Loyal, Oklahoma

... Late week storm will bring strong winds and colder air... and
maybe some snow...

Hazardous winter weather conditions may develop over the Southern
Plains later this week as an upper level trough... and associated
surface low... intensify and track from the southern rockies
eastward into the plains and Midwest Wednesday and Thursday. Strong
north to northwest winds and much colder air will result in a cold
and blustery Christmas eve with wind chills in the teens and 20s.
Wind and cold will continue into Thursday night before winds
decrease on Christmas day. But it will still be a cold Christmas...
with temperatures on Friday not likely to make it out of the 30s.

Colder air will begin to invade northwestern Oklahoma by Tuesday
night and will continue to spread slowly south and east over the
rest of the northwestern half of Oklahoma by the end of the day
Wednesday. The colder air will accelerate southeastward Wednesday
night and will overspread the rest of Oklahoma and northern Texas by
Thursday morning.

Latest computer forecasts suggest that the storm system might track
farther north toward the Central Plains Wednesday night and
Thursday. This track would still allow wind and cold to overspread
the area late in the week... but would pull drier air into the area
and reduce the chances of any significant rain or snow. But it still
appears more likely that the storm will take a more southern
track... from western North Texas across southern and eastern
Oklahoma. On this track... the potential would be higher for moist
air to wrap around the storm.

Initially... the air will be warm enough for rain at most locations
through at least Wednesday. But as the colder air overspreads the
area Wednesday night into Thursday... there will be potential for
rain to change to snow. The greatest potential for accumulating
snow appears to be over northern Oklahoma. But due to uncertainties
in the exact storm track there is still a chance that snow
accumulations will shift farther north or south by Thursday.
Snowfall totals... if any... will depend on how quickly cold air
arrives... and how long the storm lasts. At a minimum... it appears
that some snow accumulation is likely... and that increasingly
blustery winds will cause blowing snow... low visibility... and low
wind chill temperatures. As the forecast intensity of snow and winds
comes into focus... a Winter Storm Watch may be issued for part of
the region later tonight or on Tuesday.

Looking beyond Thursday... it is important to note that hazardous
winter weather will likely persist even after the storm exits. It is
very likely that a large mass of Arctic air... the coldest yet this
season... will overspread all of Oklahoma and western North Texas.
Wind chill temperatures may become dangerously low... and air
temperatures across northern Oklahoma could remain near or below
freezing for as long as three or four days.

216 PM CST Mon Dec 21 2009

... A late week storm will bring snow... winds... and bitter cold...

The ingredients for a hazardous winter storm will converge on the
Southern Plains later this week. The storm will be driven by an
upper level trough... and surface low pressure. Both will intensify
while they track from western North Texas through southern and
eastern Oklahoma. These features will produce strong lift and
widespread precipitation beginning Wednesday... and lasting well into
Thursday.

Initially... the air will be warm enough for rain at most locations.
Cold air will then rush in from the north and west. Rain will change
to snow beginning in northwest Oklahoma Wednesday evening. The
changeover to snow will proceed toward the south and east... and
should reach western North Texas up through central Oklahoma by
Thursday morning. Before the storm exits Thursday night... even
southeast Oklahoma will have a chance at seeing snow.

The area of greatest concern... however... is northern and western
Oklahoma... generally north of a line from Elk City to Clinton... to
Kingfisher and Stillwater. Parts of that region will see the
earliest changeover to snow... and other parts will see snow persist
through the day Thursday. A secondary area of concern will be from
Quanah Texas... to Altus and Lawton... towards Chickasha Oklahoma
where an additional band of accumulating snowfall will be possible.
Snowfall totals will depend on how quickly cold air arrives... and
how long the storm lasts. At a minimum... it appears that some snow
accumulation is likely... and that increasingly blustery winds will
cause blowing snow... low visibility... and low wind chill
temperatures. As the forecast intensity of snow and winds comes into
focus... a Winter Storm Watch may be issued for part of the region.

Looking beyond Thursday... it is important to note that hazardous
winter weather will likely persist even after the storm exits. It is
very likely that a large mass of Arctic air... the coldest yet this
season... will overspread all of Oklahoma and western North Texas.
Wind chill temperatures may become dangerously low... and air
temperatures across northern Oklahoma could remain near or below
freezing for as long as three or four days.