Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 242159

Area Forecast Discussion
National Weather Service Cheyenne WY
259 PM MST Fri Nov 24 2017

.SHORT TERM...(This evening through Sunday Night)
Issued at 259 PM MST Fri Nov 24 2017

Tonight...Few showers around through late afternoon with the cold
front and shortwave trough aloft passage, then showers ending with
some clearing noted.

Saturday...Flow aloft continues from the northwest with rising
heights aloft. Dry with lack of low and mid level moisture.
Relatively mild with highs in the 50s at lower elevations with 700
mb temperatures near 2 Celsius.

Saturday night...Not as cool as tonight with airmass modification
and decent winds.

Sunday...Considerable warming trend with the ridge aloft moving
overhead and with 700 mb temperatures climbing to near 8 Celsius,
yielding highs in the 60s at lower elevations. Low and mid levels
too dry to support precipitation.

Sunday night...Even more mild than Saturday night due to airmass
moderation and a decent lee surface trough keeping the low levels
well mixed.

.LONG TERM...(Monday through Friday)
Issued at 259 PM MST Fri Nov 24 2017

Both the operational GFS and EC continue to show lots of run to
run inconsistency regarding the evolution of the next deep upper
trough progged to dig into the western US early next week. Trend
has been towards a more elongated positively tilted trough with
the energy splitting by Monday evening and the southern end
becoming more of a closed cut off low over southern CO. This would
keep the majority of the precipitation south of the region as
well as tone down the strength of any bora wind event. Overall a
pretty low confidence forecast for Monday/Tuesday due to
significant model variability. With this said, there remains at
least some potential for a significant frontal passage with
mountain snow and strong winds so did not make too many changes to
the long term forecast at this time.


.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 259 PM MST Fri Nov 24 2017

VFR conditions will prevail through the period with just some
mid/high clouds passing from time to time. Winds will subside this
evening, with less than 10 knot winds overnight. Breezy winds will
develop once again after 15z for southeast Wyoming airfields,
where gusts of 25-35 knots are expected to continue thru Saturday


Issued at 259 PM MST Fri Nov 24 2017

Minimal concerns based on projected winds and humidities.





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