757
FXUS66 KMFR 212112
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
212 PM PDT Tue Jul 21 2026

.KEY MESSAGES...

* Today and Wednesday will be the hottest of the next several days
  with highs generally 5 to 10 degrees above normal (mid 80s to
  mid 90s on the east side and lower 90s to 103 for west side
  valleys). Near or slightly below normal temperatures at the
  coast will reach the 60s.

* Isolated light showers and thunderstorms are expected this
  afternoon/evening. Highest risk is in the Cascades north of
  Crater Lake, but can occur anywhere from the mountains of
  western Siskiyou County up the Cascades, over to Winter Rim and
  the Warner mountains. Rainfall amounts will be light.

* The highest risk of thunderstorms for the area will be on
  Wednesday (scattered coverage Cascades/Foothills eastward),
  including lesser chances for areas west of the Cascades. Some
  storms will be strong with gusty winds and possible hail. Best
  chance for this is up the Cascades into the Douglas County
  foothills and over to NW Klamath County.

* A drier pattern takes hold late week into the weekend, but
  probably with an increase in afternoon/evening breezes,
  especially east of the Cascades.

&&

.DISCUSSION...The forecast area remains wedged in between a strong
ridge over the nation`s mid section/Rockies and low pressure off
the California coast (including tropical remnants). Monsoonal
moisture continues to stream northward into the area and is
generating a few light showers from Modoc into Lake County this
morning. This flow pattern hasn`t allowed things to cool off as
readily at night, as evidenced by the daily record highest
minimum set here at Medford yesterday morning (71F). The record
was 68F set in 2023. As a result of the moist south flow, we are
seeing plenty of mid to high level clouds, along with some
scattered light high-based showers across the area, and
especially over Modoc and Lake counties, where some light
accumulations have been recorded (generally a few hundredths to a
tenth of an inch). With somewhat thinner high cloud cover than
yesterday, some instability could generate isolated
thunderstorms, mainly near or just north of Crater Lake in the
Cascades and southeastward down to around the Warners during the
afternoon/evening.

As the tropical remnants move northward over the coastal waters,
some models are indicating a low possibility of showers or even
thunderstorms tonight into Wednesday morning, focusing on areas
along the coast and into the Umpqua Basin where some upper level
support will increase ahead of the approaching remnants.
Confidence is low, given the difficulty models have with this type
of event, but it is worth mentioning as a possibility.

Wednesday, stronger southerly flow aloft is expected between the
trough offshore tracking northward (including the remnants of
Tropical Storm Elida) and the persistent ridge over the Great
Basin/Rockies. There is still a modest amount of uncertainty in
the convective forecast (especially with areal extent), but there
is a decent chance of scattered thunderstorm coverage over a
broad portion of our area, to include areas from the Cascades
eastward and also portions of the west side (most likely Douglas
County east of Roseburg, but also along the western foothills of
the Cascades east of the Rogue Valley). Farther south and west,
where dry air is expected to intrude the lower levels, coverage
should be more isolated or non-existent (coast and northern CA).
Storms do look to trend wetter over time with highest precipitable
water values at around 200% of normal (perhaps near or above 1.50
inches). While a widespread severe weather outbreak is not
likely, a stronger cell or two could produce strong, gusty winds
and hail. This appears most likely over the Cascades near/north of
Crater Lake, the eastern Douglas Foothills and also NW Klamath
County. Generally, any storms that develop Wednesday will move to
the north to northeast, contain frequent lightning, small hail,
and gusty winds, and could produce periods of heavy rainfall.

The region of greatest instability looks to shift northeastward
out of the area Thursday with a shift to an onshore flow pattern
Friday into this weekend. The result will be a more stable, dry
air mass, but along with enhanced afternoon and evening winds.
This will be the case here in the Rogue Valley, but also
especially for areas east of the Cascade. -Spilde/BPN


&&

.AVIATION...21/18Z TAFs...LIFR ceilings and low visibility remain
over North Bend at the start of the TAF period, but with signs of
clearing on satellite. A brief period of VFR levels is possible
before stratus reforms and brings IFR/LIFR levels through the end of
the TAF period.

