Winter Weather in Oregon, December 26, 2024

Area Forecast Discussion
National Weather Service Medford OR
412 AM PST Thu Dec 26 2024

.DISCUSSION...Satellite image shows strong low pressure just west of
Astoria. Plenty of energy is wrapping around the low resulting in
numerous thunderstorms over the marine waters and a line of
thunderstorms earlier that was oriented from northeast of Roseburg
southwest towards Gold Beach. A few Special Marine Warnings were
issued due to the storms. The storms have moved inland, and while a
few storms could be strong at times, so far there's no indication of
any of them getting to severe. However, we'll continue to keep a
watch on this closely.

Showers will continue today as an upper trough moves overhead.
However, precipitation rates will diminish later this morning into
this afternoon weak ridging builds in. Moderate to strong winds will
continue in the Shasta Valley and east of the Cascades this morning,
with winds diminishing in the Shasta Valley around mid morning and
east of the Cascades late this morning.

This will be short lived with another storm moving into the area
this evening and tonight. Some of the models show a surface low
developing just outside of the marine waters which could result in a
brief period (2-4 hours) of strong winds along the coast later this
from Cape Blanco south as the winds will have a slight onshore
component to it. Winds will then shift to the southwest along the
coast and diminish. Meanwhile moderate to strong winds are likely
again in the Shasta Valley and east of the Cascades. However the
duration of moderate to strong winds are not expected to last as
long in these areas. Once the current high wind warnings expire this
morning, it's likely another one will be issued for this evening and
tonight.

The next storm will also bring another round of moderate to heavy
precipitation, but this also will be short lived with the highest
precipitation rates expected to be from later this evening through
tonight, then rates will diminish Friday morning as steady
precipitation becomes showery. Weak ridging will build into the area
Friday afternoon resulting in another break in the action.

As with the other systems, this will be short lived again with
another storm impacting the area Friday night into Saturday. Some
evidence suggest the front on Friday night could get hung up and
stall over southwest Oregon and northern California late Friday
night through Saturday resulting in a prolonged period of steady
moderate to occasionally heavy precipitation. It won't be until the
"kicker" comes in Sunday morning pushing the front east of the area
during the day Sunday, that we'll see precipitation rates diminish.

The concern for snow will remain around Crater and Diamond Lake
areas, highway 140, and around the Mount Shasta area today.
Precipitation is expected to be all rain along I-5 and it's won't be
as heavy because the flow is not favorable for it. This will also
keep snow levels from being lower than surrounding areas. Snow levels
will rise this evening and tonight and remain high will be mainly
confined to the Crater Lake area. Snow levels some down briefly
Friday afternoon, but that will come at the time when precipitation
will be light. Snow levels will then come up Friday night to around
7000 feet and remain there through Saturday night. So we will
need to monitor river rises from heavy rain and snow melt through
this weekend. After this week's parade of storm systems, we are
seeing signs of potential flooding for some our of rivers and
tributaries starting Sunday night. -Petrucelli

&&

.AVIATION...26/12Z TAFS...Active weather continues across the area,
with passing showers bringing VFR or MVFR ceilings. Occasional
thunderstorms have been popping up along the Oregon coast south of
Cape Blanco, but the frequency of these thunderstorms is decreasing.
Showers will decrease into this afternoon before another disturbance
brings another round of activity tonight into Friday morning. Snow
levels of 4500 to 5500 feet will limit most snowfall to elevated
areas, but showers can locally lower snow levels and bring snow
showers to lower elevations.

Guidance shows low level wind shear across the area with the current
trough moving over the area. In general, southwesterly winds of 40
to 50 kts are present at 2000 feet. These winds will ease through
the morning. Low level wind shear could return tonight into Friday
morning. -TAD

&&

.MARINE...Updated 230 AM PST Thursday December 26, 2024...An
approaching upper level trough is bringing storm force gusty winds
to area waters early this morning. While winds will ease through the
day, very steep and hazardous seas will continue in all area waters.

These continuing conditions will be supported by continuing active
weather through the rest of the week and into the weekend. Fronts
moving over area waters tonight into Friday morning and Friday night
into Saturday will bring periods of gusty southerly winds. These
winds will have 40-60% chances of reaching gale speeds. A Gale
Warning is currently in place from 4 am this morning until Saturday
at 4 am to cover these incoming fronts as well as very steep and
hazardous seas continuing in between.

Beyond this weekend, seas look to decrease through the end of
December. Steep to very steep seas will continue for some time
beyond the currently forecasted fronts. -TAD

&&

.BEACH HAZARDS...Updated 200 AM PST Thursday December 26, 2024...
Seas will continue to build as the latest in a seemingly endless
parade of fronts approaches this afternoon. This will result in
continued extremely hazardous conditions on local beaches.
Conditions will be particularly dangerous just behind the fronts
as seas become west swell dominated and during the time of high
tide - this occurs both this morning and behind another front
Friday morning. Breaking waves may reach 35 feet both mornings.
The high surf warning remains in effect through Friday.

During these events, extremely large breaking waves will create very
hazardous and dangerous conditions along beaches and area
shorelines. Waves will inundate beaches and surge into normally dry
areas. Infrastructure damage and significant beach erosion can be
expected. Stay away from area beaches during this period of active
weather. -Wright/Petrucelli

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 10 AM PST Friday for ORZ027-028-
     030.

     High Wind Warning until 7 AM PST this morning for ORZ021-022-030-
     031.

     High Surf Warning until 4 PM PST Saturday for ORZ021-022.

     Wind Advisory until 4 AM PST early this morning for ORZ024-026.

CA...Winter Weather Advisory until 10 AM PST Friday for CAZ080-082-
     083.

     High Wind Warning until 7 AM PST this morning for CAZ081-085.

PACIFIC COASTAL WATERS...Storm Warning until 4 AM PST early this
     morning for PZZ350-356-370-376.

     Gale Warning until 4 AM PST Saturday for PZZ350-356-370-376.

&&

Preliminary Local Storm Report
National Weather Service Medford OR
449 AM PST Thu Dec 26 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0449 AM     Rain             2 SSW Obrien            42.05N 123.71W
12/26/2024  M1.00 Inch       Josephine          OR   Trained Spotter

            Trained spotter reported an inch of rain
            since midnight (4.5 hours).

&&

TAD