Weed, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

941
FXUS66 KMFR 201138
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
338 AM PST Sat Dec 20 2025

.SYNOPSIS...
The leading edge of an atmospheric river will produce minor
travel impact this weekend. Our region will likely see
accumulating snow over higher terrain through the Christmas break.
The bulk of the snow will fall over northern California next week.

.DISCUSSION...

A few echos are showing up along the coast this morning as a cold
front become stationary to our south under this stronger west to
east zonal flow. Precipitation coverage and rates will pick up as
we move through the day and especially towards the overnight hours
in northern California and some of the higher terrain. Integrated
water vapor transport(IVT) is about 250, which is considered a
fairly weak atmospheric river(AR) compared to the 750 to 1000 IVTs
we can see during these winter storms. In addition, the extreme
forecast index for QPF is showing some values around 0.8 in our
northern California areas, which suggests decent rain and snow
fall, although nothing extreme with rain or snow.

Therefore, we decided to stay away from a flood watch for our
forecast area for today into Sunday night. Snow accumulation
suggests some decent accumulation above 6000 feet. We`re
forecasting up to 12 inches around Crater Lake and 5 to 7 inches
around Willamette Pass through Sunday night. Therefore, impacts
will be minor and concentrated in the higher Cascades around
Diamond Lake and highway 62 going to Crater Lake.

A warm front and the leading edge of the next AR will push into
northern California and southern Oregon sometime around Sunday
night, so look for snow levels to shoot higher in California and
stay relatively lower farther to the north. For example, snow
levels will reach around 6500 feet around Modoc County, although
remain around 4000 feet over most of southern Oregon Monday night

Tuesday will kind of be a transition day as the AR will weaken
over our forecast area and mean sea level pressure begins to
build just briefly. Showers will likely linger around the forecast
area, although accumulation should be pretty limited during the
day.

By morning of Christmas Eve, the forecast looks a little more
uncertain. Ensembles are showing a deep trough in the Pacific.
There is a small subset of ensembles members(~20%) showing a meso
low spinning up off the northern California coast and bringing
quite the snow storm down to the valley floors to our region.
However, a larger set of ensemble members keep us much drier and
postpone the snow to later around Christmas and at a much higher
elevation. So that will be something to look for in the next set
of ensemble runs to see where ensemble members fall in these
scenarios.

The one common theme in all this is the ski resorts and high
terrain locations will see at least some snow through Christmas
break. Shasta Ski Part might be the exception here as northern
California will likely see a fair chunk of snow through Christmas.
A 50th percentile 72 hour NBM forecast ending Thursday evening
shows 2 feet of snow around 5000 feet in northern California.
Farther north, the totals drop to around 9 inches in the Siskiyous
and high central Cascades over Crater Lake.

Towards next weekend, conditions will likely trend drier as the
probability of precipitation is about 10 to 20 percent with 40
percent along the coast.

-Smith


&&

.AVIATION...20/06 TAFs...A few isolated showers are passing
over the Oregon coast and Modoc County, but overall VFR ceilings are
present across northern California and southern Oregon tonight.
These levels should continue through the TAF period for most areas.
Guidance continues to suggest chances for lower levels developing in
the Rogue and Umpqua valleys, but the signals for those developments
are marginal. Possible timing remains in the forecasts for Roseburg
and Medford. Any overnight development should clear out by late
Saturday morning or early in the afternoon. Cloud cover starts to
increase towards the end of the TAF period as showers develop in
northern California. Showers may bring locally lower flight levels
in Modoc and Siskiyou counties, with showers moving northward into
Oregon on Sunday. -TAD


&&

.MARINE...Updated 200 AM PST Saturday, December 20, 2025...Seas
will remain elevated through early Saturday morning. Calmer
conditions are expected this afternoon into Sunday morning. A
front will bring moderate south winds, north of Cape Blanco
Sunday, then a stronger front could bring moderate to occasionally
strong south winds, especially north of Cape Blanco with at least
Small Craft conditions.


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 10 AM PST this
     morning for PZZ350-356-370-376.

&&

$$