765 
FXUS65 KCYS 150420
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1020 PM MDT Sat Aug 14 2021

.UPDATE...
Issued at 332 PM MDT Sat Aug 14 2021

Severe Thunderstorm Watch 440 issued for the Nebraska Panhandle
today through 11 PM this evening.

&&

.SHORT TERM...(This evening through Sunday)
Issued at 150 PM MDT Sat Aug 14 2021

Latest surface obs and satellite scanning convergence boundary
stretching across portions of southeastern WY and the NE Panhandle
with early convection across the the SD Black Hills and light echo
now over the Laramie Range. CAM guidance remains split in thinking
with the HRRR once again being the quiet outlier this afternoon
with limited convection across the Panhandle while the NAMNEST has
stayed consistent with more widespread thunderstorms from now
through late tonight. SPC continues a sliver of slight risk for
far eastern NE Panhandle with marginal including only eastern tier
of counties from Dawes south to Cheyenne. 

Latest PRECIP sounding from CSU shows robust CAPE profile of over
1000 J/kg but lackluster 0-1 km shear of about 7 kts. CIN is the
kicker again today as inversions in the sounding and values into
the 150 to 200 J/kg range. So similar to yesterday, topography 
will be key to help spur initiation. LLJ again could play a bit of
a spoiler tonight across the Panhandle with any remaining 
convection and energy remaining. Highs today on the warmer side 
from Friday into the upper 80s and low 90s for many. 

Sunday will see an uptick in low and midlevel moisture coupled
with passing upper level shortwave that again will spur convection
perhaps more widespread including into SE WY. Highs near-similar
to today's forecast. 

.LONG TERM...(Monday through Friday) 
Issued at 220 AM MDT Sat Aug 14 2021

Monday...With some decrease in low and mid level moisture, we should 
see a decrease in late day shower and thunderstorm coverage. 
Slightly cooler temperatures for most locations, notably across the 
Nebraska Panhandle.

Tuesday...Even warmer temperatures as the flow aloft becomes 
southwest with 700 mb temperatures near 18 Celsius. Looks like 
enough low and mid level moisture for isolated to scattered late day 
thunderstorms.

Wednesday...Shower and thunderstorm coverage becomes scattered to 
numerous in the afternoon and evening with a monsoonal moisture 
increase, and with a cold front progressing into our counties. 
Somewhat cooler temperatures on tap with considerably more cloud 
cover and increased precipitation chances.

Thursday...Cooler temperatures expected in the wake of a passing 
shortwave trough aloft and its associated cold front. Chances for 
showers and thunderstorms will likely decrease by the evening as 
more stable air moves into the region.

Friday...Northwest flow aloft continues. Still looks like 
isolated to scattered showers and thunderstorms possible in the 
afternoon and evening with adequate low and mid level moisture.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1007 PM MDT Sat Aug 14 2021

Fairly active day today as storms developed east of Cheyenne and 
into the Nebraska Panhandle. Have seen much of the storm activity 
calm down over the last couple of hours, with a few lingering 
showers across the CWA. Should be mostly calm through the 
nighttime hours, primarily after 05z tonight. VFR and MVFR 
conditions are likely for all terminals through the early part of
tomorrow before our next round of widespread precipitation 
continues in the early afternoon. Main concerns exist with any fog
potentials in the early morning for terminals KCDR and KAIA with 
plenty of moisture from today's storms, light winds, and clearing 
overhead skies. Went ahead and started trending visibilities down 
to account for these conditions.

&&

.FIRE WEATHER...
Issued at 135 PM MDT Sat Aug 14 2021

Limited fire weather conditions next few days with isolated to
scattered chances of precipitation coupled with lackluster winds
although min RHs will teeter if not go into critical conditions.
With thunderstorm chances, lightning sparked fires remain a
possibility. 

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&

$$

UPDATE...GCC
SHORT TERM...WM
LONG TERM...RUBIN
AVIATION...MD
FIRE WEATHER...WM