Wildfire in California, July 11 to 15, 2021

Area Forecast Discussion
National Weather Service Medford OR
913 AM PDT Sun Jul 11 2021

.UPDATE...

&&

.DISCUSSION...Today's smoke pattern should be similar to
yesterday's, with the north to northeast flow over the west side
bringing smoke from the Jack fire into Jackson, Josephine, and
western Siskiyou counties this morning. Afternoon upvalley flow
should once again push the smoke east late this afternoon into the
evening. East of the Cascades the Bootleg fire has doubled in size
and will cover most of the area east of the Cascades with
widespread reductions in visibilities. Current forecast looks on
track and will not update this morning.

&&

.PREV DISCUSSION... /Issued 348 AM PDT Sun Jul 11 2021/

DISCUSSION...Hot dry and breezy conditions will continue over the
next several days. High resolution models like the HRRR show a
tightening of thicknesses across southern Oregon and northern
California which indicates that the thermal trough will move
farther inland today. Areas like Montague reached 106 degrees
today which was only one degree off their daily record. Klamath
Falls was also one degree off the daily record of 100 degrees. In
fact, the only temperature record broken yesterday was Mt. Shasta
City. Today, similar temperatures are expected for most areas.
Have brought down temperatures in Klamath and Lake Counties a
little below guidance due to ongoing smoke from the Bootleg and
Jack wildfires. Still, this multi-day heatwave will continue the
need for heat advisories and the excessive heat warning that
remains in effect. Please see the NPWMFR for more details, and
check in on friends and family to make sure they are doing alright
in the heat and the smoke.

The other big thing to discuss in the forecast for today is the
smoke. Have updated the forecast with the latest thoughts on how
smoke will move. Winds are shifting from east to west in a diurnal
cycle much like a sloshing wave in a bathtub, and this is pushing
the smoke with it. However, at peak smoke production in the
afternoon, expect winds from the west or northwest to push the
smoke toward the east or southeast. This smoke has prompted the
Oregon Department of Environmental Quality to issue an Air Quality
Alert for portions of southern Oregon. Please see the AQAMFR for
more details. For folks living in northern California, please note
that you can expect smoke to impact air quality for periods of
time as well. Information about the fire weather forecast can be
found in the fire weather discussion below.

This pattern will continue through the weekend with periods of
hot, dry, and breezy conditions. As the thermal trough moves
farther inland on Monday, expect temperatures to lower slightly
west of the Cascades while remaining really hot east of the
Cascades through Tuesday. A weak upper level trough will move
through the area early next week bringing additional periods of
breezy winds.

Temperatures will return to near normal or slightly above normal
by mid to late next week. However, with high pressure sitting over
the area, expect the next thermal trough to begin building next
weekend bringing yet another heat wave. We are at that time of
year.

Precipitation remains non-existent in the forecast, except
for maybe some light drizzle at the coast overnight with the
marine layer. Speaking of the coast, they will be much closer to
average conditions for this time of year, with sun peaking through
the marine stratus in the afternoons. Smoke should also stay away
from the area, making it an idea location for those inland looking
to escape the ongoing heat and smoke. -Schaaf

AVIATION...For the 11/12Z TAF Cycle...IFR/LIFR marine stratus
persist along the coast and in the coastal valleys, especially north
of Cape Blanco and south of Gold Beach. Conditions will improve
through the morning with mainly VFR expected this afternoon, but low
flight conditions are likely to return this evening and tonight.

Elsewhere, VFR will prevail with gusty afternoon and evening
westerly winds, and thick smoke from area wildfires remaining the
main concerns. Smoke will be thickest near the Jack fire in the
upper Umpqua Basin, and the Bootleg fire, northeast of Klamath
Falls. Visibilities will be reduced in the vicinity of these fires
and in much of the area from the Cascade foothills eastward,
especially during the late night and morning hours. Visibilities
generally improve away from the fires and as winds increase during
the afternoons. -BPN/BR-y

MARINE...Updated 200 AM PDT Sunday, 11 July 2021...A thermal
trough will continue to strengthen into next week. Model boundary
layer winds are expected to peak around 50kt each afternoon/evening
in an area of the expansion fan south of Gold Beach and about 10-30
NM from shore, where the worst conditions can be expected. Expect
gusty north winds and steep wind-driven seas over all the waters,
with gales and very steep, hazardous seas expected south of Port
Orford. These conditions will persist through at least the middle of
next week. Guidance then suggests the thermal trough will at least
weaken somewhat (but not go away completely) late next week.
-Spilde/BPN

FIRE WEATHER...The overall pattern is not expected to change
much through at least the middle of next week. This means we can
expect much of the same with continued dry and hot conditions for
all locations away from the coast.

The big story once again today is the unstable nature of the
atmosphere. Haines indices of 5 (Moderate) are expected everywhere
west of the Cascades. For areas east of the Cascades, the Haines
index will be 5 for most of the day, however expect the
instability to increase to a haines 6 (High) across the southern
half of Oregon fire zones 624, 625, as well as all of California
fire zones 284, and 285 in the afternoon. Overall, the high haines
is expected from 2 pm through 8 pm PDT today, and pyrocumulus will
be possible for the Coyote and Juniper fires with pyrocumulus very
likely at the Bootleg fire. Will coordinate with the meteorologist
on site in charge of the fire on the critical nature of the
situation.

For those folks in evacuation zones near the Bootleg Fire, I want
to stress how dangerous of a situation this is, and you will be
much safer well away from the fire. If you live in a level 2
evacuation zone, consider evacuating early, or at the very least
go over your fire evacuation plan and gather your go kits so you
can leave at a moment's notice. As much as it is painful to have
to prioritize what to take and what to leave behind (a lesson I
had to learn last year with the Almeda fire), no possessions are
worth your life.

Otherwise, for areas east of the Cascades, we'll continue to
headline for breezy winds and low relative humidity. Of note:
Could not rule out a few isolated locations the next couple of
afternoons briefly touching Red Flag conditions, but winds should
be a little less breezy today than they were yesterday.

Meanwhile the thermal trough pattern along the south Oregon coast
will continue for the next several days, this will result in
moderate to locally poor overnight recoveries at the mid slopes
and ridges in fire zones 618, 619, western 620 and western fire
zone 280 in California. Guidance suggest breezy east to northeast
winds, except for fire zone 280.

Mid to late next week, we'll see an increase in troughiness the
area resulting in gradual cooling, slightly higher relative
humidities, and increasing winds across much of the area.
-Schaaf

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory until 8 PM PDT Tuesday for ORZ029>031.
     Heat Advisory until 8 PM PDT Tuesday for ORZ024-026.

CA...Excessive Heat Warning until 8 PM PDT Tuesday for CAZ080>082.
     Heat Advisory until 8 PM PDT Tuesday for CAZ083>085.

Pacific Coastal Waters...Small Craft Advisory until 11 PM PDT Wednesday for
     PZZ350-356-370-376.
     Gale Warning until 11 PM PDT Wednesday for PZZ356-376.

SBN/SBN/SBN