792
FXUS66 KMFR 141125
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
425 AM PDT Mon Jul 14 2025

...New Aviation Section...


.AVIATION (12Z TAFs)...

A strong marine layer evident on satellite this morning will
likely persist through the entirety of this TAF cycle with very
little relief this afternoon. We could see conditions improve to
MVFR this afternoon along the coast. Inland TAF sites will likely
see plenty of sunshine today with VFR conditions dominating much
of the region, but a small chance of thunderstorms today could
impact northern California and south central Oregon. Blow off
clouds from these thunderstorms could impact KLMT, but it should
be noted there is a 10% chance Klamath terminal could see an
isolated thunderstorm.

-Guerrero

&&

.PREV DISCUSSION... /Issued 340 AM PDT Mon Jul 14 2025/

DISCUSSION (Today through Sunday)...

Overview:

A very similar day to yesterday is shaping up for today as we are
once again looking at a small chance (~20%) for thunderstorms in
addition to heat related hazards across the area. The heat will
also play a role on elevated fire weather conditions this
afternoon/early evening, but we will fall short of critical winds
and RH that would warrant a Red Flag Warning. Beyond today, heat
related hazards will be the main impact as triple digits are
possible for low elevation areas west of the Cascades through mid-
week.

Further Details:

At 500mb, we have a broad area of high pressure over western parts
of the CONUS which is part of a larger area of high pressure that
includes an area farther west over the Pacific. At the same time, we
have a shortwave trough passing over southern parts of British
Columbia. We will see weak PVA across the area today under this
setup, and as we reach peak heating today we will likely see
convective temperatures reached. In a similar fashion as yesterday,
during peak heating there may be just enough upper level dynamics to
support a couple isolated thunderstorms through early parts of the
evening. These chances are for mainly northern California, and
southern parts of both Klamath and Lake counties with these chances
around 15-20 percent. Not expecting much--if any--activity after
sunset. Main threat with these thunderstorms if they form would be
lightning and gusty erratic wind speeds.

With high pressure dominating the region, expecting the NWS HeatRisk
today to be moderate to perhaps isolated Major, and our heat related
hazards will continue through this afternoon and early evening.
These hazards will remain in place for tomorrow and likely extended
into Wednesday as well. Slightly "cooler" temperatures expected on
Thursday, but upper 90s still possible for westside areas.
Temperatures may finally get back down near normal by Sunday.

Lastly, while its not currently mentioned in the forecast, there
will be very weak upper level energy across the area Tuesday, and
as we enter peak heating there could be towering cumulus that
mature into a thunderstorm. That said, after today chances for any
precipitation or thunderstorms is less than 10 percent in the
official forecast.

-Guerrero

AVIATION (06Z TAFs)...

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...

Our thermal trough pattern will continue through at least the
middle of this week. This will maintain strong 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 as we transition away from wind-driven seas

FIRE WEATHER...

Elevated fire weather concerns expected again today as we fall short
of any overlap of critical winds and RH. A thermal trough continues
over locations west of the Cascades through tomorrow with easterly
breezes over the Cascades tomorrow evening and Wednesday morning. A
cold front is forecast to pass through the region today/tonight
behind an upper level wave diving south/southeast from British
Columbia. There may be just enough upper level energy this afternoon
when coupled with peak heating could produce an isolated
thunderstorm or two this afternoon/early evening. This chances are
low (~20%) and primarily for northern California and both Klamath
and Lake counties. We will need to monitor Tuesday as we could see
another round of low end thunderstorm chances, but these chances are
very low (~5-10%) at this time.

This hot and dry weather pattern will persist through this week, but
temperatures do trend a bit lower by the weekend with temperatures
near normal by Sunday.

&&

.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.

&&

$$