Fort Rock, Oregon Weather Forecast Discussion

237
FXUS66 KMFR 212343
AFDMFR
Area Forecast Discussion
National Weather Service Medford OR
443 PM PDT Sun Sep 21 2025
.DISCUSSION...Updated Aviation Section...
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.AVIATION...22/00Z TAFs...A few showers are on radar east of the
Cascades, and this area will continue to see that and some drizzle
as it continues to dry out through the evening after the front
passes. Some lower ceilings and patchy fog could develop tonight.
For now, looking to bring MVFR around 09Z to North Bend and lower
ceilings are possible after and through 15Z, but this will be
analyzed at the next TAF update. This could also occur in coastal
valleys and perhaps the Umpqua Basin tonight, but these should break
to VFR again mid-late morning.
Inland, gusts near 20-25 mph are found in the Rogue Valley and
Umpqua Basin, but these will subside later this evening. -
Spilde/Hermansen
&&
.PREV DISCUSSION... /Issued 219 PM PDT Sun Sep 21 2025/
DISCUSSION...
Overview:
Overall, weather hazards/impacts continue to be minimal, but we do
have a threat of frost tonight into Monday morning behind a cold
front currently passing through the region. After this weekend,
unseasonably warm temperatures are anticipated, especially Tuesday
and Wednesday afternoon when some areas will be close to triple
digits. This will coincide with generally dry conditions as we
experience poor overnight recoveries Monday night and Tuesday night.
Please see the Fire Weather Discussion below for more details.
Further Details:
A cold front will pass through the region today, and we have seen
light rainfall along/near the coast, the Umpqua Basin, and part of
Josephine County. We are not expecting much in regards to amounts
but several areas did pick up a trace to several hundredths of an
inch as of writing this (1pm). Highest amounts across northern Coos
County and north/northwestern parts of Douglas County. Not expecting
much activity later this afternoon as we are already seeing returns
decrease on radar. The cold front will also usher in a colder
airmass, and areas on the eastside in particular could see a threat
of frost/freeze. A Frost Advisory is in effect tonight into Monday
morning for the Lower Klamath Basin (includes Klamath Falls) and
parts of Modoc County in and around the Alturas area. Anyone with
sensitive vegetation may want to cover or protect plants that could
be damaged from these cold temperatures.
Thereafter, a low will slide south from Canada, and traverse along
the Rockies over into the Central/Southern Plains. This will set the
stage for an Omega Block type of pattern over the Conus by
Wednesday, while a westerly jet stream will be noted over much of
southern Canada. This split flow pattern will stick around through
at least Saturday. This will result in above normal temperatures and
dry conditions through much of next week. In fact, some records may
be in jeopardy Tuesday and Wednesday as we flirt with triple digits
on the westside. For example, the record for Medford is 100 on
Tuesday and 99 on Wednesday, and we are forecasting 97 and 96,
respectively. These records are certainly within reach as
temperatures will be about 15 degrees above normal for this time of
year. This stagnant pattern looks to stick around through at least
next weekend, but the following week could see changes as
deterministic models are hinting at a trough moving through the
region. That said, uncertainty does exist as ensemble members are
split on rainfall amounts, so confidence is not the greatest with
regards to rainfall, but chances are high we will be more seasonable
with regards to temperatures (70s/80s). -Guerrero
MARINE...Updated 100 PM PDT Sunday, September 21, 2025...A thermal
trough starts to develop this evening, bringing gusty northerly
winds to area waters. These winds will be strongest south of Cape
Blanco and will build steep seas in this area from late tonight
through Monday afternoon. Localized areas of very steep and
hazardous seas are possible south of Gold Beach. Gusty northerly
winds increase tomorrow evening, with current forecast showing steep
seas building as far north as Reedsport from Monday evening through
Tuesday afternoon.
FIRE WEATHER...Updated 200 PM PDT Sunday, September 21, 2025...
A cold front is pushing east of the Cascades this afternoon. Very
light precip over the west side will fizzle as the moisture gets
wrung out by the Cascades, but radar is showing isolated
showers/thunderstorms in SE Siskiyou, Modoc and SE Lake counties.
But, these should end early this evening. Gusty west winds are
possible east of the Cascades through this evening with peak gusts
of 25-35 mph in the typically windier sites. Some west side valleys
too could have locally breezy winds into this evening.
Upper ridging builds Monday to Wednesday with rapid warming and
drying as a thermal trough takes hold along the NorCal and SW Oregon
coast. That said, there will be some cool to chilly mornings with
steep inversions (coldest east of the Cascades with temps possibly
down near freezing). Expect a period of N-NW through E-NE winds (not
too strong) on the upper slopes/ridges tonight/Monday (with good RH
recovery), but NE-E winds will be a bit stronger Monday
night/Tuesday morning with poor to moderate RH recovery developing
over the ridges. The dry air mass will be in place over the area
through at least midweek (the driest air appears to be Tuesday
night into Wednesday). We`ll carry a headline at the top of the
Fire Weather Planning Forecast for locally gusty east winds and
poor RH recoveries during this period over the upper
slopes/ridges. Expect high temps both Tue/Wed to be in the mid-
upper 90s west of the Cascades, and in the 80s over the East Side
(about 10-15F above normal). So, those out on the landscape this
week should plan for the expected hot weather/unusual warmth. Take
breaks during the peak of the heat in the afternoons and stay
hydrated. The good news is that the days keep getting shorter and
peak warm periods aren`t as long (generally 2-6 pm).
The upper ridge should largely hold across southern Oregon and
NorCal through late this week as a closed upper low wobbles into the
Great Basin. This should keep the thunder risk to the SE of the area
with probabilities generally 10% or less.  The air mass should
modify some west of the Cascades during this stretch (especially
Thu/Fri), so, it won`t be quite as hot as earlier in the week, but
still above normal. -Spilde
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Frost Advisory from 8 PM this evening to 8 AM PDT Monday for
     ORZ028-029.
CA...Frost Advisory from 8 PM this evening to 8 AM PDT Monday for
     CAZ084-085.
PACIFIC COASTAL WATERS...Small Craft Advisory from 5 PM Monday to 5
     PM PDT Tuesday for PZZ350-356-370-376.
&&
$$

NWS MFR Office Area Forecast Discussion