706
FXUS65 KCYS 071127
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
527 AM MDT Fri Jun 7 2024

.KEY MESSAGES...

- Warm weather will continue through late week, with widespread
  highs in the 80s and lower 90s Friday.

- Threat for strong downburst winds this afternoon and evening
  from high based thunderstorm development.

- Monday and Tuesday will see the greatest coverage of late day
  showers and thunderstorms, while Wednesday and Thursday will
  be warmer with a general decrease in shower and thunderstorm
  coverage.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 235 AM MDT Fri Jun 7 2024

Low pressure analyzed over northern Carbon County this morning.
Stationary front extends from this low eastward to near
Torrington and then into southern Nebraska. South of this
front...dewpoints are being observed in the 50s across northeast
Colorado into southern Nebraska. Upper shortwave currently
located in northwestern Wyoming.

Front surges eastward after 18Z today with the surface low
located near Chadron. Initial thunderstorms will be high based
with GFS soundings showing inverted V soundings and DCAPE near
1000-1200 J/KG. Day crew will need to watch for severe down
drafts from these high based storms.

Mesoscale simulated radar shows a line of thunderstorms possibly
developing across Carbon County after 00Z that eventually move
into northern Platte and Goshen Counties before decreasing
overnight.

After a brief lull in convection...showers and thunderstorms
redevelop late Saturday morning into the afternoon as PWATs
increase up near 1 inch. ECMWF/GFS/NAM and SREF all painting
widespread QPF across southern Wyoming and the southern
Panhandle Saturday afternoon. Afternoon instability up near 1200
to 1500 J/KG for the southeast WYoming plains into the Panhandle
Saturday afternoon. A Marginal Risk for severe thunderstorms
has been highlighted for parts of the CWA.

For Sunday...a stronger cold front surges south across our
entire northern and eastern CWA as a stronger upper shortwave
tracks into South Dakota. 700mb temperatures fall considerably
into the single digits with below zero temperatures to near the
South Dakota/Nebraska Panhandle state line. Much cooler Sunday
which will limit thunderstorm activity. Would envision low
stratus and fog across the Panhandle to the east slopes of the
Laramie Range with this scenario.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Issued at 235 AM MDT Fri Jun 7 2024

Sunday night/Monday...As daytime heating wanes, isolated to widely
scattered showers and thunderstorms will end from west to east
overnight Sunday night. West northwest flow aloft develops on
Monday, and with plenty of low and mid level moisture available,
scattered late day showers and thunderstorms will be on tap again.
Temperatures slightly warmer than Sunday with less cloud coverage.

Tuesday...Northwest flow aloft remains, though with increasing
heights aloft along with warmer temperatures, and a decrease in low
and mid level moisture, we should see less coverage of late
day showers and thunderstorms. Slightly warmer with more sunshine
expected.

Wednesday...Even warmer as the flow aloft turns westerly, and with
700 mb temperatures near 15 Celsius, maximum temperatures will be in
the mid 80s to lower 90s. Warmer temperatures aloft will increase
the convective inhibition, and with less low and mid level moisture
around, only a few late day showers and thunderstorms are expected
mainly near the mountains.

Thursday...Similar synoptic pattern as on Wednesday, though low
level winds will become upslope northeast, and with an increase in
low and mid level moisture, we expect to see isolated to widely
scattered late day showers and thunderstorms.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 522 AM MDT Fri Jun 7 2024

West northwest flow aloft will prevail.

Wyoming TAFS...Scattered to broken clouds around 15000 feet will
lower to ceilings from 8000 to 10000 feet by this afternoon.
Thunderstorms will be in the vicinity from 21Z to 01Z. Winds
will gust to 32 knots from 15Z to 01Z.

Nebraska TAFS...Scattered clouds around 15000 feet this morning
will lower to ceilings from 8000 to 15000 feet by late
afternoon. Thunderstorms will be in the vicinity of Scottsbluff
and Sidney from 22Z to 02Z. Winds will gust to 25 knots from
14Z to 02Z.

&&

.HYDROLOGY...
Issued at 400 PM MDT Thu Jun 6 2024

Several days of above normal temperatures have accelerated snowmelt
runoff in the North Platte and Laramie River basins. Temperatures
for the next several days are forecast to remain high enough to
sustain rapid snowmelt and the subsequent high flows including minor
flooding through Saturday. Snowmelt from the Sierra Madre and
Snowy Ranges has driven the Encampment and North Platte Rivers
to bankfull stages. The Encampment River is forecast to crest
above flood stage on Saturday morning. Emergency management has
reported minor flooding along the Little Laramie River. This
flooding is expected to continue through the weekend.

&&

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

&&

$$

SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...RUBIN
HYDROLOGY...WFOCYS