661
FXUS66 KMFR 261137
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
437 AM PDT TUE MAY 26 2026
DISCUSSION
UPDATED AVIATION DISCUSSION FOR 12Z TAFS.
AVIATION...26/12Z TAFS
MVFR AND AREAS OF IFR (SOUTH COAST) WILL
CONTINUE AT THE COAST WITH RAIN SHOWERS THROUGH THIS MORNING.
INLAND, EXPECT RAIN SHOWERS, MOUNTAIN OBSCURATIONS, AND LOWER
CEILINGS WITH AREAS OF MVFR, MAINLY FROM THE CASCADES WEST, BUT ALSO
LOCALLY EAST OF THE CASCADES. CONDITIONS GRADUALLY IMPROVE TO
VFR LATE THIS MORNING AND AFTERNOON, THOUGH HIGHER MOUNTAINS
PROBABLY REMAIN AT LEAST PARTIALLY OBSCURED. THERE IS A SLIGHT
CHANCE OF THUNDERSTORMS THIS AFTERNOON/EARLY EVENING, BUT
ESPECIALLY IN NORCAL. AREAS OF MVFR MAY REDEVELOP (20-30% CHANCE)
LATE TUESDAY EVENING/NIGHT ALONG THE COAST AND INTO THE UMPQUA
VALLEY. -SPILDE
PREV DISCUSSION
/ISSUED 248 AM PDT TUE MAY 26 2026/
KEY MESSAGES...
* MUCH COOLER AREA WIDE TODAY COMPARED TO YESTERDAY WITH INLAND
AREAS ABOUT 10-20F BELOW NORMAL. BREEZY EAST SIDE, BUT NOT AS
WINDY AS YESTERDAY.
* SHOWERS AND THUNDERSTORMS CONTINUE THROUGH THE REST OF THE WEEK
WITH A PEAK IN COVERAGE WED/THU. SOME STORMS COULD BE STRONG
(SEVERE?), EACH OF THOSE AFTERNOONS. HIGH TEMPERATURES RANGE
FROM NEAR NORMAL TO ABOUT 10F BELOW NORMAL.
* ANOTHER TROUGH SWINGS THROUGH SATURDAY WITH ISOLATED
SHOWER/T-STORM ACTIVITY, MAINLY NORCAL AND FAR EAST SIDE.
* DRIER AND WARMER CONDITIONS ARE LIKELY TO FOLLOW SUNDAY INTO
NEXT WEEK.
DISCUSSION...A COLD FRONT AND WELL-MIXED LOWER ATMOSPHERE
BROUGHT QUITE THE WIND STORM TO PORTIONS OF THE ROGUE VALLEY
YESTERDAY AFTERNOON. IT WAS ONE OF THE WINDIEST DAYS THAT I CAN
REMEMBER WITH WINDS FROM A WNW DIRECTION. MOST OF OUR STRONGEST
WIND STORMS ARE FROM OFFSHORE LOWS THAT BRING SE WINDS. THE
AIRPORT HERE IN MEDFORD MEASURED A PEAK WIND GUST OF 60 MPH AND
THERE WERE QUITE A FEW POWER OUTAGES REPORTED ALONG WITH BRANCHES
AND TREE LIMBS DOWN. WHILE IT WAS WINDY IN MOST AREAS YESTERDAY,
THE STRONGEST WINDS WERE FAIRLY LOCALIZED TO HERE (PEAK GUSTS OVER
THE EAST SIDE AND IN NORCAL WERE MOSTLY IN THE 35-55 MPH RANGE).
THE REMAINS OF THE FRONT ARE PUSHING WELL TO THE EAST OF THE
CASCADES EARLY THIS MORNING. MEANWHILE, A DEEP CLOSED, UPPER LOW
WILL BREAK AWAY FROM THE MAIN BRANCH OF THE JET STREAM AND DRIFT
SOUTHWARD OVER THE AREA TODAY. IT WILL SETTLE INTO THE GREAT
BASIN AROUND LAKE TAHOE TONIGHT, THEN WILL SIT AND SPIN THERE FOR
A COUPLE OF DAYS (WED/THU). THIS WILL BRING COOLER, UNSETTLED
WEATHER TO MUCH OF SW OREGON AND NORCAL DURING THE NEXT FEW DAYS
WITH SCATTERED/NUMEROUS SHOWERS AND ALSO ISOLATED/SCATTERED
THUNDERSTORMS. WHILE THE FORECAST SOUNDS WET (AND SOME PLACES WILL
BE - ESPECIALLY FROM THE CASCADES EASTWARD), THERE SHOULD BE
PLENTY OF LONGER, DRIER BREAKS DUE TO THE SHOWERY NATURE OF
PRECIPITATION.
RADAR IMAGERY THIS MORNING IS SHOWING A FAIRLY PERSISTENT AREA OF
RAIN FROM WESTERN MODOC UP INTO LAKE COUNTY WITH PRECIPITATION
MORE SHOWERY FROM THE CASCADES WESTWARD. WETTING RAIN DID FALL AT
THE COAST AND OVER TO THE CASCADES YESTERDAY AS WELL AS PARTS OF
THE EAST SIDE (TO THE NORTH AND EAST OF KLAMATH FALLS). BUT, MANY
VALLEY LOCATIONS DID INDEED GET SKIPPED OVER SO FAR WITH ONLY
TRACE AMOUNTS MEASURED AT MEDFORD AND ROSEBURG AND NO RAIN
MEASURED AT KLAMATH FALLS. EVEN SO, FIRE WEATHER RISK IS MUCH
LOWER TODAY DUE TO HIGHER HUMIDITY AND LIGHTER WINDS. TODAY WILL
BE THE COOLEST DAY SINCE THE CORE OF THE CLOSED LOW WILL BE MOVING
OVERHEAD (H5 TEMPS OF APPROX -25C). THIS WILL BRING HIGH
TEMPERATURES GENERALLY 10-20F BELOW NORMAL FOR AREAS INLAND FROM
THE COAST (50-55F EAST SIDE AND 55-65F WEST OF THE CASCADES).
