Beach Hazards Statement 1, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
958 AM PST Mon Jan 10 2022

.DISCUSSION...The forecast has been updated to expand coverage of
a slight chance to chance mention of very light precipitation,
mainly this morning and mainly across southwest Oregon into
northern Klamath County. There have been many reports of around
0.01 to 0.03 inches to the west and north of Jackson County.

A very weak front will dissipate as it moves inland today. A warm
front will brush our coast late tonight into Tuesday morning with
a slight chance of very light coastal showers. Another slightly
stronger front is expected late Wednesday evening into Thursday
with perhaps up to a tenth of an inch for our coastal counties,
and a measureable amount for southwest Oregon into northern
Klamath and far northwest Siskiyou Counties. The snow level with
this minor event is expected to be around 5500 feet. Otherwise,
high pressure will likely be in control during the next week.

&&

.AVIATION...10/18Z TAFs...Some weak showers will continue to move
onshore through the TAF period, causing patchy light rain along and
near the coast and, some snow flurries across the Oregon Cascades.
Otherwise, VFR conditions are expected to prevail.

Tonight into Tuesday morning a mix of mid and high level clouds are
likely to limit or even prevent fog and low cloud formation,
especially the further north and west one goes on the Oregon west
side. ~BTL/Miles

&&

.MARINE...Updated 930 AM PST Monday, 10 January 2022...
Southerly winds combined with steep wind waves and westerly swell
will bring conditions hazardous to small craft the coastal waters
area today. An area of very steep seas is also likely beyond 10 NM
of the coast during the daylight hours today. Longer period westerly
swell will build tonight and then peak combined seas in the 12 to 15
foot range Tuesday continuing advisory level conditions. Southerly
winds with high and steep seas are then likely to continue into
Thursday. Thursday afternoon into Friday steep seas are also likely
as thermal trough conditions bring a period of gusty northerlies
which may continue through the weekend. ~BTL/Miles

&&

.PREV DISCUSSION... /Issued 410 AM PST Mon Jan 10 2022/

DISCUSSION...Upper level ridging will remain over the forecast
area, keeping mostly quiet weather in place for at least the next
week, with a few exceptions. Overall, expect daytime temperatures
to generally trend about 5 to 10 degrees above normal for this
time of year, although nightime lows will likely trend at or
below normal due to radiational cooling provided by mostly clear
skies, and for some areas, persistent snowpack. Valley fog and
freezing fog will be common, but may be limited by the drier area
we expect to see over the coming days. Valley inversions will be
strong, with air likely becoming stagnant beneath them. Air
quality will be a concern throughout this week and into the next.

Although ridging will be the primary feature overhead, a very
large upper level trough resides to our west, centered along the
Aleutian Islands but coverage a significant swatch of the north
central and northeastern Pacific. A few waves are expected to exit
the trough and attempt to push into the West Coast, but will have
great difficulty making it very far inland due to the resilient,
unmoving ridge already here.

The first of these waves is expected today, and is in fact
already producing a few showers just offshore as the trough moves
from southwest to northeast within the prevailing Westerlies. The
feature is likely to ride up and over the ridge, preventing it
from making any real progress inland. As moisture and energy will
be sin short supply, showers are likely to remain primarily along
and west of the coastal mountain ranges today, although some light
rain is possible within the Umpqua basin and the Cascades north
of Crater Lake due to upslope flow and very weak lift. A few
additional waves will follow the first tonight through Tuesday
night, but will remain much farther offshore, providing little if
any precipitation to even the nearshore coastal waters.

A more robust wave then approaches the coast during the latter
half of Wedensday, and should be able to make slightly better
progress inland, although even this progress will be limited
significantly. Precipitation chances begin at the coast late
Wednesday afternoon, then spread to areas along and west of the
Cascades overnight (with the exception of the upper Rogue Valley
and northern California). With the ridge only giving way
slightly, the parent surface low remaining well to our north in
the Canadian maritimes, and the trough itself cut off from
sufficient moisture flow, the front will have little support.
Therefore, precipitation is likely to remain relegated to the
Cascades and the West Side.

Once the front passes and precipitation chances end Thursday
morning, surface high pressure will take up station to the east
of the Cascades, while a thermal trough develops along the coast.
The result will be easterly offshore winds, providing their
typical drying and warming trend to much of the area through the
weekend. This pattern invariably results in strong valley
inversions, especially this time of year, and more valley fog is
possible as the warm, dry winds are likely to just flow over the
top, having little influence on the trapped air below. Little
change is expected heading into early next week, with all model
trends pointing to a continuation of the current pattern. -BPN

&&

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

Pacific Coastal Waters...
     Small Craft Advisory until 10 AM PST Wednesday for
     PZZ350-356-370-376.
     Hazardous Seas Warning until 4 PM PST this afternoon for
     PZZ370-376.