436
FXUS66 KMFR 150527
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
927 PM PST SUN DEC 14 2025
UPDATE
AVIATION DISCUSSION UPDATED.
AVIATION...15/06Z TAFS
ALONG THE COAST AND INTO THE UMPQUA
VALLEY, A WEAK FRONT WILL MOVE INLAND TONIGHT AND MONDAY BRINGING
MVFR CONDITIONS WITH LOCAL IFR. LOW LEVEL WIND SHEAR IS EXPECTED
ALONG THE COAST FROM 10-18Z AND IN THE UMPQUA VALLEY 13-21Z. CEILINGS
WILL LOWER IN THE AFTERNOON AND EVENING, BECOMING IFR AND LOCAL
LIFR.
FOR INLAND AREAS SOUTH OF THE UMPQUA AND WEST OF THE CASCADES, AREAS
OF LOW STRATUS AND FOG ARE PRESENT IN VALLEYS WEST OF THE CASCADES,
RESULTING IN LIFR CONDITIONS AT MEDFORD, GRANTS PASS, AND LOCAL IFR
IN THE SHASTA VALLEY. THESE CONDITIONS WILL PERSIST OVERNIGHT.
GUIDANCE SHOWS LIFR CEILINGS AND IFR/LIFR VISIBILITIES FOR THE
ROGUE VALLEY (MEDFORD) CONTINUING INTO MONDAY. HOWEVER, AS RAIN
MOVES INLAND WITH A FRONT, MAY SEE CEILINGS LIFT WITH A MIX OF
MVFR AND IFR EXPECTED FOR MOST AREAS WEST OF THE CASCADES LATE
MONDAY MORNING AND MONDAY AFTERNOON. GUIDANCE SUPPORTS CONDITIONS
LOWERING BACK DOWN TO LIFR AT MEDFORD MONDAY EVENING.
ELSEWHERE, FOR AREAS EAST OF THE CASCADES, EXPECT VFR THROUGH MONDAY
MORNING THEN LOCAL MVFR AND MOUNTAIN OBSCURATIONS WILL DEVELOP IN
THE LATE MORNING AND AFTERNOON. AREAS OF MVFR CEILINGS ARE EXPECTED
WITH RAIN MONDAY EVENING, INCLUDING AT KLAMATH FALLS.
PREV DISCUSSION
/ISSUED 326 PM PST SUN DEC 14 2025/
DISCUSSION...MUCH LIKE THE LAST SEVERAL DAYS, SATELLITE IMAGE
SHOWS LOW CLOUDS PERSISTING IN THE ROGUE, ILLINOIS, AND SHASTA
VALLEYS. ABOVE THE LOW CLOUD LAYER, WERE SEEING INCREASING HIGH AND
MID LEVEL CLOUDS AHEAD OF A WEAK FRONT. IT'S LIKELY THE LOW CLOUDS
WILL PERSIST ROGUE AND ILLINOIS VALLEY THROUGH EARLY THIS EVENING.
THE ABOVE MENTIONED WEAK FRONT COULD BE ENOUGH TO LIFT THE LOWER
CLOUD DECK IN THE ROGUE AND ILLINOIS VALLEY. OTHERWISE, THE FRONT
WILL HAVE NO IMPACT ON OUR WEATHER. A FEW SPRINKLES COULD DEVELOP IN
COOS AND NORTHWEST DOUGLAS COUNTY. PER THE USUAL THE NBM SOLUTION IS
TOO BULLISH (MEANING POPS ARE TOO HIGH AND TOO FAR INLAND) THIS
AFTERNOON AND EVENING WHICH DOES NOT ADD GIVEN THAT THE OPERATIONAL
MODELS AND MAJORITY OF THE INDIVIDUAL ENSEMBLE MEMBERS SHOW NOTHING.
TODAY WILL BE THE LAST QUIET DAY OF THE FORECAST PERIOD. THE PATTERN
WILL BECOME MORE ACTIVE STARTING MONDAY AND IS LIKELY TO LAST FOR
THE NEXT 7-10 DAYS. IN A RELATIVE SENSE, IT WILL SEEM LIKE A
SIGNIFICANT CHANGE WITH BOUTS OF MODERATE TO HEAVY RAIN HIGH
ELEVATION MOUNTAINS SNOW, AND MODERATE TO STRONG WINDS. HOWEVER,
IT'S NOT ALL THAT UNUSUAL TO HAVE ACTIVE WEATHER OF THIS MAGNITUDE
THIS TIME OF THE YEAR.
THE FIRST FRONT WILL ARRIVE AT THE COAST EARLY MONDAY MORNING
BRINGING RAIN AND GUSTY WINDS TO THE COAST, NORTH OF CAPE BLANCO.
