Alturas, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

288
FXUS66 KMFR 200542
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1042 PM PDT Thu Jun 19 2025

.DISCUSSION...Updated AVIATION and MARINE Sections.

&&

.AVIATION...20/06Z TAFs...Tonight, VFR will prevail, but MVFR
ceilings have been in and out at North Bend. Expect MVFR to become
more widespread at the coast overnight, especially north of Cape
Blanco with showers developing around/after 09Z. Expect widespread
showers for areas west of the Cascades during Friday, where there
can also be isolated thunderstorms. These, however, are most likely
along the coast and into the Umpqua Friday afternoon. Expect some
gusty winds again Friday afternoon, especially east of the Cascades
with peak gusts of 20-30kt. Thunder risk wanes Friday evening, but
showers are likely to continue with areas of MVFR and terrain
obscuration Friday night into Saturday. -Spilde

&&

.MARINE...Updated 830 PM Thursday, June 19, 2025...Winds and seas
ease tonight into Friday. Low pressure will bring unseasonably
cool air, numerous showers and also isolated thunderstorms,
especially north of Cape Blanco, Friday afternoon and evening.
Expect moderate west winds and fresh swell dominated seas.
Cool, showery, unsettled weather continues Saturday. A thermal
trough returns Sunday through Monday with north winds and steep
seas likely south of Cape Blanco. -DW/Spilde

&&

.PREV DISCUSSION... /Issued 450 PM PDT Thu Jun 19 2025/

DISCUSSION...Updated AVIATION Section.

AVIATION...20/00Z TAFs...VFR this evening. Breezy northwest winds
will continue for all TAF sites with peak gusts generally in the 20-
25 kt range easing 03-05Z.

Isolated thunderstorms developed across SE Modoc County in the last
hour or so and could also graze SE Lake County this evening. Any of
these cells can contain gusty winds and frequent cloud to ground
lightning. They should all be east of the area by around 03Z.

Tonight, MVFR ceilings may develop at the coast late this evening,
especially north of Cape Blanco with showers developing around 09Z.
Expect widespread showers for areas west of the Cascades during
Friday, where there can also be isoalted thunderstorms. These,
however, are most likely along the coast and into the Umpqua Friday
afternoon. Expect some gusty winds again Friday afternoon,
especially east of the Cascades with peak gusts of 20-30kt.
-Spilde

PREV DISCUSSION... /Issued 316 PM PDT Thu Jun 19 2025/

DISCUSSION...A big change to cool and wet weather is coming for
Friday and Saturday, and another big change, back to very warm
weather will follow for next week. In between, Sunday looks to be
the transition day with conditions near normal.

First, with the alaskan trough now looming northwest of Vancouver
Island, high clouds have increased and gusty west to northwest
winds have also begun to increase in speed. Today`s breezy
afternoon and evening will resemble conditions from yesterday at
the same time with gusts of 20 to 30 mph expected to be common,
strongest over the higher terrain, along the Curry County coast,
in the Shasta Valley, and east of the Cascades. There is also a
slight chance of thunderstorms late this afternoon into this
evening in southeast Lake County, with a barely mentionable slight
risk also extending a bit farther south to the Warner Mountains of
northeast Modoc County.

A thickening marine layer could bring a few drizzly showers to the
coast north of Cape Blanco as early as this evening, but the real
start to our wet, very cool weather looks to begin after 3 AM late
tonight. Rainfall amounts during Friday and Saturday still look
to be focused in southwest Oregon, especially north of the Umpqua
Divide...with a quarter to three quarters of an inch forecast for
Coos and Douglas counties into far western Klamath County.
Around a quarter of an inch is forecast for Curry County. Total
Rogue Valley rainfall looks to be around a tenth of an inch. The
bulk of the rainfall is expected during Friday afternoon and
evening, and Saturday afternoon. A storm total of 4 inches is
forecast for Crater Lake above 5500 feet. Most of northern
California and south central Oregon still are expected to receive
measureable rain, but the main story there will be cooler
temperatures and cloudy skies.

A warming and drying trend begins Sunday with highs near normal on
Sunday and expected to be consistently several degrees above
normal for the remainder of next week. Also of note, the SREF is
showing weak instability for the Cascades from Crater Lake
northward on Sunday with a 10% probability of late day
thunderstorms. This is supported by the 12Z NAM, but the 12Z GFS
indicates a dry air mass. We will expect a consensus to form as
the time draws nearer. More broadly, but beyond the shorter term
models, the 12Z GFS does indicate weak instability for the
southern Oregon Cascades into south central Oregon and northern
California. So, the probability of thunderstorms has been nudged
up to 10% for that area on Monday afternoon and evening.
Otherwise, next week looks to be generally stable and very warm
inland while night and morning low clouds will be prevalent at the
coast with typically cool temperatures.

AVIATION...19/18Z TAFs...Some of the smoke from the Applegate Fire
settled in underneath a low-level inversion, which is now breaking.
So, locally reduced visibility can be expected to improve in the
vicinity of the fire. But, breezy northwest winds will develop
there, and for all TAF sites, again this afternoon into this evening.
Peak gusts again will be in the 20-25 kt range.

Also, marine stratus along the Umpqus Divide and southern portions
of the Umpqua Basin will continue to erode during the remainder of
the morning.

Afternoon/evening cumulus buildups are expected to occur in Lake
County, out near the Warner Mtns, with a slight chance of
thunderstorms in far southeast Lake County.

MVFR ceilings may develop at the coast, especially north of Cape
Blanco this evening with rain developing around 09Z, late tonight.
-DW

MARINE...Updated 230 PM Thursday, June 19, 2025...Breezy north
winds continue north of Cape Blanco tonight, with stronger winds and
steep, hazardous seas from Cape Blanco southward. An unseasonably
cool and wet system arrives Friday and Saturday with breezy west to
northwest winds, and fresh swell dominated seas. Isolated
thunderstorms are possible Friday afternoon and evening, mainly
north of Cape Blanco. A thermal trough returns Sunday through Monday
with north winds, and steep seas likely south of Cape Blanco. -DW

&&

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

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 2 AM PDT Friday
     for PZZ356-376.

&&

$$

MAS/MAS/MAS