090
FXUS66 KMFR 121831
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
1131 AM PDT SUN OCT 12 2025
DISCUSSION
UPDATED AVIATION DISCUSSION.
AVIATION...12/18Z TAFS
LOW PRESSURE WILL MOVE SOUTHWARD ALONG THE
COAST TONIGHT THROUGH MONDAY. SOME LIGHT RAIN AND MVFR CEILINGS ARE
DEVELOPING ALONG THE COAST AND NW PORTIONS OF THE FORECAST AREA NOW,
WHILE AREAS FARTHER INLAND TO THE SOUTH AND EAST ARE VFR. EXPECT
CEILINGS TO LOWER WEST OF THE CASCADES THIS AFTERNOON AND,
ESPECIALLY TONIGHT FOR MOST OF THE REMAINDER OF THE REGION AS THE
LOW PUSHES SOUTHWARD. THIS LOW WILL BRING WIDESPREAD LIGHT RAIN AND
SNOW IN THE MOUNTAINS WITH AREAS OF MVFR AND HIGHER TERRAIN
OBSCURATIONS. LOCAL IFR CEILINGS AND/OR VISIBILITIES ARE POSSIBLE IN
HEAVIER RAIN. FREEZING LEVELS WILL BE PRETTY LOW FOR THIS TIME OF
YEAR, GENERALLY 4500-5500 FEET. THERE IS ALSO ABOUT A 20-30% RISK OF
THUNDERSTORMS OVER THE MARINE WATERS AND ALONG THE IMMEDIATE COAST
LATER TONIGHT INTO MONDAY. THE MAIN AXIS OF PRECIPITATION WILL SHIFT
SOUTHWARD INTO NORCAL MONDAY, BUT SHOWERS CAN PERSIST INTO THE
AFTERNOON JUST ABOUT ANYWHERE BENEATH CYCLONIC FLOW ALOFT. -SPILDE
PREV DISCUSSION
/ISSUED 630 AM PDT SUN OCT 12 2025/
DISCUSSION...
COOL ONSHORE FLOW WILL CONTINUE THIS MORNING BEHIND THIS UPPER
LEVEL LOW. SHOWERS WILL REMAIN IN THE FORECAST MAINLY AROUND
ROSEBURG AND COOS BAY FOR THIS MORNING BEFORE THE NEXT UPPER
LEVEL WAVE APPROACHES LATER THIS EVENING. RAIN PROBABILITIES WILL
GRADUALLY INCREASE INTO TONIGHT AND PEAK CLOSE TO 100 PERCENT FOR
MANY LOCATIONS WEST OF THE CASCADES.
THIS LOW WILL LIKELY PRODUCE WETTING RAIN WEST OF THE CASCADES
WITH WIDESPREAD 0.25 TO 0.5 INCHES OF ACCUMULATING PRECIPITATION.
HIGHER TOTALS UP TO 1 INCH OF PRECIPITATION ARE EXPECTED IN THE
HIGHER CASCADES, ALTHOUGH THAT WILL FALL AS SNOW WITH 4500 FOOT
TO 5000 FOOT SNOW LEVELS THROUGH THE EVENT. CRATER LAKE WILL GET A
GOOD SHOT OF SNOW HERE WITH ENSEMBLE DATA SUGGESTING 6 INCHES IS
PRETTY LIKELY WITH UP TO 8 INCHES ALSO PRETTY REASONABLE. MOST OF
THAT IS FALLING AROUND 7000 FEET AND JUST AT CRATER LAKE, SO WE
OPTED TO STAY AWAY FROM A WINTER WEATHER ADVISORY. HOWEVER, IF ONE
IS CONSIDERING TRAVELING TO CRATER LAKE, PREPARE FOR WINTER
PRECIPITATION AND SOME DIFFICULT TRAVEL CONDITIONS.
THIS LOW WILL DIVE DOWN THE COAST AND BRING IN SOME UNUSUALLY COOL
CONDITIONS EVEN FOR MID OCTOBER. SNOW LEVELS WILL BE AROUND 3700
FEET BY MONDAY MORNING, ALTHOUGH SNOW WILL STRUGGLE TO ACCUMULATE
AT THAT ELEVATION AS PRECIPITATION MODE WILL TURN SHOWERY. SO THE
SUN SHOULD BREAK THROUGH BETWEEN THE SHOWERS AND GET SOME HEAT ON
ROADS AND LOWER SURFACES.
IT'S WORTH NOTING THE GFS AND OTHER DETERMINISTIC MODELS ARE
SHOWING SOME WEAKER EASTERLY WINDS BY MONDAY AFTERNOON, WHICH
SHOULD WARM AND DRY US OUT. IN ANY CASE, TEMPERATURES SHOULD HOVER
IN THE MID TO LOWER 50'S WEST SIDE AND UPPER 40'S EAST OF THE
CASCADES.
ONCE THIS LOW DEPARTS THE AREA ON TUESDAY, WE'LL SEE DRIER
CONDITIONS SETTLE INTO THE AREA ON THE BACKSIDE OF THIS LOW. THERE
IS STILL SOME VORTICITY AROUND, SO CLOUD COVER SHOULD LINGER IN
THE MID TO UPPER LEVELS, BUT IT WILL BE TRENDING WARMER AND DRIER
TUESDAY ONWARDS.
THE LATEST NBM FORECAST HAS US REVISITING THE 70 DEGREE MARK HERE
IN MEDFORD BY SATURDAY. THE NBM 10TH PERCENTILE FORECAST HAS A
HIGH OF 67, SO WE'LL DEFINITELY BE TRENDING WARMER TOWARDS THE END
OF THE WEEK.
-SMITH
AVIATION...12/12Z TAFS... AN UPPER LEVEL HAS DEPARTED THE REGION
WITH DEEP NORTHWESTERLY FLOW WITH A FEW AREAS REPORTING MVFR
CONDITIONS EAST OF THE CASCADES. OTHERWISE, WIDESPREAD VFR
CONDITIONS CONTINUE THIS MORNING UNDER CHAOTIC MIXED CEILINGS.
WE'LL SEE THE CHANCE OF RAIN INCREASE LATER THIS EVENING INTO
TONIGHT AHEAD OF THE NEXT LOW. THERE IS A GOOD CHANCE IT WILL RAIN
AND CEILINGS SHOULD STAY WITHIN VFR THRESHOLDS WITH PERIODS OF LOWER
VISIBILITIES UNDER THE HEAVIER RAIN. -SMITH
MARINE...NORTHWEST SWELL WILL BUILD OVER THE WATERS TODAY. ANOTHER
LOW WILL MOVE IN LATER THIS EVENING AND LAST INTO MONDAY EVENING.
SIMILAR TO THE LAST LOW, IT WILL BRING WIDESPREAD SHOWERS AND A
CHANCE OF THUNDERSTORMS. STRONGER NORTH WINDS WILL ACCOMPANY THIS
SYSTEM, WHICH WILL MAINTAIN STEEP SEAS, ESPECIALLY OVER THE OUTER
WATERS THROUGH TUESDAY. LIGHTER WINDS AND LOWER SEAS SHOULD RETURN
ON WEDNESDAY.
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS
EVENING FOR PZZ350-370-376.
MAS/MAS/MAS
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