Area Forecast Discussion
Issued by NWS Cheyenne, WY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
000
FXUS65 KCYS 172128
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
328 PM MDT Thu Aug 17 2017

.SHORT TERM...(This evening through Saturday night)
Issued at 330 PM MDT Thu Aug 17 2017

Isolated thunderstorms from earlier this afternoon have pushed
southeast into Colorado. Expected brief scattered rain showers and
an isolated thundershower into this evening as an upper level
disturbance, currently over northeast Wyoming, continues to
rapidly move eastward through tonight. Most of this activity
should be confined to the I-80 corridor and diminish shortly
after sunset. Once the upper level disturbance moves east into the
northern plains, warmer and drier air aloft will move over the
forecast area. This drier air aloft will greatly suppress
convective activity on Friday and most of Saturday with high
temperatures rising into 80`s to low 90`s across the region,
warmest over the lower elevations below 4500 feet. Thunderstorm
activity is slightly more favorable on Saturday near the Colorado
border as some moisture will return due to backing winds from the
south and southeast.


.LONG TERM...(Sunday through Thursday)
Issued at 242 PM MDT Thu Aug 17 2017

The main weather concern for Eclipse Day (Monday) will be a threat
for mid/high level cloud cover. The models continue to show decent
H7-H3 RH values across the CWA, suggesting at least periodic shots
of moisture embedded within southwest flow aloft. We may also have
some remnant shower activity early Monday morning which could lead
to the potential for lingering cloud cover. We have maintained the
Partly Cloudy wording along the Path of Totality based on forecast
soundings relatively dry below 300 mb. A couple of mountain storms
are possible in the afternoon, but overall do not expect any major
weather impacts to travelers on Monday. Precipitation chances Tue/
Wed are challenging, with the GFS/ECM disagreeing on the placement
of the shortwave ridge axis. There is potential for each afternoon
and/or evening to be fairly active though if southwesterly mid-lvl
flow is able to take control.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 242 PM MDT Thu Aug 17 2017

VFR prevails. Scattered showers and a few thunderstorms will occur
this afternoon and early evening, with gusty/erratic surface winds
the primary hazard.

&&

.FIRE WEATHER...
Issued at 242 PM MDT Thu Aug 17 2017

Low Fire Weather concerns will continue late this week with
moderate concerns likely this weekend due to low humidities and
some gusty winds across southeast Wyoming. Drier conditions with
warmer temperatures are expected Friday and this weekend with
little or no precipitation across southeast Wyoming and western
Nebraska. Any thunderstorms that do form will likely be in the
mountains this weekend. Relative Humidities will trend lower into
this weekend with values between 15 to 20 percent each afternoon.
Concerns may become elevated on Saturday in localized areas west
of Interstate 25 due to winds gusting between 20 to 25 MPH.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&

$$

SHORT TERM...TJT
LONG TERM...CLH
AVIATION...CLH
FIRE WEATHER...TJT



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