661
FXUS66 KMFR 200524
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1024 PM PDT Mon May 19 2025

...New Aviation Section...


.AVIATION (06Z TAFs)...

While low to mid level clouds will be present tonight through
late tomorrow morning, VFR conditions are anticipated through the
valid TAF period. Skies will generally clear tomorrow except for
areas along and near the coast as well as areas around Roseburg,
but even these areas will see generally thinning of the cloud
decks. Otherwise, typical diurnal breezes expected tomorrow
afternoon.

-Guerrero

&&

.PREV DISCUSSION... /Issued 322 PM PDT Mon May 19 2025/

DISCUSSION...Seasonable conditions are expected this week. A
very weak disturbance could bring a few showers to the coast and
Douglas County tonight into early Tuesday. Warmer and drier
weather on Wednesday will be followed by another couple of weak
disturbances Wednesday night into Thursday, and on Friday. A
stronger trough early next week may bring a higher probability
of showers and a slight chance of thunderstorms.

A westerly flow pattern looks to persist through Saturday with a
series of small scale and larger scale embedded troughs that will
bring mainly slight chance to chance probabilities of showers. The
probabilities will generally be highest from Coos and Douglas
counties northward. The next associated front will arrive late
tonight into early Tuesday morning. The results will bear some
resemblance to this morning`s, but it will only be about half as
strong. This should be enough for measureable rain at the coast
north of Cape Blanco and into northern Douglas County from around
8 PM tonight through 10 AM Tuesday. But, for most of our area on
Tuesday, the sun will have an easier time breaking through
dissipating clouds, and it will be about the same to a few
degrees warmer than today.

Ridging will result in warmer and drier conditions on Wednesday,
with the several degrees of additional heating taking readings to
a few degrees above normal.

The next trough will be more organized as it arrives Wednesday
night into Thursday, but a majority of ensemble members show it to
be accompanied by meager amounts of low and mid-level moisture.

A brief break is expected ahead of the next weak trough on Friday.
The timing and track of the trough looks to bring the highest
probability of showers, aided by the heating of the day, on the
east side in the afternoon.

Ridging is likely Saturday into Sunday with significant warming
and drying of the air mass.

Uncertainty in the forecast increases beyond Sunday, with about
30-40% of ensemble members bringing a stronger trough toward our
area on Monday, though possibly as early as Sunday night.
Depending on the track of the trough, a risk of thunderstorms may
develop for late Monday into Monday evening.

AVIATION...19/18Z TAFs...Along the coast and just offshore,
MVFR/IFR conditions continue through early this afternoon.

Inland, west of the Cascades, MVFR ceilings will be present through
the morning and will start rising to VFR ceilings this afternoon.
Gusty breezes are likely at Roseburg and Medford this afternoon into
early this evening.

East of the Cascades, VFR ceilings are expected with gusty breezes
in the afternoon and early evening. However, Klamath Falls will
experience MVFR ceilings this morning, followed by improving
ceilings. Partial obscurations will be possible through the morning.
-Petrucelli/Hermansen

MARINE...Updated 215 PM Monday, May 19, 2025...A weak frontal
system is moving across the waters this afternoon. Winds are turning
northwesterly behind the front late this afternoon, and steep west-
Northwest swell builds into the waters. Additionally, a thermal
trough will result in breezy north winds and steep seas Tuesday
morning into the afternoon. Winds and seas trend lower beginning on
Thursday. -Petrucelli/Hermansen

&&

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

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

&&

$$

JWG/JWG/JWG