INSTABILITY IS GREATEST OVER NORCAL, BUT THERE COULD BE A RUMBLE
OR TWO OF THUNDER JUST ABOUT ANYWHERE SHOWERS POP UP THIS
AFTERNOON/EVENING.
MULTIPLE SHORT WAVE DISTURBANCES WILL ROTATE AROUND THE CLOSED
LOW TONIGHT THROUGH THURSDAY AND THIS WILL KEEP THINGS ACTIVE OVER
THE AREA WITH COVERAGE OF SHOWERS/THUNDERSTORMS GREATEST FROM THE
CASCADES SOUTH AND EAST. EVEN SO, MID-LEVEL FLOW SURROUNDING THE
LOW IS FAIRLY STRONG AND WILL CARRY CONVECTION OFF TO THE WEST,
WHICH COULD TRAVERSE THE CASCADES AND MOVE OVER PORTIONS OF THE
WEST SIDE AT TIMES. MODELS ARE SHOWING AN AREA OF SHOWERS ROTATING
THROUGH FROM ENE TO WSW TONIGHT, EVENTUALLY FALLING APART OR
DISSIPATING WEDNESDAY MORNING.
THINGS DESTABILIZE AGAIN WEDNESDAY AFTERNOON, AS ANOTHER SHORT
WAVE ARRIVES FROM NORTHERN NEVADA. MODEL LIGHTNING PROBABILITIES
INCREASE WED AFTERNOON, ESPECIALLY OVER THE EAST SIDE WITH SHEAR
(40-50KT) AND CAPE VALUES BECOMING ROBUST (>500 J/KG). SOME OF THE
HI-RES GUIDANCE (PARTICULARLY HRRR) SHOW CELLS ORGANIZING INTO A
LINE OF STORMS AS IT MOVES WESTWARD OVER THE AREA. IT'S DIFFICULT
TO ASSESS EXACTLY WHERE AND IF THIS WILL OCCUR, BUT COULD RESULT
IN SOME STRONG TO POSSIBLY SEVERE STORMS WITH GUSTY OUTFLOW WINDS
AND HAIL. WE'LL CONTINUE TO MONITOR THIS POTENTIAL. AS IT MOVES
OVER THE WEST SIDE, IT SHOULD RUN INTO MORE STABLE AIR, SO THUNDER
PROBABILITY DECREASES FARTHER WEST. THURSDAY APPEARS TO BE THE
MOST ROBUST DAY IN TERMS OF CAPE, SO WE'LL PROBABLY HAVE ANOTHER
FAIRLY ACTIVE AFTERNOON/EVENING.
EVENTUALLY, ENOUGH ENERGY WILL MOVE ACROSS THE NORTH PACIFIC TO
CAUSE THE LOW TO EJECT TO THE ENE INTO UTAH/IDAHO/WESTERN WYOMING
LATE THIS WEEK INTO THIS WEEKEND (FRI/SAT) WITH ANOTHER WEAKER
UPPER TROUGH MOVING THROUGH THE PACNW SATURDAY INTO SUNDAY. DRIER
AND MUCH WARMER CONDITIONS SHOULD DEVELOP BY EARLY NEXT WEEK.
-SPILDE
MARINE...UPDATED 230 AM PDT TUESDAY, MAY 26, 2026...STEEP TO
LOCALLY VERY STEEP (OUTER WATERS BEYOND 40NM FROM SHORE) NORTHWEST
SWELL-DOMINATED SEAS WILL CONTINUE TO BUILD INTO THE WATERS TODAY,
PEAKING AT 13 TO 18 FT AT 14 SECONDS. WHILE SEAS WILL GRADUALLY
SUBSIDE TONIGHT INTO WEDNESDAY MORNING, THEY ARE EXPECTED TO REMAIN
STEEP AND HAZARDOUS.
AFTER BRIEF, SLIGHT IMPROVEMENT, HIGH PRESSURE OFFSHORE AND
LINGERING LOW PRESSURE INLAND WILL AGAIN BRING INCREASING NORTH
WINDS ON WEDNESDAY AFTERNOON WITH THE STRONGEST WINDS LIKELY TO
OCCUR SOUTH OF GOLD BEACH. THE GUSTY NORTH WINDS AND A LONG PERIOD
WEST-NORTHWEST SWELL WILL CONTINUE STEEP SEAS WEDNESDAY NIGHT, AND
POSSIBLY DURING THURSDAY AND THURSDAY NIGHT ALSO. CONDITIONS MAY
BRIEFLY IMPROVE ON FRIDAY. -SPILDE
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 5 AM PDT THURSDAY
FOR PZZ356-370-376.
SMALL CRAFT ADVISORY UNTIL 8 AM PDT WEDNESDAY FOR PZZ350.
HAZARDOUS SEAS WARNING UNTIL 5 PM PDT THIS AFTERNOON FOR PZZ370-
376.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page