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  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab OR Page
The Nexlab CA Page Main Text Page