Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 220545

Area Forecast Discussion
National Weather Service Cheyenne WY
1145 PM MDT Wed Jun 21 2017

.SHORT TERM...(This evening through Friday)
Issued at 233 PM MDT Wed Jun 21 2017

Convection continues to percolate across Carbon and Albany
counties. Instability and shear are pretty weak in these areas so
we would not expect much more than a few showers and isolated
thunderstorms this afternoon. However, would not be surprised to
see some wind gusts up to 50 mph due to very dry air mass in
place underneath some of the showers. This activity is expected
to translate east across the Laramie Range this evening. Some of
this convection may bleed over to the Nebraska panhandle this
evening where the better instability is in place, especially in
the northern Panhandle. As a result, we could see a few strong
storms in that region during the evening. Latest satellite loop
was also showing some convection trying to build across Converse
and Niobrara counties. We will need to keep an eye on this
convection as well where the better shear and instability will be
in place. Most of the convection should dissipate by midnight.

This timeframe is looking to be a little less promising for
convection. Latest surface analysis was showing a frontal boundary
along the Wyoming/Montana border. This frontal boundary is progged
to push through the forecast area late tonight into tomorrow
morning. As a result, it will drive the low level moisture south
into Colorado. Right now, we are not too excited about the
convection chances even along I-80 and points south Thursday
afternoon. However, we will have to see how things pan out in
later runs, and hang on to small convection chances. The rest of
the forecast looks to be on track with cooler conditions moving
into the area during next couple of days.

.LONG TERM...(Friday night through Wednesday)
Issued at 233 PM MDT Wed Jun 21 2017

Friday night...Weak disturbance in northwest flow aloft may aid in
producing isolated to scattered late night showers east of a Douglas
to Kimball line.

Saturday...Northwest flow aloft prevails. With low levels relatively
cool and stable, shower and thunderstorm chances appear quite
minimal. Cool with cloud cover and high temperatures mainly in the

Sunday...Cool and relatively stable airmass remains in place, though
a bit warmer than Saturday. Continued dry.

Monday...Warming trend starts in earnest as heights aloft rise and
the surface winds become more of a downslope direction. Continued
dry with limited low and mid level moisture.

Tuesday...Decent warming trend continues with strong zonal flow
aloft and a relatively dry airmass.

Wednesday...Continued mostly dry and mild with zonal flow aloft and
mild mid level temperatures.


.AVIATION...(For the 06Z TAFS through 06Z Thursday evening)
Issued at 1145 PM MDT Wed Jun 21 2017

VFR. Cold front pushes south along and east of the Laramie Range
Thursday morning with northerly winds gusting to 30 kt. Winds
become northeasterly and remain breezy Thursday afternoon across the
plains, while westerly winds prevail over Carbon County. Widely
scattered t-storms develop after 18Z from the southern Laramie Range
eastward across the Cheyenne Ridge into the early evening, with VCTS
at KLAR, KCYS and KSNY. Gusty outflow winds to 45 kt, small hail and
brief MVFR visibility in heavy rain may accompany the stronger


Issued at 233 PM MDT Wed Jun 21 2017

Cooler and drier conditions are anticipated during the next
couple of days, due to high pressure building in from the north.
This will result in higher relative humidity values, but gusty
north winds. The lack of precipitation will also result in fuels
continuing to dry out. There is a chance of rain Friday night
mainly in the Nebraska panhandle, but lack of precipitation will
persist through the weekend across Wyoming.




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