770
FXUS66 KMFR 151021
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
321 AM PDT Tue Jul 15 2025

.DISCUSSION...Hot weather will be the main weather headline
through the middle of this week. There is also a low chance
(~10-15%) of thunderstorms across portions of NorCal and perhaps
into Lake County at times, but overall, a dry forecast will
persist over the next week. Fairly typical afternoon/evening
breezes are expected over the interior, though a trough this
weekend could bring locally breezier conditions on Saturday.

While we usually associate our biggest heat waves with persistent
upper ridging along the West Coast, this one is a bit different
with the axis of the upper ridge mostly out over the ocean, but
also to our south over the Four Corners. There is a weakness in
the ridge over us, but this is still allowing us to get quite hot.
We`ve had 3 consecutive 100+ days here in Medford. We`ll get
close to triple digits again today (NBM is showing 99F, though
there`s a 1 in 4 chance for 100F or above). The hottest day will
likely be Wednesday with 90% of model solutions showing high temps
greater than 100F). Official forecast is for 103F. For these
reasons, we have a heat advisory for most of our west side
valleys. We also looked into the possibility of a heat advisory
over the east side, but temps the next couple of days, while warm,
don`t rise to levels that pose more than a low to moderate heat
risk. Generally, highs over there will be in the low to perhaps
mid 90s (again, highest on Wednesday). So, we`ve opted to forgo an
advisory there.

We expect some instability just due to surface heating each of the
next few afternoons. As such, we`ll likely see a few cumulus
buildups, especially in the mountains of NorCal and up into the
Cascades and over the East Side. Moisture is limited even moreso
than it was yesterday and forcing is weak, so we`re not too
concerned about a significant lightning outbreak. But, there is a
low chance, generally a 10-15% chance of thunderstorms in those
areas through Thursday (best chance in NorCal).

Late this week, but especially this weekend, models are showing a
bit stronger trough swinging through. While this is unlikely to
result in any significant precipitation, it should take the edge
off the heat for at least a little while. Models are showing
temperatures dropping back closer to normal levels (low to mid 90s
Medford and in the mid to upper 80s at KFalls). It may induce a
bit breezier conditions, especially Saturday, so that could pose a
risk for spread of any wildfires out on the landscape. -Spilde


&&

.AVIATION...15/12Z TAFs...Marine layer will be confined to the
coastal waters and portions of northern Curry and Coos counties
this morning. Stratus has been mostly south of North Bend, but
we`re still allowing it to fill in there by morning. Expect most
to burn back to the immediate coast or just over the coastal
waters this afternoon. Gusty north winds redevelop this afternoon.
Inland, VFR will prevail the next 24 hours, though some
locations will have reduced visibility due to wildfire smoke
and/or haze. This is most likely in the immediate vicinity and
downwind of the most persistent fires. Overall, afternoon/evening
breezes should be fairly typical of mid-summer. -Spilde


&&

.MARINE...Updated 230 AM PDT Tuesday, July 15, 2025...The thermal
trough pattern will continue through Wednesday. This will
maintain strong north winds and steep to very steep wind-driven
seas across all waters. Gales are expected in the
afternoons/evenings mainly south of Port Orford and beyond 5 nm
from shore. Conditions will begin to improve around mid-week as we
transition away from wind- driven seas. However, steep seas will
be found in all areas Tuesday evening through Thursday morning.
-Spilde

&&

.FIRE WEATHER...Main fire weather risks today are the hot, dry
weather. There is a low chance (10-15%) of thunderstorms too,
mainly in NorCal, but we`re not expecting more than a couple of
pop-up cells. Overall, RH recovery has been moderate at best over
the ridges this morning with some higher altitude RAWS only
reporting 35-45% in the NorCal mountains. Some ENE winds have
also been present at the usual suspect locations (Slater Butte,
Quail Prairie and Onion Mtn) with peak gusts in the 20-25 mph
range. Another afternoon of dry humidity with RHs bottoming out in
the 15-20% range, though a few spots could fall below 15%. E winds
probably show up again over the ridges tonight into Wednesday. The
hot weather will continue through at least Wednesday, with some
gradual "cooling" expected late week. With a weak trough pushing
through this weekend, we may see temps get back closer to normal
values, though this may be at the expense of some breezier
conditions, especially Saturday afternoon/evening. -Spilde

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory until 8 PM PDT Wednesday for ORZ023>026.

CA...Heat Advisory until 8 PM PDT Wednesday for CAZ080-081.

PACIFIC COASTAL WATERS...Gale Warning until 11 PM PDT this evening
     for PZZ356-376.

     Small Craft Advisory from 11 PM this evening to 5 AM PDT
     Thursday for PZZ350-356-370-376.

&&

$$

MAS/MAS/MAS