266
FXUS66 KMFR 222151
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
251 PM PDT Sat Jun 22 2024

.DISCUSSION...A decline in temperatures is expected Sunday and
Monday as front moves across the region, most notably west of the
Cascades. This won`t be before we have one last hot day, today. Mt.
Shasta City is already within three degrees of the previous record
max temperature today of 96 degrees (1992), is on track to at least
tie it, and there is a 40% chance the temperature rises above this
record. Some cumulus is beginning to pop along and east of the
Cascades as well, but we are not expecting any of these to become
rain producers.

The rain production, or more likely drizzle, production will be
possible tonight into Sunday morning as moisture gets pooled along
the front, and wrung out through topographic lifting into the Coast
range and Cascade Foothills in Douglas County. The more noticeable
impact from this front will be a strong marine push and the stratus
that will accompany it. There is a high chance that this stratus
fills the coastal valleys, but there remains uncertainty if the
clouds will push into the central Umpqua Basin because of the
existing dry air. Winds will also be amplified today about 4-8 mph
faster than normal, but still from the typical afternoon direction.
Sunday, winds will peak behind this front east of the Cascades and
this will drive gusts of 25 to 35 mph. This could have implications
for fire weather, and is covered in the fire weather discussion
below.

Transient high pressure will build over the region Monday and
Tuesday. That said, the heat risk will remain low, with overnight
low temperatures remaining below 60 degrees.

The next trough is expected on Wednesday and will need some close
monitoring because the mid-level and upper-level jet appear stacked
in many model solutions, and could bring some elevated wind speeds
to the area Wednesday and Thursday. This trough also has some strong
instability and lift associated with it and I would not totally rule
out this having some low end thunderstorm potential. While most of
these impacts will fall into the realm of fire weather, it could
create less than favorable conditions for anyone working or
recreating out in the mountains.

After this trough, the cycle of 2-3 days of high pressure and heat,
followed by another trough looks to repeat.

-Miles

&&

.AVIATION...(22/18Z TAFs)...Aside from some lingering LIFR
ceilings over portions of the marine waters and along the coast
south of Gold Beach, VFR conditions prevail across the region.
Conditions may improve briefly south of Gold Beach this afternoon
but confidence is low in the duration and extent. Otherwise, VFR
will prevail for all other areas through the afternoon. Expect the
typical increase in afternoon breezes today, though slightly
enhanced due to an incoming upper level trough.

Late this afternoon and overnight, this trough will push the
marine layer back along the coast and into the Umpqua Basin
overnight tonight. Expect the return of LIFR/IFR conditions along
the coast, especially north of Cape Blanco between 23z-03z, lifting
to IFR around 04-06z. Conditions in the Umpqua Basin are expected to
be MVFR, including at Roseburg (KRBG). The marine layer does not
look deep enough to "spill over" the Rogue-Umpqua Divide, but there
could be some scattered clouds that develop over the Illinois and
Applegate Valleys around sunrise Sunday morning. /BR-y

&&

.MARINE...Updated 115 PM Saturday, June 22, 2024...The thermal
trough will weaken today, but gusty north winds and steep seas will
persist south of Cape Blanco through the weekend. A weak front will
bring a surge of stratus late today into Sunday with light showers
possible mainly across the northern waters. By late Sunday
afternoon, the thermal trough will restrengthen, bringing increasing
north winds and steepening seas. Steep seas are expected for much of
the waters south of Cape Blanco, with very steep and hazardous seas
developing south of Pistol River late Sunday afternoon and evening.
These conditions will persist through Monday evening before another
front disrupts the pattern either Tuesday or Wednesday. /BR-y

&&

.FIRE WEATHER...Updated 200 PM Saturday, June 22, 2024...East of
the Cascades, brief durations of both critical wind & humidity are
possibly today through Monday. Modoc County in particular will
reach critical RH/wind tomorrow for more than 50% of the county,
and after talking with fuels experts, we felt it was necessary to
issue a warning for areas where fuels are more receptive, albeit
perhaps still on the moderate side.

Critical fire weather conditions are not expected for areas on the
westside. This will be thanks to good overnight recoveries (80% and
higher) in valleys and moderate to good humidity recoveries over
upper slopes and ridges (50-70%) overnight. Afternoon humidities in
these areas will bottom out in in the 20 percent range with typical
afternoon breezy conditions.

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

Looking ahead, Wednesday in particular could bring elevated to
critical fire weather conditions as a strong low pressure system
moves into the area. The threat of strong winds associated with this
system has our attention. Stay tuned as this is Day 5 so changes
could occur. Specifically, if the system trends farther south, we
may have stronger wind speeds and a chance for thunderstorms.

-Guerrero

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...CA...Red Flag Warning from noon to 8 PM PDT Sunday for CAZ285.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT Monday
     for PZZ356-376.

Hazardous Seas Warning from 5 PM Sunday to 11 PM PDT Monday for
     PZZ356-376.

&&

$$