554
FXUS66 KMFR 131115
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
315 AM PST THU NOV 13 2025
DISCUSSION
WATER VAPOR IMAGERY SHOWS A DEEPENING CYCLONE OUT
AROUND 41N AND 129W EARLY THIS MORNING. THIS SYSTEM IS IN THE
PROCESS OF SPLITTING OFF FROM THE NORTHERN BRANCH JET, WHICH IS
SENDING A TROUGH INTO WESTERN CANADA. THE CLOSED LOW IS REACHING ITS
PEAK INTENSITY RIGHT NOW (THIS MORNING) AND WILL FILL (WEAKEN) AS IT
MEANDERS SOUTHWARD OFFSHORE OVER THE NEXT 24 HOURS. THE PRESSURE
GRADIENT MFR-RDD IS AROUND -6 MB AND WITH THE FLOW AROUND THE LOW
FROM THE S-SE, THIS IS LEADING TO SOME GUSTY WINDS. PEAK GUSTS SO
FAR HAVE BEEN IN THE 45-55 MPH RANGE IN THE AREAS WHERE WE HAVE WIND
HEADLINES. THESE WINDS WILL CONTINUE THROUGH MORNING HOURS AND STILL
EVEN REMAIN GUSTY INTO THE AFTERNOON, THOUGH PROBABLY NOT QUITE AS
STRONG. WIND PRODUCTS CONTINUE THROUGH 10 AM HERE IN THE ROGUE
VALLEY (MEDFORD SOUTH), TIL 10 AM IN THE SHASTA VALLEY AND WE'VE
ADJUSTED THE END TIME OVER THE EAST SIDE TO END LATE THIS EVENING
(10 PM). IN STARK CONTRAST (AND ONE OF THE REASONS THIS AREA IS
ONE OF THE HARDEST LOCATIONS THIS FORECASTER HAS EVER HAD TO
FORECAST FOR), AREAS THAT DON'T HAVE THE WIND RIGHT NOW (ILLINOIS
VALLEY, GRANTS PASS AND ROSEBURG) HAVE ALL FILLED IN WITH LOW
CLOUDS/FOG. SO, WE HAVE WIND ADVISORIES IN MEDFORD/ASHLAND, BUT
DENSE FOG IN SOME AREAS AROUND GRANTS PASS. FUN. PLEASE USE
CAUTION OUT THERE, WHATEVER WEATHER IS OCCURRING AT YOUR LOCATION!
THE FOG/LOW CLOUDS *SHOULD* LIFT THIS MORNING AS RAIN FROM THE
FRONTAL BAND MOVES IN.
SPEAKING OF THE FRONTAL BAND, IT IS BRINGING SOME RAIN TO COASTAL
AREAS AND INTO NORCAL EARLY THIS MORNING, AND WILL MOVE ONSHORE
TODAY. THE STEADIEST/HEAVIEST RAIN WILL OCCUR IN THE UPSLOPE
REGION AROUND MT. SHASTA/DUNSMUIR WHERE AMOUNTS OF 2-4" ARE MOST
LIKELY. THIS MAY RESULT IN SOME NUISANCE PONDING OF WATER ON
ROADWAYS OR EVEN SOME URBAN FLOODING WHERE LEAVES MAY TEND TO CLOG
DRAINS THIS TIME OF YEAR. RIVERS ARE RUNNING LOW, SO WE'RE NOT
CONCERNED ABOUT MAIN STEM FLOODING. 1-2" OF RAIN WILL OCCUR FROM
THE CURRY COAST RANGE MOUNTAINS DOWN INTO PORTIONS OF WESTERN
SISKIYOU COUNTY. OVERALL, FARTHER NORTH AND EAST, RAIN AMOUNTS
WILL BE MUCH LOWER, ESPECIALLY IN THE DOWNSLOPE FLOW REGIONS
(VALLEYS WEST OF THE CASCADES) AND ALSO THE EAST SIDE DESERTS.
BEST CHANCE OF RAIN IN THE ROGUE VALLEY APPEARS TO BE THIS
AFTERNOON WHEN WINDS SHIFT TO SW. MOUNTAINS PROBABLY HAVE AMOUNTS
OF 0.25-0.50", WHILE VALLEYS AVERAGE 0.10-0.25", THOUGH SOME MAY
NOT EVEN GET THAT. SNOW LEVELS WILL BE WAY UP THERE ABOVE 9000
FEET TODAY, SO REALLY THE ONLY PLACE THAT'LL GET SNOW IS THE TOP
OF MT SHASTA. SNOW LEVELS DROP TO AROUND 6000-6500 FEET TONIGHT,
BUT WITHOUT MUCH PRECIP LEFT, THERE PROBABLY WON'T EVEN BE THAT
MUCH ACCUMULATION (IF ANY) UP AT CRATER LAKE.
