488
FXUS66 KMFR 021159
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
459 AM PDT SAT MAY 2 2026
UPDATED AVIATION DISCUSSION
AVIATION...02/12Z TAFS
ASIDE FROM MVFR/IFR CEILINGS ALONG THE
COAST AND IN THE UMPQUA BASIN, VFR CONDITIONS PREVAIL ACROSS THE
REGION AND WILL DO SO THROUGH THE TAF PERIOD. ISOLATED SHOWERS WITH
SOME OCCASIONAL LIGHTNING CONTINUE WEST OF THE I-5 CORRIDOR NORTH
OF GRANTS PASS. EXPECT SHOWER/THUNDERSTORM COVERAGE TO 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.
PREV DISCUSSION
/ISSUED 256 AM PDT SAT MAY 2 2026/
DISCUSSION...UPPER LEVEL LOW PRESSURE LINGERS OFFSHORE THIS
MORNING, MAINTAINING SOUTHERLY FLOW AND BRINGING A BLANKET OF MID
TO HIGH LEVEL CLOUDS TO THE REGION. MEANWHILE, MARINE STRATUS HAS
RETURNED TO THE MARINE WATERS, COASTAL LOCATIONS AND HAS PUSHED
INLAND INTO THE UMPQUA BASIN AND PORTIONS OF THE ILLINOIS VALLEY.
SHOWER AND THUNDERSTORM ACTIVITY FROM YESTERDAY HAS MOSTLY COME TO
AN END, THOUGH THERE ARE SOME RADAR RETURNS INDICATING SHOWERS IN
PORTIONS OF DOUGLAS/COOS COUNTIES WEST OF THE I-5 CORRIDOR,
MOVING NORTHWARD. SATELLITE DERIVED LIGHTNING DATA INDICATES SOME
IN CLOUD LIGHTNING ACTIVITY WITH THESE SHOWERS, BUT GROUND SYSTEMS
HAVE ONLY RECORDED ONE CLOUD TO GROUND STRIKE SO FAR. MODELS
MAINTAIN THIS CORRIDOR OF ELEVATED INSTABILITY PERSISTING INTO THE
EARLY MORNING HOURS, WITH SOME INCREASED SHOWER ACTIVITY AROUND
SUNRISE.
LOW PRESSURE OFFSHORE WILL START TO CUT OFF TODAY AND GRADUALLY
DRIFT SOUTHWESTWARD INTO SUNDAY. MEANWHILE, HIGH PRESSURE TO THE
WEST OF THAT LOW, AMPLIFIES, THEN ALSO CLOSES OFF TO THE NORTH OF
THE LOW PRESSURE FOR A BRIEF TIME SUNDAY. LOW PRESSURE TO THE SOUTH
GRADUALLY MOVES INLAND INTO CENTRAL CALIFORNIA ON MONDAY, THEN
EASTWARD INTO THE DESERT SOUTHWEST BY TUESDAY. AS THIS LOW PRESSURE
CUTS OFF TODAY AND DRIFTS SOUTHWESTWARD, SOUTHERLY FLOW WILL
CONTINUE TO BRING MOIST, UNSTABLE AIR TO THE REGION, MAINTAINING
DAILY SHOWER/THUNDERSTORM CHANCES DURING THE AFTERNOON AND EVENINGS
TODAY THROUGH MONDAY.
FRIDAY AFTERNOON'S (YESTERDAY) ACTIVITY WAS FAIRLY MINIMAL WITH TWO
MAIN CELLS PRODUCING THE BULK OF THE ~70 CLOUD TO GROUND STRIKES
YESTERDAY...ONE THAT MOVED THROUGH WESTERN JACKSON COUNTY AND THE
OTHER NORTH OF CHEMULT IN NORTHERN KLAMATH COUNTY. WE EXPECT MORE
ACTIVITY TODAY WITH MORE INSTABILITY (-3 TO -5 LI, 1000-1500 J/KG
CAPE) IN THE REGION COMPARED TO YESTERDAY. THE HIGHEST CHANCES FOR
LIGHTING (50-70%) ARE FOCUSED ACROSS PORTIONS OF MODOC/EASTERN
SISKIYOU COUNTIES, ALONG THE CASCADES FROM CRATER LAKE NORTHWARD AND
OVER WESTERN JOSEPHINE/EASTERN DOUGLAS IN THE KALMIOPSIS REGION. WE
DON'T EXPECT ANY SEVERE WEATHER TODAY, BUT THERE COULD BE A FEW
STRONGER CELLS AT TIMES. THE MAIN THREATS WILL BE GUSTY OUTFLOW
WINDS, LIGHTNING, AND BRIEF DOWNPOURS DIRECTLY UNDER STORM CORES.
