848
FXUS66 KMFR 020604
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
1104 PM PDT WED APR 1 2026
..UPDATED THE AVIATION AND MARINE SECTIONS
AVIATION (06Z TAFS)
A SLIGHT CHANCE OF THUNDERSTORMS WILL
CONTINUE INTO THURSDAY MORNING FROM THE SOUTHERN OREGON COAST TO THE
SOUTHERN OREGON CASCADES. CEILINGS WILL BE MAINLY A MIX OF MVFR AND
VFR THROUGH THURSDAY EVENING. SHOWERS AND SNOW SHOWERS BEHIND A COLD
FRONT WILL BE MOST NUMEROUS OVERNIGHT INTO EARLY THURSDAY MORNING,
THEN LINGERING/TAPERING OFF FROM THE COAST TO THE CASCADES DURING
THE REMAINDER OF THURSDAY INTO THE EARLY EVENING. THIS WILL CONTINUE
AREAS OF MOUNTAIN OBSCURATION, AND ALSO BREEZY TO WINDY WESTERLY LOW
LEVEL WINDS WITH STRONGEST GUSTS EAST OF THE CASCADES.
LASTLY, ISOLATED THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON AS
WELL.
MARINE...UPDATED 800 PM PDT THURSSDAY, APRIL 1, 2026
SHOWERS AND
ISOLATED THUNDERSTORMS CONTINUE TONIGHT BEHIND A STRONG COLD FRONT.
WHILE WINDS ARE EXPECTED TO EASE THIS EVENING, VERY STEEP SWELL
DOMINATED SEAS ARE EXPECTED TO CONTINUE TO BUILD INTO THURSDAY
MORNING. THEREAFTER, STEEP SEAS ARE LIKELY THURSDAY AFTERNOON
THROUGH THURSDAY EVENING. BRIEF IMPROVEMENT ON FRIDAY WILL BE
FOLLOWED BY STRONGER, ADVISORY STRENGTH NORTH WINDS WITH STEEP SEAS
LIKELY FRIDAY EVENING THROUGH SATURDAY EVENING.
PREV DISCUSSION
/ISSUED 1124 AM PDT WED APR 1 2026/
DISCUSSION...A POTENT COLD FRONT AND UPPER LEVEL LOW PRESSURE
SYSTEM IS SWINGING THROUGH THE REGION TODAY THROUGH TONIGHT,
BRINGING MODERATE/HEAVY RAIN, MOUNTAIN SNOW AND GUSTY WINDS.
PRESSURE GRADIENTS WILL PEAK THIS AFTERNOON, WITH MID-LEVEL WINDS
PEAKING AROUND 55 KT. IT WILL BE WINDY EVERYWHERE TODAY, WITH
GUSTS OF 20-30 MPH COMMON, EVEN FOR WEST SIDE AREAS. WE EXPECT
WIDESPREAD PEAK WIND GUSTS IN THE 40-50 MPH RANGE FOR AREAS FROM
THE CASCADES EASTWARD, PERHAPS 55 MPH IN SOME AREAS. WIND
ADVISORIES HAVE BEEN ISSUED FOR PORTIONS OF LAKE/MODOC COUNTIES
WHERE WINDS WILL BE STRONGEST, AND NOW ALSO INCLUDE THE SHASTA
VALLEY WHERE A QUICK BURST OF PRE-FRONTAL SOUTH WINDS (WITH GUSTS
TO 45 MPH) ARE EXPECTED TODAY BEFORE THEY SHIFT TO SOUTHWEST
DURING THE AFTERNOON. STRONG WINDS ARE ALSO EXPECTED ALONG THE
COAST, BUT SHOULD REMAIN JUST BELOW WARNING LEVELS. WITH MODEL
PRESSURE GRADIENTS (OTH-ACV) SHOWING -8 TO -9, IT'S POSSIBLE THAT
THE CAPES AND HEADLANDS, ESPECIALLY CAPE BLANCO, COULD BRIEFLY SEE
GUSTS UP TO 60 MPH, BUT OVERALL, GUSTS IN THE 40-50 MPH RANGE ARE
THE MORE LIKELY SCENARIO FOR THE MAJORITY OF THE IMMEDIATE
COASTLINE.
