High Wind in Wyoming, December 14, 2021

Area Forecast Discussion
National Weather Service Cheyenne WY
1015 PM MST Mon Dec 13 2021

.UPDATE...
Issued at 803 PM MST Mon Dec 13 2021

Deer Creek observation in Converse County has hit 53 mph. WYDOT
sites just west in Natrona County hitting well above 65
mph...namely Hat Six and WYO 258. Gradients forecast to continue
increasing late this evening into Tuesday. Decided to upgrade
watch to warning for Converse County. Confidence still low for
Rawlins...so will keep as a watch for now. Will continue to
monitor closely. Updates sent.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 220 AM MST Mon Dec 13 2021

Southwest flow aloft continues over the forecast area Monday
afternoon with mid and high-level moisture streaming across the
region. Lee enhanced clouds remain along and downstream of the
Laramie Range crest and the Snowy Range. While wind speeds have
increased, overall performance is underwhelming thus far. Adjusted
wind forecast and associated high wind watches to reflect a later
start time of 09Z/Tuesday. Temperatures remain well above seasonal
averages even in snow-covered areas. Most locations already 45F to
55F as of early Monday afternoon with a few more hours of heating
and wind to go.

Mid and high-level cloud cover remains overnight within warm,
southwest flow aloft. Mid-level wind increases steadily this
evening through at least midday Tuesday, with 700 mb wind climbing
to 55-65 kts during this time period. However, lapse rates remain
relatively stable throughout this time frame and south-southwest
wind direction may be less than ideal for reaching widespread high
wind potential. Nonetheless, the wind potential is there through
Tuesday afternoon and have adjusted the wind highlights
accordingly. No chance of precipitation through Tuesday as the
next weather system is well upstream of the forecast area.
Temperatures are a bit tricky overnight and again Tuesday given
existing snow cover, wind speeds, and mild airmass. Biggest
adjustments were to Tuesday highs and minimum relative humidity.
Daytime highs will be around 15 to 20 degrees above normal and
relative humidity may very well dip into the teens in southeast
Wyoming and the southwest Panhandle.

Things begin to change late Tuesday evening into Wednesday morning
as the digging upstream trough approaches. Moisture does begin to
increase after midnight, but believe the blended solutions may be
too aggressive between 06Z-12Z/Wednesday. Tried to trend downward
initially and then blend into the 12Z-18Z/Wednesday time frame,
mainly in the western reaches of the forecast area. Overall,
Tuesday night is likely to be dry east of the Laramie Range
stretching across the Panhandle. The better chance of
precipitation and cooler temperatures arrives between 12Z-
18Z/Wednesday. Tuesday night lows are likely to remain mild ahead
of the digging trough as most areas will be breezy and within the
warm sector.

.LONG TERM...(Tuesday night through Sunday)
Issued at 220 AM MST Mon Dec 13 2021

The trough transits the area late Wednesday morning through the
afternoon. Precipitation with this system will be fairly brief, but
could be intense for the few hours that it occurs. The higher
terrain of the Sierra Madres could see 4 to 8 inches of snow with
a tad less in the Snowy Range. The precipitation could certainly
be in the form of rain initially on the eastern Plains and in the
Panhandle before switching over to snow by late Wednesday morning
as the cold front blasts south. The exception could be the far
east zones of the Panhandle where the changeover may take until
early afternoon. Three-hourly pressure rises and 700 mb winds
indicate a very gusty northwest wind Wednesday afternoon that may
need to get tweaked upward east of the Laramie Range. Conditions
dry quickly Wednesday night and temperatures will be colder and
more seasonal.

The next weather system could bring snow into the mountains
Thursday into Friday with mostly dry weather over the rest of the
area. Lower elevations may see snow showers Friday with the trough
moving through the region. Looks to be windy at times through
Thursday night, then less wind Friday into Saturday. Saturday and
Sunday look dry at this time. As for temperatures, highs will be
more like December normals Wednesday and Thursday, then colder
Friday, but quickly moderating Saturday and Sunday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1014 PM MST Mon Dec 13 2021

The remainder of the night is expected to be fairly quiet. VFR
conditions will persist through the day tomorrow. Winds remain light
at most terminals, with the exception of KRWL. Gusts at KRWL may
exceed 30 kts at times. KLAR may even see some gusts to 25 kts
tonight. Widespread LLWS is a concern overnight with strong flow
aloft. Turbulence is also a concern tonight with mountain wave
activity still present on low-level water vapor imagery.

