431
FXUS66 KMFR 180003
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
403 PM PST MON FEB 17 2025
UPDATE AVIATION DISCUSSION
AVIATION...18/00Z TAFS
SCATTERED SHOWERS CONTINUE ACROSS THE
REGION THIS AFTERNOON, MOST NUMEROUS ALONG THE CASCADES. OVERALL,
VFR CONDITIONS PREVAIL WITH TERRAIN OBSCURATIONS, THOUGH SHOWERS ARE
RESULTING IN A MIX OF LOW END VFR/MVFR CEILINGS. NOT MUCH CHANGE IS
EXPECTED THROUGH THIS EVENING, THEN SHOWERS WILL DIMINISH OVERNIGHT
AS A WARM FRONT PUSHES INTO THE REGION. CLOUDS WILL GRADUALLY
DISSIPATE LATE TONIGHT INTO EARLY TUESDAY MORNING, AND THIS COULD
LEAD TO THE DEVELOPMENT LIFR CONDITIONS IN FOG/LOW CLOUDS FOR A
BRIEF PERIOD AROUND 10-12Z FOR VALLEYS BOTH EAST AND WEST OF THE
CASCADES. CONFIDENCE IS HIGHER FOR AREAS EAST OF THE CASCADES. ANY
LOWER CONDITIONS SHOULD IMPROVE BY LATE MORNING, WITH VFR PREVAILING
THEREAFTER. /BR-Y
PREV DISCUSSION
/ISSUED 219 PM PST MON FEB 17 2025/
DISCUSSION...MOIST ONSHORE FLOW CONTINUES THROUGH THIS EVENING
WITH SHOWERS MAINLY CONCENTRATED ALONG THE CASCADES.
SNOWFALL ACCUMULATIONS FOR THE CASCADES WILL BE MITIGATED DURING
THE DAY DUE TO DAYTIME HEATING, AND SHOULD PUT A CAP ON THE
AMOUNT OF SNOW THE REST OF THE AFTERNOON.
SHOWERS WILL CONTINUE INTO THIS EVENING, THEN DIMINISHING OVERNIGHT
TONIGHT, AND MOST WILL BE CONCENTRATED ALONG THE CASCADES.
UPPER RIDGING BUILDS INTO THE AREA LATE TONIGHT WITH THE UPPER RIDGE
AXIS OVERHEAD TUESDAY. PAST DATA WAS HINTING AT WARM FRONTAL
PRECIPITATION MOVING IN LATE TUESDAY MORNING AND AFTERNOON, BUT NOW
THE GENERAL CONSENSUS IS FOR THE MAJORITY OF PRECIPITATION TO REMAIN
OFFSHORE, AND NORTH OF OUR FORECAST AREA. HOWEVER, SOME OF THE HIGH
RES SHOW SOME LIGHT REFLECTIVITY (SIMULATED FORECAST RADAR) RETURNS
IN THE AFTERNOON. THEREFORE COULD NOT RULE OUT INTERMITTENT LIGHT
PRECIPITATION MAINLY NORTH OF THE UMPQUA DIVIDE TUESDAY AFTERNOON.
THERE'S INCREASING EVIDENCE WHATEVER PRECIPITATION WE DO GET NORTH
OF THE UMPQUA DIVIDE TUESDAY AFTERNOON WILL LIFT NORTH TUESDAY
EVENING AND WE COULD ACTUALLY CATCH A BREAK IN PRECIPITATION
UNTIL LATE TUESDAY NIGHT WHEN THE COLD FRONT REACHES THE COAST.
THIS IS BEING SUPPORTED BY SEVERAL OF THE HIGH RES GUIDANCE AND
INDIVIDUAL ENSEMBLE MEMBERS.