THE SHARP COLD FRONT WILL BLAST THROUGH THE AREA THIS AFTERNOON AND
THIS WILL BRING PERIODS OF MODERATE RAINFALL ALONG WITH HEAVY
MOUNTAIN SNOW (MOSTLY ABOVE 5000 FEET). THE HEAVIEST PRECIPITATION
IS EXPECTED FROM THE COAST TO THE CASCADES THROUGH THIS AFTERNOON.
OTHER THAN SOME MINOR/TYPICAL NUISANCE PONDING OF WATER ON ROADWAYS,
WE ARE NOT CONCERNED ABOUT FLOODING SINCE RIVER LEVELS ARE VERY LOW
FOR THIS TIME OF YEAR. MOST OF THE RAIN EXPECTED FROM THIS SYSTEM
WILL BE BENEFICIAL/WELCOME. AMOUNTS OF 1-3 INCHES ARE LIKELY ALONG
THE COAST, WITH 0.50-1.00 INCH COMMON INLAND TO THE CASCADES WITH
0.25-0.50 INCH OVER THE EAST SIDE. SNOW LEVELS CURRENTLY HOVER
AROUND 5000-5500 FT, BUT WILL DROP TO 2500-3000 FEET BY THURSDAY
MORNING. WE HAVE WINTER STORM WARNINGS UP FOR THE CASCADES WHERE
SNOWFALL RATES COULD BE 1-2" PER HOUR AT TIMES THIS AFTERNOON DURING
THE HEIGHT OF THE PRECIP. TIMING FOR HIGHEST SNOWFALL RATES APPEARS
TO BE 1-5 PM. IT SHOULD BE NOTED THAT AS THE COLD POOL ALOFT MOVES
IN BEHIND THE COLD FRONT, INSTABILITY INCREASES OVER THE MARINE
WATERS AND INLAND LATE THIS AFTERNOON INTO TONIGHT. THIS COULD
GENERATE ISOLATED THUNDERSTORMS, MOST LIKELY ALONG THE COAST (50-70%
CHANCE) WITH LOWER PROBABILITIES INTO THE UMPQUA AND EAST OF THE
CASCADES (20-40%).
WITH SNOW LEVELS CRASHING DOWN TO AROUND 2500 FEET TONIGHT, WINTER
WEATHER ADVISORIES ARE ALSO UP FOR THE SISKIYOU MOUNTAINS AND FOR
THE "SPILLOVER" AREA EAST OF THE CASCADES (HIGHWAY 97 CORRIDOR) AND
THE MOUNTAINS EAST OF THERE (WARNERS), WHERE A FEW TO SEVERAL INCHES
COULD ACCUMULATE. ALL IN ALL, EXPECT SIGNIFICANT WINTER TRAVEL
IMPACTS IN THE MOUNTAINS AND OVER SOME OF THE HIGHER PASSES,
ESPECIALLY AT LAKE OF THE WOODS BY THURSDAY MORNING. MAIN I-5 PASSES
SHOULD BE OK, BUT SOME SLIPPERY SPOTS COULD DEVELOP AT SISKIYOU
SUMMIT AND/OR AROUND MT SHASTA CITY/SNOWMAN SUMMIT EARLY THURSDAY
MORNING. THERE COULD BE A LITTLE DUSTING OF SNOW TOO FOR SOME OF THE
LOWER SPOTS IN NORCAL AND OVER THE EAST SIDE, BUT GROUND
TEMPERATURES ARE WARM, SO MOST NON-MOUNTAINOUS LOCATIONS WON'T SEE
ROAD ACCUMULATION (EXCEPTION CHILOQUIN NORTHWARD). EVEN SOME OF THE
HIGHER SPOTS AROUND THE WEST SIDE VALLEYS (~2500 FEET) COULD SEE
SNOWFLAKES IN THE AIR THURSDAY MORNING, BUT SNOW ACCUMULATIONS ARE
UNLIKELY GIVEN THE WARM GROUND TEMPERATURES AND RELATIVELY LIGHT
PRECIPITATION RATES BEING UNABLE TO OVERCOME THESE WARM GROUND
TEMPERATURES.
