Area Forecast Discussion
Issued by NWS Cheyenne, WY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

FXUS65 KCYS 150837

Area Forecast Discussion
National Weather Service Cheyenne WY
237 AM MDT Sat Oct 15 2016

.SHORT TERM...(Today through Monday)
Issued at 300 AM MDT Sat Oct 15 2016

Winds and fire weather are the main concerns in the short term.
Going to have plenty of both over the next couple days.

Currently...Cold frontal boundary looks to be stalled out to our
north. Roughly laying along a line from Rapid City to Casper out
to Rock Springs this morning. Skies look to be mostly clear this
morning off IR satellite imagery. CYS VWP showing fairly light
winds overhead at 25kts, though we just received a wind gust
report of 54MPH at Cooper Cove out by Arlington. With the WRKHGT
product showing 850/700mb Craig to Casper gradients decreasing,
decided to expire the High Wind Warning early and start turning
attention to the next wind event.

GFS 700mb winds today roughly 30kts across southern Wyoming
through the day. They then begin to increase this evening, up to
45kts by 03Z across Carbon County and 55kts by 06Z and finally
60kts by 09Z. NAM Craig to Casper 850/700mb height gradients
really begin ramping up as well. They climb to above 50mtrs by 09Z
tonight and peak out around 12Z Sunday. Decided to go with a High
Wind Watch for the Interstate 80 Corridor from the eastern
foothills to Arlington for Sunday. Added the Laramie Valley and
eastern foothills of the South Laramie Range into the Watch Sunday
after 12Z as GFS soundings showing 55kts right off the surface
over Laramie. We should be able to mix up to about 600mb Sunday,
so these winds easily should mix down to the surface.

Downsloping winds off the Laramie Range will make for another very
dry day Sunday. Getting afternoon humidities below 15 percent for
most areas east of the Laramie Range for Sunday afternoon. Will go
with a Fire Weather Watch for these area with the morning package.

Looks like the front finally moves into our western CWFA Sunday
night into Monday as a 145kt jet max pushes the system eastward.
Still seeing 50-55kts of wind at 700mbs Monday morning. GFS showing
Craig to Casper gradients increasing above 60mtrs late Monday
morning, so we could be looking at a more widespread high wind

.LONG TERM...(Monday night through Friday)
Issued at 300 AM MDT Sat Oct 15 2016

Temperatures will decrease behind the fropa on Monday, with highs
dropping back into the upper 50s and 60s by Tuesday. The models
have a shortwave digging into northwest Colorado by Tuesday night
with upper level diffluence increasing in areas along the Colorado
border. Have 20-40 percent pops over much of the southeastern half
of the CWA by Tuesday night into Wednesday morning. The snow level
looks to be around 7000 ft by sunrise Wednesday, so could see
minor accumulations in southeast WY. A stronger push of colder air
moves into the region by Wednesday with 700 mb temps dropping to
-7C. Started to decrease highs on Wednesday into the 40s and low
50s. Heights rise on Thursday/Friday as a strong upper ridge
builds into the Great Basin and Intermountain West. Benign weather
with moderating temps will occur.


.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 230 AM MDT Sat Oct 15 2016

Southwest winds will increase by late morning across southeast WY
with gusts to 25-35 kts at LAR/RWL through the afternoon. Winds
will be weaker at sites to the east of the Laramie Range. Mid to
high level clouds will pass over the area throughout the taf


Issued at 300 AM MDT Sat Oct 15 2016

Windy pattern to continue for next several days as low pressure
west slowly moves into western Wyoming and western Montana. A warm
day on tap for Sunday and winds are expected to be quite strong.
Afternoon humidities along and east of the Laramie Range into the
Nebraska Panhandle will fall to critical Sunday afternoon. A Fire
Weather Watch is in effect for FWZs 310-313 from noon until 6PM
Sunday. A stronger widespread wind event looking likely for


WY...Fire Weather Watch Sunday afternoon for WYZ310.

     High Wind Watch from late tonight through Sunday afternoon for

     High Wind Watch from Sunday morning through Sunday afternoon for

NE...Fire Weather Watch Sunday afternoon for NEZ311>313.



FIRE WEATHER...GCC is the U.S. government's official web portal to all federal, state and local government web resources and services.