT, MID-LEVEL CLOUDS WILL LOWER AS A FRONTAL SYSTEM OFFSHORE
APPROACHES. THIS COULD BRING A LITTLE LIGHT RAIN TO THE COAST AND AS
FAR INLAND AS THE UMPQUA BASIN, BUT RAIN CHANCES AT BOTH MEDFORD AND
KLAMATH FALLS ARE 20% OR LESS. LARGELY, CONDITIONS WILL STAY VFR,
BUT IT'S CONCEIVABLE THAT CEILINGS LOWER TO MVFR IN SOME AREAS FROM
THE CASCADES WESTWARD WITH PARTIAL OBSCURATION OF HIGHER TERRAIN.
-SPILDE
MARINE...UPDATED 200 AM PST FRIDAY, FEBRUARY 21, 2025
AN ACTIVE
WEATHER PATTERN WILL CAUSE HAZARDOUS CONDITIONS OVER ALL WATERS THIS
WEEKEND INTO NEXT WEEK. AHEAD OF A COLD FRONT TODAY, EXPECT
INCREASING SOUTH WINDS AND BUILDING SEAS WITH CONDITIONS HAZARDOUS
TO SMALL CRAFT. WINDS INCREASE TO GALES SATURDAY INTO SUNDAY WITH
VERY STEEP, HAZARDOUS SEAS, ESPECIALLY FROM AROUND CAPE BLANCO
NORTHWARD. ANOTHER STRONG FRONTAL SYSTEM WILL MOVE THROUGH MONDAY
WITH ANOTHER ROUND OF GALES POSSIBLE. STEEP TO VERY STEEP SEAS
PERSIST INTO TUESDAY, THEN THINGS SHOULD CALM DOWN FROM WEDNESDAY
ONWARD. -SPILDE
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 10 AM PST SUNDAY
FOR PZZ356-376.
SMALL CRAFT ADVISORY UNTIL 10 AM PST SATURDAY FOR PZZ350-370.
GALE WARNING FROM 10 AM SATURDAY TO 10 AM PST SUNDAY FOR PZZ350-
370.
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