826
FXUS66 KMFR 101036
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
336 AM PDT FRI OCT 10 2025
DISCUSSION
SATELLITE IMAGE SHOWS A RATHER STRONG,CLOSED UPPER LOW
CENTERED NEAR 43N/130W. AHEAD OF THE LOW LIGHTENING HAS BEEN
OBSERVED OVER THE MARINE WATERS AS SHORTWAVES ROUND THE BASE OF THE
UPPER LOW. THE SHORTWAVES HAVE PLENTY OF ENERGY WHICH WILL KEEP THE
THREAT OF ISOLATED THUNDERSTORMS GOING OVER THE MARINE WATERS AND
COAST THROUGH THE DAY. ADDITIONALLY, INSTABILITY WILL ALSO BE
SUFFICIENT ENOUGH TO SUPPORT ISOLATED THUNDERSTORMS ALONG THE
NORTHERN CASCADES THIS MORNING, THEN EXPANDING INTO PORTIONS OF
DOUGLAS COUNTY THIS AFTERNOON. MEANWHILE, 500MB TEMPERATURE BETWEEN
- 25 AND -27C WILL BE SUFFICIENT ENOUGH FOR ISOLATED THUNDERSTORMS
OVER THE MARINE WATERS.
AT THE SURFACE, A COLD FRONT WILL REACH THE COAST THIS MORNING
BRINGING A PERIOD OF MODERATE TO OCCASIONALLY HEAVY PRECIPITATION.
HEAVIEST ALONG THE COAST, COASTAL MOUNTAINS AND CASCADES. ONCE THE
FRONT MOVES INLAND, PRECIPITATION RATES IN THE ABOVE MENTIONED AREAS
WILL DECREASE, BUT WE'LL HAVE PLENTY OF POST FRONTAL SHOWERS BEHIND
THE FRONT. ADDITIONALLY, IT WILL BE WINDY IN THE USUALLY PRONE AREAS,
LIKE THE COAST, SHASTA VALLEY AND EAST OF THE CASCADES, ESPECIALLY
OVER THE SUMMER LAKE AREA. HOWEVER, WE DON'T EXPECT WINDS TO REACH
ADVISORY CRITERIA.
AS THE FRONT MOVES INLAND, A COLDER AIR MASS WILL MOVE OVERHEAD WITH
SNOW LEVELS LOWERING IN THE AFTERNOON. THEREFORE THE THE HIGHEST
PEAKS COULD SEE A CHANGEOVER FROM RAIN TO SNOW SHOWERS IN THE
AFTERNOON AND EVENING. HOWEVER, THE GROUND IS STILL RATHER WARM FROM
THE RECENT WARMTH, AND FOR THE MOST PART SNOW WILL MELT ON THE
GROUND. THE EXCEPTION WILL BE IN THE PRESENCE OF HEAVIER SHOWERS
WHERE THERE COULD BE A BRIEF PERIOD OF TIME WHERE SNOW COULD STICK
TO THE GROUND OVER THE HIGHEST PEAKS.
THE UPPER TROUGH WILL MOVE OVER THE AREA TONIGHT WITH SHOWERS LIKELY
TO PERSIST INTO THE OVERNIGHT HOURS. PRECIPITATION IS EXPECTED TO
BE LIGHT TO OCCASIONALLY MODERATE. SNOW LEVELS TONIGHT WILL CONTINUE
TO FALL TO AROUND 5800 FEET BY EARLY SATURDAY MORNING, BUT WITH
PRECIPITATION AMOUNTS EXPECTED TO BE LIGHT, THE AMOUNT OF SNOW
EXPECTED IN THE OVERNIGHT HOURS WILL BE LIMITED AND CONFINED TO THE
HIGHEST TERRAIN.
THE UPPER TROUGH AXIS WILL SHIFT SOUTHEAST OF THE AREA DURING THE
DAY SATURDAY. HOWEVER ADDITIONAL IMPULSES WILL RESULT IN SHOWERS,
ESPECIALLY ALONG AND WEST OF THE CASCADES. AS IS TYPICAL FOR THIS
TIME OF THE YEAR, SNOW LEVELS WILL RISE DURING THE DAY SATURDAY DUE
TO DIURNAL EFFECTS. THIS IN COMBINATION WITH A WARM GROUND SHOULD
LIMIT THE AMOUNT OF SNOW THAT ACCUMULATES ON THE GROUND. THE BEST
CHANCE FOR SNOW TO ACCUMULATE WILL BE IN HEAVIER SHOWERS. EVEN THEN
ANY ACCUMULATION WILL BE AROUND 6000 FEET AND HIGHER. GUSTY WINDS
ARE EXPECTED AGAIN SATURDAY AFTERNOON AND EVENING EAST OF THE
CASCADES, BUT REMAINING BELOW ADVISORY CRITERIA.
WE'LL HAVE A RELATIVE BREAK IN THE WEATHER SATURDAY NIGHT THROUGH
SUNDAY MORNING. A FEW SHOWERS WILL LONGER DURING THIS TIME MAINLY
ALONG THE COAST, COASTAL MOUNTAINS AND NORTH OF THE UMPQUA DIVIDE.
SNOW LEVELS WILL CONTINUE TO DROP SATURDAY NIGHT TO AROUND 5000
FEET, BUT AS MENTIONED PRECIPITATION IS EXPECTED TO BE MAINLY LIGHT,
THUS LIMITING SNOW ACCUMULATION.
