030
FXUS66 KMFR 170550
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1050 PM PDT Mon Sep 16 2024

...Updated AVIATION discussion...

.DISCUSSION...The forecast is on track for tonight. A few
scattered showers are moving over Siskiyou and Modoc counties,
spinning around a low pressure system moving across California.
Moderate chances for showers (30-60%) and thunderstorms (20-30%)
will remain over eastern Lake and Modoc counties through Tuesday
morning. Another low pressure system looks to pass to the west
tomorrow, with precipitation focused on areas west of the
Cascades (60-100% through the day), with lesser chances (50-80%)
east of the Cascades. Higher elevation areas are expected to see
0.5 and 1.0 inches of rainfall, while lover elevations will see
0.25 inches or less through early Wednesday morning.

Please see the previous discussion for more details on the short-
and long-term forecasts. -TAD

&&

.AVIATION...17/06Z TAFS...Cloud cover remains over much of northern
California and southern Oregon due to a lingering low pressure
system to the south. Little shower activity remains on radar, with
MVFR and IFR ceilings remaining over areas east of the Cascades and
VFR ceilings over other inland areas. Marine stratus is at MVFR
levels as well for areas north of Cape Blanco, with IFR levels
possible but not strongly expected.

Another low pressure system will move south over the Pacific through
the day Tuesday, with precipitation mostly falling west of the
Cascades. Thunderstorms are possible over the ocean but have single
digit chances over land. Showers may locally lower visibility and
ceilings as well as obscure elevated terrain through Tuesday and
possibly into early Wednesday morning. -TAD

&&

.MARINE...Updated 800 PM Monday, September 16, 2024...Overall
conditions will improve through tonight as the thermal trough
weakens and the upper level low moves inland.

Winds will shift to the south ahead of an incoming front Tuesday,
but winds and seas will remain relatively light with widespread rain
and a slight chance (15-20 percent) for thunderstorms. Any
thunderstorms that develop will have the potential for strong,
erratic and gusty winds. Moderate to occasionally strong north winds
and steep seas will develop Wednesday as the thermal trough
redevelops, with small craft advisory conditions expected through
the rest of the week. -BPN


&&

.PREV DISCUSSION... /Issued 506 PM PDT Mon Sep 16 2024/

SHORT TERM...Tonight (9/16) through Wednesday night (9/19)...
Satellite imagery is showing extensive cloud cover across portions
of southern Oregon and northern California. Above the lower cloud
layer is a second layer of higher clouds that are circulating anti-
clockwise indicative of a low pressure system traversing across
northern California and northwest Nevada. Meanwhile, RADAR imagery
is showing some showers pushing from northeast to southwest across
portions of Klamath, Siskiyou, and Modoc Counties. There may be
additional showers and thunderstorms later this afternoon and
evening, specifically for portions of Lake and Modoc Counties.

This low will traverse out of our area this evening and tonight
and the next low will approach the Pacific Northwest on Tuesday.
This will bring the next set of precipitation across the area,
mainly favoring West Side. In general, rainfall will be wetting
along and west of the Cascades. Temperatures will remain cooler
than normal as well.

Showers may linger on Wednesday, but gradually dissipate.
Temperatures will start to warm up on Wednesday as well. -Schaaf

LONG TERM...Thursday (9/20)through Monday (9/23)...A ridge of
high pressure returns to the area, allowing conditions to dry out
and temperatures to warm up. Another front will push through the
Pacific Northwest over the weekend, and ensembles differ on the
strength and location of the front. That being said, the National
Blend of Models favors a 20 percent chance or less for
precipitation for the coast, Umpqua Basin and the Cascades from
Highway 140 northward. Stay tuned to the forecast as we are
entering the shoulder of fire season where wetter weather begins
to return. This is the case as ensembles suggest that another
system could return by midweek next week. Fire season is not quite
over, but it has slowed significantly by this point, and we will
continue to see how things play out. -Schaaf

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Tuesday
     for PZZ350-356-370-376.

Hazardous Seas Warning until 5 AM PDT Tuesday for PZZ356-376.

&&

$$