FXUS65 KCYS 161124

Area Forecast Discussion
National Weather Service Cheyenne WY
524 AM MDT Sun Jun 16 2019

.SHORT TERM...(Today through Monday night)
Issued at 345 AM MDT Sun Jun 16 2019

Overnight WV/IR loop revealed a shortwave trough moving east across
eastern WY and far northern CO. Scattered showers and a few tstorms
will accompany this feature through the early morning hours. Skies
were partly to mostly cloudy. Winds were variable 10 mph or less,
except southwesterly gusting to around 25 mph in the wind corridor
between Laramie and Rawlins. Temperatures ranged from the mid 40s
to mid 50s.

Active west to southwest flow aloft will prevail for the next 24
to 48 hours. Embedded shortwaves in the flow combined with lingering
mesoscale boundaries, ample moisture and instability will produce
showers and tstorms, most numerous during the afternoons and
evenings. Axis of combined MUCAPEs to 1500 j/kg and bulk shear of
30-35 kt will develop south and east of a line from Laramie to
Alliance this afternoon. Therefore, a few strong to marginally severe
tstorms producing brief wind gusts up to 60 mph and hail to an inch
in diameter are possible. On Monday afternoon, the marginal severe
threat shifts to east of a line from Chadron to Cheyenne. Besides
the wind/hail threat, there is the potential for locally heavy
rainfall. Model precipitable water values range from 0.50 to 1.0
inches today, and 0.70 to 1.1 inches Monday. Areas east of I-25
can expect 0.25 to 0.50 inch with localized 0.75 inch amounts
this afternoon/evening. More widespread 0.25 to 0.50 inch amounts
are forecast Monday afternoon/evening. Convection will decrease in
coverage/intensity later in the evening and overnight tonight and
Monday night. Below average high temperatures in the upper 60s to
mid 70s are forecast today and Monday.

.LONG TERM...(Tuesday through Saturday)
Issued at 330 AM MDT Sun Jun 16 2019

General model/ensemble consensus with good coverage of showers/tstorms
Tuesday with the passage of a shortwave trough. More isolated coverage
of showers/tstorms forecast Wednesday/Thursday with drier zonal flow
aloft. Models diverge late in the week with GFS placement of upper
level trough to the north, while ECMWF/Canadian centered over the
northern Rockies with southwest flow aloft. Went with consensus
PoPs, in the scattered category for Friday and Saturday. High
temperatures will average 5 to 10 degrees below seasonal normals.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 524 AM MDT Sun Jun 16 2019

Some showers and a few storms moving over the Panhandle this
morning. Expect another round of showers and tstms to develop over
se Wy this afternoon with more isolated showers over the area
tonight. There could be some low stratus/MVFR-IFR cigs/ over parts
of the Panhandle later tonight.


Issued at 225 AM MDT Sun Jun 16 2019

Fire weather concerns will remain low early this week with green fuels
and fairly widespread wetting rains from showers and scattered
thunderstorms. Locally heavy rain will be possible. Prevailing winds
will be light, except variable and gusty near thunderstorms. Shower
coverage will become more isolated to scattered mid to late week.


Issued at 245 AM MDT Sun Jun 16 2019

Hydrologic concerns will continue for the Upper North Platte and
Laramie Rivers and their tributaries due to a ripe high elevation
snow pack and increasing chances for rain on snow-melt today through
Tuesday. Latest RFC forecasts maintain minor flood potential near
Saratoga and along portions of the Laramie Watershed. Current model
QPF indicates the potential for significant precipitation above
9000 feet in the form of rain with daytime temperatures in the 50s
to lower 60s and nighttime low temperatures of 35 to 40 degrees.
Runoff due to saturated soils will likely cause streams and rivers
to rise through Tuesday. A River Flood Warning remains in effect
for the Upper North Platte River near Saratoga. Additional flood
watches and warnings may be required with the potential for
heavier, slow moving convection.




Back to Main Forecast Discussion Page