889
FXUS66 KMFR 140609
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1109 PM PDT Sun Jul 13 2025

.Updated AVIATION and MARINE Discussions...

&&

.AVIATION...VFR conditions will prevail through the TAF period
for most locations. The marine layer remains just offshore north
of Cape Blanco as well as from Gold Beach southward. Isolated
showers continue east of the Cascades, but lightning activity has
come to an end. Marine stratus is expected to return to coastal
locations much like previous nights. However, guidance shows the
potential for gusty winds to persist overnight along the coast and
this may keep visibilities from reaching LIFR conditions.
Regardless, LIFR ceilings are expected.

Strong north winds return to the coast and Umpqua Basin fairly early
on Monday (between 16z-18z), and gusts up to 35 kts are possible at
North Bend. Additionally, another round of isolated showers
thunderstorms will be possible across northern California and
southern Lake/Klamath Counties Monday afternoon. /BR-y

&&

.MARINE...Updated 830 PM PDT Sunday, July 13, 2025...The thermal
trough pattern will continue through at least the middle of the
week. This will maintain strong gusty north winds and steep to very
steep wind-driven seas across all waters. Gales are expected in the
afternoons/evenings mainly south of Port Orford and beyond 5 nm from
shore. Conditions could begin to improve around mid-week. Otherwise,
daily conditions will remain quite similar for the next several
days.

&&

.PREV DISCUSSION... /Issued 449 PM PDT Sun Jul 13 2025/

DISCUSSION...It will be another warm afternoon with locations
reaching 99-104 degrees. Taking the warmer morning in the 65-70
degree range today and the expected highs, the Rogue and Shasta
Valleys and Umpqua Basin are under a significant heat risk. This
will impact anyone that does not have effective cooling and/or
adequate hydration. An Extreme Heat Warning and Heat Advisory is
in effect through Tuesday evening for this heat risk. Details can
be found in NPWMFR.

This afternoon a shortwave will be moving through which could
develop some thunderstorms. There is now a 30-40% probability of
thunder in portions near central Klamath and Lake counties, so have
added this to the 5-8 PM time frame. However as noted in the
previous discussion, convective temperatures will need to be met to
kick off these storms, and this could be a factor that limits
development if it`s not warm enough. Forecast soundings have
forecast convective temperatures in the 91-94 degree range this
afternoon, and temperatures around that time are expected to be
around 90-92 degrees.

In terms of overnight temperatures, forecast lows will be in the 60s
for more locations including east of the Cascades. There is an 80-
85% probability to see lows at or above 65 degrees in Medford and
Roseburg tonight. The northerly/northwesterly flow we`ll have the
next few days will bring near surface smoke to central Lake and
Klamath counties and Siskiyou and Modoc counties. Higher
concentrations of smoke from the Green Fire is forecast in Modoc
County Monday afternoon because of a more westerly flow there. Smoke
higher in the atmosphere will create hazy skies for more parts of
southern Oregon the next few afternoons.

Monday afternoon`s temperatures will still be in the 90-100 degree
range for most locations. There will be another 10-20% chance of
thunderstorms Monday afternoon as another shortwave passes through.
This will be concentrated in far eastern Siskiyou and Lake
counties. Tuesday`s temperatures will be similar to today, but
conditions are forecast to stay dry.

Long Term...Wednesday through Sunday...Wednesday`s heat risk has
been under review for the need to extend the current heat products.
On Wednesday there is still a 70-90% probability to see triple
digits in the Medford area with a 60-80% probability for other spots
in the Rogue Valley and in the Umpqua Basin. Areas east of the
Cascades will likely not be under the risk for the heat, so the Heat
Advisory for that side will be finished Tuesday evening. The likely
scenario is that Monday afternoon`s update will include having a
Heat Advisory for west side locations in Southern Oregon. This has
been included in the details section of the NPWMFR.

Ridging continues through the rest of the work week with
temperatures 5-10 degrees above normal for this time of year. After,
a low starts to develop into western Canada. This will help "cool"
temperatures back to below the 99-101 degree mark for more west side
locations. Looking to still favor drier conditions next weekend and
the week after will have cooler temperatures back to near normal.
-Hermansen

FIRE WEATHER...Updated 200 PM PDT Sunday, July 13, 2025... There
are a few fire weather concerns this afternoon. First and foremost
is the thunderstorm potential this afternoon and Monday, which is
discussed in the discussion above.

Secondly, we`ll see a thermal trough build over locations west of
the Cascades through Tuesday with some easterly breezes over the
Cascades Tuesday evening and Wednesday morning. It looks like a dry
cold front does indeed make it down here behind an upper level wave
diving south from British Columbia. The fire weather risk here is
limited to moderate as the driest air seems to be above 7000
feet. One would expect some of that drier air to make it lower
with some easterly breezes Tuesday night. In any case, we did
lower humidities overnight 5 to 10 percentage points below current
guidance on the mid slopes west of the Cascades, although that
might not be enough.

The thermal trough hangs around on Wednesday and temperatures still
remain hot west of the Cascades with highs in the lower to mid
100`s. This hot and dry weather persists through the week,
although temperatures do trend a bit lower by the weekend.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Extreme Heat Warning until 8 PM PDT Tuesday for ORZ024-026.

     Heat Advisory until 8 PM PDT Tuesday for ORZ023-025-029>031.

CA...Extreme Heat Warning until 8 PM PDT Tuesday for CAZ080-081.

     Heat Advisory until 8 PM PDT Tuesday for CAZ082>085.

PACIFIC COASTAL WATERS...Gale Warning until 11 PM PDT Tuesday for
     PZZ356-376.

     Small Craft Advisory until 11 PM PDT Tuesday for PZZ350-370.

&&

$$