151
FXUS66 KMFR 162338
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
338 PM PST SUN FEB 16 2025
..UPDATED AVIATION DISCUSSION
AVIATION...17/00Z TAFS
ONSHORE FLOW CONTINUES TO BRING
ATMOSPHERIC MOISTURE, SUPPORTING ONGOING PRECIPITATION. VFR AND MVFR
CEILINGS AND SCATTERED SHOWERS CONTINUE ACROSS NORTHERN CALIFORNIA
AND SOUTHERN OREGON, AND MVFR WILL BECOME MORE WIDESPREAD OVERNIGHT
AND THROUGH MUCH OF MONDAY. MOST SHOWER ACTIVITY IS OVER COASTAL
RANGES, WESTERN SISKIYOU COUNTY, AND ALONG THE CASCADES, BUT SHOWERS
ARE POSSIBLE ACROSS THE MAJORITY OF THE REGION. SNOW LEVELS REMAIN
AT 4000 TO 4500 FEET, AND RAIN SHOWERS CAN LOCALLY LOWER SNOW
LEVELS. HEAVIER SHOWERS CAN BRING AREAS OF LOW VISIBILITY AND
OBSCURED TERRAIN. -BPN
PREV DISCUSSION
/ISSUED 212 PM PST SUN FEB 16 2025/
DISCUSSION...MOIST ONSHORE FLOW WITH FAVORABLE OROGRAPHICS FOR THE
CASCADES WILL CONTINUE THROUGH MONDAY AFTERNOON. SHOWERS WILL BE
MAINLY CONCENTRATED ALONG THE CASCADES AND COASTAL MOUNTAINS IN
SOUTHWEST OREGON.
SNOW WILL BE PERSISTENT IN THE CASCADES IS EXPECTED TONIGHT WITH A
MOIST WESTERLY FLOW PROVIDING GOOD OROGRAPHICS ALONG THE CASCADES
THROUGH AT LEAST MONDAY AFTERNOON. GUIDANCE SUGGEST SNOWFALL RATES
INCREASE LATE THIS AFTERNOON THROUGH TONIGHT AND IT'S LIKELY (80-
100%) CHANCE FOR SNOWFALL RATES OF AN INCH PER HOUR DURING THIS
TIME. THIS WILL BE THE MAIN DRIVING FORCE FOR THE WINTER STORM
WARNING. UNDER DIFFERENT CIRCUMSTANCES, STORM TOTAL SNOW IS OVER A
LONG DURATION AND THIS IN ITSELF WOULD NOT BE ENOUGH TO WARRANT A
WINTER STORM WARNING, BUT SNOWFALL RATES WILL.
MOIST ONSHORE FLOW WITH AN UPPER TROUGH OVER THE AREA MONDAY WILL
KEEP THE SHOWERS GOING, WITH MOST CONCENTRATED IN THE OROGRAPHIC
FAVORED UPSLOPE AREAS ALONG THE CASCADES, AND THE COASTAL MOUNTAINS,
IN SOUTHWEST OREGON.
SNOWFALL ACCUMULATIONS FOR THE CASCADES COULD BE MITIGATED DURING THE
DAY MONDAY DUE TO DAYTIME HEATING SHOULD PUT A CAP ON THE AMOUNT OF
SNOW IN THE AFTERNOON.
SHOWERS WILL CONTINUE INTO MONDAY NIGHT, BUT THEY WILL BE GRADUALLY
DIMINISHING AND MOST WILL BE CONCENTRATED ALONG THE CASCADES.
UPPER RIDGING BUILDS INTO THE AREA BRIEFLY TUESDAY MORNING WHICH
SHOULD GIVE US A BREAK IN PRECIPITATION. THIS WON'T LAST LONG WITH
WARM FRONTAL PRECIPITATION MOVING INTO THE AREA (CASCADES WEST)
TUESDAY AFTERNOON. SNOW LEVELS TUESDAY AFTERNOON WILL BE ON THE RISE
TO AROUND 5500 FEET TUESDAY AFTERNOON AND NEAR 6000 FEET TUESDAY
EVENING.
A COLD FRONT AND UPPER TROUGH WILL MOVE IN EARLY 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, BUT
WILL GENERALLY BE BETWEEN 4000-4500 FEET. WEDNESDAY WILL BE SIMILAR
TO TODAY WITH VALLEY RAIN AND MOUNTAINS SNOW SHOWERS.
SHOWERS WILL CONTINUE WEDNESDAY EVENING, THEN DIMINISHING WEDNESDAY
NIGHT AS THE UPPER TROUGH SHIFTS SOUTH.
UPPER RIDGING WILL BUILDS INTO THE AREA THURSDAY AND FRIDAY
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. IN CONTRAST THE NBM IS ONE AGAIN
TOO HIGH AND TOO FAR SOUTH, ESPECIALLY ON FRIDAY.
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. HOWEVER ABOUT 50% OF THE
INDIVIDUAL ENSEMBLE MEMBERS KEEP 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. THE POSITION OF THE UPPER RIDGE SUGGEST
THE STORM TRACK SHOULD REMAIN JUST NORTH OF OUR AREA. HOWEVER IT'S
STILL CLOSE ENOUGH TO AT LEAST WARRANT A CHANCE OF PRECIPITATION
ALONG THE COAST AND NORTH OF THE UMPQUA DIVIDE NEXT SUNDAY. T
-PETRUCELLI
MARINE...UPDATED 200 PM PST SUNDAY, FEBRUARY 16, 2025
STEEP SEAS
CONTINUE THIS AFTERNOON, SUPPORTED BY LINGERING FRESH SWELL. LONG
PERIOD WESTERLY SWELL IS FORECAST TO BUILD IN AREA WATERS THIS
EVENING. WHILE A CHANGE IN HAZARD LEVEL IS NOT IN PLACE, SEAS ARE
EXPECTED TO BECOME 12 TO 15 FEET AT 13 TO 15 SECONDS TONIGHT AND
THROUGH THE DAY MONDAY. AN EXISTING SMALL CRAFT ADVISORY HAS BEEN
EXTENDED UNTIL TUESDAY AT 5 AM, SUPPORTED BY THIS SWELL.
AFTER A BRIEF PERIOD OF BELOW ADVISORY SEAS ON TUESDAY MORNING, A
FRONT WILL BRING MORE MARINE SHOWERS AND ANOTHER ROUND OF GUSTY
SOUTHERLY WINDS. EXPECTED WIND SPEEDS HAVE BEEN INCREASING WITH
ADDITIONAL GUIDANCE, WITH A 50% CHANCE OF GALE GUSTS ACROSS AREA
WATERS. A GALE WATCH IS IN PLACE FOR ALL WATERS FOR TUESDAY
AFTERNOON INTO EARLY WEDNESDAY MORNING. ADDITIONAL STEEP TO VERY
STEEP AND HAZARDOUS CONDITIONS ARE EXPECTED TUESDAY AFTERNOON AND
THROUGH THE DAY WEDNESDAY.
BEYOND THE MID-WEEK FRONT, IMPROVEMENT TO BELOW ADVISORY SEAS LOOKS
POSSIBLE ON THURSDAY BEFORE SWELL-BUILT STEEP SEAS RETURN ARE
FORECAST FOR FRIDAY. -TAD
MFR WATCHES/WARNINGS/ADVISORIES
OR...WINTER STORM WARNING UNTIL 4 PM PST MONDAY FOR ORZ027-028.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 4 AM PST TUESDAY
FOR PZZ350-356-370-376.
GALE WATCH FROM TUESDAY AFTERNOON THROUGH LATE TUESDAY NIGHT FOR
PZZ350-356-370-376.
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