Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 161919

Area Forecast Discussion
National Weather Service Cheyenne WY
119 PM MDT Sun Jul 16 2017

.SHORT TERM...(This evening through Tuesday night)
Issued at 300 PM MDT Sun Jul 16 2017

Tonight...Upper ridging aloft and dry air aloft will continue to
limit areal thunderstorm development. However, storms are beginning
to develop over the Northern Laramie, Snowy and Sierra Madre Ranges
and thus will carry isolated to scattered POPS for these locations
into the evening hours. Elsewhere, dry and relatively mild.

Monday...Weak near zonal west to east flow aloft prevails. With the
addition of more low and mid level moisture, expect isolated to
scattered afternoon showers and thunderstorms to develop along and
west of Interstate 25, moreso than today.

Monday night...Isolated to scattered showers and thunderstorms will
continue much of the evening with more low and mid level moisture
availability, especially east of Interstate 25. Showers and
thunderstorms dissipating by midnight or shortly thereafter with the
loss of daytime heating and the lack of other lifting mechanisms.

Tuesday...Zonal flow aloft prevails with low level upslope developing
east of I-25, helping to generate scattered showers and
thunderstorms in the afternoon over and near the Snowy, Sierra Madre
and southern Laramie Ranges. Mostly dry elsewhere. With a rise in
heights aloft and a rise in 700 mb temperatures, maximum
temperatures will correspondingly rise.

Tuesday night...Showers and thunderstorms decreasing quickly in the
evening across the mountains with loss of daytime heating, then
clearing skies.

.LONG TERM...(Wednesday through Sunday)
Issued at 300 PM MDT Sun Jul 16 2017

Upper high continues to shift east into western/central Kansas and
Nebraska Wednesday opening the door to monsoonal moisture moving
into the area. Very weak steering flow will contribute to slow
moving storms mainly out west over the Snowy and Sierra Madre
Ranges Wednesday afternoon.

Still looking like Thursday could be a pretty widespread
shower/thunderstorm event across southeast Wyoming and Nebraska
Panhandle. ECMWF much more robust on QPF across the CWFA over the
GFS. Weak steering flow again Thursday for another slow/little
movement day on storms.

This pattern continues into the weekend for daily chances of
showers and thunderstorms. Will begin hyping up Thursday if the
models continue to show this pattern over the next few model runs.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1003 AM MDT Sun Jul 16 2017

Minimal weather impacts to southeast Wyoming and Nebraska
Panhandle airports this afternoon and evening. Convection returns
Monday late afternoon into the evening hours. This should be our
next impacts. Until then, sunny skies and dry conditions.


Issued at 1253 PM MDT Sun Jul 16 2017

Low afternoon relative humidities from 15 to 20 percent prevail
through Wednesday, especially along and west of Interstate 25.
Fortunately, wind speeds will be relatively light, limiting fire
weather concerns.




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