986
FXUS66 KMFR 211248
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
548 AM PDT MON OCT 21 2024
..UPDATED THE AVIATION AND MARINE SECTIONS
AVIATION...21/12Z TAFS
ALONG THE COAST AND JUST OFFSHORE. A
COLD FRONT HAS MOVED INLAND. THERE IS A MIX OF IFR AND MVFR CEILINGS
IN SCATTERED SHOWERS IN THE POST-FRONTAL AIR MASS. SHOWERS WILL
DIMINISH, AND AREAS OF VFR AND BREAKS IN THE CLOUDS WILL GRADUALLY
DEVELOP AND INCREASE AFTER 14Z THIS MORNING THROUGH THE AFTERNOON.
PATCHY MVFR CEILINGS ARE EXPECTED TONIGHT INTO TUESDAY MORNING, WITH
THE AID OF RESIDUAL LOW LEVEL MOISTURE.
INLAND. THE FRONT IS BETWEEN THE COAST RANGE AND CASCADES WITH LIGHT
TO MODERATE RAIN, A MIX OF MVFR AND VFR CEILINGS AND VISIBILITIES,
AND AREAS OF MOUNTAIN OBSCURATION. THE FRONT WILL WEAKEN AS IT
CONTINUES EAST ACROSS THE AREA TODAY. WIND SHEAR AHEAD OF THE FRONT
THIS MORNING WILL NOT BE STRONG, BUT STRONG ENOUGH TO MENTION WITH
LOW LEVEL SOUTHWEST WINDS ALOFT AT AROUND 25 KT.
EAST SIDE LOCATIONS WILL LIKELY STAY VFR, WITH SPOTTY SHOWERS MAINLY
IN KLAMATH COUNTY. BRIEF REDUCTIONS TO MVFR ARE POSSIBLE WITH THE
FRONTAL PASSAGE. WINDS ARE SOUTHERLY AT MOST LOCATIONS AHEAD OF THE
FRONT. THE FRONT WILL PRODUCE A WIND SHIFT WITH GUSTY, BREEZY WEST
WINDS EXPECTED IN THE AFTERNOON, INCLUDING AT KLAMATH FALLS.
-DW
MARINE (UPDATED 300 AM)
THE MAIN UPDATE THIS MORNING WAS TO ISSUE
A SMALL CRAFT ADVISORY SOUTH OF CAPE BLANCO OUT TO AROUND 30 NM FROM
SHORE FOR TUESDAY AFTERNOON AND TUESDAY NIGHT.
A COLD FRONT MOVED INLAND EARLY THIS MORNING. WINDS HAVE DIMINISHED,
BUT MODERATE WEST-NORTHWEST SWELL DOMINATED SEAS WILL RISE SLIGHTLY
TO A PEAK THIS EVENING.
CONDITIONS THEN IMPROVE INTO EARLY TUESDAY. GUSTY NORTH WINDS AND
STEEP WIND DRIVEN SEAS RETURN SOUTH OF CAPE BLANCO FOR TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT AS A THERMAL TROUGH BRIEFLY
DEVELOPS. CONDITIONS IMPROVE AGAIN WEDNESDAY, BEFORE A STRONGER
THERMAL TROUGH DEVELOPS FOR THURSDAY. STEEP SEAS ARE POSSIBLE ACROSS
ALL OF THE SOUTHERN OREGON WATERS ON THURSDAY AFTERNOON AND NIGHT.
ANOTHER BRIEF BREAK IS POSSIBLE FRIDAY BEFORE THE NEXT FRONT ARRIVES
LATE IN THE WEEK. THERE IS A WIDE VARIETY OF MODEL SOLUTIONS REGARDING
THE STRENGTH AND TIMING OF THE FRONT, BUT STEEP TO VERY STEEP
SEAS AND GALES ARE POSSIBLE.
