843
FXUS66 KMFR 092121
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
221 PM PDT Tue Jul 9 2024

.DISCUSSION...Satellite image shows clear skies over most of the
forecast area. The exception is for marine stratus along the coast
from Cape Blanco south and some cumulus build ups along the
Cascades and higher terrain east of the Cascades. Smoke from the
Shelly and Salt Creek fires are mainly concentrated in the
vicinity of these fires and will be the case for the next hour,
then once the typical northwest flow kicks in, the smoke from the
Salt Creek fire will get transported southeast towards Klamath
Falls, but not should not be in Klamath Falls proper. Also the
smoke from the Shelly Fire will also get pushed southeast late
this afternoon and evening.

In the meantime, dry and hot weather will continue through the end
of the week. Afternoon temperatures will be at their highest today
for most inland locations, with a slow downward trend tomorrow
through Friday, although they will still be near or at triple
digits for most interior west side valley locations and low to mid
90s east of the Cascades. The one notable improvement will be
cooler overnight lows the latter part of the week. However.
overnight lows tonight and Wednesday night will be similar to this
morning (maybe a degree or two lower).

The weather situation this weekend will need to be watched
carefully. This will especially be the case along and east of the
Cascades and northern California. The upper ridge that`s been over
the area for the past week is expected to shift to the four
corners this weekend. At the same time an upper low will develop
off the California coast Saturday. This will result in a
southerly flow pushing into our area and could tap into a bit of
monsoonal moisture. The amount of moisture is limited, but the
pattern that`s setting up is a bit concerning in that it typically
results in an elevated risk for isolated thunderstorms east of
the Cascades and northern California. For Saturday, the biggest
risk for isolated storms should be mainly confined to Lake and
southeast Modoc County in the afternoon and evening hours. This is
by no means a slam dunk, but at the same time it cannot be
discounted.

Sunday, the situation should be more favorable for isolated
storms. Some evidence supports most of the action could end up
northeast of our forecast area. However, there` still sufficient
evidence to suggest the threat at risk for isolated storms Sunday
afternoon and Sunday evening will be in Lake, eastern Klamath and
eastern Modoc County.

Once we get by this weekend, a dry and stable southwest flow will
return with any threat for storms ending, but afternoon
temperatures will still remain above normal for the interior.
-Petrucelli


&&

.AVIATION...09/18Z TAFS...Along the coast and just offshore,
LIFR and IFR in fog and low clouds will linger today south of Cape
Blanco, including at Brookings (KBOK). Then IFR and LIFR will expand
to a larger area along the coast this evening through Wednesday
morning, including at North Bend (KOTH).

VFR conditions will continue inland through the TAF period.
However, areas of wildfire smoke in the vicinity of the Salt Creek,
Shelly and Bogus fires could cause MVFR visibility. Even local
IFR/LIFR is possible (but isolated and in very close proximity to
the fires themselves).

Local wind gusts of 20-25 kt can be expected at most terminals later
this afternoon and early this evening. -Spilde/CC


&&

.MARINE...Updated 200 PM Tuesday, July 9th, 2024...A thermal
trough will strengthen late today through Thursday resulting in
increasing north winds and elevated seas. Small Craft Advisory
conditions are expected to develop this evening through Thursday
morning for areas south of Cape Blanco, with moderate north winds
and steep wind driven seas. Winds and seas increase Wednesday
afternoon into Thursday with gales and very steep seas expected from
Gold Beach south beginning Wednesday evening then for areas south of
Cape Blanco Thursday afternoon and night.  North of Cape Blanco,
winds will be weaker today but increase Wednesday evening and
Thursday with gusty, north winds and steep seas likely. Moderate to
strong north winds and steep to very steep seas may linger on
Friday. Then winds and seas are expected to gradually lower Saturday
and Sunday. -CC


&&

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

Our trend of hot, breezy, low humidities, and occasional unstable
afternoon conditions will persist through this weekend, and this
will lead to elevated to critical fire weather conditions.
Additionally, we have a chance for thunderstorms this weekend across
the eastside of the forecast area.

Wind speeds are not too crazy this week, but they certainly will be
on the breezy side around 10-20 mph. Single digit RH values are also
forecast this week during the afternoon hours across the eastside
and some isolated westside valleys like Northern California. These
factors, on top of this prolonged drying stretch will result in
elevated to critical fire weather conditions nearly every day this
week. There may be a couple hours here and there when critical
thresholds are met, but this afternoon and tomorrow afternoon may
fall just short of actually reaching those critical thresholds.
While no official warnings are out now, it will be very borderline
today and tomorrow afternoon for fire weather conditions, so the
threat is there even if we aren`t hitting "criteria". Conditions
worsen as the week progresses, and we will likely see Red Flag
Warnings coming to fruition as early as Thursday (if conditions do
not change sooner).

There is some relief from this heat by Wed/Thurs 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
either, so fuels are only going to worsen as this prolong dry
stretch continues with above normal temperatures. The heat is
obviously of importance for those outside fighting the fires as
well.

For the thunderstorm potential, it should be noted that the trend
has increased over the last 48 hours for both Saturday and Sunday. A
lot will depend on how a ridge of high pressure sets up over the
Four Corners region because this will directly impact our moisture
source. There is about a 10-20 percent chance for isolated
thunderstorms both Saturday and Sunday. Of these days, Sunday
currently looks like the best shot for thunderstorms, and this will
be primarily over the eastside of the forecast area.

-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.

&&

$$