051
FXUS66 KMFR 281809
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1109 AM PDT Thu Aug 28 2025

.Updated Aviation Discussion.

.DISCUSSION...Main update this morning was to increase wind
speeds across the region for this afternoon and to bring the
current forecast in line with observations. We expect another
round of typical afternoon breezes and the inherited forecast was
underdone in that regard. Gusts up to 15 mph are likely in the
valleys west of the Cascades this afternoon. Additionally,
southerly flow will bring some enhanced breezes to the Shasta and
Scott valleys in Siskiyou County where gusts of 15-25 mph will be
common today. Otherwise, the going forecast is on track and no
other updates are needed this morning.

The overall pattern will be rather benign, with subtle day to day
differences. There could be times through the forecast period that
warrant more attention than others, with some slight chances for
thunderstorms east of the Cascades and another warm up possible
later next week. We`ll be sussing out those details with the
afternoon package today. /BR-y

&&

.AVIATION....AVIATION...28/18Z TAFs...Along the coast and just
offshore, IFR and LIFR conditions are currently being observed.
However, satellite image and guidance suggest ceilings will
gradually increase later this afternoon. It`s possible the south
coast could clear out towards 21-22z, but confidence on the timing
and if it will clear out is low. North Bend may not clear out, but
ceilings should improve briefly to MVFR before IFR and local LIFR
ceilings reform between 2-3z.

Inland, the marine stratus in the Coquille Basin is burning off and
will peel back towards the coast between 19-20z, with VFR conditions
through this evening, otherwise the inland terminals will remain VFR
through the TAF period with the typical mid to late afternoon and
early evening diurnal breezes. -Petrucelli

&&

.MARINE...Updated 800 AM PDT Thursday, August 28, 2025...Relatively
light south winds and low seas will persist through Saturday. Winds
turn northerly Sunday and increase as a weak thermal trough
develops. Gusty north winds return Sunday afternoon, especially
south of Cape Blanco, then seas are likely to become steep on
Monday. These conditions are likely to persist through at least mid-
week. /BR-y

&&

.PREV DISCUSSION... /Issued 500 AM PDT Thu Aug 28 2025/

DISCUSSION...Warm temperatures continue across the area today
under a broad upper level ridge. A weak area of low pressure had
been supporting southerly flow and monsoonal moisture, but that low
pressure has dissipated. Drier air aloft is expected today, with
precipitable water values dropping down to 0.3-0.4 inches over most
areas. To compare, these values were 0.8-1.0 inches over the past
days of thunderstorm activity. These drier conditions have taken
thunderstorm chances out of the forecast for today.  Southerly winds
in the morning looks to keep bringing smoke from the Dillon Fire
over west side areas, making periods of hazy conditions possible. In
the afternoon, low level winds look to turn northerly, bringing
smoke from the Emigrant Fire over east side areas. Mixing looks to
be good enough to prevent any significant smoke accumulation.

Deterministic imagery shows an area of low pressure approaching the
Oregon coast to end the week and through the weekend. This is
looking to bring breezy conditions over terrain, especially east of
the Cascades. Daytime highs are forecast to cool to seasonal levels
through the weekend. While southerly flow can sometimes mean
thunderstorms, persisting dry air is keeping storm activity out of
the forecast.

The forecast beyond this weekend remains oddly complicated for
overall stable conditions. Deterministic imagery shows multiple
areas of low pressure shifting under and over the broader ridge.
There`s some agreement that the broad ridge remains in place to
start the week, with chances of another warming trend through the
middle of the week. NBM probabilistic guidance has 50% chances for
triple digit temperatures in Medford in the middle of next week, but
a large range of possibilities. Passing low pressure may flatten the
ridge to end next week, helping to cool temperatures but with
dry conditions expected to continue. -TAD

AVIATION...28/12Z TAFs...IFR and LIFR levels continue along the
Oregon coast under a persisting marine layer. Periods of MVFR to VFR
levels may be possible this afternoon, but marine stratus looks to
lower back to IFR/LIFR conditions by the evening.

Inland areas look to remain at VFR levels with normal diurnal
breezes. Smoke from area fires may cause periodic MVFR visibilities
for the Medford and Klamath Falls terminals, but this is not
generally expected. -TAD

MARINE...Updated 800 PM PDT Wednesday, August 27, 2025...Relatively
calm winds and seas will persist through the end of the week.  After
the passage of a weak system, the thermal trough will redevelop
along the coast. Gusty north winds return Sunday afternoon,
especially south of Cape Blanco, then seas are likely to become
steep on Monday. Steep seas may then persist through mid-week. -DW

FIRE WEATHER...Updated 200 PM PDT Wednesday, August 26, 2025...
Lowering humidities will coincide with continuing warm
temperatures Thursday into Friday. A building pressure gradient
will result in breezy winds across portions of western and central
Siskiyou County Thursday and Friday afternoons. With the drying
humidities, these winds will push conditions toward critical
values for a few hours each afternoon, particularly in the
southern Shasta Valley and along the ridges. Will not issue a Red
Flag for these areas as the criteria will not be met, but will
highlight the conditions in the forecast products.

Heading into the weekend, an upper level low will edge closer to the
coastline and pass to our northwest, allowing temperatures to cool a
bit more down towards seasonal normals, but also resulting in
breezier winds for the weekend. We will likely see enhanced fire
weather concerns due to low humidity and gusty winds this weekend,
and while we may approach headline thresholds, we do not expect to
reach critical conditions at this time. -BPN

&&

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

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$