409
FXUS66 KMFR 021046
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
346 AM PDT Thu Oct 2 2025

.DISCUSSION...Satellite image shows an upper low just west of
Vancouver Island with a upper trough axis west of the forecast area.
Satellite image slow shows a shortwave rounding the base of the
upper trough and this will move into the area later this morning.
The net result will be increasing showers over the forecast area
late this morning into this afternoon. For this morning, showers
will be isolated, with most focused over the marine waters and
coast.

Instability will increase enough this afternoon and guidance suggest
isolated thunderstorms could develop along the northern Cascades
later this afternoon.

Showers will continue into tonight, but will gradually diminish as
most of the significant energy shifts south of the forecast area as
the upper trough axis moves overhead and another upper low develops
south of the area as the upper flow splits.

The upper low will move south through the area Friday. Most
locations will be dry, except for a few showers in southeast Lake,
and Modoc County on the backside of the departing upper low.

Dry weather is likely this weekend into the early part of next week
with a dry northerly flow aloft with a strong upper ridge positioned
offshore. It will be milder with afternoon temperatures slightly
above normal for the interior. Overnight lows will be chilly,
especially east of the Cascades starting Saturday morning with
mostly clear skies and longer nights.

At the same time, thermal trough will develop with offshore flow
setting up with gusty breezes near and at the ridges in southwest
Oregon and western Siskiyou County Saturday and this will persist
into the early part of next week.

It will remain dry for at least the first half of next week, beyond
that, the operational ECMWF and ensemble mean shows another trough
dropping in from the northwest the latter part of next week and
eventually becoming cut off from the main flow. In contrast the GFS
and ensemble means show more ridging with the ensemble mean showing
more of a zonal to weak ridging scenario. The NBM in the extended
suggest it was leaning more towards the wetter solution. Even if
one takes the operational and ensemble mean ECMWF solution at face
value, the main question will be the over water trajectory which
right now suggest it`s not sufficient enough to warrant the high
pops being indicated by the NBM, therefore pops beyond Wednesday
have been adjusted downward. -Petrucelli


&&

.AVIATION...02/12Z TAFs......VFR conditions will be the predominate
condition through the TAF period with weak instability over the
area. There could be brief periods of MVFR ceilings in showers along
the coast, but confidence is not high enough to include the lower
conditions in the North Bend TAF. -Petrucelli


&&

.MARINE...Updated 215 AM PDT Thursday, October 2, 2025...Steep seas
will continue today, but will gradually diminish. A thermal trough
will develop  Saturday with increasing north winds near or above
advisory strength and steep seas likely later Saturday into Sunday
night. -Petrucelli


&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 9 PM PDT this
     evening for PZZ350-356-370-376.

&&

$$