257
FXUS66 KMFR 201546
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
846 AM PDT SUN OCT 20 2024
DISCUSSION
THE FORECAST IS ON TRACK FOR THE AREA TODAY. A COLD
FRONT STILL LOOKS TO BRING SHOWERS TO THE COAST THIS EVENING INTO
MONDAY MORNING. SHOWERS WILL MOVE OVER WEST SIDE VALLEYS AND TO
THE CASCADES THROUGH MONDAY MORNING, WITH ACTIVITY CALMING IN THE
AFTERNOON AND EVENING. AREAS EAST OF THE CASCADES WILL GET MINIMAL
PRECIPITATION FROM THIS FRONT. NO HAZARDS ARE EXPECTED THROUGH THE
DAY, ALTHOUGH LOCALLY MODERATE TO HEAVY SHOWERS MAY MAKE TRAVEL
DIFFICULT.
PLEASE SEE THE PREVIOUS DISCUSSION FOR MORE DETAILS ABOUT THE
SHORT- AND LONG-TERM FORECAST. -TAD
AVIATION (12Z TAFS)
AN APPROACHING FRONT WILL BRING RAIN SHOWERS, LOW CLOUDS, AND
POSSIBLY VISIBILITY RESTRICTIONS TO AREAS ALONG AND NEAR THE COAST
WHICH WILL IMPACT KOTH (IFR/LIFR) THIS MORNING. ROSEBURG IS
LIKELY TO BE INFLUENCED BY THIS MARINE LAYER AND RAIN SHOWERS AS
WELL, BUT CONDITIONS ARE EXPECTED TO BE MVFR AT THIS TIME. THERE
IS UNCERTAINTY WHETHER OR NOT SHOWERS WILL IMPACT KMFR/KLMT
THROUGH THIS CYCLE, AND CURRENT THINKING IS THIS MAY BE AFTER 12Z
(18Z TAF CYCLE).
-GUERRERO
MARINE (UPDATED 200 AM)
WINDS SWITCH TO SOUTHERLY LATER THIS MORNING AND INCREASE AHEAD OF A
COLD FRONT THIS AFTERNOON. AS THE FRONT COMES THROUGH OUR WATERS,
CONDITIONS MAY BRIEFLY BECOME HAZARDOUS TO SMALLER CRAFT DUE TO A
COMBINATION OF STEEP WIND WAVES AND WESTERLY SWELL, MAINLY ISOLATED
AREAS NORTH OF CAPE BLANCO. EXPECT RAIN WITH THE FRONT THIS
AFTERNOON, BUT THEN THE FRONT MOVES ONSHORE WITH IMPROVING
CONDITIONS MONDAY. A THERMAL TROUGH DEVELOPS ALONG THE COAST
TUESDAY, AND THIS WILL BRING GUSTY NORTH WINDS AND WIND DRIVEN SEAS
THAT WILL REACH AT LEAST ADVISORY LEVELS TUESDAY INTO WEDNESDAY,
ESPECIALLY SOUTH OF CAPE BLANCO.
-GUERRERO
PREV DISCUSSION
/ISSUED 342 AM PDT SUN OCT 20 2024/
SHORT TERM...
PLENTY OF STRATUS AND FOG IS COVERING LOCATIONS ALONG THE COAST
THIS MORNING WITH SOME HIGH CLOUDS MOVING OVERHEAD AS WELL. TODAY
WILL BE A PRETTY QUIET MORNING TO START OFF WITH PARTLY CLOUDY
SKIES AND HIGH TEMPERATURES 5 TO 10 DEGREES WARMER THAN NORMAL.
OTHERWISE, A COLD FRONT WILL SLOWLY DESCENT ON THE OREGON COAST BY
THE EVENING HOURS. THE PROBABILITY OF PRECIPITATION JUMPS UP TO 50
TO 60 PERCENT BETWEEN 4 AND 7PM THIS EVENING. THE FRONT WILL MOVE
INLAND SUNDAY NIGHT WITH A NEAR 100% CHANCE OF RAIN FOR LOCATIONS
WEST OF THE CASCADES IN OREGON. THOSE PROBABILITIES DROP OFF THE
FARTHER ONE MOVES SOUTH AND EAST AWAY FROM THE BEST DYNAMICS AND
MOISTURE SUNDAY NIGHT. IT LOOKS LIKE THE COAST COULD SEE UP TO 1
INCH OF RAIN BASED ON THE LATEST FORECASTS WITH UP TO 0.5 INCHES
OVER LOCATIONS WEST OF THE CASCADES.
