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 41 42
FXUS65 KCYS 121711

Area Forecast Discussion
National Weather Service Cheyenne WY
1111 AM MDT Mon Mar 12 2018

.SHORT TERM...(Today and tonight)
Issued at 315 AM MDT Mon Mar 12 2018

Latest water vapor loop was showing a fairly wound up vort. lobe
moving through western Wyoming. Ahead of this wave, there is quite
a bit of mid-level cloud cover with even some snow near Driggs WY.
This feature is progged to continue to move east today and will
cause increasing clouds across the forecast area by midday. Could
see a few breaks in the cloud cover at times, but generally mostly
cloudy. Would also not be surprised to see a few isolated snow
showers between Cheyenne and Rawlins due to good instability in
place and low wet bulbs. The only impact may be reduced
visibility.  This shortwave and cloud cover should push east of
the area this evening and allow for clearing skies to prevail

.LONG TERM...(Tuesday through Sunday)
Issued at 315 AM MDT Mon Mar 12 2018

After a couple of days of dry and warmer temperatures on Tuesday
and Wednesday we are looking at a more active pattern setting up
late this week into the weekend. The models are still showing
quite a bit of uncertainty on the timing of the shortwaves moving
through. Case in point, the GFS is not as keen on bringing any
shortwaves into the picture until late this weekend, while the
GEM/ECMWF/GEFS is showing a shortwave tracking through southeast
Wyoming and Nebraska panhandle Thursday night into Friday with
another shortwave moving through late this weekend. We are going
to lean towards the GEM/ECMWF/GEFS solutions at this point, where
shortwave #1 may bring a couple of inches of snow to the mountains
Thursday night into Friday. Elsewhere, we are little more
uncertain on the snow levels. However, since this is showing
better isentropic lift and is drawing more moisture from the
southwest it may not be able to draw the colder into the area. As
a result, this should keep the snow levels on the higher side and
bring mostly rain. Shortwave #2 may be a different story,
especially if it closes off, and pulls the colder air into the
region later this weekend. Please stay tuned!!!


.AVIATION...(For the 18Z TAFS through 18Z Tuesday morning)
Issued at 1111 AM MDT Mon Mar 12 2018

VFR expected across for all terminals through the period with light
winds.  Some mid and high clouds passing across this afternoon
with an isolated shower possible over the mtns.


Issued at 315 AM MDT Mon Mar 12 2018

An upper level ridge will dominate the area during the next couple
of days. This will provide light wind speeds and dry conditions.
Meanwhile, a couple of upper level disturbances will start to
impact the area on Thursday and continue into weekend. This first
disturbance may bring a couple of inches in the mountains with
mainly a rain/snow mix elsewhere Thursday into Friday. The second
disturbance should begin to impact the area later in the weekend,
with more chances of rain and snowfall.




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