Very heavy northwest swell moved into the southern Oregon coastal waters on these days, leading to heavy surf on the beaches.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MFR wrote it up.
Very heavy northwest swell moved into the southern Oregon coastal waters on these days, leading to heavy surf on the beaches.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Medford, OR wrote its last area forecast discussion before the first event at Nov 25, 5:17 AM PST, 4 hours 9 minutes earlier.
Area Forecast Discussion
National Weather Service Medford OR
517 AM PST Wed Nov 25 2020
.DISCUSSION...Only one change was made to the forecast since the
previous update. That is to include a slight chance for thunder
offshore this morning from Coos Bay north and includes a small
sliver inland near Reedsport. The overall atmospheric stability
is not that low, but enhanced lifting along the coast at the same
time as the cold pool swings through could provide enough
stretching and lift to enhance the showers into producing a few
lightning strokes.
The area of most concentrated precipitation has moved east of the
Cascades and is beginning to exit eastern Lake and Modoc
Counties. In its wake showers will continue through Wednesday
night. Snow levels during this showery activity will be around
3000 feet through the morning before rising to around 3500 feet in
the afternoon. Much of the snow during this afternoon should be
less impactful to roadways, but the Winter Weather Advisory will
continue through tonight as a heavy shower could cause visibility
reducing snowfall and create slippery driving conditions.
Additionally, further snowfall in the backcountry is expected that
could increase risk for anyone out there.
The ridging pattern that sets up on Thursday could cause stagnant
air in many of our southern Oregon and northern California
valleys into the weekend. This will be further assessed by the
day shift in coordination with the Oregon DEQ later this morning.
Cold nights during this ridging pattern means that freezing fog
could develop resulting in black ice on roads and walkways. Friday
morning will have the most extensive cold temperatures. This
includes portions of the immediate oregon coast from Bandon north
to Coos Bay where chances of temperatures conducive to frost are
roughly 45% and may require issuing one of the last frost
advisories of this season. A front will approach the area on
Saturday, but does not show as being strong enough to break down
the ridge and scour out the stagnant air.
The next chance for a change in the pattern is Sunday night into
Monday. There is a high degree of positional variation in the low
track, so there is a high amount of uncertainty in the forecast as
a whole. The leading solution at the moment is for the ridge to
hold and the front to fizzle out offshore. That said, the
forecast is currently one of broad, low-to-moderate PoP and
trace-to-low QPF amounts from the Cascades west to account for
the broader suite of possible outcomes, wherein a few show a
front capable of bringing precipitation inland. -Miles
&&
.AVIATION...For the 25/12Z TAFS...A cold front has moved through the
region this morning with widespread VFR ceilings. There have been
periods of MVFR ceilings this morning, but they have been very
brief. As some drier air sinks in, look for VFR ceilings to continue
through the day. However, periods of MVFR visibilities are possible
in heavier showers later today. Look for IFR and LIFR later tonight
as fog and low stratus form in many of the valleys.
-Smith
&&
.MARINE...Updated 230 AM PST Wednesday 25 Nov 2020...A high long
period swell is currently moving into the waters. This swell will
likely peak around 18 feet later this afternoon and early evening.
Eventually, seas will begin to subside Wednesday night as they lower
to 10 - 12 feet. North winds will gradually increase Thursday night
into Friday morning. However, winds will probably stay below 20
knots. Another long period swell will enter the waters around
Monday. Wave heights will probably be around 10 to 12 feet as this
new swell group moves in. It's possible that wave heights end up a
bit higher around 14 to 16 feet if a low moves directly through the
waters.
-Smith
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...High Surf Warning until 4 AM PST Thursday for ORZ021-022.
Winter Weather Advisory until 1 AM PST Thursday for ORZ027-028.
CA...None.
Pacific Coastal Waters...Hazardous Seas Warning until 4 AM PST Thursday for
PZZ350-356-370-376.PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
806 AM PST WED NOV 25 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0805 AM HEAVY RAIN 6 E GOLD BEACH 42.42N 124.31W
11/25/2020 M0.94 INCH CURRY OR TRAINED SPOTTER
24 HOUR AMOUNT ENDING AT 8 AM PST.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
815 AM PST WED NOV 25 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0812 AM HEAVY RAIN 2 N PROVOLT 42.32N 123.23W
11/25/2020 M0.39 INCH JOSEPHINE OR TRAINED SPOTTER
24 HOUR AMOUNT ENDING AT 7 AM PST.
&&The national radar mosaic for the moment the first event began.
2 high surf. Local standard time, as filed.
The Umpqua Offshore Buoy (46229) reported swell that would support high surf from 25/0926 PST until 25/1056 PST. The buoy 15 NM west of Port Orford (46015) reported swell that would support high surf at 25/0950 PST and again at 25/1250 PST.
The Umpqua Offshore Buoy (46229) reported swell that would support high surf from 25/0926 PST until 25/1056 PST. The buoy 15 NM west of Port Orford (46015) reported swell that would support high surf at 25/0950 PST and again at 25/1250 PST.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2020Every state in 2020This day in weather historyWarnings in Oregon, November 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 922354, 922355.