317
FXUS66 KMFR 022118
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
218 PM PDT SAT MAY 2 2026
DISCUSSION
A DEVELOPING CUTOFF LOW REMAINS THE GUIDING INFLUENCE
FOR WEATHER ACROSS NORTHERN CALIFORNIA AND SOUTHERN OREGON THIS
WEEKEND. FOR TODAY, SOUTHERLY FLOW ALOFT AND UNSTABLE ATMOSPHERIC
CONDITIONS WILL KEEP THUNDERSTORM CHANCES IN THE FORECAST FOR TODAY.
AS OF THIS DISCUSSION, A PAIR OF THUNDERSTORMS HAVE ALREADY
DEVELOPED OVER NORTHERN LAKE COUNTY. MODEL GUIDANCE SHOWS THE
HIGHEST CAPE VALUES (900-1200 J/KG) OVER JOSEPHINE COUNTY AND ALONG
THE CASCADES, AS WELL AS SOME 400-600 J/KG VALUES OVER MODOC AND
EASTERN SISKIYOU COUNTIES. SPC CAMS ARE FOCUSING EXPECTATIONS ON
THESE AREAS, WITH CHANCES OF ISOLATED TO SCATTERED DEVELOPMENT
ACROSS LAKE AND KLAMATH COUNTIES AS WELL. ANY THUNDERSTORMS THAT
DEVELOP ARE LIKELY TO BE PULSE/CELLULAR, AND SEVERE THUNDERSTORMS
ARE NOT EXPECTED. ACTIVITY DECREASES QUICKLY INTO TONIGHT.
THE CUTOFF LOW WILL MOVE EASTWARDS OVER CALIFORNIA THROUGH SUNDAY
AND MONDAY. THIS WILL BRING MORE RAIN SHOWERS AS WELL AS EMBEDDED
THUNDERSTORMS. WITH THE TRACK OF THE CUTOFF REMAINING FARTHER SOUTH,
SISKIYOU AND MODOC COUNTIES WILL SEE CHANCES FOR RAINFALL (50-70%)
AND THUNDERSTORMS (20-30%) ON BOTH SUNDAY AND MONDAY. LOOKING INTO
OREGON, CHANCES FOR RAINFALL (40-60%) AND THUNDERSTORMS (20-25%) ON
SUNDAY AFTERNOON AND EVENING WILL BE FOCUSED WEST OF THE CASCADES,
ALTHOUGH SOME EAST SIDE AREAS MAY SEE LIGHT RAINFALL. ON MONDAY,
ACTIVITY LOOKS TO BE MOSTLY LIMITED TO SOUTHERN LAKE AND KLAMATH
COUNTIES WITH STRAY ACTIVITY FARTHER NORTH. THESE CHANCES CAN
FLUCTUATE DEPENDING ON THE ACTUAL PATH OF THE LOW, AS CUTOFFS CAN BE
FINICKY WITH HOW THEY TRAVEL.
A FEW SHOWERS MAY LINGER INTO TUESDAY MORNING IN EASTERN MODOC AND
SOUTHEASTERN LAKE COUNTIES AS THE CUTOFF'S INFLUENCE DWINDLES. AN
UPPER RIDGE SETTLES IN PLACE, SETTING UP A WARM AND DRY PERIOD FOR
THE WEEK AHEAD. INLAND VALLEYS AND BASINS ON EITHER SIDE OF THE
CASCADES ARE FORECAST TO BE IN THE HIGH 70S TO MID 80S ON WEDNESDAY
AND THURSDAY WHILE THE OREGON COAST STAYS IN THE MID 60S. A FRONT
PASSING TO THE NORTH COULD FLATTEN THE RIDGE AND BRING SLIGHT RELIEF
ON FRIDAY AND POSSIBLY INTO THE WEEKEND. -TAD
AVIATION...02/18Z TAFS
ASIDE FROM MVFR/IFR CEILINGS ALONG THE
COAST AND IN THE UMPQUA BASIN THIS MORNING, VFR CONDITIONS PREVAIL
ACROSS THE REGION AND WILL DO SO THROUGH THE TAF PERIOD. A FEW
ISOLATED SHOWERS ARE ONGOING TODAY, THEN SHOWER/THUNDERSTORM
COVERAGE WILL INCREASE LATER THIS AFTERNOON AS THE ATMOSPHERE
DESTABILIZES AGAIN. THE HIGHEST CHANCES (50-70%) FOR LIGHTNING ARE
FOCUSED ALONG THE CASCADES NORTH OF CRATER LAKE, ACROSS THE
MODOC/WARNERS EAST OF THE CASCADES AND IN THE KALMIOPSIS REGION.