STORMS TODAY WILL GENERALLY MOVE FROM SOUTH TO NORTH, BECOMING MORE
SOUTHEAST TO NORTHWEST THIS EVENING AS THE LOW CONTINUES MOVING
SOUTHWESTWARD. SHOWER/THUNDERSTORM ACTIVITY DIMINISHES AFTER SUNSET
WITH THE LOSS OF DAYTIME HEATING.
SUNDAY INTO MONDAY, THE LOW IS FORECAST TO ELONGATE AND SHIFT
EASTWARD -- MOVING ONSHORE INTO CALIFORNIA JUST SOUTH OF SF BAY
DURING THIS TIME. THE FOCUS FOR SHOWERS AND STORMS WILL BE DIRECTED
INTO NORCAL, BUT ALSO STILL INTO PORTIONS OF SOUTHERN OREGON. WE'LL
PROBABLY START OFF SUNNY SUNDAY AND IT WILL REMAIN QUITE WARM/EVEN
HUMID. THERE SHOULD BE ENOUGH MOISTURE, INSTABILITY AND FORCING FOR
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS DURING THE
AFTERNOON/EVENING. HIGHEST POPS AND THUNDER CHANCES WILL BE ACROSS
NORCAL AND UP THE CASCADES WITH LOWER CHANCES IN NW SECTIONS
(NORTHWEST OF ROSEBURG). STORM MOTION ON SUNDAY IS EXPECTED TO START
OUT FROM THE SOUTHEAST, BACKING TO EASTERLY AS THE PATTERN EVOLVES.
BY MONDAY, WE'LL BE DECIDEDLY ON THE NORTHERN PERIPHERY OF THE LOW
WITH UPPER RIDGING TO THE NORTH AND MID-LEVEL FLOW AROUND THE LOW
FROM THE ENE. MOST AREAS WILL BE AT LEAST SLIGHTLY COOLER, BUT
ESPECIALLY NORCAL WHERE CLOUDS/SHOWERS WILL BE MOST PERSISTENT.
THERE'S STILL A CHANCE OF THUNDERSTORMS, BUT THE BEST CHANCES SHIFT
TO EAST OF THE CASCADES. RAIN AMOUNTS WITH THIS ENTIRE SYSTEM WILL
LIKELY VARY QUITE A BIT DUE TO THE SHOWERY NATURE OF THE
PRECIPITATION (AND ALSO THE POTENTIAL FOR THUNDERSTORMS). SOME
PLACES COULD END UP WITH NOTHING AT ALL, WHILE THOSE THAT GET UNDER
MORE PERSISTENT SHOWERS COULD HAVE 0.25-0.50 OF AN INCH (MOST LIKELY
IN SISKIYOU COUNTY OF NORCAL) WITH UP TO AN INCH IN AREAS THAT
MANAGE TO GET BENEATH A THUNDERSTORM CORE FOR A WHILE.
TUESDAY INTO WEDNESDAY, THE UPPER RIDGE TO THE NORTH WILL WIN OUT AS
THE CLOSED LOW SETTLES INTO THE GREAT BASIN AND DESERT SOUTHWEST.
THIS WILL KEEP SHOWER/THUNDER CHANCES MOSTLY TO OUR SOUTH AND EAST,
AND BRING ANOTHER PERIOD OF ABOVE NORMAL TEMPERATURES. AFTERNOON
HIGHS WILL PEAK ABOUT 10 TO 15 DEGREES ABOVE NORMAL (MID 80S
WEST/UPPER 70S-LOW 80S EAST), FEELING MORE LIKE LATE JUNE THAN EARLY
MAY. SUBTLE COOLING IS POSSIBLE FRIDAY WITH LONG RANGE GUIDANCE
HINTING AT THE POTENTIAL FOR A WEAK TROUGH TO ARRIVE LATE NEXT WEEK.
THE VAST MAJORITY OF ENSEMBLE GUIDANCE MAINTAINS DRY CONDITIONS WITH
THIS TROUGH.
MARINE...UPDATED 130 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 115 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 THIS EVENING THROUGH SUNDAY MORNING
FOR ORZ021-022.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS
EVENING FOR PZZ350-356-370-376.
HAZARDOUS SEAS WARNING UNTIL 11 AM PDT THIS MORNING FOR PZZ376.
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