Alturas, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

670
FXUS66 KMFR 141139
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
Issued by National Weather Service Portland OR
439 AM PDT Wed May 14 2025

.DISCUSSION...A weak disturbance, more or less a marine push,
will move onshore this morning. This will bring some clouds to
Coos County and into portion of the Umpqua Basin along with some
light rain showers. Most of this moisture will be shallow, so
while we can`t completely rule out a few spits here and there,
little or no precip is expected south of the Umpqua Divide.
Clouds will generally break up into stratocumulus this afternoon.
THis will keep things on the cool side of normal with high
temperatures mostly in the 60-65F range for the west side valleys
(except 70-75F in lower Klamath Valley of western Siskiyou
County). Highs east of the Cascades will be in the upper 50s to
low 60s. Expect fairly typical N-NW breezes this afternoon/evening
before decoupling occurs tonight.

Weak short wave ridging moves in tonight into Thursday resulting
in dry weather. Some of the typically colder west side valleys
(Scott, Shasta, and Illinois) will get down into the mid 30s for
lows tonight, though patchy frost won`t be enough to warrant an
advisory. Thursday`s highs will be up slightly compared to today
and closer to seasonal normals.

The next weak disturbance in NW flow aloft will move in Thursday
evening with another chance of showers, mainly across northern
sections of the CWA. Once again, we`re not expecting much, if any
precipitation. A few hundredths here or there, mainly in the
mountains and north/west of the Umpqua Divide/coast should about
cover it.

Friday will be another dry, mild day with some sunshine and high
temps 70-75F west side valleys and in the 65-70F range east of the
Cascades.

Another stronger upper trough will move in from the northwest
late Friday night into Saturday, with showers from late Saturday
morning through Saturday afternoon. Showers Saturday will tend to
be isolated in the morning, then increase in coverage as the
upper trough moves overhead in combination with daytime heating.
Instability is marginal, and will be greatest east of the
Cascades, therefore could not rule out isolated afternoon and
early evening thunderstorms. Showers will continue Saturday night
as the upper trough remains overhead. Precipitation amounts will
generally be light Saturday through Saturday night. Snow levels
Saturday night are expected to be around 5000 feet and could
result in a brief accumulation of snow around Crater and Diamond
Lake, but with road temperatures warm due to stronger mid May sun,
snow for the most part should just melt.

Sunday will be a transition day as the upper trough departs with
upper ridging nosing into the area. Therefore any showers will be
isolated and confined to the morning hours along the northern
Cascades and north of the Umpqua Divide.

All signs are pointing towards dry weather for most of next week.
The operational ECMWF shows a stronger upper trough moving into
the area Thursday with cooler and unsettled weather. However, the
majority of the individual ECMWF ensembles members show a dry
solution and the operational GFS and their individual ensemble
members show a dry solution. Additionally, the majority of the
cluster solutions favor stronger upper ridging. -Petrucelli/Spilde


&&

.AVIATION...14/12Z TAFS....Mostly a mix of VFR/MVFR out there this
morning, except areas of higher terrain obscured. Some light
rain/drizzle and local IFR is possible along the coast this morning.
Isolated showers could also affect the Umpqua Basin today. Ceilings
mostly lift to VFR this afternoon, with VFR persisting into this
evening. Expect mostly VFR tonight into Thursday morning, with
some local MVFR ceilings near the terrain west of the Cascades.
-Spilde


&&

.MARINE...Updated 230 AM PDT, Wednesday May 14, 2025...Steep
swell- dominated seas lower today. A thermal trough will develop
along the coast and this will bring a return of gusty north winds,
highest south of Cape Blanco this afternoon, persisting through
at least Thursday evening. Steep short period seas will develop,
with conditions hazardous to small craft, especially from Gold
Beach southward. Wave conditions improve a bit Friday, but low
pressure will bring showers Friday night into Saturday followed by
increasing west-northwest swell this weekend. -Spilde


&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT early
     this morning for PZZ350-356-370-376.
     Small Craft Advisory from 2 PM PDT this afternoon through
     8 PM PDT Thursday for PZZ356-376.

&&

$$

MAS/MAP