CHANCES ARE FAIRLY LOW FOR THUNDERSTORMS AT THE TAF LOCATIONS, BUT
THERE IS ABOUT A 10-20% CHANCE OF A THUNDERSTORM IMPACTING MEDFORD
AND/OR KLAMATH FALLS THIS AFTERNOON. EXPECT GUSTY AND ERRATIC
OUTFLOWS IN THE VICINITY OF THUNDERSTORMS TODAY. ADDITIONALLY, GUSTY
SOUTH TO SOUTH TO SOUTHEAST WINDS ARE EXPECTED THIS
AFTERNOON/EVENING.
A WIND REVERSAL IS EXPECTED ALONG THE COAST TONIGHT INTO TOMORROW
MORNING, WITH LOW CEILINGS AND/OR FOG SPREADING NORTH ALONG THE
COASTLINE AND INTO THE COASTAL VALLEYS, INCLUDING AT NORTH BEND,
THROUGH THE LATTER HALF OF THE TAF PERIOD.
MARINE...UPDATED 730 AM PDT SATURDAY, MAY 2, 2026.
A THERMAL
TROUGH PATTERN WILL BRING GUSTY NORTH WINDS WITH STEEP TO VERY STEEP
AND HAZARDOUS SEAS THROUGH THIS EVENING. THE STRONGEST WINDS AND
VERY STEEP SEAS ARE EXPECTED SOUTH OF GOLD BEACH TODAY, WITH STEEP
SEAS ELSEWHERE. CONDITIONS IMPROVE SOME THIS AFTERNOON AS WINDS
BEGIN TO WEAKEN, WITH ONLY STEEP SEAS EXPECTED FOR ALL AREAS FROM
COOS BAY SOUTHWARD. WINDS DIMINISH MORESO LATE TONIGHT WHILE A
LONGER PERIOD NORTHWEST SWELL BUILDS, THEN BECOMES DOMINANT LATER
SUNDAY INTO MONDAY ALONG WITH A FRESH NORTH SWELL. RELATIVELY QUIET
CONDITIONS ARE EXPECTED FOR MUCH OF NEXT WEEK.
BEACH HAZARDS...UPDATED 1100 AM PDT SATURDAY MAY 2, 2026
A SHORT
PERIOD NORTHWEST SWELL AND A BUILDING LONG PERIOD NORTHWEST SWELL
MAY COMBINE THEIR ENERGY TO PRODUCE UNPREDICTABLE WAVES WASHING UP
ON AREA BEACHES THIS WEEKEND. THE RISK WILL BE HIGHEST AROUND
SUNRISE ON SUNDAY MORNING.
SNEAKER WAVES CAN RUN UP SIGNIFICANTLY FARTHER ON BEACHES THAN
NORMAL, INCLUDING OVER ROCKS AND JETTIES. THESE WAVES CAN SUDDENLY
KNOCK PEOPLE OFF OF THEIR FEET AND SWEEP THEM INTO THE OCEAN. THE
WAVES CAN ALSO MOVE LOGS OR OTHER OBJECTS WHICH COULD CRUSH OR TRAP
ANYONE CAUGHT UNDERNEATH. NEVER TURN AWAY FROM THE OCEAN!
MFR WATCHES/WARNINGS/ADVISORIES
OR...BEACH HAZARDS STATEMENT FROM 11 PM PDT THIS EVENING THROUGH
SUNDAY MORNING FOR ORZ021-022.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 5 AM PDT SUNDAY
FOR PZZ350-356-370-376.
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