878
FXUS66 KMFR 211806
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
1106 AM PDT MON OCT 21 2024
UPDATED AVIATION DISCUSSION.
AVIATION...21/18Z TAFS
AS OF 18Z, THE COLD FRONT IS LOCATED
APPROXIMATELY OVER LAKE AND MODOC COUNTIES AND WILL CONTINUE MOVING
EAST AND OUT OF OUR AREA THIS AFTERNOON. VFR TO MVFR CONDITIONS WITH
RESIDUAL SHOWERS ARE LEFT IN ITS WAKE THROUGH THIS EVENING.
SHOWERS WILL GRADUALLY DRY UP THIS EVENING, AND THEN OVERNIGHT THE
FOCUS FOR AVIATION TURNS TO FOG POTENTIAL. GUIDANCE HAS A 40-50%
CHANCE OF IFR CONDITIONS DUE TO CEILING AND AROUND A 30% CHANCE FROM
VISIBILITY, BOTH CENTERED OVER THE UMPQUA BASIN. THE LOCATION MAKES
SENSE, AND THERE IS PLENTY OF SURFACE MOISTURE FOR FOG WEST OF THE
CASCADE CREST, BUT EXPERIENCE SUGGESTS THAT THIS WILL DEPEND ON THE
DEGREE OF CLEARING TONIGHT. FOR NOW, WE HAVE INCLUDED DEGRADED
CONDITIONS IN THE TAF FOR KRBG AND TRENDED THAT WAY IN BOTH KOTH AND
KMFR. KLMT RECEIVED LITTLE RAIN, SO THEY ARE THE LEAST LIKELY TO SEE
ANY DEGRADED CONDITIONS TONIGHT. -WRIGHT
PREV DISCUSSION
/ISSUED 831 AM PDT MON OCT 21 2024/
DISCUSSION...A COLD FRONT BROUGHT RAIN TO AREAS WEST OF THE
CASCADES THIS MORNING AND LINGERING SHOWERS ARE NEAR THE CASCADES
NOW. 12 HOUR PRECIPITATION TOTALS SHOW THAT THERE WAS 0.75" TO
1.00" OF RAIN FROM CENTRAL DOUGLAS COUNTY TO THE COAST AND INTO
CURRY COUNTY. A FEW MORE SHOWERS WILL PASS INTO COOS AND DOUGLAS
COUNTIES TODAY BEFORE DRIER CONDITIONS RETURN LATER THIS
AFTERNOON. HIGHS IN THE 50S AND 60S ARE POSSIBLE TODAY. THE NEXT
AREA OF CONCERN WILL BE LATER THIS WEEK WITH THE RETURN OF RAIN
CHANCES.
PREV DISCUSSION... /ISSUED 548 AM PDT MON OCT 21 2024/
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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