Area Forecast Discussion
Issued by NWS Cheyenne, WY

Home | 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 191543

Area Forecast Discussion
National Weather Service Cheyenne WY
943 AM MDT Wed Oct 19 2016

Issued at 938 AM MDT Wed Oct 19 2016

Forecast for today looks good. New model data is starting to hint
towards greater amounts of boundary layer instability as the
shortwave disturbance aloft enters the Cowboy state over the next
few hours. With model soundings indicating a some potential for
thunder showers...added thunder to the forecast for areas north of
I-80 across the High Plains this afternoon. Shower activity may
linger into this evening hours since models are trending slower
with the movement of the shortwave. This feature may actually
linger across western Nebraska through midnight tonight.


.SHORT TERM...(Today through Friday)
Issued at 253 AM MDT Wed Oct 19 2016

Today...Narrow band of rain showers moving eastward across the
southern half of the Nebraska panhandle early this morning based on
radar reflectivity. Clearing skies working eastward across our
counties in the wake of the shortwave. NAM hints at another weaker
shortwave moving across eastern Wyoming this afternoon in cyclonic
flow aloft, which seems reasonable, thus will continue to paint
isolated to scattered showers this morning and afternoon, roughly
north of a Rawlins to Kimball line. Continued cool with expected
cloud cover and 700 mb temperatures near -4 Celsius, and have gone
close to the NAM and GFS MOS maximum temperatures.

Tonight...Clearing skies will lead to a cold overnight with light

Thursday...Decent warming trend on tap as heights and thicknesses
rise significantly and minimal cloud cover exists. Compromised
between the NAM and GFS MOS guidance maximums for high temperatures.

Thursday night...Not quite as cold as Wednesday night as our airmass
moderates and low level winds aid in mixing.

Friday...Significant warming trend continues as the ridge aloft
builds overhead and 700 mb temperatures rise to near 5 Celsius.
Plenty of sunshine will also aid in warming as will downslope
warming winds. Compromised between the NAM and GFS MOS maximums for
high temperatures.

.LONG TERM...(Friday night through Tuesday)
Issued at 253 AM MDT Wed Oct 19 2016

The main concern with this portion of the forecast is how the
upper level trof will evolve during the middle of next week.

Friday night-Monday:
No real major concerns during this timeframe as the upper level
ridge keeps its grip over the region. It may become more breezy on
Saturday in response to a shortwave moving along the U.S./Canadian
border. This may result in some critical fire weather conditions
on Saturday. Otherwise, mostly sunny and mild conditions will be
the rule with afternoon highs in the 60s and 70s.

Monday night-Tuesday:
There is still some uncertainty on how much shortwave energy will
move ahead of the trof next week. This will certainly play a role
on how much moisture feeds into the region. At this point, it
appears like the mountains have the best shot of seeing rainfall
due to upslope effects. Temperatures will continue to be on the
mild side with afternoon highs mostly in the 60s to around 70. It
may be a bit cooler on Tuesday in areas west of the Laramie Range
due to the potential for more cloud cover with highs mostly in the


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 534 AM MDT Wed Oct 19 2016

Latest radar loop was showing the back edge of the showers moving
through the KAIA/KSNY TAF sites. Based on its current movement, we
would anticipate these showers to end by 13z or so. The remainder
of the area will have sct to bkn vfr conditions this morning/aftn.
Still cannot rule out some mvfr ceilings around KRWL, but it
should not last long. Meanwhile, isolated to scattered showers
should pop up today in response to the cyclonic flow aloft. The
only area where a snow shower could develop will be around
Laramie. The wind is expected to be a bit gusty today mainly
around KRWL. Otherwise, wind speeds will generally be light.


Issued at 253 AM MDT Wed Oct 19 2016

with wet ground and higher humidities, minimal concerns today and
Thursday. Humidities lower again on Friday and Saturday as the
airmass moderates, and concerns will increase again.




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