THE FRONT WEAKENS ON MONDAY AND BECOMES MORE STATIONARY, ALTHOUGH
THE UPPER LEVEL TROUGH WILL MOVE THROUGH OREGON BY MONDAY
AFTERNOON. AS A RESULT, THE PROBABILITY OF PRECIPITATION CHANCES
LINGER IN OREGON, ESPECIALLY WEST OF THE CASCADES. IT SEEMS THE
PRECIPITATION MODE WILL BE MORE SHOWERY GIVEN THE LIMITED
CONVECTIVE AVAILABLE POTENTIAL ENERGY(CAPE). RIGHT NOW, WE SEE
ABOUT 100 J/KG OVER LOCATIONS WEST OF THE CASCADES BY LATE MONDAY
MORNING. WITH A RELATIVELY COOL MOIST AIRMASS LINGERING IN THE
VALLEYS, PATCHY FOG SEEMS REASONABLE MONDAY NIGHT INTO TUESDAY
MORNING.
ONCE THE UPPER LEVEL TROUGH MOVES THROUGH THE FORECAST AREA LATE
MONDAY NIGHT AND TUESDAY MORNING, WE'LL SEE A VERY WEAK THERMAL
TROUGH SET UP ALONG THE COAST WITH EAST BREEZES AROUND 5 TO 10
KNOTS. TEMPERATURES WILL RISE SLIGHTLY ON TUESDAY, ALTHOUGH THE
WARMUP WILL BE MORE NOTABLE WEDENSDAY WITH MORE CLEARING IN THE
SKIES. -SMITH
LONG TERM...
WEDNESDAY AND THURSDAY SHOULD BE PRETTY MUNDANE WEATHER WISE WITH
AN UPPER LEVEL RIDGE BUILDING INTO OREGON AND NORTHERN CALIFORNIA.
NORMAL FALL TEMPERATURES ARE EXPECTED WITH THE TYPICAL WEAK
LATE AFTERNOON BREEZES.
THE MAIN WEATHER FEATURE IN THE EXTENDED FORECAST APPEARS TO BE A
WEAK LOW PRESSURE SYSTEM HITTING SOUTHERN OREGON SOMETIME BETWEEN
THURSDAY NIGHT AND SATURDAY. THERE ARE DIFFERENCES IN THE
ENSEMBLES ON WHEN OR WHERE THIS LOW WILL ARRIVE IN THE PACIFIC
NORTHWEST, ALTHOUGH THE MOST LIKELY TIME SEEMS TO BE MID DAY
FRIDAY. FOR THE ENSEMBLE MEMBERS(~15%) THAT ARE DRY THROUGH
THURSDAY AND FRIDAY, THEY BRING SOME PRECIPITATION TO THE REGION
EVENTUALLY ON SATURDAY. SO THERE ARE INDEED PLENTY OF VARIABLES
THIS FAR OUT, ALTHOUGH AGAIN THE MOST LIKELY IS A LOW PRESSURE
SYSTEM BRINGING PRECIPITATION AROUND MID DAY FRIDAY.
IF A LOW DOES HIT SOUTHERN OREGON, IT 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. THE EXTREME FORECAST INDEX SHOWS NOTHING NOTABLE IN THE
EXTENDED PORTION OF THE FORECAST AS WELL. THE OTHER THING WE
WANTED TO NOTE IS WE'LL LIKELY BE UNDER SOME SOUTHWEST FLOW WHEN
THIS WEATHER HITS BETWEEN THURSDAY INTO SATURDAY, SO SNOW LEVELS
WILL LIKELY REMAIN ON THE HIGH SIDE(7000-8000 FEET).
-SMITH
MFR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
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