Gale Warning 9, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
1053 AM PDT Fri Mar 14 2025

.Updated Aviation Discussion.

.DISCUSSION...Another upper trough and frontal occlusion will
swing through the area today. There were reports of snow
accumulation down to around 1300 feet (at least briefly) on
roadways around the Illinois Valley, parts of the Rogue Valley and
on the passes north of Grants Pass earlier this morning and web
cams are also showing some snow on the edges on the road
currently. This is also occurring in the Shasta Valley. A winter
weather advisory remains in effect in these areas until 11 am
PST. Some areas could still see another burst of snow, but we'll
see snow levels rising today, so valley snow potential west of the
Cascades will end this afternoon. Winter Storm Warnings will
continue through this evening in the NorCal mountains, but
precipitation should taper off there tonight. Precipitation will
persist in the Cascades/Siskiyous, especially around Mt Ashland
and from Highway 66 northward, so the Winter Storm Warning
in those areas continues through the rest of the weekend. There
may be periods where snow lets up for a while, but snow will just
keep piling up (esp above 5000 feet) through at least Sunday
evening. Today, we'll be evaluating the potential impacts of an
atmospheric river that will take aim at SW Oregon and NorCal
Saturday night into Sunday. This will cause significant rainfall
west of the Cascades with a high probability of urban and small
stream flooding as well as some main stem river flooding as much
of the rain runs off. Snow levels will rise to around 5000 or even
5500 feet for a time Sunday afternoon, leading to some snow melt
and exacerbating the flood risk. As such, look for flood watches
to go up later today for this time period. Since snow levels will
be rising, winter impacts with the AR will be confined to the
higher elevations of the Cascades, though some winter impacts
still could be felt across northern Klamath/Lake counties since
those areas will be in the areas where the heaviest precipitation
spills over and snow levels will be right near the surface. We may
need to have winter storm warnings Saturday afternoon/night as the
heavier precip moves in. Eventually, a changeover to rain is
expected Sunday for all but the higher peaks of the east side
before snow levels drop back Sunday night into Monday. There will
also be a wind element to this, so be on the look out for
additional wind headlines. -Spilde

&&

.AVIATION...14/18Z TAFs...In the wake of the front, we'll be in a
convective environment. This along with a tighter pressure gradient
will result in moderate to occasionally strong winds at the coast,
including North Bend, and east of the Cascades, including Klamath
Falls. Wind gusts at North Bend and at Klamath Falls could approach
30kts through early this evening (03z).

West of the Cascades, VFR conditions will be the predominate
condition through the TAF period. However, because were in a
convective environment, convective showers are likely through
tonight. Thus, ceilings are likely to vary from VFR to brief periods
of MVFR in showers. This will also result in partial terrain
obscurations.

East of the Cascades, convective environment is also expected
through tonight. VFR ceilings are expected to be the predominate
condition, however both ceilings and visibility could be reduced to
MVFR in snow showers along with the terrain bring partly obscured.
-Petrucelli

&&

.MARINE...Updated 900 AM PST Friday, March 13, 2025...Buoy
observations show moderate to strong south winds, but they will
quickly shift southwest and diminish later this morning. Despite the
winds diminishing, seas will remain hazardous and very steep through
Saturday afternoon.

Out next attention will be Saturday evening through Sunday afternoon
where strong south winds are expected that will reach gale force
winds Saturday evening through Sunday afternoon. We will likely
issue a Gale Warning for the stronger front by this afternoon.
-Petrucelli

&&

.PREV DISCUSSION... /Issued 352 AM PDT Fri Mar 14 2025/

DISCUSSION...Updated Aviation Section...

AVIATION...14/12Z TAFs...Snow levels could drop as low as 1000 feet
tonight. However, temperatures in the Rogue and Umpqua valleys are
rising, lowering the threat for snow this morning. An approaching
front will bring additional moisture and precipitation during
daylight hours. This is expected to bring moderate to heavy snow
showers over western Siskiyou County, around the Mount Shasta
region, and along the Cascades. Light snow showers could get past
the Cascades and affect eastern areas through the end of the TAF
period. Widespread rain showers will affect west side areas, and
gusty winds will develop, especially over high elevation areas. -
TAD/Hermansen

PREV DISCUSSION... /Issued 251 AM PDT Fri Mar 14 2025/

DISCUSSION...The trough axis has pushed to the east, and showers
had only briefly tapered off early this morning before a large
swath of precipitation began moving into the region ahead of the
next front.

Multiple additional fronts will bring snow/wind/rain to the area
late tonight through the weekend. We'll address each impact below.

SNOW: Another fast-moving disturbance (a warm/occluded front)
will spread light to moderate precipitation back over the area
from west to east late today. Snow levels will be quite low
initially, down around 1000-1500 feet, so don't be surprised to
see some wet snow falling this morning, even in some west side
valleys. But, given recent warmer weather, we expect most
road/paved surfaces down that low to be wet. We have gone ahead
and issued a winter weather advisory for above 1500 feet with a
chance at a little accumulation (Trace-2 inches) for the lower I-5
passes south of Roseburg, Camas Mtn, and Hayes Hill; also around
Jacksonville Hill, Prospect and perhaps even higher spots above
Medford/Ashland). Snow levels should rise some to around 3000,
maybe 3500 feet Friday afternoon. We have also upgraded winter
storm watches to warnings for the Cascades/Siskiyous, and much of
Siskiyou County above 2000 feet (including the Mt. Shasta region).
For Siskiyou County, the warning goes through Friday evening, but
the main thrust of snow will be in the 5-11 am PDT time frame.
Snowfall rates could reach 1 inch per hour at times then.
Additional winter weather advisories have been issued for the
Shasta Valley and the East Side. For the Cascades/Siskiyous, we
have decided to just make the warning go through the weekend.
Multiple periods of moderate to heavy snow (with little
discernible break) are expected and snow will be measured in feet
up there. Expect widespread 1-2 foot amounts in the mountains
above 4500 feet with up to 4 feet up around Crater Lake. We should
note that the main impact period for Siskiyou Summit will be
similar to the Mt Shasta region late tonight into Friday morning
(could be 3-6 inches of snow there). Snow levels will gradually
rise this weekend and probably surge to around or even above 5000
feet during Sunday before falling back to around 3000 feet by
Monday morning. -Spilde

WIND: Two strong fronts today and late Sunday afternoon will
result in moderate to strong winds for the coast, Shasta Valley,
south end of the Rogue Valley, and portions of the east side.
Details on this follow below.