OVERNIGHT TUESDAY, THERE'S SOME EVIDENCE SHOWING A SURFACE LOW
DEVELOPING INSIDE OF 130W AND TRACKING NORTHEAST NORTH OF OUR
FORECAST AREA. AS OF THIS WRITING, THERE A COUPLE OF MODELS THAT DO
NOT SHOW THE DEVELOPING LOW, BUT A FEW OF THE HIGH RES MODELS THAT GO
OUT TO 48 HOURS (4AM PST WEDNESDAY MORNING) SHOW THE DEVELOPING
LOW. SHOULD THIS PAN OUT, WE COULD BE LOOKING AT A 4-6 HOUR PERIOD
OF MODERATE TO STRONG WINDS OVER EXPOSED AREAS ALONG THE COAST AND
HEADLANDS, AND SOUTH COASTAL MOUNTAINS THAT COULD GET CLOSE TO HIGH
WIND WARNING CRITERIA. HOWEVER, WE'LL HOLD OFF ON THIS AND WAIT FOR
THE NEXT RUN OF THE HIGH RES TO SEE IF THERE'S A BETTER CONSENSUS ON
THIS. ALSO MODERATE TO OCCASIONALLY STRONG WINDS ARE POSSIBLE IN THE
SOUTH END OF THE SHASTA VALLEY NEAR WEED, AND SOUTH END OF THE ROGUE
VALLEY TOWARDS TALENT AND ASHLAND.
A COLD FRONT AND UPPER TROUGH WILL REACH THE COAST LATE TONIGHT,
THEN MOVING INLAND WEDNESDAY MORNING WITH SNOW LEVELS FALLING IN THE
MORNING, THEN REBOUNDING SOME IN THE AFTERNOON DUE TO DIURNAL
EFFECTS. SNOW LEVELS WILL VARY DEPENDING ON PRECIP INTENSITY SINCE
WE'LL BE IN A CONVECTIVE ENVIRONMENT FROM LATE WEDNESDAY MORNING AND
AFTERNOON. GENERALLY THEY ARE EXPECTED TO BE BETWEEN 4000-4500 FEET.
PRECIPITATION WEDNESDAY WILL BE MAINLY CONCENTRATED ALONG THE
CASCADES AND COASTAL MOUNTAINS IN SOUTHWEST OREGON.
SHOWERS WILL CONTINUE WEDNESDAY EVENING, THEN DIMINISHING WEDNESDAY
NIGHT AS THE UPPER TROUGH SHIFTS SOUTH.
UPPER RIDGING WILL BUILDS INTO THE AREA THURSDAY RESULTING IN DRY
AND MILDER WEATHER WITH THE STORM TRACK SHIFTING NORTH. THIS IS
BEING SUPPORTED BY THE CLUSTERS, AND THE MAJORITY OF THE INDIVIDUAL
ENSEMBLE MEMBERS.
THE UPPER RIDGE WILL FLATTEN OUT SOME FRIDAY, BUT THE GENERAL
CONSENSUS IS FOR THE STORM TRACK AND THUS BEST CHANCE OF
PRECIPITATION TO REMAIN NORTH. THE REASON FOR THIS IS THE FRONTAL
BOUNTY AND UPPER FLOW WILL BE NEARLY PARALLEL WHICH WILL KEEP THE
FRONT FROM PUSHING SOUTH INTO OUR AREA. IN CONTRAST THE NBM IS TOO
HIGH AND TOO FAR SOUTH, ESPECIALLY ON FRIDAY, BUT IT IS TRENDING
IN THE RIGHT DIRECTION WITH THE HIGHEST POPS IN THE NORTHWEST PART
OF THE AREA.
THERE ARE SIGNS THE STORM TRACK COULD SHIFT SOUTH SATURDAY AND BRING
A CHANCE OF PRECIPITATION IN THE NORTHWEST PART OF THE FORECAST AREA
SATURDAY AFTERNOON, THEN ALONG THE COAST AND NORTH OF THE UMPQUA
DIVIDE SATURDAY NIGHT AND SUNDAY. THE INDIVIDUAL ENSEMBLE MEMBERS
SHOW VARYING SOLUTIONS, WITH A SLIGHT MAJORITY OF THEM KEEPING THE
STORM TRACK FAR ENOUGH NORTH TO KEEP IT DRY IN OUR AREA ON SATURDAY.
