Alva, Oklahoma

... Winter Storm Watch remains in effect from Saturday morning
through Sunday morning...

A Winter Storm Watch remains in effect from Saturday morning
through Sunday morning.

* Timing: early Saturday morning through Sunday morning.

* Main impact: heavy snow reducing visibility and accumulating.
Snowfall over 4 inches is likely in many areas. Local amounts
over 8 inches are forecast in north central Oklahoma. It is also
possible that the area of heaviest snow will expand toward central
Oklahoma.

* Other impacts: wind gusts over 45 mph will produce blowing and
drifting snow. Blizzard conditions may exist at times...
especially in north central and central Oklahoma Saturday
afternoon and evening. Wind chill temperatures will fall into
the teens.

Precautionary/preparedness actions...

A Winter Storm Watch means there is a potential for significant
snow accumulations along with strong winds that may impact travel
and stress livestock. Continue to monitor the latest forecasts.

... Abrupt onset of wind... rain... and snow expected early this weekend...

Although mild weather will persist into the first half of Friday...
there are several features approaching the Southern Plains that
will bring rapidly deteriorating conditions beginning late Friday.
On Thursday evening... satellite loops showed one upper level
trough approaching from Nevada. Southerly winds ahead of this
feature will tap into a modified return of Gulf moisture. Meanwhile...
another trough passing through the northern plains will push a
strong cold front southward. A late season Arctic air mass will
catch up to the leading edge of cooler air... resulting in a
single... very strong... front when it reaches northwest Oklahoma
Friday afternoon. Finally... a third upper level trough will
intensify as it tracks through the Red River valley on Saturday.

The result of all this will be the rapid onset of wind... rain and
a few thunderstorms Friday evening... followed by a change to snow
and blowing snow on Saturday. Rain and thunderstorms will first
break out along and behind the cold front Friday afternoon...
affecting southwest through west central and northern Oklahoma.
Storms will spread east and south Friday night as the cold air
plunges deeper into the region. The strongest thunderstorms may
produce brief heavy rain... small hail... and strong or locally
damaging wind gusts. Of much greater impact... will be the
widespread strong winds developing behind the cold front...
combined with a change to heavy snowfall.

Just after the cold front arrives... north to northwest winds will jump to
near 30 mph... with gusts over 40 mph. Winds may actually strengthen
further as the storm matures during the day Saturday. Meanwhile...
rain will change to snow in northern and western Oklahoma by early
Saturday morning... and as the day progresses... snow will develop as
far south as Vernon Texas... Duncan... and Seminole in Oklahoma.
Given the expected track and intensity of the storm... moderate to
heavy snow may occur over a fairly broad area for an extended
period of time between Saturday morning and Sunday morning.
Blowing and drifting is very likely to occur wherever snow
accumulates. The greatest drifting and reduction to visibility
will take place in northern and western Oklahoma... where
temperatures will be the coldest... and snow the driest. But
substantial drifting and blowing snow may also affect central
Oklahoma. Generally... at least 4 inches of snow is forecast in
northern... western... and central Oklahoma. Embedded areas of 6 to
8 inches appear likely... and greater than 8 inches may fall in
parts of central and north central Oklahoma. Light snow accumulations
may extend down into western North Texas and southern Oklahoma by
Saturday night.

Moderate snow may then continue to wrap around the storm...
affecting the Interstate 35 corridor and eastward during the first
part of Sunday. Travel and outdoor plans will be best accomplished
prior to Saturday morning. Conditions will improve only slowly on
Sunday... with milder weather on Monday.