ANOTHER UPPER LOW WILL DROP SOUTH TOWARDS OUR AREA SUNDAY AFTERNOON
AND WERE LIKELY TO SEE A NET INCREASE IN PRECIPITATION ALONG THE
NORTH COAST, NORTH OF THE UMPQUA DIVIDE AND NORTHERN CASCADES AS A
FRONT MOVES INTO THE AREA.
THE UPPER LOW WILL MOVE SOUTH INTO NORTHWEST OREGON SUNDAY NIGHT
INTO EARLY MONDAY MORNING WITH A NET INCREASE IN PRECIPITATION. SNOW
LEVELS SUNDAY NIGHT WILL LOWER TO AROUND 5000 FEET. THIS WOULD PUT
SNOW OVER OUR HIGHER MOUNTAIN PASSES, BUT AS THIS IS EXPECTED DURING
PERIODS OF MORE SHOWERY PRECIPITATION. AND THE GROUND REMAINS
SOMEWHAT WARM, ACCUMULATIONS OF ONLY A COUPLE OF INCHES IS FORECAST.
HIGHER ELEVATIONS, SUCH AS CRATER LAKE NATIONAL PARK RIM DRIVE OVER
7000 FEET, COULD SEE HEAVIER SNOW WITH UP TO 6 INCHES OF SNOW
POSSIBLE BY EARLY MONDAY MORNING. OTHERWISE, ONLY A TRACE TO AN INCH
OF SNOW IS EXPECTED FOR THE HIGHER TERRAIN OF THE EAST SIDE.
THE GENERAL CONSENSUS AMONG THE OPERATIONAL MODELS AND ENSEMBLES
SHOW THE UPPER LOW MOVING SOUTH OF THE AREA MONDAY AND REMAINING
SOUTH TUESDAY AND WEDNESDAY NEXT WEEK. THE POSITION OF THE UPPER LOW
IS ONE THAT WILL KEEP THE BEST CHANCE OF PRECIPITATION SOUTH OF THE
FORECAST AREA, THUS RESULTING IN MOST AREAS AND HOURS BECOMING DRY
TUESDAY AND WEDNESDAY. HOWEVER MOISTURE WRAPPING AROUND THE UPPER LOW
COULD BRING PRECIPITATION TO PORTIONS OF NORTHERN CAL DURING THIS
TIME. -PETRUCELLI
AVIATION...10/12Z TAFS
VFR CONDITIONS WILL BE THE PREDOMINATE
CONDITION TODAY AS THE ATMOSPHERE REMAINS UNSTABLE. THE EXCEPTION
WILL BE ALONG THE COAST, COASTAL MOUNTAINS, AND CASCADES WHERE
HEAVIER PRECIPITATION COULD RESULT IN MVFR CEILINGS.
ALONG THE COAST AND JUST OFFSHORE, THERE IS A CONCERN FOR ISOLATED
THUNDERSTORMS DURING THE DAY. ISOLATED STORMS COULD PUSH INLAND
LATER THIS MORNING AND AFTERNOON WITH THUNDERSTORMS IN THE VICINITY
OR MOVING INTO THE NORTH BEND AND ROSEBURG TERMINALS.
GUSTY WINDS ARE LIKELY EAST OF THE CASCADES MAINLY BETWEEN 18Z AND
3Z WITH GUSTS APPROACHING 30 KTS AT KLAMATH FALLS AIRPORT.
-PETRUCELLI
MARINE...UPDATED 200 AM PDT FRIDAY, OCTOBER 10, 2025
A STRONG
UPPER TROUGH WILL APPROACH THE AREA TODAY, WITH SHORTWAVES ROTATING
AROUND THE BASE OF THE UPPER LOW. SATELLITE IMAGE SHOWS ONE
SIGNIFICANT PIECE OF ENERGY MOVING INTO THE MARINE WATERS NOW WHICH
HAS RESULTED IN ISOLATED THUNDERSTORMS OVER THE OUTER WATERS.
SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO BE A CONCERN
AND THERE IS A LOW END PROBABILITY OF THUNDERSTORMS PRODUCING WIND
GUSTS OF 35 KTS OR GREATER DURING THE DAY, BUT ESPECIALLY DURING THE
MORNING HOURS. THIS IS SOMETHING WE'LL CONTINUE TO MONITOR AND
SHOULD THE SITUATION WARRANT, A MARINE WEATHER STATEMENT MAY NEED TO
BE ISSUED.
MEANWHILE, THE COMBINATION OF MODERATE SOUTH WINDS, AND STEEP DRIVEN
SEAS WILL RESULT IN SMALL CRAFT CONDITIONS INTO THIS EVENING. WINDS
AND SEAS WILL DIMINISH TONIGHT, WITH RELATIVELY CALMER CONDITIONS
EXPECTED INTO SATURDAY MORNING. NORTHWEST SWELL ARE EXPECTED TO
INCREASE SATURDAY AFTERNOON INTO SATURDAY NIGHT AND COULD BE HIGH
ENOUGH TO BRING SMALL CRAFT CONDITIONS BACK TO THE MARINE WATERS.
ANOTHER SIMILAR OR SLIGHTLY STRONGER LOW PRESSURE SYSTEM IS LIKELY
LATE SUNDAY NIGHT INTO MONDAY EVENING, WITH ANOTHER SLIGHT CHANCE OF
THUNDERSTORMS. THIS FRONT COULD ALSO RESULT IN STEEP SEAS.
-PETRUCELLI
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 8 PM PDT THIS
EVENING FOR PZZ350-356-370-376.
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