THE CLUSTERS ARE ALSO IN AGREEMENT SHOWING UPPER RIDGING BUILDING IN
FOR THE LATTER PART OF NEXT WEEK INTO NEXT WEEKEND, BUT DOES SHOW A
SLIGHT FLATTENING OF THE RIDGE SATURDAY WHICH COULD RESULT IN SOME
PRECIPITATION SLIPPING THROUGH THE CRACKS IN PORTIONS OF COOS AND
DOUGLAS COUNTY.
PRECIPITATION CHANCES INCREASE NEXT SUNDAY INTO MONDAY AS THE STORM
TRACK SHIFTS SOUTH AS THE UPPER LEVEL RIDGE FLATTENS OUT MORE.
-PETRUCELLI
MARINE...UPDATED 230 PM PST MONDAY, FEBRUARY 17, 2025...STEEP
SEAS CONTINUE IN ALL WATERS SUPPORTED BY CONTINUING WESTERLY
SWELL. THESE CONDITIONS ARE EXPECTED TO CONTINUE INTO EARLY
TUESDAY MORNING.
SEAS WILL BRIEFLY FALL BELOW ADVISORY CONDITIONS DURING THE DAY
TUESDAY BEFORE A SYSTEM APPROACHES ON TUESDAY AFTERNOON. MARINE
SHOWERS ARE EXPECTED AND GUSTY SOUTHERLY WINDS WILL DEVELOP. A GALE
WARNING IN PLACE COVERS THE EXPECTED TIMING OF IMPACTFUL CONDITIONS.
THERE ARE TWO ADDITIONAL CONSIDERATIONS IN THE FORECAST. CURRENTLY,
CHANCES OF STORM FORCE GUSTS ARE PRESENT IN CERTAIN GUIDANCE. WHEN
THESE GUSTS DO APPEAR IN GUIDANCE, THEY'RE PRESENT EARLY WEDNESDAY
MORNING NEAR THE COAST ESPECIALLY NEAR CAPE BLANCO. THERE IS A 25%
CHANCE FOR STORM FORCE GUSTS TO DEVELOP OVER OUTER WATERS AS WELL.
AN ADDITIONAL CONSIDERATION WILL BE FOR GUSTY WINDS TO WRAP AROUND
THE SYSTEM AND CONTINUE BEYOND THE INITIAL FRONT. THESE WINDS COULD
BE AT OR NEAR GALE STRENGTH, AND COULD EXTEND UNSETTLED CONDITIONS.
MOST HIGH-RESOLUTION GUIDANCE SHOWS THESE WRAP-AROUND WINDS NEAR THE
END OF THE GALE WATCH. WITH THESE LONGER DURATION WINDS, STEEP SEAS
COULD CONTINUE THROUGH THE DAY THURSDAY. WITH ANOTHER FRONT EXPECTED
ON FRIDAY, ADVISORY-LEVEL SEAS COULD CONTINUE INTO THE WEEKEND.
IN SHORT, THERE'S HIGH CONFIDENCE IN STEEP TO VERY STEEP SEAS AND
THE POSSIBILITY OF GALE GUSTS IN ALL WATERS FROM TUESDAY EVENING
INTO WEDNESDAY MORNING, WITH STEEP SEAS THROUGH WEDNESDAY.
ADDITIONAL GUIDANCE WILL HELP TO DETERMINE THE CHANCES OF STORM
FORCE GUSTS AND HOW LONG STEEP SEAS CONTINUE INTO THE END OF THE
WEEK. -TAD
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 4 AM PST TUESDAY
FOR PZZ350-356-370-376.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING FOR
PZZ350-356-370-376.
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