PRECIPITATION WILL MOVE INLAND DURING THE DAY MONDAY, WITH WINDS
INCREASING EAST OF THE CASCADES. THE BULK OF THE PRECIPITATION
MONDAY WILL BE ALONG THE COAST, COASTAL MOUNTAINS AND CASCADES, MOST
OF THE ROGUE VALLEY COULD END UP DRY DURING THE DAY MONDAY WITH NOT
MUCH MORE THAN A FEW LIGHT RAIN SHOWERS DUE TO THE NON-FAVORABLE
SOUTHWEST FLOW. ALSO AREAS EAST OF THE CASCADES WILL LIKELY GET
LITTLE TO NOTHING, BUT IT WILL BE WINDY IN THE AFTERNOON.
FOR THE REMAINDER OF WEEK, WE'LL HAVE A SERIES OF FRONTS MOVING
THROUGH THE AREA BRINGING MORE RAIN, MODERATE TO STRONG WINDS AND
HIGHER ELEVATION MOUNTAINS SNOW. DETAIL'S ON THE TIMING MENTIONED
BELOW COULD VARY WITH EACH INDIVIDUAL STORM, SO BE ON THE LOOKOUT
FOR UPDATES TO THE FORECAST IN THE DAYS TO COME.
A SECOND AND STRONGER SYSTEM WILL ARRIVE TUESDAY NIGHT INTO
WEDNESDAY BRINING MODERATE TO HEAVY RAIN TO THE COAST, COASTAL
MOUNTAINS AND CASCADES. MODERATE TO OCCASIONALLY STRONG WINDS ARE
POSSIBLE AT THE COAST, BUT RIGHT NOW, NOT ALL OF THE INGREDIENTS ARE
THERE FOR A WINDS TO REACH HIGH WIND WARNING CRITERIA AT THE COAST,
BUT THEY DO FOR EAST OF THE CASCADES, ESPECIALLY NEAR AND AT THE
RIDGES. GUIDANCE SHOWS 700 MB WINDS BETWEEN 55-65 KTS TUESDAY NIGHT
THROUGH WEDNESDAY MORNING, THEN DECREASING SOME WEDNESDAY AFTERNOON.
THUS, A HIGH WIND WATCH HAS BEEN ISSUED FOR PORTIONS OF LAKE,
KLAMATH AND MODOC COUNTY. PLEASE SEE NPWMFR FOR MORE DETAILS.
SNOW LEVELS WILL BE BETWEEN 7000-8000 FEET TUESDAY, THEN LOWERING
BETWEEN 4500-5500 FEET WEDNESDAY, BUT BY THE TIME SNOW LEVELS GET TO
THE LOW END WEDNESDAY THE HEAVIEST PRECIPITATION WILL HAVE ALREADY
ENDED. THAT MEANS ROAD SNOW CONCERNS WILL BE LIMITED.
A STRONGER STORM WILL ARRIVE THURSDAY AND LAST THROUGH THURSDAY
NIGHT BRINGING ANOTHER ROUND OF MODERATE TO HEAVY PRECIPITATION AND
STRONG WINDS. STRONG WINDS WILL BE A CONCERN THURSDAY, ESPECIALLY
EAST OF THE CASCADES WHERE SOME OF THE GUIDANCE SHOWS 700 MB WINDS
BETWEEN 70-80 KTS OVER A LARGE CHUNK OF REAL ESTATE EAST OF THE
CASCADES. IT'S ALSO WORTH NOTING, STRONG WINDS EAST OF THE CASCADES
COULD BE OF LONGER DURATION (12-18 HOURS). ALTHOUGH NOT AS HIGH OF A
CONCERN, MODERATE TO STRONG WINDS WILL BE A CONCERN ALONG THE COAST,
AND SHASTA VALLEY. CURRENT GRADIENTS BETWEEN ARCATA AND NORTH BEND
PEAK OUT AT ALMOST 10 MB THURSDAY AND ALMOST 9 MB BETWEEN REDDING
AND MEDFORD WHICH ARE SIGNIFICANT ENOUGH FOR STRONG WINDS IN THESE
AREAS. HOWEVER THE WIND DIRECTION IN THE SHASTA VALLEY HAS A
WESTERLY COMPONENT WHICH COULD PUT A CAP ON THE MAGNITUDE OF THE
WINDS. STILL SOMETHING WE'LL HAVE TO KEEP A CLOSE WATCH ON.