&&

.FIRE WEATHER...
Issued at 220 AM MST Mon Dec 13 2021

Fire concerns will be low over the snow covered areas today and
Tuesday. For the places with no snow cover, fire concerns will be
low to moderate. Afternoon humidity will be low in these areas
with above normal temperatures today and again Tuesday. With
breezy to windy conditions, fire spread could be rapid if new
fires were to start.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch from Wednesday morning through Wednesday evening
     for WYZ107-108-118-119.

     High Wind Warning until 5 PM MST Tuesday for WYZ101-104-105-110.

     High Wind Watch from Wednesday morning through Thursday morning
     for WYZ106-110-115>117.

     High Wind Watch from 2 AM MST Tuesday through Tuesday afternoon
     for WYZ109.

NE...High Wind Watch from Wednesday morning through Wednesday evening
     for NEZ019>021-054-055.

&&

UPDATE...GCC
SHORT TERM...WFORIW
LONG TERM...WFORIW
AVIATION...SF
FIRE WEATHER...WFORIW

Hazardous Weather Outlook
National Weather Service Cheyenne WY
Issued by National Weather Service Riverton WY
225 AM MST Mon Dec 13 2021

WYZ101-106-109-111-116-117-141300-
Converse County Lower Elevations-
Central Laramie Range and Southwest Platte County-
Central Carbon County-Southwest Carbon County-South Laramie Range-
South Laramie Range Foothills-
225 AM MST Mon Dec 13 2021

This hazardous weather outlook is for portions of east central
Wyoming...south central Wyoming and southeast Wyoming.

.DAY ONE...TODAY and TONIGHT

Increasing wind speeds and gusts during the afternoon through
tonight. High Wind Watches are in effect. Some blowing and
drifting snow will occur.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

Wednesday...A chance of snow along with windy conditions.

.Spotter information statement...

Spotter activation will not be needed today.

WYZ112-114-141300-
Sierra Madre Range-Snowy Range-
225 AM MST Mon Dec 13 2021

This hazardous weather outlook is for portions of south central
Wyoming.

.DAY ONE...TODAY and TONIGHT

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

A chance of snow Wednesday. A chance of snow showers Thursday and
Friday.

.Spotter information statement...

Spotter activation will not be needed today.

NEZ002-003-019>021-054-055-095-096-WYZ102-103-107-108-113-115-118-
119-141300-
Dawes County-Box Butte County-Scotts Bluff County-Banner County-
Morrill County-Kimball County-Cheyenne County-
Northern Sioux County-Southern Sioux County-Niobrara County-
North Laramie Range-East Platte County-Goshen County-
Upper North Platte River Basin-Laramie Valley-
Central Laramie County-East Laramie County-
225 AM MST Mon Dec 13 2021

This hazardous weather outlook is for portions of panhandle
Nebraska...east central Wyoming...south central Wyoming and
southeast Wyoming.

.DAY ONE...TODAY and TONIGHT

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

A chance of snow Wednesday with strong wind gusts possible.

.Spotter information statement...

Spotter activation will not be needed today.

WYZ104-105-110-141300-
Ferris/Seminoe/Shirley Mountains-Shirley Basin-
North Snowy Range Foothills-
225 AM MST Mon Dec 13 2021

This hazardous weather outlook is for portions of south central
Wyoming.

.DAY ONE...TODAY and TONIGHT

Strong wind and gusts will occur today and tonight. Some blowing and
drifting snow will occur. A High Wind Warning is in effect.
Please see high wind statements for more details.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

A chance of snow Wednesday. A chance of snow Thursday and Thursday
night.

.Spotter information statement...

Spotter activation will not be needed today.