Mount Shasta, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

652
FXUS66 KMFR 281216
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
416 AM PST Sat Dec 28 2024

.DISCUSSION...Radar is showing the core of moderate to heavier
precipitation having shifted south into northern California. In
Oregon, were catching a break in precipitation with showers starting
to become far and few in between. We could actually see most
locations west of the Cascades stay dry for the morning hours.

The HREF high res guidance and the operational models are in pretty
good agreement suggesting the core of heavier precipitation will
remain south in northern Cal this morning, then gradually shifting
back north early to mid afternoon as the frontal boundary lifts as a
warm front.

Moderate to heavy precipitation will continue later this afternoon
through tonight, especially along the coast and northern part of the
forecast area. There`s some evidence suggesting precipitation rates
will diminish in portions of the Rogue Valley, Northern Cal and east
of the Cascades late tonight into Sunday morning. This is being
supported by the HREF high res guidance and operational models. The
NBM QPF field shows a solution similar to the ones just mentioned.
Meanwhile WPC precipitation forecast was a bit on the high side for
areas south and east, including the Rogue Valley and eastside.
Therefore, we`ll lean towards the NBM precipitation forecast, but
not completely discounting the WPC solution.

Any break in precipitation for the above mentioned areas will be
short lived as a cold front pushes into the coast late tonight and
moves inland Sunday morning. During this time we`ll see
precipitation rates increasing, then it will diminish again Sunday
afternoon as the front moves east and the upper trough moves in with
post frontal showers.

Snow levels will hover around 7000 feet and remain there through
tonight. This will keep any snow concerns confined to the Crater and
Diamond Lake areas. Even then 24 hour snowfall accumulations are
expected to be around 6-8 inches around Crater Lake, 3-6 inches
around Diamond Lake, and 2-4 inches near Lake of the Woods. It`s
possible these areas could reach borderline advisory criteria, but
confidence is not high enough to issue a Winter Weather Advisory.

Moderate to heavy precipitation will continue into Sunday morning,
then diminish Sunday afternoon as the cold front pushes inland as an
upper trough moves overhead. Showers will continue Sunday night with
snow levels lowering with minor road snow accumulation possible down
to highway 140 near Lake of the Woods and Siskiyou Summit. However
precipitation is expected to be light to occasionally moderate which
should keep road snow accumulations in check.

With all the moderate to heavy rain recently and yet to come today
through most of the weekend, this will result in rivers rising. The
Coquille River at Coquille is already at minor flooding and flood
warning remains in effect. The Rogue River at Agness, and Deer Creek
at Roseburg are also expected to reach minor flooding Sunday evening
and a Flood Watch remains in effect. Additionally a Flood Watch
remains in effect for the westside and Siskiyou County. Please see
FFAMFR for more details. We`ll also keep a watch on these as
additional flood products may be needed in the coming days.

More strong wind will accompany the rain tonight into Sunday
morning, and the High Wind Watches have been upgraded to High Wind
Warnings for the coast, Shasta Valley and East Side. In addition A
Wind advisory has been issued for the rest of the eastside. There is
some concern for winds to reach advisory criteria in the south end
of the Rogue Valley from around Phoenix south to Ashland, but
confidence was not high enough to issue anything. This will be
passed on to the day shift and they will take another look at this.

All signs are pointing to a less active weather pattern starting
Monday and possibly lasting into most of next week. Showers will
linger monday, with most along the coast and north of the Umpqua
Divide, followed by dry weather Tuesday and Wednesday. A front could
get close to the area next Thursday, with the best chance of
precipitation over the northwest part of the forecast area.
-Petrucelli


&&

.AVIATION...28/12Z TAFS...While most areas are under VFR
ceilings early this morning, flight levels vary under continuing
showers moving across northern California and southern Oregon early
this morning. Radar indicates most activity is continuing over Modoc
and Siskiyou counties, although passing showers are bringing LIFR
ceilings to Medford.

Showers will move northward through the morning, spreading back over
southern Oregon, then a wave of moderate to heavy precipitation will
move from west to east from Saturday night into Sunday morning. The
heaviest amounts look to be over Coos Curry, and Douglas counties,
making lower flight levels possible at Roseburg and North Bend.
Showers continue into future TAF periods.

Guidance suggests low level wind shear developing over the area as
active weather continues. Winds at 2000 feet are forecast to be
southerly with speeds of 40 to 50 kts. -TAD


&&

.MARINE...Updated 200 AM PST Saturday December 28, 2024....Very
steep and hazardous seas continue in all waters early this morning.
Winds have eased from a front moving over the area, but unsettled
conditions remain. Another front will bring 30-60% possibilities of
gale winds to area waters tonight into early Sunday morning.
Conditions start to improve later in the morning, with steep seas
persisting until late Monday afternoon.

Currently, a period of below advisory conditions is forecast from
Monday evening into Wednesday morning. Swell-built steep seas could
start to build later in the morning, although there is uncertainty
in the timing and height of this incoming swell. -TAD

&&

.BEACH HAZARDS...Updated 400 AM PST Saturday December 28, 2024...
Heavy, long period swell dominated seas will continue to produce
dangerous surf conditions through the weekend. Surf conditions
will be occasionally worsened by high winds and seas as fronts
pass tonight and Saturday night into early Sunday. Large breaking
waves 25 to 30 feet are expected through the weekend, highest
this afternoon.

During these events, extremely large breaking waves will create very
hazardous conditions along beaches and area shorelines. Waves will
inundate beaches and surge into normally dry areas, especially at
times of high tide. Infrastructure damage and significant beach
erosion can be expected. Stay away from area beaches during this
period of active weather. /BR-y/Petrucelli


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Flood Watch from 10 AM PST this morning through Sunday afternoon
     for ORZ021>026.

     Wind Advisory until 8 AM PST this morning for ORZ029>031.

     High Wind Warning from 7 PM this evening to 7 AM PST Sunday for
     ORZ021-022-030-031.

     High Surf Warning until 7 AM PST Sunday for ORZ021-022.

CA...Flood Watch from 10 AM PST this morning through Sunday afternoon
     for CAZ080>083.

     Wind Advisory until 8 AM PST this morning for CAZ081-084-085.

     High Wind Warning from 7 PM this evening to 7 AM PST Sunday for
     CAZ081-085.

PACIFIC COASTAL WATERS...Gale Warning until 7 AM PST Sunday for
     PZZ350-356-370-376.

     Small Craft Advisory from 7 AM Sunday to 4 PM PST Monday for
     PZZ350-356-370-376.

&&

$$