WITH THE CORE OF THE UPPER LEVEL COLD POOL SHIFTING INTO NORTHEAST
OREGON AND IDAHO ON THURSDAY, SHOWERS AND PERHAPS AN ISOLATED
THUNDERSTORM WILL CONTINUE FOR A WHILE INTO THE AFTERNOON, BUT THEN
DIMINISH RAPIDLY AROUND SUNSET AS HIGH PRESSURE BUILDS IN. MODELS
CONTINUE TO SHOW A HIGH PROBABILITY (70-90% CHANCE) OF TEMPERATURES
DROPPING INTO THE LOW TO MID 30S FOR THE WEST SIDE VALLEYS BY FRIDAY
MORNING. SO, THAT WILL BRING FROST/FREEZE RISK, WITH CLOUD COVER
DIMINISHING AFTER 8 PM PST THURSDAY NIGHT. GREATEST RISK OF THAT
OCCURRING IS IN THE ILLINOIS VALLEY (CAVE JUNCTION/OBRIEN/SELMA),
BUT ALSO HERE IN THE ROGUE VALLEY. THE PROBABILITY OF TEMPERATURES
LESS THAN 28F HAVE ALSO INCREASED, A 10-20% CHANCE HERE, WITH
AROUND 40% CHANCE FROM AROUND CAVE JUNCTION SOUTHWARD. WE'VE GONE
FORWARD WITH A FREEZE WATCH FOR JACKSON/JOSEPHINE COUNTIES AS WELL
AS THE KLAMATH RIVER VALLEY IN WESTERN SISKIYOU. CLIMATOLOGICALLY
SPEAKING, AREAS EAST OF THE CASCADES AND IN THE SHASTA/SCOTT
VALLEYS STILL FREQUENTLY SEE FROST/FREEZE CONDITIONS THIS TIME OF
YEAR, SO NO PRODUCTS ARE CONSIDERED FOR THOSE AREAS AT THIS TIME.
WE MAY NEED TO CONSIDER THE NEED FOR FROST ADVISORIES FOR PORTIONS
OF THE UMPQUA BASIN AND POTENTIALLY ALONG THE COAST, BUT
CONFIDENCE IS LOWER FOR THOSE AREAS ON THERE BEING ENOUGH CLEAR
SKIES TO LEAD TO FROST CONDITIONS. STAY TUNED FOR UPDATES.
MODELS ARE SHOWING THE UPPER RIDGE REBUILDING ACROSS THE AREA FRIDAY
INTO THE WEEKEND, SO LOOK FOR TEMPERATURES TO REBOUND TO ABOVE
NORMAL LEVELS AGAIN (HIGHS IN THE 70S AND EVEN LOW 80S AGAIN WEST
SIDE VALLEYS) ALONG WITH LITTLE TO NO CHANCE AT PRECIPITATION. NEXT
CHANCE AT PRECIP WON'T BE UNTIL MONDAY AT THE EARLIEST, BUT MORE
LIKELY TUESDAY/WEDNESDAY NEXT WEEK. EARLY INDICATIONS SHOW THAT THE
NEXT POTENTIAL PRECIP EVENT WILL BE SHORTER-LIVED THAN THE CURRENT
SYSTEM, WITH LOWER AMOUNTS AND ALSO LESS WIDE-SPREAD. -SPILDE/BR-Y
MFR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY UNTIL 11 AM PDT THURSDAY FOR ORZ029-030.
FREEZE WARNING FROM 2 AM TO 9 AM PDT FRIDAY FOR ORZ024-026.
WINTER STORM WARNING UNTIL 5 PM PDT THURSDAY FOR ORZ025-027-028.
CA...WINTER WEATHER ADVISORY UNTIL 11 AM PDT THURSDAY FOR CAZ080-085.
FREEZE WARNING FROM 2 AM TO 9 AM PDT FRIDAY FOR CAZ080.
PACIFIC COASTAL WATERS...HAZARDOUS SEAS WARNING UNTIL 11 AM PDT
THURSDAY FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY FROM 11 AM TO 11 PM PDT THURSDAY FOR PZZ350-
356-370-376.
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