775
FXUS65 KCYS 202329
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
530 PM MDT Sat Jul 20 2024

.KEY MESSAGES...

- Strong storms are possible again Sunday, with a couple of storms
  producing damaging winds and isolated large hail possible.
  Expecting slightly cooler temperatures for Sunday.

- Cooler weather expected through Monday ahead of a gradual
  warming trend to above average temperatures through next week.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 259 PM MDT Sat Jul 20 2024

Latest radar loop was showing clusters of showers and thunderstorms
continuing to build south across the forecast area. These
showers and storms appear to be triggered from the jet streaks
moving central and southeast Wyoming combined with various
outflow/differential heating boundaries, and full sunshine early
on which helped reach our convective temperature early in the
afternoon. The bulk of the scattered convection should be south
of a Torrington to Alliance line by 03z and dissipate or head
south into Colorado by midnight. Until then, we are still
looking at small hail, gusty winds with an isolated damaging
wind threat with the storms moving through Goshen, Platte and
Scottsbluff counties late this afternoon and early this evening.
This environment has around 1200-1500j/kg of SBCAPE as well
which could be enough to trigger a couple of storms with larger
hail. These showers and storms may affect Laramie and
Kimball/Banner counties around 5 to 6 pm. Meanwhile, not as
confident about the rest of the Nebraska panhandle since most of
the environment has been worked over. Cannot rule out a few
isolated showers overnight, but they should be should be few and
far between.

Sunday could be somewhat similar to today, but a little less
coverage. The upper level flow will continue to be out of the
north with instability around 700-1000j/kg mainly along and east
of the Laramie Range with very marginal shear of 25 to 30kts.
Once again cannot a couple of strong storms, but should continue
to bring some beneficial rainfall to some locations. &&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 116 AM MDT Sat Jul 20 2024

CWA stays under northwest flow through Wednesday in the long
term with upper high firmly in place over Nevada and Idaho
through most of the upcoming week. We continue to see monsoonal
moisture streaming north into the CWA interacting with upper
shortwaves in the northwest flow just about every day. So shower
and storm chances expected each afternoon and evening.

Wednesday begins the warm up as the high begins to shift
eastward. Seeing 700mb temperatures up near +18C across western
Wyoming into Carbon County Wednesday and by Friday...GFS
advertising +20C over southeast Wyoming. Look for mid 90s
Wednesday for highs to near 100 degrees Friday across the
Panhandle.

A pretty strong upper level low tracks across southern Canada
Friday with a trough moving through Friday evening into
Saturday. Could see fairly widespread rainfall Friday afternoon
as the trough approaches.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 530 PM MDT Sat Jul 20 2024

North flow aloft will continue.

Wyoming TAFS...Scattered to broken clouds from 5000 to 10000 feet
will prevail, with occasional thunderstorms at Cheyenne until 02Z,
producing wind gusts to 35 knots and visibilities to 4 miles, with
thunderstorms in the vicinity at Rawlins and Laramie until 02Z.
Outside of thunderstorms, winds will gust to 35 knots until 02Z.

Nebraska TAFS...Scattered to broken clouds from 5000 to 9000 feet
will continue, with occasional thunderstorms until 02Z at
Scottsbluff and Sidney, producing wind gusts to 35 knots and
visibilities to 4 miles. Thunderstorms will be in the vicinity at
Chadron and Alliance until 02Z. Outside of thunderstorms, winds will
gust to 20 knots at Scottsbluff and Sidney until 02Z.

&&

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

&&

$$

SHORT TERM...REC
LONG TERM...GCC
AVIATION...RUBIN