244
FXUS66 KMFR 242342
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
442 PM PDT FRI APR 24 2026
DISCUSSION...UPDATED AVIATION SECTION
AVIATION...25/00Z TAFS
GUSTY NORTHERLY WINDS WILL BE SEEN NEAR
THE COAST BEFORE WEAKENING THIS EVENING. VFR CONDITIONS ARE FORECAST
TO PREVAIL THROUGH THE TAF PERIOD, WITH A FEW EXCEPTIONS.
PROBABILITIES FOR CEILINGS OF <3KFT NEAR THE COAST IS NEAR 35-45%,
SO HAVE ADDED A SCATTERED PROB, AND THIS WOULD MOST LIKELY BE SEEN
BETWEEN 11-14 Z. LOW CLOUDS COULD DEVELOP IN WEST SIDE LOCATIONS
INCLUDING THE UMPQUA BASIN (ROSEBURG), MAINLY BETWEEN 11-16Z. THE
06Z TAF WILL HAVE MORE INFORMATION ON LOW CEILING DEVELOPMENT. -
HERMANSEN
PREV DISCUSSION
/ISSUED 146 PM PDT FRI APR 24 2026/
KEY MESSAGES...
-SLIGHTLY COOLER WEATHER IS EXPECTED THIS WEEKEND (AND INTO MON)
WITH ISOLATED TO SCATTERED SHOWERS FROM THE CASCADES EASTWARD.
-ISOLATED PM/EVE THUNDERSTORMS ARE ALSO POSSIBLE, BUT PRIMARILY
ACROSS NORCAL (MT SHASTA REGION EASTWARD).
-SHOWERS CHANCES ARE LOWER WEST OF CASCADES, BUT CAN'T RULE ONE
OUT HERE OR THERE SUN/MON, ESPECIALLY HIGHER TERRAIN.
-ACTIVITY DIMINISHES IN COVERAGE AND SHIFTS EASTWARD TUE/WED.
-WARMING TREND AGAIN WED-THU.
DISCUSSION...THE FORECAST AREA IS CURRENTLY WEDGED IN BETWEEN
WEAK LOW PRESSURE OFF THE CALIFORNIA COAST AND A DEEPER LOW
SITUATED OVER SOUTHERN CANADA (SASKATCHEWAN). MEANWHILE, A STRONG
ELONGATED UPPER RIDGE EXTENDS OVER THE EASTERN PACIFIC INTO NW
BRITISH COLUMBIA. THE UPPER RIDGE IS EFFECTIVELY BLOCKING ANY
STRONG PACIFIC SYSTEMS FROM REACHING THE WEST COAST. SO, WE'LL
CONTINUE TO BE IMPACTED BY MOSTLY MINOR DISTURBANCES OVER THE NEXT
FEW DAYS.
ONE SUCH DISTURBANCE IS COMING SOUTHWARD INTO THE PACNW (ON THE
BACK SIDE OF THE DEEP SOUTHERN CANADA LOW). THIS WILL PRODUCE AN
AREA OF CONVERGENCE AS MOISTURE ADVECTS NORTHWARD INTO NORTHERN
CALIFORNIA FROM THE WEAK LOW OFFSHORE. RIGHT NOW, MOISTURE IS
LIMITED, SO NOT MUCH IS GOING ON. BUT SATELLITE IMAGERY DOES SHOW
SOME CUMULUS DEVELOPING IN THE MOUNTAINS OF NORTHERN CALIFORNIA
(PARTICULARLY THE SIERRA, BUT ALSO ALONG THE NORTHERN COAST
RANGES). IT ISN'T OUT OF THE QUESTION ISOLATED SHOWERS POP UP IN
TRINITY COUNTY ABUTTING SOUTHERN SISKIYOU COUNTY THIS EVENING,
THEN MOVE OFF TO THE EAST ACROSS SE SISKIYOU INTO SOUTHERN MODOC
COUNTY OVERNIGHT. PROBABILITIES OF PRECIPITATION IN THESE AREAS
ARE IN THE 10-15% RANGE, SO NOT TOO LIKELY.
