827
FXUS66 KMFR 231722
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
1022 AM PDT WED OCT 23 2024
UPDATED AVIATION SECTION
DISCUSSION
A COLD FRONT WILL MOVE OVER THE AREA TODAY, BRINGING
30-60% CHANCES OF SHOWERS OVER WEST SIDE AREAS THIS AFTERNOON AND
50-90% CHANCES ALONG AND EAST OF THE CASCADES THIS AFTERNOON AND
EVENING. EXPECTED AMOUNTS REMAIN LIGHT, WITH 0.25 INCHES POSSIBLE
OVER THE CASCADES AND AREAS EAST OF SUMMER LAKE AND OTHER AREAS
GETTING LESS. WITH SNOW LEVELS DROPPING TO 4500-5000 FEET AT THE
LEADING EDGE OF THE FRONT, LIGHT SNOWFALL WILL BE POSSIBLE OVER
ELEVATED TERRAIN. -TAD
AVIATION...23/18Z TAFS
A FRONT FORMING OVER THE REGION LATE
THIS MORNING CONTINUES TO BRING WIDESPREAD CLOUD COVER, THOUGH
MOSTLY VFR AS OF THIS WRITING (~1030 AM PDT). HOWEVER, LOWER
CEILINGS (MVFR) PERSIST IN THE UMPQUA/ROGUE VALLEYS ALONG WITH AREAS
OF HIGHER MOUNTAIN OBSCURATION.
THE FRONT WILL SLOWLY SHIFT EASTWARD THIS AFTERNOON, PUSHING EAST OF
THE CASCADES AFTER 22Z AND CLEARING EASTERN LAKE COUNTY BY AS LATE
AS 02Z. SOME LIGHT RAIN AND HIGHER ELEVATION SNOW WILL ACCOMPANY THE
FRONT AS IT MOVES THROUGH, PERHAPS BRIEFLY LOWERING CEILINGS TO MVFR
IN SOME AREAS THAT ARE VFR CURRENTLY.
CEILINGS IMPROVE RAPIDLY AFTER THE FRONT MOVES THROUGH LATE THIS
AFTERNOON/EVENING AS MUCH DRIER AIR MOVES IN ALOFT. WINDS WILL
GENERALLY REMAIN LIGHT FOR INLAND PORTIONS OF THE WEST SIDE INTO
THURSDAY MORNING, BUT WEST TO NORTHWEST WINDS WILL BE BREEZY THIS
AFTERNOON ON THE EASTSIDE, INCLUDING KLAMATH FALLS.
TONIGHT INTO THURSDAY MORNING, VALLEY MVFR/IFR IS EXPECTED EARLY
THURSDAY MORNING, PARTICULARLY IN THE UMPQUA VALLEY, BUT MOST
EVERYWHERE ELSE WILL BE VFR. -SPILDE
MARINE...UPDATED 200 AM PDT WEDNESDAY, OCTOBER 23, 2024
A
THERMAL TROUGH PATTERN WILL MAINTAIN LOW END ADVISORY STRENGTH NORTH
WINDS THROUGH THURSDAY NIGHT, WITH STEEP SEAS SOUTH OF CAPE BLANCO
THROUGH THURSDAY MORNING THEN SOUTH OF CAPE ARAGO THROUGH THURSDAY
NIGHT. A BRIEF PERIOD OF IMPROVED CONDITIONS IS EXPECTED EARLY
FRIDAY BEFORE A PATTERN CHANGE THAT IS EXPECTED FRIDAY THROUGH THE
WEEKEND. A LOW MOVING NORTH TOWARDS THE GULF OF ALASKA WILL BRING
INCREASING SOUTHERLY WINDS AND BUILDING SEAS FRIDAY INTO THE
WEEKEND, WITH STEEP SEAS LIKELY TO DEVELOP BY FRIDAY AFTERNOON AND
GALES POSSIBLE ON FRIDAY NIGHT. STEEP TO VERY STEEP SEAS ARE THEN
LIKELY TO CONTINUE IN THIS ACTIVE PATTERN DURING THE WEEKEND INTO
EARLY NEXT WEEK. /DW
PREV DISCUSSION
