059
FXUS66 KMFR 200932
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
232 AM PDT MON APR 20 2026
DISCUSSION
KEY POINTS:
* ONLY MINOR IMPACTS EXPECTED THE NEXT SEVERAL DAYS
* LOW PRESSURE OFF THE COAST WILL WINDS AND PRECIPITATION
- PRECIPITATION GRADUALLY SPREADS INLAND TODAY AND TONIGHT,
WITH SHOWERS PERSISTING THROUGH WEDNESDAY.
- BREEZY TO GUSTY WINDS TODAY, LOCALLY STRONG.
- ISOLATED THUNDERSTORMS POSSIBLE ON TUESDAY.
- ADVISORY SNOWFALL FOR MOUNTAINS IN SISKIYOU COUNTY MON-
TUES
* DRYING TREND TOWARDS THE END OF THE WEEK
AN UPPER LOW OFFSHORE WILL APPROACH THE COAST OF SOUTHERN OREGON
AND NORTHERN CALIFORNIA LATE TODAY, THEN REMAIN JUST OFF THE COAST
TUESDAY BEFORE GRADUALLY MOVING INLAND ACROSS THE REGION TUESDAY
NIGHT AND WEDNESDAY.
THIS LOW WILL SEND SOUTHERLY MOISTURE INTO THE AREA TODAY WITH
SHOWERS SPREADING INLAND FROM THE COAST TO THE CASCADES . WINDS
WILL INCREASE OUT OF THE SOUTH TODAY WITH BREEZY TO GUSTY
CONDITIONS AFFECTING THE AREA. STRONG WINDS ARE EXPECTED IN THE
SHASTA VALLEY WITH GUSTS UP TO 50 MPH. A WIND ADVISORY (NPWMFR) IS
IN EFFECT FOR THIS AREA. GUSTY WINDS ARE ALSO EXPECTED OVER
HIGHER MOUNTAINS AND EAST OF THE CASCADES (GUSTS OF 30 TO 40 MPH).
PRECIPITATION WILL INITIALLY SPREAD ALONG THE COAST THIS MORNING
THEN INLAND DURING THE DAY WITH THE MOST WIDESPREAD PRECIPITATION
ACROSS CURRY COUNTY AND SOUTHERN AND WESTERN SISKIYOU COUNTY WITH
MORE SHOWERY PRECIPITATION ELSEWHERE.
PRECIPITATION WILL BE GENERALLY LIGHT TO LOCALLY MODERATE WITH
THIS SYSTEM BUT EXPECT SHOWERS TO CONTINUE THROUGH WEDNESDAY AS
THE LOW GRADUALLY MOVES ONSHORE AND INLAND. ALTHOUGH INITIALLY
AREAS FROM THE CASCADES WEST WILL BE AFFECTED TODAY, TONIGHT AND
TUESDAY, SHOWERS WILL SPREAD INLAND ACROSS THE AREA. THE MODELS
AND ENSEMBLES SHOWER THAT SHOWERS WILL PERSIST THROUGH WEDNESDAY.
HEAVIEST AMOUNTS OVER THE NEXT 3 DAYS ARE EXPECTED ACROSS
WESTERN/SOUTHERN SISKIYOU COUNTY (1-2 INCHES) WITH MODERATE
PRECIPITATION (0.5-1.0) IN CURRY COUNTY, SOUTHERN JOSEPHINE COUNTY
AND THE SOUTHERN OREGON CASCADES AND SISKIYOUS. WITH LOWERING SNOW
LEVELS TONIGHT INTO TUESDAY (5000-6000 FEET), EXPECT MAINLY LIGHT
SNOW ACCUMULATIONS IN THE CASCADES (1-5") AND MOUNTAINS IN
SISKIYOU COUNTY. ONE AREA THAT MAY SEE HIGHER SNOWFALL AMOUNTS IS
THE THE MOUNTAINS NEAR THE TRINITY ALPS IN SISKIYOU COUNTY,
INCLUDING SOUTH OF CALLAHAN. A WINTER WEATHER ADVISORY IS IN
EFFECT FOR THIS AREA. PLEASE SEE THE WSWMFR FOR DETAILS.
