713
FXUS66 KMFR 020510
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1010 PM PDT Sat Nov 1 2025

.UPDATE...Aviation Discussion Updated.


&&

.AVIATION...02/06Z TAFs...IFR/MVFR with local LIFR conditions and
light rain are occuring along the coast with areas of MVFR and local
IFR/LIFR inland from the Cascades west.  Conditions are expected to
lower to IFR/LIFR in many valleys west of the Cascades late
tonight and early Sunday morning. East of the Cascades, areas of
MVFR/IFR will develop tonight into Sunday morning. Low clouds are
expected to lift and clear to VFR areawide between 17-20z Sunday.

&&

.PREV DISCUSSION... /Issued 812 PM PDT Sat Nov 1 2025/

UPDATE...Updated Marine Discussion.

MARINE...Updated 800 PM PDT Saturday, November 1, 2025...Steep seas
will persist through at least Monday. Seas will be dominated by west-
northwest swell. However, wind seas will mix with swell on Sunday
afternoon and Sunday night as gusty northerly winds develop.
A strong front approaches late Tuesday, then moves across the area
Tuesday night and Wednesday. This is followed by another strong
front on Thursday. These fronts will bring the potential for gales.
Additionally, expect building west swell late Wednesday and Thursday
which combined with wind seas may result in dangerous and chaotic
high to very high seas. This may result in hazardous seas and
dangerous bar crossings. We will be monitoring this period and
updating as confidence increases in the timing and details.


PREV DISCUSSION... /Issued 221 PM PDT Sat Nov 1 2025/

DISCUSSION...An active pattern will continue through the next
several days, with only a few breaks here and there all the way
into next weekend. There will be several frontal passages in that
time, the first weak front is passing today, then a very robust
system arrives Monday into early Wednesday, followed by another
front around Thursday, then finally another system arrives next
weekend. Wet and windy weather will accompany nearly all of these
systems, but winter weather will not be too much of a concern
given the expected higher snow levels.

A narrow band of precipitation has moved onshore this morning,
and as of this writing is stretched along a corridor from coastal
Curry County northeast to the Cascades just west of Bend. This
area of rain will push eastward through the afternoon, then
dissipate as it crosses the Cascades this evening and tonight.
Most rain will fall along and west of the Cascades, but a few
hundredths are possible to the east, with any stronger showers
that make it over the mountains. Breezy winds are accompanying
this front, but nothing impactful is expected. Conditions should
improve by tomorrow, and although temperatures will be cooler
behind the front, skies will be mostly clear after any early
morning valley fog dissipates.

After a rather quiet Sunday, a warm front will arrive from the
south and linger in the area Monday through midday Tuesday. The
overrunning of warm air over the cooler surface air will result in
widespread light precipitation, but temperatures will not warm
much at the surface, remaining at or just below seasonal normals.

The most impactful system in the forecast is then set to arrive
late Tuesday into Wednesday, with a intense front and a
substantial moisture plume bringing strong winds and heavy
precipitation to southern Oregon and far northern California.
With surface pressure gradients ranging roughly between -6 and -8
mb across the area, and with 700mb winds of 50 to 70 kts, it is
looking more and more likely that wind headlines will be
necessary, especially along the coast, in the Shasta Valley, and
across the East Side. Some guidance suggests that strong winds
could impact portions of the West Side as well, including near
Ashland, and in some ofthe other roughly south/north oriented
valleys. Meanwhile, moisture transport values for this front, as
measured by IVT, a function of wind and humidity, are approaching
values of 1000 to 1250 (a typical front would average about 500).
This would be considered a strong atmospheric river, or a rather
classic "Pineapple Express." A substantial amount of rain is
possible for much of the area, especially along the coast and in
Siskiyou County. However, the front is a fast mover, and some
locations, such as the Rogue Valley near Medford and much of the
East Side, will see lesser amounts due to significant downsloping
winds off the Siskiyous and Cascades. While widespread flooding
is not expected at this time, we will likely see nuisance type
flooding with ponding on roadways and blocked drains due to
recently fallen leaves. Additionally, King Tides are expected Nov
5-7 (Wednesday through Friday) which could bring additional
impacts to the coast as this system enters the region, especially
with heavy rains putting additional water into area rivers and
estuaries. Some localized coastal flooding is possible,
particularly for low lying areas and roads around Coos Bay.
Lastly, snow levels will remain high through next week, between
6000 and 8000 feet, so we are not expecting any impactful winter
weather.

Another robust front arrives Thursday, and although it looks
weaker than the previous one, most model guidance suites are
depicting somewhat similar potential for impactful winds and rain.

After a brief break Friday, we are seeing the signs of another
frontal system Saturday/Sunday. There is quite a bit of variation
in model guidance at this time range, so confidence is low, but it
does look like the active pattern shows very little sign of
slowing down as we head into next week. -BPN

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 4 PM PDT Monday
     for PZZ350-356-370-376.

&&

$$