102
FXUS66 KMFR 091035
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
335 AM PDT Tue Jul 9 2024

.DISCUSSION...Satellite imagery is showing some coastal stratus
along the southern Oregon coast and offshore south of Cape Blanco.
Clearer skies are being observed elsewhere. Satellite imagery is
showing sowing some hot spots for the Salt Creek, Shelly, and
Bogus Fires in our area.

We remain under the influence of a ridge of high pressure,
centered across southern Nevada. This ridge which will continue
to bring us mostly cloud-free skies and hot temperatures. At the
time of writing this discussion, low temperatures inland were in
the 70s for most of the area, and if not in the 70s, temperatures
were in the upper 60s. While temperatures will still decrease a
few more degrees tonight, it is clear that we are in for another
hot day across much of the area.

The ridge of high pressure will begin to weaken somewhat as it
slowly meanders eastward toward the four corners region of the US.
This means that temperatures of Wednesday should be several
degrees less across much of the West Side, but only a little less
east of the Cascades. Still, with temperatures reaching above the
century mark across portions of the Rogue, Illinois, and Siskiyou
County Valleys; have extended the excessive heat warning for
Jackson, Josephine, and Siskiyou Counties through Wednesday and
the Heat Advisory for Modoc, Klamath, and Lake Counties until
Wednesday evening. This is mainly due to the cumulative nature of
impacts on the human body due to heat.

After Wednesday, overnight low temperatures lower into the 50s to
low 60s which will help people start getting relief from the heat.
Still temperatures will reach into the 90s to low 100s across
inland areas. Meanwhile, the coast will continue to see
temperatures reach into the 70s each day this week.

It is worth noting that as the ridge continues to break down, it
will allow an area of low pressure to move northward across the US
West Coast. This juxtaposition will mainly affect winds,
increasing them in the afternoons and evenings. With still
relatively dry humidities, this could spell issues for area fires.
Also, for the weekend, this low could cause enough disturbance for
cumulus buildups and a possible thunderstorm. The NBM is not
extremely high on the thunderstorm threat quite yet with areas
east of the Cascades seeing a 10 percent chance for thunderstorms
or less over the weekend; but will need to monitor this pattern for
additional details. -Schaaf

&&

.AVIATION...09/06Z TAFS...Along the coast and just offshore.
Marine stratus will form later this evening with IFR ceilings and
visibility from Cape Blanco north and possibly lasting until mid
morning tomorrow. The timing of when conditions go from VFR to IFR
could end up developing on either side of the hour that`s in the
North Bend TAF. South of Cape Blanco, marine stratus should remain
beyond 5 nm from shore.

Inland VFR conditions will continue through the TAF period. The
exception will be in the vicinity of the Salt Creek and Shelly fires
where visibility could be reduced to less than 4 miles due to the
smoke. Smoke will settle back into the area tonight.
-Petrucelli/Hermansen


&&

.MARINE...Updated 200 AM Tuesday, July 9th, 2024...A thermal
trough will remain in place through the reminder of the week
resulting in north winds and elevated seas. Small Craft Advisory
conditions are expected through Wednesday south of Cape Blanco with
moderate north winds and steep wind driven seas. North of the Cape,
winds will be weaker, and so seas will be lower. As such, for now,
we have cancelled the advisory in the northern outer waters.
However, the thermal through will strengthen late Wednesday and
Wednesday night, possibly bringing gales and very steep, hazardous
seas south of Cape Blanco and beyond 5 nm from shore Thursday. The
Gale Watch remains in effect. Conditions hazardous to small craft
are likely to spread north of the Cape again during this time.

While gale force winds could diminish some Friday into the weekend,
seas will likely remain very steep and hazardous south of Cape
Blanco, with conditions hazardous to small craft elsewhere.
-Spilde


&&

.FIRE WEATHER...Issued 200 PM Monday July 8, 2024...

...Elevated to critical fire weather conditions possible all week...

Our trend of hot, breezy, low humidities, and occasionally unstable
afternoon conditions will persist through this weekend. Our
afternoons are forecast to be above normal with deep mixing.
Fortunately the wind speeds are not too crazy this week, but they
certainly will be on the breezy side around 10-15 mph. Single digit
RH values are also forecast during the afternoon hours across the
eastside this week. These factors during this prolonged drying
stretch will result in elevated to critical fire weather conditions
nearly every day this week. There are going to be a couple hours
here and there with criteria being met, but this afternoon and
tomorrow afternoon may fall just short of actually reaching
criteria. While no official warnings are out now, it will be very
borderline today and tomorrow afternoon. Conditions worsen as the
week progresses, and we will likely see Red Flag Warnings coming to
fruition as early as Thursday. That said, if conditions change now
through Thursday, we could see these conditions sooner as we are
already close each afternoon of reaching critical thresholds.

There is some relief from this heat by mid-week with a slight cool
down, but the reality is that temperatures are still going to be on
the warm side. Much of the area hasn`t received much rainfall, so
fuels are only going to worsen as this prolonged drying stretch
continues with above normal temperatures. The heat is obviously of
importance for those outside fighting the fires.

-Guerrero

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Excessive Heat Warning until 9 PM PDT Wednesday for ORZ023>026.

     Heat Advisory until 9 PM PDT Wednesday for ORZ029>031.

CA...Excessive Heat Warning until 9 PM PDT Wednesday for CAZ080>082.

     Heat Advisory until 9 PM PDT Wednesday for CAZ083>085.

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Thursday
     for PZZ356-376.

     Gale Watch from late Wednesday night through late Thursday night
     for PZZ356-376.

&&

$$