098
FXUS66 KMFR 050520
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1020 PM PDT Sat Apr 4 2026

.UPDATE...Aviation Discussion updated.


&&

.DISCUSSION.../Issued 1240 PM PDT Sat Apr 4 2026/


Other than some morning valley fog in the Umpqua Valley this
morning, not a whole lot going on as high clouds will start to
move through the forecast area tonight. A thermal trough set up
along the Oregon coast will keep us warm and dry through the
weekend with temperatures pushing into upper 70`s and perhaps
lower 80`s over some locations.

Fog will likely fill into the Umpqua Valley tonight around 12Z as
there is some boundary layer moisture there, although the drier
air today could dry things out. Plus, the higher clouds could
reflect some of that long wave radiation back to earth. In any
case, we kept fog in the forecast, although confidence still isn`t
high in the formation.

Sunday will be another warm day as the thermal trough begins to
move farther inland. However, our temperatures stay put with highs
in the upper 70`s west of the Cascades and low 70`s east of the
Cascades.

Monday is an interesting day as the ridge breaks down and a short
wave moves into southern Oregon early in the day. A few models and
about 15-25% of GEFS/ECMWF ENS are bringing precipitation to the
Cascades and other portions of our forecast area. Looking at GFS
model soundings, there is convective available potential
energy(CAPE) along the Cascade crest with some of that CAPE
is between -10C to -20C. The latest and greatest experimental
rapid refresh forecast system(RRFS) is modeling echos >40dbz with
some lightning east of the Cascades mostly in our CWA. Therefore,
we put some thunderstorms in the forecast along the Cascades,
although they will most likely be showers with some occasional
rumbles of thunder. Its more of a question of where these will
develop not if they will develop. Keep a look out for showers east
of the Cascades on Monday as well.

By Tuesday, a cold/stationary front will settle over central Oregon
with a cutoff low off the coast of northern California. The
models are bringing a 10-20% chance of rain to the area. A trough
in Canada then slides down the Cascades and it seems the chances
of rain increase to about 50% on Wednesday. There is still a lot
of variability on Wednesday with some ensemble members keeping
things completely dry, while others bring in plenty of
precipitation with some thunderstorms. The variability could
continue give the split flow and cut off low in the Pacific.
Given the higher snow levels, don`t expect any significant snow
with the precipitation on Wednesday.


&&

.AVIATION...05/06Z TAFs...VFR conditions will persist through the
TAF period for most the area. The exception is that areas of
LIFR/IFR conditions could return to the Umpqua Basin (including
Roseburg) around sunrise Sunday morning. Additionally, the flow will
turn to southeast at North Bend early Sunday morning, which supports
a a period of IFR to MVFR conditions due to patchy fog spreading in
from the Coquille Basin. Over the coastal waters, LIFR/IFR
conditions in marine stratus may develop south of Cape Blanco
tonight, spreading into areas north of Cape Blanco on Sunday. Areas
along the coast will see increasing chances for LIFR/IFR conditions
with marine fog and stratus Sunday evening.


&&

.MARINE...Updated 1200 PM PDT Saturday, April 4, 2026...Gusty
north winds will persist today, maintaining steep seas for all
areas into tonight. Winds gradually ease tonight into Sunday,
allowing for improving conditions for the inner waters by late
tonight. Steep seas persist for the outer waters into Sunday
morning, then relatively calm conditions are expected through
early next week. Another thermal trough develops next week,
bringing another round of strong north winds and steep seas by
Tuesday afternoon and strengthening through at least Wednesday
night. /BR-y


&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 2 AM PDT Sunday
     for PZZ350-356-370-376.

&&

$$