-DW
PREV DISCUSSION
/ISSUED 400 AM PDT MON OCT 21 2024/
SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)...RADAR IMAGERY
SHOWS A BAND OF RAINFALL FALLING ACROSS PORTIONS OF SOUTHERN
OREGON AND NORTHERN CALIFORNIA. THIS RAIN HAS BEEN MODERATE AT
TIMES AND A HALF AN INCH OF RAIN HAS FALLEN AT THE ROSEBURG
AIRPORT ALREADY. RAIN SHOULD BEGIN FALLING IN MEDFORD IN A FEW
MINUTES. THIS FRONT IS EXPECTED TO STALL OUT AND WEAKEN LATER THIS
MORNING WITH LINGERING SHOWERS OCCURRING THROUGH THE DAY MAINLY
ALONG AND WEST OF THE I-97 CORRIDOR. REGARDING THUNDERSTORM
CHANCES, A RUMBLE OF THUNDER MAY BE POSSIBLE, BUT AT A 10% CHANCE
OR LESS, REMAINS UNLIKELY.
SNOW LEVELS WILL REMAIN RELATIVELY HIGH AT ABOVE 6000 FEET AND
WILL FALL TO AROUND 5000 FEET TONIGHT AFTER THE PRECIPITATION
ENDS. THIS MEANS THAT SNOW WILL BE CONFINED TO THE HIGHER PEAKS OF
THE CASCADES, SISKIYOUS, AND MT. SHASTA ITSELF.
A DRY PERIOD WILL FOLLOW THE FRONT AND CONTINUE THROUGH MOST OF THE
WEEK. SEASONAL TEMPERATURES ARE EXPECTED ACROSS THE AREA ON MONDAY
AND TUESDAY, WITH WARMING ON WEDNESDAY AND THURSDAY BRINGING LOW 70S
WEST OF THE CASCADES AND MID TO HIGH 60S TO THE EAST. THERE ARE
SLIGHT CHANCES (15-25%) FOR FOG AND/OR FROST IN LOW LYING AREAS
ON MONDAY NIGHT INTO TUESDAY MORNING AND LOWER CHANCES ON
WEDNESDAY MORNING. -SCHAAF
LONG TERM...PREVIOUS LONG TERM DISCUSSION ISSUED SUNDAY 10/20...A
HIGH PRESSURE RIDGE WILL REMAIN IN PLACE ON THURSDAY. MEANWHILE
MODELS SHOW GOOD AGREEMENT WITH A WEAK LOW APPROACHING FROM THE
WEST LATE THURSDAY INTO FRIDAY. THIS LOW IS EXPECTED TO WEAKEN AS
IT TRACKS NORTHWARD ALONG THE OREGON COAST FRIDAY INTO EARLY
SATURDAY. MODEL SOLUTIONS VARY ON THE EXACT TIMING AND TRACK
THOUGH. THIS WILL PLAY A ROLE IN HOW MUCH RAINFALL SPREADS INLAND
FROM THE COAST AS THE LOW MOVES NORTHWARD. GIVEN THESE
DIFFERENCES, CONFIDENCE IS LOW ON THE DETAILS OF HOW MUCH
PRECIPITATION IT MAY BRING. THE MAJORITY OF THE MODELS INDICATE
RAINFALL NEAR THE COAST AND INLAND INTO PORTIONS OF THE AREA FROM
THE CASCADES WEST WITH LOWER CHANCES FOR RAIN EAST OF THE
CASCADES(15-30%). OVERALL, THIS SYSTEM DOESN'T LOOK IMPACTFUL AS
ALMOST ALL THE MODEL SIMULATIONS HAVE A LOW AROUND 990 TO 1000
MILLIBARS AND SOME MEMBERS DO NOT HAVE A DISTINGUISHABLE LOW
CENTER. ADDITIONALLY, WE WILL BE UNDER SOUTHWEST FLOW WHEN THIS
WEATHER HITS BETWEEN THURSDAY NIGHT INTO SATURDAY, SO SNOW LEVELS
WILL LIKELY REMAIN ON THE HIGH SIDE(7000-8000 FEET).
THEREAFTER, WE MAY SHIFT TO A COOLER AND WETTER PATTERN. MODELS AND
ENSEMBLES SHOW A LOW PRESSURE SYSTEM IN THE GULF OF ALASKA BRING A
FRONT INTO THE REGION NEXT WEEKEND, WITH ADDITIONAL DISTURBANCES
LEADING UP TO HALLOWEEN. -SCHAAF/CC
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 2 PM TUESDAY TO 2
AM PDT WEDNESDAY FOR PZZ356-376.
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