119
FXUS66 KMFR 241816
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1016 AM PST Sun Nov 24 2024

.DISCUSSION...The forecast is on track for this morning. Fog
currently remains in the Rogue Valley, but southeast winds are
expected to increase this morning. Between winds and daylight, the
fog should clear out before noon. Chances for showers remain in
the forecast for coastal and mountainous areas, and impactful
snowfall is expected for the Mount Shasta region through Tuesday
morning. Please use extra care if you must travel through this
area. -TAD

&&

.AVIATION...24/18Z TAFS...Fog remains in the Rogue Valley this
morning. Expected southeast winds should help to improve conditions
before this afternoon, but as of the start of the TAF period
improvements are not yet noticeable.

More broadly, a persisting upper trough continues to support shower
chances over the Oregon coast and parts of western Siskiyou County
including the Mount Shasta region. Snow levels stating at 3500-4000
feet make snow showers in the Mount Shasta region likely. Snow
showers are also possible over the Cascades. These showers look to
move eastward through the TAF period as the upper trough moves
inland. Ceilings and visibilities may be lower than expected, and
elevated terrain may be obscured under both rain and snow showers.

Guidance also shows wind shear over elevated terrain, especially the
Cascades and across Siskiyou County. Shear is not indicated directly
over area terminals, and generally looks to be from the south at
2000 feet with speeds of 35 to 45 kts. This shear starts to diminish
early Tuesday morning and is nearly absent by the end of the TAF
period. -TAD

&&

.MARINE...Updated 200 AM PST Sunday, November 24, 2024...South
gales continue today with very steep and hazardous seas. Isolated
thunderstorms are also possible. Low pressure moves onshore Sunday
evening and winds will decrease, but conditions remain unsettled
through at least Tuesday morning. Then, high pressure builds for the
remainder of the week with north winds and relatively low seas.
-BPN


&&

.PREV DISCUSSION... /Issued 318 AM PST Sun Nov 24 2024/

DISCUSSION (Today through Saturday)...

Overview:

Recent moisture has led to the development of dense fog across
portions of the Rogue Valley. An advisory is in place this morning
for visibilities of a quarter mile of less. The fog will burn off
late this morning as wind speeds pick up today. In fact, we added a
wind advisory for today in the Rogue Valley, and this will be in
addition to the Wind Advisory already in place for Shasta Valley.
Then our attention turns to snow impacts as precipitation spreads
west to east today through tomorrow night. Then we get a break in
precipitation through the Thanksgiving weekend starting Tuesday
evening.

Further Details:

An area of cyclonic circulation will be noted northwest and
eventually west of the area through Tuesday before this closed upper
low finally pushes inland. In the wake of this departing low, we
will have a trend of dry weather through early next week which will
include a dry pattern through Thanksgiving. Wednesday in
particular looks nice with plenty of sunshine, light winds, and
cool seasonable temperatures.

A vorticity maxima will develop off the coast today and spread
energy over the forecast area through the next 36-48 hours as it
slowly advances east towards the coast. 1000mb-500mb moisture will
ramp up along the coast this morning/afternoon, and will spread east
through tomorrow night. Not seeing a lot of instability inland, but
at least a couple hundred to upwards of 500 J/kg of CAPE could be
realized over the waters and near the coast the next couple of
afternoons. Not expecting severe weather, but could see a couple
thunderstorms near the coast and as far inland as the coastal
ranges. Areas in and around Mount Shasta will start to see snow
impacts today/tonight, especially on Highway 89 which would
include both Snowmans Summit and Dead Horse Summit. Within this
Winter Storm Warning we could have snowfall rates approach 2"/hr
between 6pm and 9pm as strong omega values will be present within
the DGZ, and then rates could be around 1"/hr Sunday night into
Monday morning as omega starts to decrease. This means both the
Sunday evening commute and the Monday morning commute could
experience dangerous driving conditions, especially this evening
as wind gusts could be around 40 mph within the Winter Storm
Warning. This means we could have visibility restrictions within
the warned area making driving further complicated. Cascades will
experience snowfall as well, but mostly at the higher elevations
and only relatively light amounts.

-Guerrero

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 8 PM PST this evening for ORZ026.

     Dense Fog Advisory until 10 AM PST this morning for ORZ026.

CA...Wind Advisory until 8 PM PST this evening for CAZ081.

     Winter Storm Warning until 4 AM PST Tuesday for CAZ082.

PACIFIC COASTAL WATERS...Gale Warning until 7 PM PST this evening for
     PZZ350-356-370-376.

     Small Craft Advisory from 7 PM this evening to 7 AM PST Tuesday
     for PZZ350-356-370-376.

&&

$$