156
FXUS66 KMFR 181147
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
347 AM PST Tue Nov 18 2025

.DISCUSSION (Today through Monday)...

Key Points:

* Overall, minimal impacts expected this week
* Next round of precipitation Wed through Thurs
    - Light snowfall also expected for elevations above 5K ft
* Lingering precipitation continues through end of week for
  coastal areas and Umpqua Basin

Further Details:

For today, the forecast area will be between systems to the north
and south, which will be followed by high pressure aloft building
into the region. This will lead to a relative break in weather
with precipitation-free conditions. Main impacts today and
tomorrow will be fog/low clouds in addition to frost/freeze
potential (Wed. morning) for westside areas. However, uncertainty
does exist as fog could limit radiational cooling and hence low
temperatures may not be cold enough for certain areas/elevations.
On the other hand, the low level moisture could bring a higher
risk for frost (maybe ice on elevation surfaces) formation if we
are allowed to maximize radiational cooling overnight. At this
time, not expecting widespread frost/freeze to come to fruition,
but will continue to monitor this threat.

Deterministic models are in fairly good agreement with the next
system coming in Wednesday through Thursday. Differences come into
play on timing for the cut-off low to develop resulting in a split
flow regime. Before the H5 low cuts off from the mean flow, we
will see moisture advection and PVA spread across the forecast
area, and precipitation could start Wednesday night.
Precipitation will spread west to east through Thursday and start
to diminish late Thursday afternoon. Not expecting any noteworthy
amounts. As a result, not expecting any hazards through this
stretch of precipitation other than nuisance type flooding like
ponding on roadways. Areas with poor drainage could also see water
build up; however, we are not anticipating widespread flooding.

We will likely see a break in activity through the weekend with
precipitation chances confined to coastal areas and the Umpqua
Basin. That said, would not be surprised to see PoPs decrease
(this trend already exists), with the next notable round of
precipitation coming early next week. In other words, these PoPs
late this week could decrease if trends hold, and perhaps we
could start to see the NBM reflect these changes in the next
24-48 hours.

Looking ahead, there is increasing confidence for a potential cold
airmass to infiltrate the region around Thanksgiving. Some westside
areas still haven`t had a freeze. For perspective, when record
keeping began in 1911 for Medford, there has only been a freeze this
late twice. The record latest freeze is 2016 for Medford when a
freeze finally came Dec 5th. Second latest is Nov 29th in 1937.
Third latest was Nov 21st in 2013. Since 1911, the mean is Oct 19th
for the first freeze.

-Guerrero

&&

.AVIATION (12Z TAFs)...

Ares of fog and low clouds will lead to MVFR to IFR conditions
this morning. Improving conditions expected late this morning to
early this afternoon with VFR conditions thereafter. Another round
of low clouds and fog will likely impact the inland TAF sites
tonight as high pressure builds into the region. Expecting
LIFR/IFR conditions tonight for these inland TAF sites as fog and
low clouds are anticipated.

-Guerrero

&&

.MARINE...Updated 300 AM PST Tuesday, November 18, 2025...North
winds and northwest swell will gradually diminish over the next 24
hours or so, with steep to very steep seas improving from north to
south through this evening. Conditions improve briefly early
Wednesday, then another frontal system is expected Wednesday evening
into Thursday with steep to very steep wind-driven seas anticipated.
After the front passes and winds diminish, large longer period swell
arrives Thursday evening into Friday. A somewhat active pattern then
continues through the weekend, with persistent elevated seas of
slightly higher than 10 feet.

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 10 PM PST
   this evening for PZZ356-376.

&&

$$