IN ADDITION TO RAIN AND MOUNTAIN SNOW, THERE IS A SLIGHT CHANCE
(15-20%) FOR THUNDERSTORMS FROM THE CASCADES WEST ON TUESDAY
AFTERNOON AS WELL. MODELS CONTINUE TO SHOW MUCAPE VALUES ON
TUESDAY CONTINUE OF AROUND 100-500 J/KG, SO WE ARE EXPECTING AT
LEAST SOME ISOLATED THUNDER. EAST OF THE CASCADES, CHANCES FOR
THUNDERSTORMS ARE AROUND 10% ON TUESDAY. MUCAPE ON WEDNESDAY IS
LOWER SO CHANCES FOR LIGHTNING ARE LOWER (5-10%). NOT EXPECTING
ANY SEVERE WEATHER BUT LIGHTNING AND OCCASIONAL STRONG GUSTS
(30-45 MPH) WILL BE POSSIBLE THROUGH THIS STRETCH.
BREEZY WINDS ARE EXPECTED ON TUESDAY THEN WINDS INCREASE SLIGHTLY
ON WEDNESDAY WITH GUSTY WINDS (25-35 MPH) EXPECTED EAST OF THE
CASCADES.
BY THURSDAY, UPPER LEVEL LOW WILL BE ABSORBED BACK INTO THE MAIN
FLOW. A DRY NORTH/NORTHWESTERLY FLOW WILL BECOME EVIDENT OVER THE
FORECAST AREA. WHILE THE NATIONAL BLEND OF MODELS HOLDS ONTO
SPOTTY POPS THURSDAY ONWARD, WE ARE ANTICIPATING PRECIPITATION
CHANCES TO DWINDLE THURSDAY AND THURSDAY NIGHT. MODEL DIFFERENCES
IN THE EXTENDED COME TO FRUITION AROUND FRIDAY NIGHT AS AN UPPER
LEVEL TROUGH DROPS DOWN FROM THE NORTH AND INTO THE REGION.
HOWEVER, THERE ARE SIGNIFICANT DIFFERENCES ON THE TRACK AND
STRENGTH OF THIS TROUGH. SO CONFIDENCE IS LOW ON THE DETAILS FOR
FRIDAY INTO THE WEEKEND.
AVIATION...20/06Z TAFS
RAIN AND LOWER CEILINGS (TO MVFR) WILL
SPREAD ONTO THE COAST THIS MORNING. INLAND AREAS WILL REMAIN MAINLY
VFR TODAY, THEN AREAS OF MVFR CEILINGS SPREADING INLAND TO AREAS
WEST OF THE CASCADES THIS EVENING AND TONIGHT. WINDS WILL INCREASE
AGAIN LATER THIS MORNING AND THIS AFTERNOON FOR SIMILAR LOCATIONS AS
YESTERDAY (SHASTA VALLEY, MEDFORD AND THE EAST SIDE). INCREASING
SOUTHERLY FLOW INTO SISKIYOU COUNTY, INCLUDING THE MT SHASTA REGION,
MAY CAUSE LOWERING CEILINGS (TO MVFR) BEGINNING LATE THIS AFTERNOON
AND CONTINUING TONIGHT ALONG WITH RAIN AND HIGH ELEVATION SNOW
(ABOVE 5000 FEET). PRECIPITATION WILL BE MORE SHOWERY NORTH OF THE
SISKIYOUS.
MARINE...UPDATED 100 AM PDT MONDAY, APRIL 20, 2026
LOW PRESSURE
OFFSHORE WILL BRING A PERIOD OF ACTIVE WEATHER TODAY INTO TONIGHT,
WITH PERIODS OF GUSTY SOUTH WINDS AND ELEVATED SEAS/SWELL. WINDS ARE
LIKELY TO BE STRONGEST THROUGH THIS EVENING WITH A PERIOD OF STEEP
SEAS HAZARDOUS TO SMALL CRAFT MOSTLY BEYOND 10 NM FROM SHORE AND FOR
AREAS WITHIN 10 NM OF SHORE FROM CAPE BLANCO NORTH. CONDITIONS
SHOULD IMPROVE TUESDAY AS THE LOW GRADUALLY PUSHES INTO NORTHERN
CALIFORNIA. THEN, INCREASING NW SWELL FOLLOWS WEDNESDAY INTO
THURSDAY WITH A RETURN OF NORTH TO NORTHWEST WINDS.
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 11 AM PDT
TUESDAY FOR CAZ080>082.
WIND ADVISORY FROM 8 AM THIS MORNING TO 6 PM PDT THIS EVENING
FOR CAZ081.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 1 PM THIS
AFTERNOON TO 8 PM PDT THIS EVENING FOR PZZ350.
SMALL CRAFT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR PZZ370-376.
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