Inland areas will generally see VFR levels under high ceilings.
Periods of patchy smoke are possible at the Medford and Klamath
Falls terminals, but should not greatly impact visibility. For this
afternoon and evening, slight chances of thunderstorms are present
for Lake, Klamath, Modoc, and Siskiyou counties as well as over the
Cascades. Thunderstorms are capable of bringing locally lower
ceilings and visibilities as well as lightning and gusty, erratic
winds. Isolated activity may continue into early Wednesday morning,
for inland areas, with slight chances for thunderstorms for parts of
the Oregon coast towards the end of the TAF period. -TAD

&&

.MARINE...Updated 200 PM PDT Tuesday, July 21, 2026...Winds and seas
are expected to remain below advisory levels through at least this
week. North winds today switch to southerly Wednesday as the
remnants of Elida move northward offshore. Isolated showers and even
a couple of thunderstorms are possible. Mixed seas with fresh short
period northwest swell and low longer period south swell are
expected through Friday. South winds switch back to northerly this
weekend, and a slight increase in southerly swell may bring some
borderline steep seas in outer waters. Wind wave dominated seas
probably hold off until early next week. -Spilde/TAD

&&

.FIRE WEATHER...Updated 200 PM PDT Tuesday, July 21, 2026...A large
upper ridge remains centered over the Great Basin/Rockies and into
the southern Plains, while low pressure is off the California coast.
Southerly flow aloft continues to bring a broad moist plume
northward across much of the West and this is resulting a swaths of
mid-high level clouds across NW Nevada, northern California and into
south-central/SW Oregon. As a result, we are seeing extensive areas
of mid to high level clouds, along with some scattered light high-
based showers across the area, and especially over Modoc and Lake
counties, where some light accumulations have been recorded
(generally a few hundredths to a tenth of an inch). The cloud
cover isn`t quite as thick (or persistent) as it was yesterday and
this should allow temps today to be near or several degrees
higher than yesterday. As such, the atmosphere should destabilize
a bit better today. This afternoon and evening, cumulus buildups
are expected with a slight chance of thunderstorms in western and
central Siskiyou County, also north and northeastward along the
Cascades and across much of south central Oregon and also Modoc
County in NE Cal. Coverage of lightning doesn`t appear to be very
high (mainly isolated), so despite the lightning risk, we aren`t
planning any red flag warnings for today.

Some models are indicating a low possibility of nocturnal convection
tonight into Wednesday morning, focusing on areas along the coast
and into the Umpqua Basin. Models typically have a hard time
nailing down overnight showers and storms in this type of
environment, so confidence is low, but worth mentioning.

On Wednesday, there is a greater concern for increased afternoon and
evening thunderstorm coverage. This is due to better instability
expected in advance of moisture arriving in southerly flow aloft at
peak heating along with the potential for better forcing as the
remnants of Elida push northward just offshore. We think the
greatest activity in terms of coverage will occur along the western
slopes of the Cascades (eastern FWZs 622/617) east across the
Cascades (FWZ623), and then also east of the Cascades in the typical
arc from Crater Lake, across Winter Rim, and down to the Warners
(FWZs 624/625). Isolated storms are also possible elsewhere across
the area, including in northern California and across the valleys
west of the Cascades, though a surge of drier air aloft does appear
to be pushing into NorCal later in the afternoon/evening (this
should keep best activity confined to areas north of the OR/CA
border). Storms that do develop should be moving at a pretty good
clip - in the 20-30 mph range, so while they are likely to be wetter
storms with higher PWs, the faster storm motions should still raise
the risk of lightning-induced fire ignitions. We have upgraded these
areas of higher concern to a Red Flag Warning. Again, isolated
thunderstorms remain possible for just about all areas outside of
the Warning.

Of note, with PW approaching or exceeding 1.50 inches, or roughly
200 percent of normal, these storms should not only be wet, but
could produce heavy rain as well. Should a storm pass directly over
a recent burn, such as the East Evans Creek fire, mud and debris
flows are possible down any adjacent drainages.

Later this week (Thursday/Friday), eastward movement in the upper
level pattern is likely, which is likely to shift the region of
instability east of our area with drier SW flow aloft winning out.
As such, lightning risk will diminish to almost nil, but at the
expense of enhanced westerly winds during the afternoons and
evenings east of the Cascades, which could overlap with low
humidity. Any new fire starts would then have the ability to
spread/grow quickly. We`ll continue to monitor this potential and
consider potential wind/low RH headlines, especially and notably for
Friday and Saturday afternoons/evenings in FWZs 624, 625, 284, and
285.

The dry, diurnally breezy pattern looks to last this weekend and
into early next week. But, temperatures should also lower some
compared to earlier this week. -Spilde/BPN

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning from 11 AM to 11 PM PDT Wednesday for ORZ617-
     622>625.

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$