850
FXUS66 KMFR 281754
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
953 AM PST MON NOV 28 2022
UPDATED AVIATION SECTION
DISCUSSION
SATELLITE AND RADAR IMAGERY SHOW NUMEROUS SHOWERS
ACROSS SOUTHWEST OREGON. SHOWERS ARE A MIX OF RAIN AND SNOW
SHOWERS. SNOW LEVELS HAVE BEEN AROUND 3000 FEET, EXCEPT LOWER
(AROUND 2500 FEET) ACROSS DOUGLAS COUNTY AND COOS COUNTIES. SNOW
LEVELS WILL GRADUALLY LOWER LATE TODAY INTO THIS EVENING, DOWN TO
AROUND 2000 FEET. HOWEVER, SHOWERS ARE EXPECTED TO DIMINISH IN
COVERAGE AND INTENSITY DURING THE EVENING. SO ANY SNOW DOWN TO
LOWER ELEVATIONS WILL BE VERY LIGHT. THEN, LINGERING SHOWERS ARE
EXPECTED AT THE COAST AND INTO THE UMPQUA AND S. OR CASCADES
TONIGHT. OTHERWISE, EXPECT CONTINUED GUSTY WINDS OVER THE
MOUNTAINS AND EAST OF THE CASCADES THROUGH THIS AFTERNOON WITH
GUSTS OF 20-35 MPH EXCEPT STRONGER IN THE AREAS NEAR SUMMER LAKE
AND OVER EXPOSED RIDGETOPS (GUSTS OF 35-40 MPH). WINDS WILL LOWER
THIS EVENING.
WEDNESDAY AND THURSDAY A STRONG AND MOIST STORM ARRIVES, BRINGING
THE POTENTIAL FOR SIGNIFICANT IMPACTS WITH HEAVY SNOW AND WINDS.
HEAVY SNOW IS POSSIBLE OVER THE MOUNTAINS, ESPECIALLY THE CASCADES
AND WESTERN/CENTRAL SISKIYOU COUNTY AS WELL AS IN THE MOUNT
SHASTA AND WEED AREAS. MODERATE TO LOCALLY HEAVY SNOW IS ALSO
POSSIBLE EAST OF THE CASCADES. GUSTY WINDS ARE ALSO EXPECTED,
ESPECIALLY IN THE SHASTA VALLEY, OVER THE MOUNTAINS AND EAST OF
THE CASCADES. GUSTY WINDS COMBINED WITH SNOW MAY RESULT IN
ADDITIONAL HAZARDS WITH BLOWING SNOW CREATING REDUCED
VISIBILITIES. WE WILL BE EVALUATING THIS PERIOD FOR POTENTIAL OF
WINTER STORM WATCH. PLEASE CHECK BACK FOR UPDATES.
AVIATION...28/18Z TAFS
EXPECT A MIX OF VFR AND MVFR CONDITIONS TO
CONTINUE THIS AFTERNOON WITH SHOWERS AND WIDESPREAD TERRAIN
OBSCURATIONS. GUSTY WINDS WILL CONTINUE ALONG THE TERRAIN
AND EAST OF THE CASCADES, INCLUDING KLMT INTO THIS AFTERNOON.
WIND GUSTS NEAR 30 KT ARE EXPECTED AT KLAMATH FALLS. THE FRONT WILL
PUSH EAST OF THE AREA THIS EVENING AND MOST SHOWERS WILL END, THOUGH
SOME MAY CONTINUE INTO THE OVERNIGHT NEAR THE CASCADES AND OVER TO
THE COAST. EXPECT SOME IFR TO DEVELOP OVERNIGHT INTO TUESDAY MORNING
FOR THE VALLEYS WEST OF THE CASCADES WITH PATCHY FOG ELSEWHERE.
-SPILDE
MARINE...UPDATED 800 AM PST MONDAY 28 NOVEMBER 2022
STEEP TO
VERY STEEP AND HAZARDOUS SEAS WILL PERSIST TODAY DUE TO A MIX OF A
SHORTER PERIOD (12-13 SECONDS) HIGHER SWELL AND A LONGER PERIOD (15-
17 SECONDS) LOWER SWELL. THE SHORTER PERIOD SWELL WILL PEAK TODAY AT
AROUND 12 TO 16 FT. SEAS DIMINISH SOME LATER TODAY INTO TUESDAY, BUT
WILL REMAIN STEEP. A PERIOD OF RELATIVELY IMPROVED CONDITIONS IS
EXPECTED TUESDAY, BUT THIS WILL BE SHORT-LIVED AS ACTIVE WEATHER
RETURNS WEDNESDAY AND CONTINUES INTO THE WEEKEND.
A COLD UPPER LEVEL TROUGH WILL MOVE INTO THE REGION LATE TUESDAY,
BRINGING A COLD FRONT ONSHORE WEDNESDAY. STRONG SOUTHERLY WINDS ARE
ANTICIPATED WITH THIS FRONT, AND A PERIOD OF GALES WITH VERY STEEP
AND HAZARDOUS SEAS ARE POSSIBLE LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING. THIS WILL BE FOLLOWED BY A BUILDING NORTHWEST SWELL
WEDNESDAY NIGHT INTO THURSDAY.