AS THE ENERGY TO THE NORTH CONTINUES TO DIG SOUTHWARD AND
MOISTURE INCREASES FROM THE SOUTH, SHOWERS BECOME MORE LIKELY
(50-70% CHANCE) AND EXPAND ACROSS NORCAL (AGAIN MAINLY FROM
EASTERN SISKIYOU COUNTY ACROSS MODOC) SATURDAY AFTERNOON/EVENING.
THESE MAY EXTEND INTO PORTIONS OF SOUTH-CENTRAL OREGON, INCLUDING
NEAR LAKEVIEW, BUT PROBABLY REMAIN SOUTH AND EAST OF KLAMATH
FALLS. HI-RES GUIDANCE INDICATES THE BEST INSTABILITY (~150-250
J/KG MUCAPE) DEVELOPING NEAR MT SHASTA AND EXTENDING OFF TO THE
ENE TO AROUND ALTURAS. THESE AREAS STAND A SLIGHT CHANCE (15-25%)
OF THUNDERSTORMS. QPF WITH THESE SHOWERS/STORMS LOOKS TO BE
MOSTLY CONFINED TO AREAS SOUTH AND DUE EAST OF MT. SHASTA, WHERE
THE PROBABILITY OF >0.25" AMOUNTS IS AROUND 40-60%. WEST OF THE
CASCADES, MOISTURE IS STILL LIMITED, SO SATURDAY SHOULD BE DRY
THERE. COMPARED TO THE LAST COUPLE OF DAYS, TEMPERATURES THIS
WEEKEND SHOULD BE A BIT COOLER, BUT STILL SEASONABLE (HIGHS
65-70F FOR MEDFORD). SNOW LEVELS MOSTLY >6000 FEET SATURDAY DROP
TO 4000-5000 FEET BY SUNDAY MORNING, BUT ACCUMULATING SNOW WILL BE
MINIMAL AND CONFINED TO THE HIGHER TERRAIN. STILL EXPECT SOME
SHOWERS OUT THERE SUNDAY AFTERNOON/EVENING AND AGAIN MONDAY
AFTERNOON/EVENING, BUT THESE WILL BE FOCUSED IN THE HIGHER TERRAIN
(AND AGAIN, MOSTLY FROM THE CASCADES EASTWARD). WE CAN'T
COMPLETELY RULE OUT A SHOWER HERE OR THERE OVER THE WEST SIDE, BUT
THESE SHOULDN'T CAUSE ANY SIGNIFICANT DISRUPTIONS TO LATE
WEEKEND/EARLY NEXT WEEK PLANS.
THE TROUGH AXIS SHIFTS EASTWARD MONDAY NIGHT, WITH SHOWER CHANCES
DIMINISHING AREA WIDE ON TUESDAY. WITH UPPER RIDGING MOVE IN WED,
THIS SHOULD SET UP A WARMING TREND MID-LATE NEXT WEEK. -SPILDE
MARINE...UPDATED 1200 PM PDT FRIDAY, APRIL 24, 2026...HIGH PRESSURE
OFFSHORE AND A LOW PRESSURE TROUGH ALONG THE COAST WILL MAINTAIN
NORTHERLY WINDS INTO SATURDAY. WINDS WILL PEAK DURING THE
AFTERNOON/EVENINGS RESULTING IN PERIODS OF ADVISORY LEVEL WINDS AND
STEEP SEAS THAT WILL COMBINE WITH A LOW BACKGROUND NORTHWEST SWELL.
STEEP SEAS WILL PERSIST FOR ALL AREAS THROUGH TONIGHT, GRADUALLY
RETREATING WEST AND SOUTH EARLY SATURDAY, BECOMING FOCUSED SOUTH OF
CAPE BLANCO SATURDAY AFTERNOON INTO EARLY SUNDAY MORNING. THE
PATTERN WEAKENS SOME SUNDAY INTO MONDAY, RESULTING IN LESS STEEP
SEAS AND IMPROVED CONDITIONS FOR EARLY NEXT WEEK. STEEP SEAS COULD
RETURN AROUND MID-WEEK WHEN THERE COULD BE AN UPTICK IN NORTHERLY
WINDS AND AN INCREASING NORTHWEST SWELL MOVES INTO THE WATERS.
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 5 AM PDT SATURDAY
FOR PZZ350.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT SUNDAY FOR PZZ356-376.
SMALL CRAFT ADVISORY UNTIL 11 AM PDT SATURDAY FOR PZZ370.
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