Gale Warning 12, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
326 PM PST Fri Mar 2 2018

.SHORT TERM...A low centered roughly 100 miles offshore will
continue to bring showers to the southwestern portion of the
Medford CWA, including Mount Shasta City, western Siskiyou County,
the Illinois Valley, and the coast/Coastal Range. Thunderstorms
have been observed over the marine waters, and a slight chance of
thunderstorms continues through tomorrow afternoon.

Strong southwest winds have helped temperatures get close to 50 here
in the Rogue Valley. Gusts of 40 mph have been observed at the Weed
airport, and at Summer Lake. Several short waves will push several
short waves inland tonight, bringing more widespread precipitation
tonight into tomorrow morning. Snow levels will drop to near the
valley floor in most areas south of the Umpqua Divide. Precipitation
will be scattered; confidence in amounts for valley locations is
low. Winter weather advisories and warnings remain in effect for
western Siskiyou County, and Mt Shasta City and surrounding areas,
in addition to portions of Josephine County and Curry County. Expect
the heaviest precipitation again in the western counties, but still
expect more spreading inland than this afternoon. Icy roads will be
a concern tomorrow morning, in areas that get any precipitation and
drop below freezing.

Snow levels will rise tomorrow afternoon, and showers will start
diminishing. The parent low will move southward along the coast,
helping support scattered showers into Saturday night. Sunday into
Monday, expect drying conditions as a ridge starts building in.

LONG TERM...Monday March 5 through Friday March 9...Deterministic
and ensemble guidance are in pretty good agreement throughout this
period, and as a result, confidence in a return to a milder, wetter
pattern is moderate to high.

An upper ridge begins building just off the coast on Monday and then
gradually shifts east with the ridge axis right over us on Tuesday.
The result will be a return to dry weather for early in the week.
Initially, snow levels don't rise as much as would be expected under
upper ridging, but surface temperatures will trend back closer to
normal by Tuesday. While we are getting beyond the typical fog
season, boundary layer moisture will likely remain high due to all
the recent rain and snow. Thus, we have put patchy fog in the
valleys for the late night and early morning hours.

The next frontal system approaches the coast Wednesday. We will see
increasing clouds, but precipitation likely stays offshore
throughout Wednesday. As this system is taking a more traditional
route into our area (from the west-southwest as opposed to north-
northwest like over the last few weeks), the southwest flow ahead of
it will drive snow levels up to around 5000 or 6000 feet by later
Wednesday into Thursday.

It will also bring a lot more moisture than we've seen in a while,
and this one looks like a typical atmospheric river as it taps
moisture from well down into the tropics. As a result, we expect to
see heavy rain at the coast and in the valleys with snow confined to
the higher peaks as it moves in Thursday and Friday. There is good
model agreement about all of this with only slight differences in
timing. This is also a classic pattern for strong winds on the east
side and Shasta Valley, and winds in the late Wed through early
Fri period have been adjusted accordingly. -Wright

&&

.AVIATION...02/18Z TAF CYCLE...Overall, expect a mix of VFR and MVFR
ceilings today into tonight as one disturbance exits to the east and
another moves onshore. Showers will be most numerous along the
coast, into the coast ranges and over western Siskiyou and Josephine
county today. Terrain will likely be obscured under these snow
showers along the coast range, so visibility will be very poor at
times.

Gusty south to southeast winds peaking at 20-30 kt are expected for
most TAF sites this afternoon. Shasta Valley and east side areas
likely have the strongest wind gusts of 35-40 kt.

Another period of steady upslope snow will develop Friday in the
Mount Shasta region, especially in the afternoon and evening, so
ceilings will likely lower to IFR there once again. -CZS

&&

.MARINE...Updated 300 PM PST Friday 02 Mar 2018...High and steep
northwest swell is currently impacting the waters as a low pressure
system occupies our waters.  We'll see gusty gale force winds
continue this afternoon around 5 to 10 nm near shore.

Winds will diminish this evening and seas will gradually subside
Saturday and Sunday, but the weakened low will linger, so it will
remain cold and unsettled with showers. Winds and seas will be
relatively calm Monday through Tuesday night with light winds and
seas at or below 9 feet. The next front will move in next Wednesday
or Thursday. -Smith/Petrucelli

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...High Surf Advisory until 4 PM PST this afternoon for ORZ021-022.
     Wind Advisory until 4 PM PST this afternoon for ORZ026.
     Winter Weather Advisory until 10 AM PST Saturday for ORZ024.
     Winter Storm Warning until 10 AM PST Saturday for ORZ024.

CA...Winter Weather Advisory until 4 AM PST Saturday for CAZ082.
     Winter Storm Warning until 4 AM PST Saturday for CAZ082.
     Winter Weather Advisory until 10 AM PST Saturday for CAZ080.
     Winter Storm Warning until 10 AM PST Saturday for CAZ080.
     Winter Weather Advisory until 4 AM PST Saturday for CAZ081.
     Wind Advisory until 7 PM PST this evening for CAZ081.

Pacific Coastal Waters...Small Craft Advisory for hazardous seas until 4 PM PST Saturday
     for PZZ350-356-370-376.
     Gale Warning until 4 PM PST this afternoon for
     PZZ350-356-370-376.
     Hazardous Seas Warning until 4 PM PST this afternoon for
     PZZ350-356-370-376.

MSC/TRW/CZS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
1207 PM PST FRI MAR 2 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0806 AM     SNOW             6 SE SELMA              42.23N 123.52W
03/02/2018  M9.6 INCH        JOSEPHINE          OR   TRAINED SPOTTER

            THE DURATION OF THE SNOW EVENT WAS 24 HOURS.

&&

CZS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
1228 PM PST FRI MAR 2 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0730 AM     HEAVY SNOW       2 WSW OBRIEN            42.06N 123.73W
03/02/2018  M9.0 INCH        JOSEPHINE          OR   TRAINED SPOTTER

            THE DURATION OF THE HEAVY SNOW EVENT WAS 24
            HOURS.

&&