PREV DISCUSSION
/ISSUED 353 AM PST MON NOV 28 2022/
SYNOPSIS...AN ACTIVE WEEK OF WEATHER IS EXPECTED. A WINTER
WEATHER ADVISORY IS DOUGLAS, JACKSON, AND KLAMATH COUNTY, THROUGH
MONDAY MORNING, WITH THE MOST INTENSE SNOWFALL EXPECTED DURING THE
MORNING COMMUTE HOURS MONDAY MORNING. ACTIVE WEATHER CONTINUES IN
THE MIDDLE OF THE WEEK WITH ANOTHER FRONT ARRIVING WEDNESDAY AND
HEAVY UPSLOPE SNOWFALL IN NORCAL AND SW OREGON IS EXPECTED. THIS
SNOW EVENT HAS THE POTENTIAL TO LEAD TO DISRUPTIONS TO TRAFFIC
ALONG I-5.
DISCUSSION...THE FORECAST IS ON TRACK WITH THE WINTER WEATHER
ADVISORY /PDXWSWMFR/ IN EFFECT THROUGH MONDAY AFTERNOON FOR
ELEVATIONS ABOVE 2500 FEET IN THE SOUTHERN OREGON CASCADES AND
FOOTHILLS OF THE CASCADES, WITH LIGHT SNOW OVERNIGHT ALSO FOR
SOUTH CENTRAL OREGON AND THE MOUNTAINS OF SISKIYOU COUNTY.
A BRIEF BREAK BETWEEN SYSTEMS IS EXPECTED TUESDAY. A STRONGER
SYSTEM WILL APPROACH AT MID-WEEK, WEDNESDAY INTO THURSDAY.
SNOWFALL FROM THIS SYSTEM MAY RESULT IN WIDESPREAD TRAVEL
DISRUPTIONS AND MUCH HAS BEEN SAID ABOUT THIS MIDWEEK SYSTEM IN
PREVIOUS FORECAST DISCUSSIONS. SO PLEASE REFER TO THOSE FOR MORE
DETAILS. THIS DISCUSSION WILL FOCUS ON SOME NOTEWORTHY THOUGH LESS
DIRECTLY IMPACTFUL PARTS OF THE FORECAST.
FIRST IS THE CHANCE FOR NEW DAILY TEMPERATURE RECORDS AT THE MT.
SHASTA CITY AND BROOKINGS CLIMATE SITES. BOTH RECORDS BEING
CHALLENGED ARE THE LOW HIGH TEMPERATURES. BOTH ARE FORECAST TO BE
WITHIN ONE DEGREE OF THE RECORD. AT BROOKINGS RECORD TEMPERATURES
ARE POSSIBLE ON TUESDAY, NOV. 29, AS WELL AS THURSDAY AND FRIDAY,
DEC. 1 & 2. FOR MT. SHASTA CITY THE RECORDS ARE BEING CHALLENGED
ON DEC. 1 & 2 AS WELL.
ADDITIONALLY ON TEMPERATURES, IS THAT FOR THE PAST 30 DAYS, THE
AVERAGE MAX AND MIN TEMPERATURES HAVE BEEN BELOW NORMAL BY 2 TO
10 DEGREES. THIS MEANS THAT WHILE THE LOOMING COLD, THERE SHOULD
HAVE BEEN SOME OPPORTUNITY TO ACCLIMATE TO THE WINTER
TEMPERATURES (OR ADD SOME WARMER LAYERS, LIKE THIS FORECASTER HAS
DONE).
SECOND IS THE NEED FOR THIS WEEK OF ACTIVE WEATHER WITH RESPECT
TO PRECIPITATION TOTALS. FOR THE PAST 30 DAYS THE DEPARTURE FROM
AVERAGE FOR PRECIPITATION LOW, BY TWO TO SIX INCHES. FOR THE WATER
YEAR, WHICH STARTED IN OCTOBER, ONLY THE ALTURAS, CA CLIMATE SITE
IS ABOVE NORMAL...BY 1%. ALL THE OTHER SITES ARE BELOW BY 22-46%.
THAT SAID, SNOW PACK DEPTH IN THE REGION IS ROUGHLY NEAR NORMAL.
THERE ARE SOME PLACES IN THE HIGHER MOUNTAINS WHERE THE SNOWPACK
IS A BIT BELOW NORMAL, FOR EXAMPLE AT CRATER LAKE THE SNOWPACK
YESTERDAY WAS MEASURED AT 10" AND NORMAL IS 23". LOOKING
REGIONALLY AT WHAT THIS MEANS FOR SNOW- WATER- EQUIVALENT (SWE)
THERE IS ENOUGH SNOWPACK THAT THE SWE IS 100+% OF NORMAL
EVERYWHERE. WITH MORE SNOW ON THE WAY, THIS IS A WELCOME, BUT
STILL EARLY SIGN, THAT WE MAY REMAIN ON TRACK FOR A GOOD SNOW
WINTER SNOWPACK.
MFR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR ORZ025.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY FOR ORZ026.
WINTER WEATHER ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR ORZ027-
028.
WINTER WEATHER ADVISORY UNTIL NOON PST TODAY FOR ORZ030.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 10 AM PST TUESDAY
FOR PZZ350-356-370-376.
HAZARDOUS SEAS WATCH FROM LATE TUESDAY NIGHT
THROUGH WEDNESDAY AFTERNOON FOR PZZ350-
356-370-376.
HAZARDOUS SEAS WARNING UNTIL 10 PM PST THIS
EVENING FOR PZZ350-356-370-376.
CC/MAS
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