Low pressure moved southeast into Oregon. An associated cold front swept across the region with high elevation snow for northern California.
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The episode as NWS MFR wrote it up.
Low pressure moved southeast into Oregon. An associated cold front swept across the region with high elevation snow for northern California.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Medford, OR wrote its last area forecast discussion before the first event at Feb 4, 2:38 PM PST, 1 hour 22 minutes earlier.
Area Forecast Discussion
National Weather Service Medford OR
238 PM PST Sat Feb 4 2023
.SHORT TERM...KMAX-88D this afternoon revealing light returns
streaming south to north along the coast region and into Northern
California. A few mtn RAWS have measured a click (.01") in the
past few hours, but things are generally still quite dry.
A deep upper trough off the Oregon coast will gradually make its
way inland through the remainder of the weekend. Tonight a strong
short wave moving through the base of the trough will move
onshore into northern California helping to enhance upslope
precipitation there. Also, a strong surface low being advertised
in the high-res models is expected to move into the coastal waters
and move onshore around Reedsport near 12z. There is uncertainty
in the track of the low and we've generally been following HRRR
guidance and are expecting Gales. Winds on the coast will likely
get quite gusty in the overnight but we feel the event will
remain below warning gusts. Wind Advisory will remain for the
Shasta Valley, and local gusts may bump around advisory levels nea
summer Lake but we've also held off on a headline there. Also
looking for 15 gust 25-type winds in the Aslhand to Medford
region tonight.
Meanwhile inland, moderate snow rates should begin this evening
in the Mount Shasta region and last into early Sunday. A Winter
Weather Advisory is in effect there above 5000 feet. We considered
extending that Winter Weather Advisory across the South Oregon
Cascades and Siskiyous but no given period seems to threaten
substantial rates, and the heaviest accumulations will be above
above the most traveled routes. Hence no Cascades/Siskiyous
headlines for snow, but it will snow tonight through Sunday with
snow levels beginning near 5000 feet, falling to 4000 overnight,
then to near 3500 feet Sunday with totals of 5-10 inches looking
common. Stavish
.LONG TERM...(Monday through Saturday)...Upper ridging will
result in dry weather for Monday. The upper ridge will flatten out
Tuesday afternoon as the next upper trough approaches from the
west. Precipitation ahead of a cold front will move into the
marine waters and coastal counties Tuesday morning, then spreading
inland west of the Cascades Tuesday afternoon. However the Rogue
Valley could remain dry into Tuesday afternoon due to the westerly
component of the upper flow which typically results in
downsloping.
The front will move through the area Tuesday night, followed by an
upper trough with scattered showers that will become more isolated
as the upper trough axis shifts east during the overnight hours.
The upper trough moves east of the area Wednesday afternoon with
upper ridging building in Wednesday night, and lasting into next
Saturday with dry weather expected. This is being supported by all
members of the GFS ensemble members and the majority of the ECMWF
ensemble members. One thing to note: There's good agreement an upper
trough will move east near 140W Thursday evening, with a split flow
developing Friday into Saturday with a cutoff low Saturday. However
the location of the low is well enough offshore to keep the best
chance of precipitation well south of our forecast area.
-Petrucelli
&&
.AVIATION...04/18Z TAFs...Low level wind shear will be the main
hazard for all terminals, except for Klamath Falls. This is due to a
strong front approaching from the west resulting in increasing winds
aloft. The other area of concern is that a few models are showing a
developing surface low that is projected to move northeast and could
result in a sudden shift and increase in the winds from the south to
southwest at North Bend between 7-9z. If this were to materialize,
the impact is only expected to last for an hour or two.
Meanwhile, VFR ceilings will continue into this evening, followed by
MVFR ceilings as the front and associated precipitation moves into
the area. The exception will be Medford where VFR ceilings should
continue through tonight due to downsloping. However partial
obscuration is possible later tonight in the higher elevations
surrounding Medford. -Petrucelli
&&
.MARINE...Updated 200 PM PST Saturday, February 4, 2023...An
offshore front will continue to bring strong SSE winds to the
offshore waters this afternoon averaging 20-30 kt with gusts to 40
kt. Steep to very steep seas can be expected due to the combination
of building wind waves and west swell. A surface low pressure center
is expected to form along the front tonight and move quickly through
the waters from southwest to northeast between 7 pm (03z) and 4 am
(12z) PST. Recent hi-res model guidance is showing this low center
having a brief period of strong winds associated with it along with
a sharp wind shift from SSE to W (or even NW). For this reason, we
have expanded the gales to include the inner waters during this time
period. Then, the front will move onshore after 4 am PST (12z). Post-
frontal winds should ease to 15-25 kt (gusts to 30kt) from the WNW.
Fresh WSW swell will then combine with incoming long period W swell
to create steep, hazardous seas Sunday. Seas will build to around 14-
16 ft at 13 seconds Sunday evening, then will gradually subside
below 10 feet by Monday afternoon. Calmer conditions will last into
Monday night before another front and high and steep west swell
builds in late Monday night into Tuesday. -Spilde
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...CA...Winter Weather Advisory until 10 AM PST Sunday above 5000 feet
for CAZ080-082-083.
Wind Advisory until 7 PM PST this evening for CAZ081.
PACIFIC COASTAL WATERS...Hazardous Seas Warning until 7 PM PST this
evening for PZZ350-356.
Gale Warning from 7 PM this evening to 4 AM PST Sunday for
PZZ350-356.
Gale Warning until 4 AM PST Sunday for PZZ370-376.
&&The national radar mosaic for the moment the first event began.
1 heavy snow. Local standard time, as filed.
Significant snowfall at elevations above 5000 feet. This includes 6 inches reported at the Sand Flat SNOTEL and National Gridded Snowfall estimates of 4 to 10 inches in the zone.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2023Every state in 2023This day in weather historyWarnings in California, February 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1084036.