/ISSUED 416 AM PDT WED OCT 23 2024/
DISCUSSION...AN ELONGATED POSITIVE TILT TROUGH RESIDES OFF THE
PACNW COAST EXTENDING FROM THE PUGET SOUND SOUTHWESTWARD TO
30S/150W. AS THIS TROUGH SPLITS, THE NORTHERN HALF IS FORECAST TO
SWING THROUGH THE CWA TODAY WITH A PRETTY GOOD THERMAL GRADIENT
AND UPPER VORTICITY MAXIMUM PAIRING UP IN THE AFTERNOON. THIS
WILL ENHANCE THE PRECIPITATION SHIELD AND ALLOW .15 T0 .25" TO
FALL OVER THE EAST WITH SNOW LEVELS FALLING TO 5000'. MOST OF THE
WEST SIDE WILL PROBABLY GET SKIPPED. EXPECT AN INCH OF SNOW ON
WINTER RIM. THIS TROUGH MOVES OUT QUICKLY TONIGHT WITH LOW
TEMPERATURES THURSDAY DIPPING BELOW FREEZING IN THE ROGUE,
ILLINOIS AND WESTERN SISKIYOU COUNTY VALLEYS. THE FREEZE WATCH HAS
BEEN UPDATED TO A WARNING FOR THESE AREAS AND HAVE ALSO INCLUDED
GLENDALE AND AZALEA. LOOK FOR SOME PATCHY FOG AND FREEZING FOG AS
WELL THURSDAY MORNING.
THURSDAY AFTERNOON THROUGH FRIDAY AFTERNOON SHOULD REMAIN DRY AND
STILL COLD AGAIN FRIDAY MORNING.
THE LINGERING SOUTHERN HALF OF THE TROUGH WILL WRAP NORTHWARD UP
THE EASTERN PACIFIC AND GRAZE THE COAST FRIDAY NIGHT. SOME
RAPIDLY INCREASING SOUTH WINDS SHOULD DEVELOP WITH SHOWERS.
THEREAFTER WE'RE EXCITED TO BE WATCHING THE PROGRESSION OF A
DEEPER AND COLDER LONGWAVE TROUGH SATURDAY NIGHT WITH PRECIP AND
LOWERING SNOW LEVELS INTO SUNDAY. THEN, SHOWERS CONTINUE INTO
MONDAY AND POSSIBLY MONDAY NIGHT. THE OREGON CASCADES WILL BE THE
MAIN RECEIVER OF SNOW HERE AS SNOW LEVELS GRADUALLY FALL TO OR
JUST BELOW THE PASSES (~4500'). THE NBM POINTS TO A 70 PERCENT
CHANCE FOR STORM TOTALS OF 10+ INCHES AT CRATER LAKE WITH THIS
SYSTEM. WE'LL BE MESSAGING PARTNERS ON THIS EVENT - NOT THAT IT'LL
BE A MAJOR STORM BUT IT LOOKS LIKE IT WILL BE BRINGING THE 1ST
IMPACTFUL WINTER EPISODE OF THE SEASON THUS FAR FOR THE CRATER
AND DIAMOND LAKE AREA NORTHWARD TO WILLAMETTE PASS. ODOT SHOULD
BE READY TO ADDRESS SOME HIGHWAY IMPACTS THERE ACROSS THE HIGHER
REACHES. LOOKING LIKE A FAIR CANDIDATE FOR A WINTER WEATHER
ADVISORY AS THE EVENT APPROACHES. STAVISH
MFR WATCHES/WARNINGS/ADVISORIES
OR...FREEZE WARNING FROM 2 AM TO 10 AM PDT THURSDAY FOR ORZ023-024-
026.
CA...FREEZE WARNING FROM 2 AM TO 10 AM PDT THURSDAY FOR CAZ080>082.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS
EVENING FOR PZZ356.
SMALL CRAFT ADVISORY FROM 2 PM THURSDAY TO 2 AM PDT FRIDAY FOR
PZZ350-356-370.
SMALL CRAFT ADVISORY UNTIL 2 AM PDT FRIDAY FOR PZZ376.
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