952
FXUS66 KMFR 181121
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
421 AM PDT Tue Aug 18 2026

.KEY MESSAGES...

* Seasonable temperatures, dry conditions, and breezy winds
  continue to be the overall theme going forward

* Isolated thunderstorms are possible Friday for areas around
  Crater Lake and north, but these chances may end up being north
  of our area

* Areas of smoke remain possible across western Siskiyou County
  and parts of Klamath and Lake counties due to nearby wildfires

&&

.DISCUSSION...

The general pattern will be noted by high pressure over the
Desert Southwest and a closed low off the coast around 140W and
34N. This will maintain south to southwesterly flow aloft through
much of this forecast period. The big question will be how far
east will the upper low move towards the PacNW on Thursday/Friday.
This will likely play a large role on our thunderstorm chances.
The signal is currently weak for thunderstorm chances, but we do
have moisture and instability across the region, so the added
dynamics aloft could help produce a thunderstorm or two Friday
afternoon/early afternoon. That said, the overall pattern doesn`t
show any strong signal for thunderstorms any day, but Friday is
currently the best chance. It will be a battle between the closed
low and the high pressure over the Desert Southwest. If the closed
low is allowed to push eastward farther we may see additional
thunderstorm chances this weekend.

Otherwise, we will be monitoring fire weather conditions this
week as there will be days with at least elevated fire weather
concerns for wind and low RH. This will be mainly for eastside
areas and northern California for the next several afternoons.

&&

.AVIATION (12Z TAFs)...

A marine layer along/near the coast will maintain IFR/LIFR
conditions with improved conditions through the afternoon, but the
marine layer is expected to reestablish again tonight bringing
further IFR/LIFR conditions. Inland TAF sites are expected to
remain in VFR through this cycle with typical diurnal breezes.

&&

.MARINE...Updated 330 PM PDT Tuesday, August 18, 2026...Gusty
north winds and steep seas, highest during the afternoons and
evenings are expected south of Cape Blanco through Wednesday
evening. Conditions are expected to improve late in the week.

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT
     Wednesday for PZZ356-376.

&&

$$