143
FXUS66 KMFR 211100
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
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
AVIATION...21/06Z TAFS
ALONG THE COAST AND JUST OFFSHORE. AN
APPROACHING FRONT WILL KEEP CEILINGS VFR TO START THE TAF PERIOD,
HOWEVER THEY WILL LOWER AS THE FRONT MOVES SOUTHEAST RESULTING IN
IFR CEILINGS, VISIBILITY COULD ALSO BE REDUCED DUE TO MODERATE TO
OCCASIONALLY HEAVY PRECIPITATION. CEILINGS ARE EXPECTED TO IMPROVE
LATER MONDAY MORNING AS THE FRONT MOVES INLAND FOLLOWED BY MARGINAL
INSTABILITY.
INLAND. VFR CEILINGS WILL CONTINUE THROUGH THIS EVENING. RAIN WITH
VFR TO OCCASIONAL MVFR CEILINGS WILL OVERSPREAD AREAS FROM THE
CASCADE CREST WEST TONIGHT, WITH BEST CHANCE FOR MVFR CEILINGS ALONG
AND NORTH OF THE UMPQUA DIVIDE, CURRY AND COOS COUNTY. MEDFORD
SHOULD REMAIN VFR, BUT THE HIGHER TERRAIN COULD END UP PARTLY
OBSCURED BETWEEN 15 AND 18Z.
EAST SIDE LOCATIONS WILL LIKELY STAY VFR BUT WITH SPOTTY SHOWERS AND
BRIEF REDUCTIONS TO CONDITIONS LATE TONIGHT INTO MONDAY MORNING.
WINDS WILL BECOME SOUTHERLY AT MOST LOCATIONS AS THE FRONT
APPROACHES, FOLLOWED BY A WIND SHIFT AND BECOMING BREEZY AT KLAMATH
FALLS MONDAY AFTERNOON. -PETRUCELLI
MARINE
A COLD FRONT WILL MOVE INTO THE WATERS
TONIGHT. CONDITIONS GENERALLY REMAIN JUST BELOW SMALL CRAFT ADVISORY
THRESHOLDS, BUT SOUTH WINDS GUSTING INTO THE 25-27 KNOT RANGE WILL
CONTINUE AHEAD OF THE FRONT, ESPECIALLY NORTH OF CAPE BLANCO. SEAS
WILL ALSO REMAIN ELEVATED BUT GENERALLY SUB SMALL CRAFT LEVELS AS
THE FRONT APPROACHES. ALONG AND JUST AHEAD OF THE FRONT WILL BE
MODERATE TO OCCASIONALLY HEAVY RAIN. CONDITIONS IMPROVE BRIEFLY
MONDAY, BUT A THERMAL TROUGH DEVELOPS ALONG THE COAST TUESDAY THAT
IS LIKELY BRING TO BRING AT LEAST SMALL CRAFT ADVISORY LEVEL NORTH
WINDS AND WIND DRIVEN SEAS LATER TUESDAY THROUGH THURSDAY.
-WRIGHT/PETRUCELLI
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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