Frost Advisory 1, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
933 AM PST Thu Feb 24 2022

.UPDATE...

Forecast remains on track this morning with a large deck of upper
level cirrus moving in. This might keep daytime highs slightly
cooler than what we have in the forecast, but we stayed with the
night shift forecast. Our main focus for today will be the
potential for more freezing temperatures along the coast tonight.

&&

.SHORT TERM.../Issued 315 AM PST Thu Feb 24 2022/

(This morning 2/24/22- Saturday Morning 2/26/22)...

Satellite imagery shows clear skies tonight across our area.
Temperatures are expected to be frigid this morning with lows
approaching records for several locations. Although records did
not work out with some of our more populated locations yesterday,
due to cloud cover, expect morning temps to be as cold or colder.

We are between a ridge to the west and a disturbance to the east.
Increasing moisture is expected to filter into our area later
today, however precipitation is largely not anticipated. Expect
higher dewpoints and maybe a stray flurry/drizzle this afternoon.

Ultimately, the dry pattern will continue into Friday as the ridge
keeps progressing across southern Oregon and northern California.
Resulting temperatures will trend warmer through Saturday morning.
Admittedly, frost/freeze products may continue to be needed at the
immediate coast each morning. Will go with a Freeze Watch, and the
next shift evaluating ensemble guidance in order to determine the
extent to where Freeze Warnings will be necessary tonight. -Schaaf

.LONG TERM...(Previous Long Term written 2/23/22...For Saturday
2/26/22 through Thursday 3/3/22)...An active pattern is in store
late Saturday through early next week. Ensembles remain in good
agreement that a front will gradually move into the area from the
west Saturday night into Sunday and weaken the ridge over the
area. With this front oriented north to south and moving into the
ridge, expect mainly light precipitation (with locally moderate
precipitation in the coastal mountains) with the best chance for
measurable precipitation will be from the Cascades west. Snow
levels are forecast around 3500 to 4500 feet Saturday night into
Sunday morning. However expect mainly light precipitation with
this front with only light snow accumulations on the higher
passes. Snow levels are then forecast to rise to 4500- 5500 feet
Sunday afternoon as some showers linger across the area.

Next a stronger and moister front is then forecast to move towards
the PacNW coast Sunday night and gradually inland  Monday into
Tuesday. Models and ensembles show a weak atmospheric river set up
with a plume of strong moisture extending from west to east aimed at
the PacNW coast. The low pressure associated with the front is
forecast to track northward Sunday night just off the Washington and
British Columbia coast with a trailing front extending from south to
southwest  along and off the Washington and Oregon coasts. There
remains variability in the ensemble solutions on how far
precipitation will spread inland over the area Sunday night into a
Monday morning, with the front stalled near the coast. With this
setup, expect to see the best chances for precipitation along the
coast and into portions of the west side (Cascades west).

As a second frontal system moves into the area late Monday and
Tuesday, there is better agreement in the model solutions that
precipitation will spread inland. The track of the low pressure
centers and location of where the best moisture sets up will be a
significant factor in determining how much precipitation falls over
the area late Monday through Tuesday night. Coastal areas may see
moderate to locally heavy precipitation. The National Blend of
Models shows a 40-60 % chance for 0.5 inches of rain in 24 hours or
1.0 inches of rain in 48 hours for areas along the coast and into
the coastal mountains as well as into portions of western Siskiyou
County. Otherwise, inland areas are more likely to see lighter
precipitation Monday night through Tuesday night. Snow levels are
forecast to be high, around 6500 to 7000 feet. So most the
precipitation that arrives will fall as rain.

With continued variability in the model solutions on the strength
and/or track of these systems late Saturday through Tuesday night,
we will monitor the forecast and continue to provide updates. -CC

&&

.AVIATION...24/18Z TAFs...VFR conditions will prevail everywhere
through Friday morning. A weak upper trough will bring some BKN VFR
ceilings to the area today, but these should thin out and move away
this afternoon and evening. -Spilde

&&

.MARINE...Updated 200 AM PST Thursday 24 February 2022...North to
northeast winds will persist through this evening with the
steepest seas from Cape Blanco southward. Winds and seas will
subside tonight with light offshore winds Friday. South winds
will increase late Friday night and Saturday as a front approaches
the area. South winds will strengthen and seas will build
Saturday evening into Sunday morning as the front moves across
the area. Gale force winds are possible with the front. Winds
will diminish behind the front Sunday, but long period west to
southwest swell may bring a mix of steep to very steep seas to the
waters. Another front will move into the area Monday.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Freeze Watch from late tonight through Friday morning for
     ORZ021-022.

CA...None.

Pacific Coastal Waters...Small Craft Advisory until 1 AM PST Friday for PZZ356-376.