449
FXUS66 KMFR 081741
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
941 AM PST Wed Jan 8 2025

.DISCUSSION...Made some minor updates this morning, mainly to
lower the afternoon high temperatures for the West Side Valleys.
With those areas socked in with fog/low clouds, high temperatures
today will likely end up lower that was in the forecast. Most
valleys should at least see some breaks in the low clouds today,
but even then, there is higher level cloud cover streaming over
the region today. Not much change in the weather is expected
until Friday, and an Air Stagnation Advisory is in effect through
then. For more details, please see the previous discussion below.

/BR-y

&&

.AVIATION...08/18Z TAFS...Fog remains in the valleys this morning
with visibilities down to 1/4 mile in a few areas. Some mid and high
level clouds remain overhead with a weak inversion. High pressure is
anticipated to build this afternoon into the overnight hours with a
very strong inversion setting up over the region with temperatures
up to 53 degrees F near 2000 feet and a few degrees above freezing
at the surface. As a result, more dense fog with visibilities down
to a 1/4 mile seems likely in many of the valleys. Spotty high
clouds could keep visibilities varying from IFR to LIFR through the
overnight hours.

-Smith

&&

.MARINE...Updated 800 AM PST Wednesday, January 8, 2025...Steep seas
will continue through tonight due to a persistent west swell.
Additionally, north winds are also expected to increase later this
afternoon, especially south of Cape Blanco. This will result in
advisory conditions across most of the waters through this evening.

Conditions briefly improve late Wednesday evening/Thursday morning
ahead of a cold front which is expected to pass through the region
on Friday. Steep seas are likely to accompany this front. Then north
winds strengthen Saturday into Sunday as high pressure builds
offshore and a thermal trough develops near the coast. Winds may
reach gale force south of Gold Beach during the weekend.

&&

.PREV DISCUSSION... /Issued 324 AM PST Wed Jan 8 2025/

DISCUSSION...Current satellite shows clearing over the southern
most counties in Oregon and in Siskiyou and Modoc counties. This
clearing has been enough for fog formation in west side valleys
with the Rogue Valley being the last to build the fog. This fog is
expected to lift by 16- 17Z, although when the cloudier skies in
the Pacific track southeastward over the valleys it could begin to
lift some of the worse fog before then.

The warmest temperatures of the week will come today and Thursday
with 60s at the coast, 50s inland west of the Cascades, and 40s
east. This is on average 5-10 degrees above normal for this time of
year with the largest difference at the coast and in western
Siskiyou County.

High pressure will continue to be the main weather factor in the
next week. However, a short wave makes its way into the picture
Friday and could bring some precipitation. With the latest models
showing a slower arrival, I toned back PoPs to support that Thursday
night. The most likely time to see precipitation will be Friday
morning and afternoon. Although PoPs will be high, 700-500 mb
relative humidity is only near 50-70% and forecast soundings
indicate dry layers across the mid and low levels, so it would be
hard to get precip to the ground. Only about a tenth to a quarter of
an inch is expected with less than an inch in the Cascades.

By the time the shortwave moves out of the area, high temperatures
will be a few degrees below normal this weekend and back to 40s and
low 50s west and 30s east. Mornings will also be colder and
near/slightly below normal this weekend with teens east and 20s and
30s west. The center of the ridge reaches the PNW Tuesday and
Wednesday of next week, and that is when afternoon temps will turn
closer to normal again. Dry conditions are favored other than the
disturbance this Friday. -Hermansen

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Air Stagnation Advisory until noon PST Friday for ORZ023>026-
     029>031.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 10 PM PST this
     evening for PZZ350-356-370-376.

&&

$$