846
FXUS66 KMFR 120941
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
241 AM PDT Mon May 12 2025

.DISCUSSION...

Overview:

An upper level disturbance is currently impacting the region with
increased shower activity and increased cloud cover. Additionally,
this system will usher in cooler air, and this will result in
snowfall for elevations mainly above 4500 feet, so not expecting
much impacts from snowfall. The biggest impact today could end up
being the thunderstorm potential with a couple storms possibly being
on the strong end (sub severe). The main threats would be wind gusts
around 40 to 50 mph and lightning. Expect cooler temperatures
through middle of the week before we trend back towards near normal
by Thursday. Our next chance for precipitation could come Friday
night into Saturday.

Further Details:

Current water vapor imagery shows a broad area of cyclonic flow just
off shore from the forecast area. Showers are noted across much of
the forecast area. These showers and isolated thunderstorms are
anticipated to continue through today/tonight and evenutally
diminish late Tuesday afternoon. MUCAPE values are generally progged
to be around 200-400 J/kg which is slightly less than 24 hours ago.
This will ultimately lead to less coverage of stronger storms, but
we still could see a couple isolated strong storms with gusts around
40 to 50 mph and lightning as the main threats. Bulk shear will not
line up today, so updrafts will likely not maintain long enough to
produce any hail, but we could see a couple isolated storms bring
brief heavy rainfall. PWATs are not overly high today, so rainfall
rates and totals will generally be on the lower end. That said,
through the next 24 to 36 hours most places will pick up at least
light rainfall (0.10") amounts, but some areas could end up with
around 0.50" to 1.00" in additional rainfall by tomorrow afternoon.

Fortunately for us ground temperatures are warm and the sun angle
will alleviate much of the impacts from snowfall. Not expecting much
accumulation for populated areas, but one area in particular near
Lake of the Woods on highway 140 and just east of there could see
light amounts. This could make for some wet and sloppy road
conditions along the highway.

Below normal temperatures are expected to last through much of the
week, but by Thursday temperatures will be back up to near normal
for much of the area. Eastside areas will experience many mornings
at or below freezing this week. Much of the westside will be safe
from these frost/freeze temperatures, especially populated lower
elevation areas.

-Guerrero

&&

.AVIATION (06Z TAFs)...

A front is moving inland this evening. Areas MVFR along the coast
will become widespread this evening and spread inland overnight.
Widespread MVFR with local IFR is expected from the Cascades west
tonight and Monday morning, with areas of MVFR east of the
Cascades. Widespread terrain obscurations are expected through
Monday morning. Isolated thunderstorms are possible, especially
along the coast and over the marine waters through tonight.
Conditions will improve to a mix of MVFR and VFR Monday afternoon.
Areas of MVFR will persist through Monday evening, especially
from the Cascades west.

&&

.MARINE...Updated 200 AM Monday, May 12, 2025...Steep seas along
with periods of rain will persist through Tuesday. Isolated
thunderstorms are possible (10-20% chance) today and early
tonight. A pattern change will come on Wedensday with the return
of a thermal trough and associated gusty north winds and wind-
driven seas through Friday morning.

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT
     Wednesday for PZZ350-356-370-376.

&&

$$