111
FXUS66 KMFR 210946
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
246 AM PDT Fri Jun 21 2024

.DISCUSSION...The official/astronomical start to summer 2024 begins with a
relatively typical summer weather pattern over Northern California
and Southern Oregon. The marine layer and associated low clouds and
fog cover much of the coastal waters and spread inland into portions
of Coos and Curry Counties. Farther inland, mostly clear skies
are being observed, with just some high clouds pushing in from the
northwest. A stable, warm and dry weather pattern will continue
through Saturday with high temperatures about 10 degrees above
normal for this time of year. Another feature that is typical of
summertime in Southern Oregon, though a little earlier than
normal, is a wildfire showing up on morning satellite imagery. The
Upper Applegate wildfire is located south of Ruch, and GOES 18
satellite imagery allowed us to observe the fire intensity
through the night, from above. Fire intensity has decreased
overnight, per the imagery, likely due to firefighting efforts
and/or increasing humidity/decreasing winds overnight. It`s not
totally clear how much smoke impact from this new fire can be
expected over the next few days. The HRRR smoke model (generally
reliable) isn`t painting much in the way of smoke near the Upper
Applegate fire over the next 48 hours, but this seems underdone,
considering the heat on the fire last night, and what looked like
plenty of smoke production yesterday afternoon. Therefore, we`ve
added patchy smoke to the forecast for areas in Jackson County
west of I-5 and south of Ruch, with winds carrying any smoke
southward towards Siskiyou County. More on the fire weather
environment can be found in the fire weather discussion below.

Given the stable, westerly to west-southwesterly flow aloft over the
next few days, no thunderstorms are expected over the forecast area.
Breezy conditions are expected this afternoon and moreso on Saturday
afternoon, especially east of the Cascades, as an upper trough
approaches from the northwest and the thermal trough that has been
at the coast the past few days, moves well inland. Speaking more to
the coast, today will feature gusty northerly winds, and then the
marine layer and gusty northerly winds will be disrupted/weakened
Saturday with the approach of the upper level trough. This
disruption won`t last for long, so expect gusty northerlies at the
coast, and marine layer stratus/fog to return Sunday into Monday at
least.

The upper trough will bring cooler conditions to the area on Sunday,
with temperatures dropping closer to normal for this time of year.
Sunday will probably be the breeziest day through at least early
next week. Winds will gust to 25 or 30 mph in areas east of the
Cascades Sunday afternoon. We`ve added some detail in that area of
the forecast to highlight these particularly gusty conditions east
of the Cascades, supported by some of our post-processed guidance
that is keying in on anomalously strong winds.

The cooldown will be shortlived though as upper troughing lifts
north and east, and heights build over the region.  We`ll return to
temperatures similar to today by Tuesday. Models show no signal for
thunderstorms over Southern Oregon or Northern California through at
least the middle of next week. Keene

&&

.AVIATION...for 21/06Z TAFs...IFR ceilings will persist tonight
with periods of LIFR ceilings in other locations. North Bend has a
chance of seeing LIFR ceilings if the inversion is stronger than
anticipated.

Inland, VFR ceilings will persist through the TAF period. A fire in
the Applegate Valley could produce local IFR visibilities near that
valley Friday afternoon.

-Smith


&&

.MARINE...Updated 200 AM Friday, June 21, 2024...High pressure
offshore and a thermal trough along/near the coast will remain in
place through Monday. This will result in persistent northerly winds
and areas of steep to very steep wind-driven seas. Winds will be
strongest south of Pistol River, with hazardous seas expected in
that area. The thermal trough is expected to peak today and this
will maintain advisory seas south of Cape Blanco, but conditions
will begin to calm north of the cape.

Slight improvement is expected Saturday into Saturday night as a
front brings a surge of stratus with light showers possible.

-DW/Hermansen


&&

.FIRE WEATHER...Given the recent wildfires that have occurred in
Southern Oregon, we`ll take a look at the near-term fire weather
environment here for those interested. For areas west of the
Cascades, focused particularly near the Upper Applegate fire, over
the next couple days expect good humidity recoveries (80% and
higher) in valleys and moderate to good humidity recoveries over
upper slopes and ridges (50-70%) overnight. Afternoon humidities
will bottom out in the mid to upper teens to 20 percent for this
area, with these minimum humidity values trending similar Friday
afternoon to Saturday afternoon. Gusty north to northwest winds
are expected in the afternoons west of the Cascades, with winds a
little higher today than tomorrow afternoon, gusting to around 20
mph each afternoon. Light winds are expected tonight and Saturday
night.

East of the Cascades, the strongest breezes are expected Sunday
afternoon, with some areas gusting to 30 mph. Humidity will trend
upward some from Saturday afternoon to Sunday afternoon.

No lightning is expected over the forecast area through at least
Tuesday. Keene


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 2 AM PDT Saturday
     for PZZ356-376.

Hazardous Seas Warning from 2 PM this afternoon to 2 AM PDT
     Saturday for PZZ356-376.

     Small Craft Advisory until 2 PM PDT this afternoon for PZZ370.

&&

$$

NSK/NSK/ANH