167
FXUS66 KMFR 172130
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
230 PM PDT Thu Jul 17 2025

.SYNOPSIS...A trough will be coming through the area this
weekend. While it is not expected to bring precipitation to the
area, it may bring periods of breezy to gusty winds; which could
increase fire weather risks. More information in the fire weather
section.

Key Points:

*A 10-15% chance for thunderstorms is possible this afternoon
 across portions of Siskiyou County, and along the Cascades and
 east in Oregon.
*Temperatures will cool toward normal this weekend into next week.
*Breezy and dry conditions are expected through this weekend.


&&

.DISCUSSION...Satellite imagery is showing some cumulus buildups
across portions of Siskiyou County, the east side of the Cascades
and portions of Klamath and Lake Counties in Oregon. Meanwhile,
the thin blanket of smoke has largely mixed or dissipated except
for a few spots in Siskiyou County near where the larger fires
area. This is congruent with the 10 to 15 percent chance for a
thunderstorm over these areas this afternoon and evening - and
looking like these areas may have to pay attention to the skies
for any thunder development.

Meanwhile, air quality remains relatively unchanged today with
most monitors in southern Oregon and northern California reading
on the good to moderate levels. The HRRR model has not really
performed great today as it tried to pick up an increase in smoke
this past morning similar to what occurred on Wednesday, but that
did not materialize. Still, expect conditions to remain similar to
what we are seeing now remain for the rest of the day.

As far as temperatures are concerned, they will continue to
moderate toward normal, with temperatures remaining in the mid to
upper 90s in the West Side Valleys (lower 90s in the Umpqua
valley) and mid to upper 80s to a couple of 90 degree temperatures
east of the Cascades on Friday. Then, a trough moves through the
area on Saturday, bringing temperatures much closer to normal for
this time of year across the board this weekend. These more normal
temperatures will continue into early next week. This should be a
little reprieve from the stretch of 95 to 100 degree weather with
major heat risk from last weekend.

This trough will not be bringing precipitation with it,
unfortunately (or fortunately); but it will bring breezy to gusty
west winds each afternoon through the weekend. With conditions
remaining dry, fire weather concerns could come into play. More
information is available in the fire weather section. -Schaaf

&&

.AVIATION...17/18Z TAFs...LIFR/IFR marine stratus/fog is present
along the entire SW Oregon coastline this morning. North of Cape
Blanco, the lower conditions extend inland to about Elkton, Sitkum
and Powers, while south of Cape Blanco, they extend inland about 10-
15 miles. These ceilings/reduced visibilities will become VFR in
some locations this afternoon, but could persist at the beaches much
of the day. Even if it breaks out for a while, the low clouds/fog
will return tonight. Over the interior, we expect most VFR
conditions through tonight, though wildfire smoke/haze will bring
reduced visibility at times. This may impact Klamath Falls. A weak
disturbance could cause a few cumulus buildups in NorCal and east of
the Cascades this afternoon/evening along with isolated showers and
thunderstorms. Best chance (~15-20%) will be in northern
Klamath/Lake counties. Expect mostly typical afternoon/evening
breezes around 10-15 kt that will subside after sunset. -Spilde

&&

.MARINE...Updated 200 PM PDT Thursday, July 17, 2025...The steep
seas are beginning to subside, and a brief period of improved
conditions is expected to last through at least Friday. A weak
thermal trough could return this weekend. Though winds are expected
to be weaker than the previous event, gusty advisory level north
winds and steep seas could return south of Cape Blanco then.
-Spilde/Schaaf


&&

.FIRE WEATHER...Updated 230 PM PDT Thursday, July 17, 2025...A
belt of SW mid-level flow with good vertical mixing up to around 600
mb could cause some gusty afternoon/evening breezes (20-30 mph) from
Modoc up into southern Lake County with humidity values down in the
10-15% range. These near-critical wind and RH values remain
headlined in the Fire Weather Planning Forecast.

After today, we expect gradual "cooling" Friday into this weekend
with temperatures getting back closer to normal values by next week.
This will again likely be at the expense of some breezier
conditions, both Friday and Saturday afternoon/evening along with
near-critical humidity levels.

Beyond that, models are showing an even deeper trough digging
southward into the PacNW Sunday into early next week. There are
still many details to be worked out with this, but confidence is
high that we`ll see further cooling Sunday-Tuesday. It`ll remain on
the breezy side and there should be at least a slight uptick in
humidity, but it`s still too early to say where precip chances are
highest. -Spilde/Smith


&&

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

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$