The first front is a front that is passing into the area this
morning with south winds increasing along the coast, and with
winds already increasing in the Shasta Valley and south end of the
Rogue Valley. The Arcata to North Bend pressure gradient peaks
out around 7 mb this morning as the front lifts north. While it's
not out of the question, peak wind gusts could reach warning
criteria along the Headlands, and exposed areas on highway 101
south of Cape Blanco. However, for only be for brief period of
time for about a 6 hour period Friday morning. Winds will quickly
shift southwest and diminish mid to late this morning into this
afternoon.

Meanwhile, winds will increase in the Shasta Valley and south end of
the Rogue Valley and will be strong enough to reach advisory
criteria today. A Wind Advisory remains in effect. Winds will
shift southwest and diminish in the Rogue Valley late this morning,
but the south wind component is likely to persist through this
afternoon in the Shasta Valley. It will be windy east of the
Cascades today as well, but evidence suggests they will remain
below advisory criteria. A few of the higher peaks could get to 40
mph.

We'll catch a brief break in the action tonight into Saturday
with winds at a relative lull. The only exception will be along
the coast where south winds will pick up later Saturday afternoon
as the next strong front approaches. There's increasing evidence
this front could bring high winds to the coast, especially south
of Cape Blanco Saturday night into Sunday afternoon. Some of the
data shows the Arcata to North Bend Pressure gradient peaking out
near 10 mb, which is pretty much a slam dunk for high winds at the
coast. Therefore a High Wind Watch has been issued for the coast.
Please see NPWMFR for more details.

This front could also bring high winds to portions of the east side
early Sunday morning through Sunday afternoon. 700mb winds are
pushing close to or just a tad bit over 70 kts during the time of
max heating during the afternoon hours. It's likely we'll hoist
up a High Wind Watch later today.

This front will also have a southwest component, therefore winds
should not be as strong in the Shasta and Rogue valleys, but this
will be something we'll keep a close watch on. -Petrucelli

RAIN/FLOOD POTENTIAL: Forecast rain amounts from now through the
weekend and into Monday total 4 to 8 inches from the Cascades
westward (locally 10 inches in the high terrain of the coast
ranges) with 1-3 inches for the valleys west of the Cascades.
Expect 0.5-2.0 inches east of the Cascades. The heaviest rain is
likely with an atmospheric river taking aim at southern
Oregon/northern California Saturday night into Sunday. We have
issued a Hydrologic Outlook to account for the expected rises on
area creeks, streams and rivers. Several river/stream gauges are
forecast to reach action stage Sunday and especially Sunday night
into Monday. Deer Creek at Roseburg (flashier) is forecast to rise
above flood stage late Saturday night/Sunday morning, and a flood
watch has been issued for this area. Also, the Rogue River near
Agness is currently forecast to go into flood stage during this
time period (Sunday night), though this may change since Army
Corps of Engineers at Lost Creek and Applegate are expected to
reduce outflows to try to limit flood impacts. We'll continue to
monitor the expected rain amounts, so be on the lookout for
potential Flood Watches over the next day or so. The frontal
system is expected to finally get a push inland Sunday night into
Monday, so the heaviest rain should shift east of the Cascades
then. -Spilde

Beyond that, there should be a break between systems Monday night
through Tuesday night as short-wave ridging builds in. However,
the jet across the Pacific remains active, so models show another
frontal system approaching the coast sometime mid next week
(probably Wednesday). -Spilde/BPN

MARINE...Updated 200 AM PST Friday, March 14, 2025...A passing
shower will occasionally lower ceilings or visibility in a localized
area. Lightning has not been an issue with these showers today.

Snow levels are currently at 1500-2000 feet and could drop as low as
1000 feet this morning. With little precipitation expected, snow
showers should not be an issue in this time frame. An approaching
front will bring additional moisture and precipitation during
daylight hours. This is expected to bring moderate to heavy snow
showers over western Siskiyou County, around the Mount Shasta
region, and along the Cascades. Light snow showers could get past
the Cascades and affect eastern areas through the end of the TAF
period. Widespread rain showers will affect west side areas, and
gusty winds will develop over high elevation areas. -TAD/Hermansen

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 5 PM PDT this afternoon for ORZ027-
     028.

     Winter Weather Advisory until 11 AM PDT this morning for
     ORZ023>026-029-030.

     Wind Advisory until 5 PM PDT this afternoon for ORZ026.

     High Wind Watch from Saturday afternoon through Sunday afternoon
     for ORZ021-022.

CA...Winter Storm Warning until 5 PM PDT this afternoon for CAZ080-
     082-083.

     Winter Weather Advisory until 11 AM PDT this morning for CAZ081.

     Wind Advisory until 5 PM PDT this afternoon for CAZ081.

PACIFIC COASTAL WATERS...Gale Warning until 11 AM PDT this morning
     for PZZ350-356-370-376.

     Hazardous Seas Warning until 5 AM PDT Saturday for PZZ350-356-
     370-376.

&&

MAS/MAS/MAS