851
FXUS66 KMFR 062336
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
436 PM PDT Mon Apr 6 2026

...New Aviation Section...


.AVIATION (00Z TAFs)...

A solid marine layer is present along the coast resulting in IFR
conditions for North Bend where AWOS data is still having issues
transmitting out. Expecting these conditions to remain in place
overnight, but we could see conditions improve tomorrow afternoon
to VFR. Otherwise, expecting a mostly VFR cycle for inland TAFs
with one caveat. There may be just enough moisture in the lower
levels to have some low clouds develop overnight, but confidence
was not high enough to result in any categorical changes outside
of VFR at this time. Hinted at this possibility with a scattered
deck, but we may need to reevaluate this in subsequent TAFs.

-Guerrero

&&

.PREV DISCUSSION... /Issued 243 PM PDT Mon Apr 6 2026/

DISCUSSION...Warm temperatures continue today across the area,
especially in valleys west of the Cascades. With a generally zonal
flow pattern in place, little activity is expected today. SPC
guidance shows some isolated thunderstorms are possible over
northern Lake and Klamath counties this evening. Cumulus
development over elevated terrain shows that the moisture is
present. Model CAPE values for these areas are in the 150-200 J/kg
range, which is enough to support some development but not
entirely threatening. Chances for thunderstorms drop quickly into
the evening.

Temperatures cool slightly on Tuesday and Wednesday but remain 10
to 15 degrees above seasonal levels. A low pressure system
passing to the northeast will allow for some higher winds over
elevated terrain on Tuesday afternoon and evening. Terrain east of
the Cascades may see gusts of 15 to 25 mph, which is safely below
Advisory levels but is still work acknowledging. Otherwise,
Tuesday looks to be an uneventful day. The upper pattern starts to
change on Wednesday as a low pressure system approaches the west
coast. Southerly flow around the periphery of the system will
allow for some slight thunderstorm chances in southern Lake and
Modoc counties on Wednesday evening, with showers possibly
continuing into the night.

Activity on Thursday and Friday will be guided by the position
and approach of the Pacific low. The low itself looks to drift
south and move inland over California. Stronger southerly flow is
forecast to push more moisture up to the area, bringing moderate
shower chances to most areas. Most areas have a 30-40% chance of
showers through Thursday and Friday, with the Siskiyou Mountains
and Cascades having higher 50-60% chances. Snow levels remain
high, generally in the 7500-8500 range, minimizing winter
concerns. Rainfall amounts are unimpactful, with Siskiyou County
and Cascades peaks currently forecast to see 0.50 to 0.75 inches
of rainfall across the two days. Lower elevations are expected to
see 0.33 inches or less. Instability may bring some thunderstorm
activity to parts of Siskiyou County, but confidence in these
chances are slight.

Activity remains in the forecast past Friday, but long-term
solutions start to diverge for the weekend and into next week.
Most guidance supports further cooling, with daytime highs
approaching seasonal norms. ECMWF guidance brings a low pressure
system from the Gulf of Alaska over the area, while the GFS keeps
this second low to the west then to the south. NBM probabilistic
guidance is leaning towards supporting snowfall, with 40-60%
chances of 1 inch of snowfall along the Cascades for Sunday and
Monday. The ECMWF outcome might also bring stronger winds over
terrain. Long-term meteograms for both models show some agreement
in unimpactful precipitation continuing further into the week, but
the timing and amounts vary. -TAD

AVIATION...06/18Z TAFs...Mostly clear skies are expected for
inland areas except for cumulus builds ups over the Siskiyous and
along the southern Oregon Cascades and eastward. There is a low
chance (15%) for thunderstorms this afternoon and evening over the
southern oregon Cascades and eastward into northern Klamath and
northern Lake. Over the Siskiyous and western slopes of the
Cascades, there is a very low (5-10%) chance for thunderstorms
this afternoon. Along the coast, there is LIFR ceilings with
IFR/MVFR visibilities in low clouds and fog. Conditions are
expected to worsen late this evening and tonight, with locally
dense fog and widespread LIFR ceilings/visibilities along the
coast. These conditions will persist into Tuesday morning, with
gradual lifting and clearing in the late morning and early
afternoon on Tuesday.

MARINE...Updated 100 PM PDT Monday, April 6, 2026...Relatively
calm conditions are expected through tonight. Fog and low clouds
will persist over the waters today into Tuesday morning. A weak
thermal trough develops on Tuesday, resulting some gusty north
winds that will create borderline advisory level seas Tuesday
through Wednesday. The thermal trough weakens on Thursday as the
upper level pattern transitions. A trough approaches the
California coast on Thursday, then shifts southward over the
weekend. This will continue the pattern of low pressure inland and
high pressure offshore, resulting in periods of increased north
winds and steep seas with borderline advisory conditions possible
through the end of the week.

&&

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

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory from 5 AM Tuesday to 5
     PM PDT Wednesday for PZZ350-356-370-376.

&&

$$