THRE'S GOOD AGREEMENT THE STORM THAT ARRIVES THURSDAY WILL HAVE AN
ATMOSPHERIC RIVER (AR) COMPONENT, WITH A LONG FETCH OF MOISTURE
EXTENDING SOUTHWEST TOWARDS 160W, WITH THE SOURCE REGION COMING FROM
THE TROPICS. ADDITIONALLY, THERE IS FAVORABLE UPSLOPE FLOW ALONG THE
COASTAL MOUNTAINS AND CASCADES. THE NET RESULT COULD BE A PROLONGED
PERIOD (12 HOURS) OF HEAVY PRECIPITATION FOR THESE AREAS ALONG WITH
MODERATE TO OCCASIONALLY HEAVY RAINFALL ELSEWHERE. THE ONE GOOD
THING IS WITH THE LACK OF RAIN THE LAST FEW WEEKS, RIVERS ARE PRETTY
LOW, BUT THEY WILL COME UP OVER TIME AND WE COULD BE LOOKING AT
POTENTIAL FLOODING ON THE COQUILLE TOWARDS THE END OF THE WEEK.
AGAIN, PLENTY OF TIME TO ADDRESS THIS, AND WE'LL KEEP EVERYONE
UPDATED ON THIS.
NEXT WEEK LEADING UP TO THE CHRISTMAS HOLIDAY, BEGINNING AROUND
SUNDAY AFTERNOON, THERE'S STRONG EVIDENCE THAT'S BEING SUPPORTED
BY THE ECMWF, GEFS ENSEMBLE MEANS AND CLUSTERS. WE'LL BE HEADING
INTO A COLDER AND WET PATTERN WITH STORMS ORIGINATING FROM THE
GULF OF ALASKA THROUGH AT LEAST CHRISTMAS DAY.
THESE TYPICALLY RESULT IN COLDER TEMPERATURES, AND PRECIPITATION
WITH LOWER SNOW LEVELS. THE PATTERN SHOWS BELOW NORMAL 500 MB
ANOMALIES WITH A STRONGER UPPER TROUGHING IN THE WESTERN U.S. WITH
RIDGING AND ABOVE NORMAL 500 MB ANOMALIES IN THE NORTHEASTERN PART
OF THE U.S. THE ANOMALIES BEING SHOWN ARE PRETTY SIGNIFICANT THIS
FAR OUT, WHICH IS UNUSUAL SINCE THEY TEND TO LEAN MORE TOWARDS
CLIMATOLOGY AS THE RIDGE DOMINATED AND TROUGH DOMINATED SOLUTIONS
AMONG THE NUMEROUS SOLUTIONS TEND TO "BALANCE OUT."
THIS IS A ALMOST THE OPPOSITE OF THE PATTERN WE HAVE EXPERIENCED
FOR ALMOST THE LAST THREE WEEKS, WITH STRONGER RIDGING IN THE
WESTERN PART OF THE U.S. AND DEEP UPPER TROUGHING IN THE
NORTHEASTERN PART OF THE U.S. IN OTHER WORDS, THE SWITCH BASICALLY
GETS FLIPPED AS THE OVERALL PATTERN CHANGES. -PETRUCELLI
MARINE...UPDATED 100 PM PST SUNDAY, DECEMBER 14, 2025...A WEAK
FRONT IS PASSING THROUGH THE REGION TODAY WITH A SLIGHTLY STRONGER
FRONT FOLLOWING IT TONIGHT INTO MONDAY. STEEP SEAS ARE ALREADY
PRESENT ACROSS THE WATERS THIS AFTERNOON UNDER GUSTY SOUTH WINDS, BUT
CONDITIONS WILL WORSEN TONIGHT WITH THE NEXT FRONT. SOUTH WINDS
INCREASE TO GALES NORTH OF CAPE BLANCO AND BEYOND 1-2 NM FROM SHORE
WITH SEAS BECOMING VERY STEEP AND HAZARDOUS FOR ALL AREAS INTO EARLY
MONDAY. WINDS EASE MONDAY AFTERNOON, BUT WESTERLY SWELL BUILDS (10-
12 FT @ 12 SECONDS) BEHIND THE FRONT WHICH WILL MAINTAIN STEEP SEAS
INTO MID-WEEK. ADDITIONAL FRONTAL SYSTEMS WILL MAINTAIN ACTIVE
WEATHER THROUGH THE WEEK WITH GALES POSSIBLE AGAIN ON TUESDAY AND
THURSDAY, ALONG WITH CONTINUED STEEP TO, AT TIMES, VERY STEEP AND
HAZARDOUS SEAS. /BR-Y
MFR WATCHES/WARNINGS/ADVISORIES
OR...HIGH WIND WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY AFTERNOON
FOR ORZ030-031.
CA...HIGH WIND WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY AFTERNOON
FOR CAZ085.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 1 AM PST MONDAY
FOR PZZ350-356-370-376.
HAZARDOUS SEAS WARNING FROM 1 AM TO 4 PM PST MONDAY FOR PZZ350-
356-370-376.
GALE WARNING FROM 1 AM TO 4 PM PST MONDAY FOR PZZ350-370.
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