023
FXUS65 KCYS 140055
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
655 PM MDT Tue Aug 13 2024

.KEY MESSAGES...

- Scattered to numerous afternoon/evening showers and
  thunderstorms are expected the next few days. Storms will
  have the potential to produce torrential rainfall, gusty
  winds, and isolated large hail.

- An active pattern continues through the week ahead with near
  normal temperatures and daily chances for afternoon and
  evening showers and thunderstorms.

- Seasonable temperatures will continue through the period. Showers
  and thunderstorms will be most likely on Friday, Sunday and
  Monday, with drier conditions for Saturday.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 147 PM MDT Tue Aug 13 2024

Scattered to mostly cloudy conditions are becoming present early
this afternoon across portions of the Intermountain West. Weak
showers and thunderstorms have initiated as of 20Z across the
I-80 corridor and the Front Range of CO. Low clouds from earlier
this morning across the Nebraska Panhandle have dissolved late
in the morning. There are some concerns with organized, stronger
convection initiating later this afternoon and evening due to
the prolonged period of cloud cover. This has stabilized the
atmosphere in areas that the morning 12Z hi-res guidance progged
thunderstorm initiation.

The remainder of today we should eventually see more widespread
coverage of thunderstorms. The primary concerns will be heavy
rainfall, lightning, and isolated hail. Still expecting there to
be a prolonged window of convection, but the coverage with the
highest intensity of thunderstorms are favored for severe
weather in the NE Panhandle. Wetting rainfall greater than 0.10
inches occurring is favored with any slow-moving thunderstorms
today, and should assist with the lingering drought concerns.
Rain showers and thunderstorms should dissipate for the most
part by midnight tonight. Lingering low clouds and light rain
may be possible across the I-80 corridor through daybreak.

Wednesday will be another day of similar weather conditions.
Daytime highs in upper 70s to near 90 degrees are likely for the
lower terrain. SLightly cooler temperatures for the mountain
zones are anticipated...upper 50s to upper 60s. Showers and
thunderstorms are expected to occur during the afternoon and
evening hours. Timeline of storms is expected of 18z-6z is
favored for Wednesday afternoon and evening. A Marginal Risk of
severe wx exists for the entire cwa, along with a chance of
excessive rainfall from the thunderstorms that slowly move from
west to east. Mild temperatures are forecast on Wednesday night
east of the Laramie Range, with a slightly cooler forecast of
the upper 30s to upper 40s for areas west of the Laramie Range.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 221 AM MDT Tue Aug 13 2024

Thursday night/Friday...Some leftover scattered showers and
thunderstorms will occur Thursday evening mainly west of a Douglas
to Sidney line, with widely scattered showers continuing after
midnight across the forecast area. Ridging aloft and drying west
winds in the mid levels of the atmosphere will help dry out the
airmass somewhat as precipitable water values decrease to 0.4 to 1
inch. Still though, with a surface trough in place near the Wyoming
and Nebraska state line, we expect isolated to widely scattered late
day showers and thunderstorms most numerous east of I-25. Warmer
temperatures anticipated with less cloud cover and with 700 mb
temperatures near 18 Celsius, maximum temperatures will be in the
80s.

Saturday...West flow aloft will continue to dry out the airmass and
thus we will see correspondingly warmer temperatures from the mid
80s to mid 90s. With precipitable water values lowering to 0.3 to
0.7 inches and warm temperatures aloft increasing the convective
inhibition. it looks dry.

Sunday...Despite ridging aloft developing, we will see an increase
in atmospheric moisture content with precipitable water values
increasing to 0.8 to 1.2 inches. Thus, we expect an increase in
widely scattered to scattered late day showers and thunderstorms,
most numerous from the Snowy Range to far southeast Wyoming.

Monday...Atmospheric moisture content remains about the same as on
Sunday, and thus we expect another round of scattered late day
showers and thunderstorms, most numerous near the Colorado state
line from the Snowy Range to far southeast Wyoming. With similar 700
mb temperatures, maximum temperatures should be about the same as
those from Sunday.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 651 PM MDT Tue Aug 13 2024

A line of thunderstorms continues to move across the southern
Nebraska panhandle with gusty winds, heavy rainfall, and
lowering flight conditions recently observed near KSNY. While
the heaviest portions of the storm has passed, expect MVFR
conditions to persist for the next hour or two within the
lingering precipitation shield. Additional showers and
thunderstorms will be possible for remaining area terminals
this evening, but coverage will likely remain isolated through
early Wednesday morning.

&&

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

&&

$$

SHORT TERM...BW
LONG TERM...RUBIN
AVIATION...MB