THE UPPER TROUGH AXIS SHIFTS THROUGH THE AREA ON FRIDAY, BUT
MODELS SHOW LITTLE IN THE WAY OF PRECIPITATION. SOME AREAS STILL
STAND A SHOT AT SOME RAIN SHOWERS, BUT POPS ARE GENERALLY MUCH
LOWER COMPARED TO TODAY. WITH THE CLOSED LOW MOVING SOUTHWARD OFF
THE CALIFORNIA COAST FRIDAY NIGHT AND EVENTUALLY INTO SOCAL AND
THE GREAT BASIN THIS WEEKEND, OUR AREA SHOULD MOSTLY BE IN THE
RIDGING TO THE NORTH. AS SUCH, WE EXPECT A DRIER PERIOD WITH
SEASONABLY MILD TEMPERATURES SATURDAY. MEANWHILE, THE NEXT UPPER
TROUGH IS FORECAST TO DROP SOUTHEASTWARD FROM THE NE PACIFIC
SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING AN INCREASE IN RAIN
CHANCES AREA WIDE, BUT ESPECIALLY ALONG THE COAST SUNDAY
AFTERNOON INTO MONDAY. MODELS ARE SHOWING ANOTHER BREAK FOLLOWING
THAT SYSTEM TUESDAY WITH THE NEXT STORM POSSIBLE WED/THU, BUT
THERE'S A LOT OF UNCERTAINTY WITH THAT ONE. -SPILDE
AVIATION...13/12Z TAFS
THE MAIN AVIATION HAZARD FOR THE TAF
PERIOD WILL BE LOW LEVEL WIND SPEED SHEAR FOR THE NORTH COAST,
INCLUDING NORTH BEND UNTIL AROUND 10Z, BUT COULD LINGER FOR
ANOTHER HOUR OR TWO BEYOND THAT. LOW LEVEL WIND SPEED SHEAR IN THE
UMPQUA BASIN, INCLUDING ROSEBURG IS EXPECTED TO LAST LONGER UNTIL
LATER THURSDAY MORNING (BETWEEN 18-19Z).
NOT TO DOWNPLAY THE STRONGER SURFACE WINDS, BUT THEY TOO WILL ALSO
BE A CONCERN AT THE MEDFORD TERMINAL WITH SOUTHEAST WINDS THAT COULD
EXCEED 35 KTS UNTIL AROUND 10 AM. SOUTHEAST WINDS AT KLAMATH FALLS
HAVE BEEN UP AND DOWN IN THE LAST FEW HOURS, BUT EXPECT STEADIER
WINDS TO DEVELOP THIS MORNING WITH GUSTS TO 35 KT STILL POSSIBLE
THROUGH THE MORNING. WE MAY NEED TO EXTEND THE AIRPORT WEATHER
WARNING THERE SINCE WINDS ALOFT ARE STILL STRONG INTO THIS
AFTERNOON AND BETTER VERTICAL MIXING IS EXPECTED THEN.
IF YOU CAN BELIEVE IT, FOG/LOW CLOUDS ACTUALLY DEVELOPED AROUND
GRANTS PASS AND ROSEBURG EARLY THIS MORNING WHERE CEILINGS AND/OR
VISIBILITY ARE LIFR. THESE SHOULD LIFT THIS MORNING AS THE
FRONTAL BAND MOVES IN WITH SOME RAIN.
THIS IS ALL DUE TO A STRONG FRONT MOVING THROUGH THE AREA. MOST
OF THE RAIN ASSOCIATED WITH THE FRONT SHOULD BE IN NORTHERN
CALIFORNIA AS A STRONG SURFACE LOW MOVES SOUTHWARD OFFSHORE.
CEILINGS AROUND MT. SHASTA WILL BE MOSTLY MVFR, THOUGH MAY DROP
TO IFR IN PERIODS OF HEAVIER RAINFALL. THERE COULD ALSO BE OTHER
AREAS OF HIGHER TERRAIN OBSCURATION TODAY. ELSEWHERE, CEILINGS
REMAIN VFR FOR MOST OF THE TAF PERIOD. -PETRUCELLI/SPILDE
MARINE...UPDATED 230 AM PST THURSDAY, NOVEMBER 13, 2025
A LARGE
STORM LOCATED OFF THE NORCAL COAST EARLY THIS MORNING WILL BRING
MODERATE TO STRONG SOUTH TO SOUTHEAST WINDS, TO GALE FORCE IN SOME
AREAS TODAY, ESPECIALLY FROM BANDON SOUTH. HIGHEST WINDS WILL
OCCUR THIS MORNING, THEN GRADUALLY SUBSIDE THIS AFTERNOON AND
TONIGHT. GIVEN THE WINDS EXPECTED, SEAS WILL BECOME STEEP TO VERY
STEEP, HIGHEST OVER THE OUTER WATERS, BUT STILL QUITE HIGH ALL
THE WAY TO THE COAST. AS SUCH, WE'LL MAINTAIN A HAZARDOUS SEAS
WARNING AS WELL NORTH OF BANDON. SEAS TRANSITION TO NORTHWEST
SWELL AND FRESH SOUTHWEST SWELL DOMINATED TONIGHT INTO SATURDAY,
SO A SMALL CRAFT ADVISORY FOLLOWS THEN. THE NEXT FRONT IS FORECAST
TO ARRIVE SUNDAY WITH INCREASING SOUTH WINDS AND SEAS INTO SUNDAY
NIGHT. -SPILDE
MFR WATCHES/WARNINGS/ADVISORIES
OR...WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR ORZ026-029>031.
CA...HIGH WIND WARNING UNTIL 10 AM PST THIS MORNING FOR CAZ081.
WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR CAZ084-085.
PACIFIC COASTAL WATERS...GALE WARNING UNTIL 4 PM PST THIS AFTERNOON
FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM PST
SATURDAY FOR PZZ350-356-370-376.
HAZARDOUS SEAS WARNING UNTIL 4 PM PST THIS AFTERNOON FOR PZZ350-
370.
MAS/MAS/MAS
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