933
FXUS66 KMFR 091218
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
418 AM PST SUN NOV 9 2025
DISCUSSION
WITH STABLE ATMOSPHERIC CONDITIONS CONTINUING THIS
MORNING AND LINGERING SURFACE MOISTURE, FOG HAS DEVELOPED IN
SEVERAL AREA VALLEYS AND BASINS. THIS INCLUDES THE UMPQUA VALLEY,
THE ILLINOIS VALLEY, PARTS OF THE ROGUE VALLEY, AND AROUND THE
KLAMATH FALLS AIRPORT. FOG MAY CONTINUE TO DEVELOP THROUGH
SUNRISE AND SHOULD CLEAR OUT BEFORE THE AFTERNOON.
WITH HIGH PRESSURE INCREASING TODAY, WARMER TEMPERATURES ARE
EXPECTED ACROSS THE AREA. MOST LOWER ELEVATION AREAS HAVE FORECAST
DAYTIME HIGHS IN THE MID 60S TO LOW 70S. NORTHERN LAKE AND
KLAMATH COUNTIES MAY STAY SLIGHTLY COOLER, WITH TEMPERATURES IN
THE LOW TO MID 60S.
ON MONDAY, DETERMINISTIC IMAGERY SHOWS A FRONT MEETING THE RIDGE
THEN PASSING OVER. WHILE THIS FRONT WILL WEAKEN WITH THAT MEETING
AND NOT DIRECTLY IMPACT THE AREA, ITS PASSAGE WILL FLATTEN THE
RIDGE AND BRING A MORE ZONAL FLOW PATTERN TO START THE WEEK. THIS
WILL HELP TO DECREASE DAYTIME HIGHS, BUT OVERALL TEMPERATURES LOOK
TO REMAIN JUST ABOVE SEASONAL NORMS. OVERALL, MILD WEATHER WILL
CONTINUE THROUGH THE MIDDLE OF THE WEEK.
AN ACTIVE PATTERN LOOKS TO DEVELOP LATE WEDNESDAY INTO EARLY
THURSDAY AND COULD CONTINUE THROUGH THE END OF THE WEEK. THE
GENERAL EXPECTATION IS A DEEP UPPER TROUGH APPROACHES THE PACIFIC
COAST. FOR THIS AREA, SOUTHERLY FLOW COULD BRING SUBSTANTIAL
RAINFALL TO CURRY COUNTY, WESTERN SISKIYOU COUNTY, AND THE MOUNT
SHASTA REGION THROUGH THURSDAY AFTERNOON. GUSTY SOUTHERLY WINDS
MAY FUNNEL INTO THE SHASTA VALLEY AND DEVELOP OVER EAST SIDE
TERRAIN. INITIAL SNOW LEVELS OF 7000-8000 FEET WOULD LIMIT
SNOWFALL DURING THE HEAVIEST PRECIPITATION. AS THE TROUGH MOVES
INLAND ON FRIDAY, COOLER AIR COULD LOWER SNOW LEVELS TO 4000-5000
FEET BUT LOWER PRECIPITATION AMOUNTS WOULD NOT PRESENT WINTER
HAZARDS.
THERE IS SOME VARIATION IN MODEL OUTCOMES THAT ARE PREVENTING
HIGHER CONFIDENCE IN SOME OF THE DETAILS WITH THIS TROUGH. ECMWF
SHOWS A CUTOFF LOW DEVELOPING IN THE TROUGH, WHICH COULD BRING A
TIGHTER PRESSURE GRADIENT ALONG THE TROUGH'S LEADING EDGE, LEADING
TO STRONGER WINDS. GFS IMAGERY DOESN'T INCLUDE A CUTOFF LOW, BUT
DOES HAVE AN OVERALL WETTER PATTERN INTO NEXT WEEKEND. SO WHILE
FUTURE MODEL RUNS WILL HELP TO RESOLVE THESE DIFFERENCES, THERE'S
GOOD AGREEMENT FOR SOME AMOUNT OF ACTIVITY TO CONTINUE THROUGH
NEXT WEEKEND AND INTO THE START OF THE FOLLOWING WEEK. -TAD
AVIATION...09/12Z TAFS
FOG HAS DEVELOPED IN THE UMPQUA,
ILLINOIS, AND PARTS OF THE ROGUE VALLEY EARLY THIS MORNING.
OBSERVATIONS AT KLAMATH FALLS BRIEFLY INCLUDED LOWER VISIBILITIES,
BUT ARE CURRENTLY AT VFR LEVELS. FOG MAY CONTINUE TO DEVELOP UNTIL
SUNRISE AND LOOKS TO CLEAR OUT BEFORE THIS AFTERNOON. ONCE THE FOG
CLEARS, VFR LEVELS ARE EXPECTED ACROSS THE AREA INTO THIS EVENING.
ONSHORE FLOW MAY SUPPORT MARINE STRATUS ALONG THE OREGON COAST
TOWARDS THE END OF THE TAF PERIOD, WHILE GUIDANCE SUGGESTS FOG
RETURNING TO THE UMPQUA VALLEY AT A SIMILAR TIME. OTHER AREAS MAY
SEE DECREASED FLIGHT LEVELS BEYOND THIS TAF PERIOD. -TAD
MARINE...UPDATED 200 PM PDT SATURDAY, NOVEMBER 8, 2025
SOUTH
WINDS AND SWELL DOMINATED SEAS WILL REMAIN BELOW ADVISORY CRITERIA
THROUGH THE REST OF THE WEEKEND INTO MONDAY. WINDS TURN NORTHERLY ON
MONDAY, AND COULD APPROACH ADVISORY STRENGTH SOUTH OF CAPE BLANCO
LATE MONDAY INTO TUESDAY, RESULTING IN BORDERLINE CONDITIONS
HAZARDOUS TO SMALL CRAFT. MORE IMPACTFUL WINDS, SEAS AND WEATHER ARE
EXPECTED TO RETURN WEDNESDAY, WITH GUSTY WINDS AND HIGH TO VERY HIGH
AND STEEP SEAS POSSIBLE THROUGH FRIDAY. /BR-Y
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
TAD
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