189
FXUS66 KMFR 172202
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
202 PM PST Mon Nov 17 2025

.DISCUSSION...Showers continue over Modoc and Siskiyou counties as a
cutoff low over California pushes moisture up from the south. A few
isolated showers may be lingering over Oregon counties, but those
will fade into the afternoon and evening. Activity should be absent
across the area by the early hours of Tuesday morning.

Mild weather is expected on Tuesday. A cold air mass lingering over
the area could bring Tuesday night/Wednesday morning lows into
frost/freeze ranges for Oregon valleys west of the Cascades. These
temperatures have been rare this year, especially this far into
November. The Rogue, Applegate, and Illinois valleys have a 50-80%
chance of seeing lows reach 32 degrees or lower, while the Umpqua
Valley has a 75% of lows below 36 degrees. Other areas will see
cooler overnight lows as well. East of the Cascades, lows are
forecast to be in the low to mid 20s, but some basins in north Lake
and Klamath counties may drop to the high teens.

Activity resumes on Wednesday as an upper trough approaches and
looks to split into a cutoff low once again. The timing and
direction of this split would have a substantial impact on any
precipitation that the trough brings. Even in the highest amounts,
this trough does not look to bring any hazardous conditions. With
both the ECMWF and GFS models keeping the cutoff near the California
coastline as it travels south, the most rainfall is forecast for
terrain over Curry County with amounts topping out at an inch from
Wednesday evening through Thursday morning. Other areas would see
lower amounts through the same timeframe. With the split bringing
winds from a more southwest direction, gusty winds in the Shasta
Valley look to stay safely out of hazardous ranges. Winds over area
terrain look unimpactful as well. Snow levels of 5500-6500 feet will
keep snowfall to the highest peaks and ridgelines.

Behind the Wednesday-Thursday trough, conditions will be dictated by
high pressure over the Pacific. Ridging around the high looks to
keep active weather out of the area for Friday and through the
weekend, although a few ensemble members still suggest some moisture
following the westerly flow and bringing coastal or Cascades
showers. These would be sporadic and light at most without a lifting
mechanism, with showers unlikely over other areas. Active weather
may return late Sunday into Monday. -TAD

&&

.AVIATION...17/18Z TAFs..Showers continue across northern California
and southern Oregon. Ceilings are generally staying at VFR, but
periods of lower flight levels have occasionally developed at area
terminals. Rainfall looks to decrease through the afternoon and
should be absent by Tuesday morning. West side valleys may see some
lower flight levels develop overnight, depending on how conditions
change through the day. -TAD

&&

.MARINE...Updated 200 PM PST Monday, November 17, 2025...West-
northwest swell of 10 to 11 feet at 11 to 12 seconds will combine
with wind seas today and bring steep to very steep seas, highest
south of Port Orford.  North winds will gradually trend lower this
evening and tonight but expect a mix of steep to very steep seas
south of Cape Blanco and steep seas north of Cape Blanco. On
Tuesday, gusty winds and steep seas will linger for the waters south
of Cape Blanco.

Conditions improve briefly early Wednesday, then another frontal
system is expected  Wednesday evening into Thursday. There remains
some uncertainty in the exact track and strength of this system,
which will factor into how strong south winds are ahead of the
front. However, confidence is moderate to high for at small craft
advisory level winds Wednesday evening into Thursday morning and
building long period swell late Thursday into Friday (with seas
peaking at around 14 to 17 feet).

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 10 PM PST Tuesday
     for PZZ350-356-370-376.

Hazardous Seas Warning until 4 AM PST Tuesday for PZZ356-376.

&&

$$