Grenada, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

306
FXUS66 KMFR 111553
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
853 AM PDT Fri Apr 11 2025

.Updated Marine Discussion.

.DISCUSSION...Satellite imagery this morning reveals most of
northern California and southern Oregon in a southwest flow aloft
as higher clouds stream from southwest to northeast across the
area. This is behind a frontal system that swung through the area
yesterday afternoon/evening. Compared to yesterday, it`ll be
about 5-10F cooler today, though some locations west of the
Cascades could see readings 10-15F lower. Overall, it probably
won`t be as breezy as yesterday, but guidance is showing some N-NW
breezes kicking up again this afternoon into early this evening w/
peak gusts in the 20-30 mph range.

Models are showing an upper trough offshore early this morning
and this will head toward the coast this afternoon, then onshore
this evening. Moisture is lacking west of the Cascades, so shower
chances there are 10% or less. However, from near the Mt. Shasta
region northeastward across most areas east of the Cascades, given
some afternoon instability w/CAPE of 200-400 J/KG, mid-level
moisture seems sufficient to support isolated to scattered shower
activity later this afternoon into this evening. Isolated
thunderstorms (15-24% chance) could also develop in these areas.
Best instability, however, is east of our area in Harney County,
where we think the risk is highest for a few lightning flashes.
The shortwave disturbance will move south and east of the area
late tonight into Saturday morning and shower chances diminish
from NW to SE. Residual cloud cover will probably bank up against
the Umpqua Divide and also the Cascades/Siskiyou Mtns. Overall,
this should preclude frost development, though patchy frost is
possible in areas that avoid cloud cover.

The upper trough axis shifts east of the Cascades on Saturday,
then in some form (open trough/closed low), pushes into the Great
Basin Saturday night. This will bring the coldest night of the
stretch with high pressure building in and clear skies providing
near ideal radiational cooling. Many west side valley locations
will likely have frost overnight into Sunday morning and some
could reach below freezing. Needless to say, if you have a
backyard garden or any agricultural interests, prepare for a cold
night Saturday night.

After the cold start Sunday, with the high building in overhead,
it`ll begin a stretch of sunny weather with warmer afternoons.
We`re forecasting highs in the 70s Sunday for most west side
valleys, with the lower Klamath Valley reaching into the 80s.
Models show the peak of the west side warmth on Monday with highs
in the low 80s in Medford/Ashland/Grants Pass/Cave Junction and
also upper 70s in Roseburg, Yreka and Mt Shasta City. Even east
side areas will have highs largely in the 70s.

A weak, probably dry, upper trough will swing through Tuesday,
but this will only serve to lower forecast high temps slightly.
In fact, we`ll likely see a rebound in temperatures again as
upper ridging re-establishes over the area Wed/Thu next week.
-Spilde

&&

.AVIATION...11/06Z TAFs...Along the coast, a mix of IFR and MVFR
conditions will persist through early Friday morning, lifting to
mainly MVFR with local IFR late Friday morning, then clearing to VFR
Friday afternoon.

Inland, west of the Cascades, conditions are mainly VFR late this
afternoon/early this evening except for MVFR ceilings in northwest
Douglas County.  Gusty surface winds will persist early this
evening, then lower late in the evening. MVFR ceilings will spread
across Douglas, Josephine and northern Jackson counties this
evening, including Roseburg (KRBG) and Merlin/Grants Pass. Then,
MVFR conditions will become widespread with local IFR from the
Southern Oregon Cascades west (including at Medford, KMFR) and in
far western Siskiyou County with generally VFR elsewhere east of the
Cascades and in central/easter Siskiyou and Modoc counties in
Northern California. Mountain obscurations are expected to develop
this evening, especially from the Cascades west, and persist through
Friday morning. Conditions will gradually lift to VFR late Friday
morning into early Friday afternoon and persist Friday evening.

&&

.MARINE...Updated 830 AM Friday, April 11th...A developing
thermal trough will result in increasing north winds during the day
with moderate to strong winds south of Cape Blanco starting late
this morning. The thermal trough is likely to remain a play maker
for most of the weekend with winds and seas highest south of Cape
Blanco. Small craft conditions are likely from later this morning
through Saturday afternoon, with small craft conditions extending
into the northern waters Saturday evening into Sunday. Hazardous
seas are likely late this morning into Saturday early Saturday
afternoon for areas south of Port Orford and out to 60 nm from shore.

Winds and seas will be highest in the southern waters through the
weekend and guidance is supporting winds reaching gales near and
south of Gold Beach Saturday afternoon/evening.

There`s some signs winds will ease slightly Sunday then moreso on
Monday, but we`ll still likely have at least Small Craft conditions.
There`s fairly good agreement that moderate to north winds will
persist into most of next week with a "classic thermal through"
pattern that is typical of the summer months, but can sometimes
occur this time of the year. Winds will be strongest south of Cape
Blanco during this time with at least Small Craft conditions.
-Petrucelli

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory from 11 AM this morning
     to 2 AM PDT Sunday for PZZ350-356-370-376.

Gale Warning from 2 PM Saturday to 2 AM PDT Sunday for PZZ356-
     376.

     Hazardous Seas Warning from 11 AM this morning to 2 PM PDT
     Saturday for PZZ356-376.

&&

$$

MAS/ANH