Special Weather Statement, NWS Cheyenne, WY

Area Forecast Discussion
National Weather Service Cheyenne WY
1159 AM MDT Tue Aug 4 2020

.SHORT TERM...(Today through Thursday)
Issued at 314 AM MDT Tue Aug 4 2020

An upper level ridge continues to transition eastward today,
strengthening across the Great Basin, and eastward towards southeast
Wyoming and the western Nebraska Panhandle. A few high clouds are
riding the wave aloft tonight, but for the most part, skies remain
clear tonight with generally light winds noted across the region.
A frontal boundary, currently pulling north over the South Laramie
Range and turning westward across central Carbon County is noted
as winds to the north and east of the front are generally south
and easterly and paired with dewpoints in the 50s, and northerly
winds to the south of the boundary paired with dewpoints in the
30s. Storms will initiate along this frontal boundary by noon
today as a strong upper level shortwave ejects east through the
flow aloft, with ML CAPE 1000 to 2000 J/kg and shear topping off
around 30 kts in the 0-6 km layer. These factors, in addition to
PWATS near 1 inch, will allow storms to form and organize, first
across central and north Carbon and Albany Counties, transitioning
east of the Laramie Range by mid- afternoon. Large hail and
strong gusty winds will be possible with these storms. As storms
transition east towards the WY-NE border, storms will begin to
coalesce into a line, with damaging winds becoming the increasing
threat. To the west of the Laramie Range, with an increasingly
deep dry surface layer in place, high-based storms will produce
strong gusty winds and dry lightning. Storms will diminish and
pass east of the Panhandle around sunset with a quiet night in
store for the region.

On Wednesday, as the ridge continues to build eastward, a frontal
boundary will set up along the lee-side of the Laramie Range.
Another strong upper level shortwave will eject east through the
500 mb flow, effectively forcing the frontal boundary eastward.
This time however, seeing indications of a surface low forming
near Chugwater and pulling southeastward over the course of the
afternoon towards Sidney creating an area of low-level helicity.
An upslope flow will combine with ML CAPE again near 1000 to 2000
J/kg, and bulk shear now around 40 kts and bring storms to the
region as the front moves east over the course of the afternoon.
Main difference will be the introduction of low level helicity
therefore cannot rule out a tornado or two, in addition to strong
winds and large hail potential. To the west of the Laramie Range,
decreasing moisture will lessen the dry thunderstorm threat.

By Thursday, the ridge will have transitioned east, with the ridge
axis passing aloft. Daytime highs will reach into the 90s across
the High Plains, and the region will dry out significantly. An
upper level shortwave will bring breezy conditions across the
region. Isolated storms are expected to remain subsevere.

.LONG TERM...(Friday through Monday)
Issued at 314 AM MDT Tue Aug 4 2020

A rather dry and warm pattern expected over the area this period
as an upper high builds over the southern plains Friday and holds
in place through early next week. This will limit moisture over
the CWA with monsoonal flow mostly cut off. As a result chances
for convection look to be pretty low with the best chance being
Saturday afternoon and evening as the CWA gets clipped by a
shortwave passing to the north. Temperatures generally above
seasonal averages through the period but not by a lot.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1134 AM MDT Tue Aug 4 2020

All Wyoming and Nebraska Panhandle sites continue in VFR
conditions. Thunderstorms will arrive in Wyoming around 19Z to
04Z. Lingering rain showers will stick around from 02-05Z. Wind
gust up to 35kts is possible for all Wyoming sites. Nebraska
Panhandle could see thunderstorms arrive as early as 23Z along
with gust up to 25kts. Thunderstorms will leave the Nebraska area
around 03Z. Clouds will continue to stay low around 8-6 thousand
feet and trend between SCT and FEW for Nebraska Panhandle.

&&

.FIRE WEATHER...
Issued at 314 AM MDT Tue Aug 4 2020

A ridge of high pressure will continue to deepen across the Great
Basin, bringing critical to near critical fire weather conditions
to southeast Wyoming and later this week to the western Nebraska
Panhandle. Relatively strong disturbances will pass through the
flow aloft both today and tomorrow for isolated to widely
scattered LAL 2 thunderstorms west of the Laramie Range.
Additionally, minimum humidities will drop day by day, with
increasing winds west of the Laramie Range each day this week.
Winds increase to the east of the Laramie Range by Thursday as a
front transitions eastwards under the influence of the ridge
aloft. A Red Flag Warning is in effect for FWZs 303, 304, and 306
today and a Watch remains for Wednesday.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning until 8 PM MDT this evening for WYZ303-304-306.

     Fire Weather Watch from Wednesday morning through Wednesday
     evening for WYZ303-304-306.

NE...None.
&&

SHORT TERM...AB
LONG TERM...RE
AVIATION...AW
FIRE WEATHER...AB

Hazardous Weather Outlook
National Weather Service Cheyenne WY
440 AM MDT Tue Aug 4 2020

WYZ104-109>114-051045-
Ferris/Seminoe/Shirley Mountains-Central Carbon County-
North Snowy Range Foothills-Southwest Carbon County-
Sierra Madre Range-Upper North Platte River Basin-Snowy Range-
440 AM MDT Tue Aug 4 2020

This hazardous weather outlook is for portions of south central
Wyoming.

.DAY ONE...TODAY AND TONIGHT

Isolated to widely scattered afternoon and early evening
thunderstorms will develop. Storms may produce strong, gusty
winds and dry lightning.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Decreasing thunderstorm potential day by day as the area dries out
under the influence of a ridge. Fire weather conditions will be
the concern.

.Spotter information statement...

Spotter activation will not be required.

NEZ002-003-019>021-054-055-095-096-WYZ101>103-105>108-115>119-
051045-
Dawes-Box Butte-Scotts Bluff County-Banner County-Morrill-
Kimball County-Cheyenne-North Sioux-South Sioux-
Converse County Lower Elevations-Niobrara County-
North Laramie Range-Shirley Basin-
Central Laramie Range and Southwest Platte County-
East Platte County-Goshen County-Laramie Valley-
South Laramie Range-South Laramie Range Foothills-
Central Laramie County-East Laramie County-
440 AM MDT Tue Aug 4 2020

This hazardous weather outlook is for portions of panhandle
Nebraska...western Nebraska...east central Wyoming...south
central Wyoming and southeast Wyoming.

.DAY ONE...TODAY AND TONIGHT

Widely scattered thunderstorms will develop over the Laramie
Range around noon and move eastward into the High Plains by
mid-afternoon, reaching the western Nebraska Panhandle by late
afternoon. Severe storms capable of producing large hail and
strong gusty winds are possible.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Scattered afternoon and evening thunderstorms will develop
through Thursday, becoming more isolated and confined to the
mountains Friday and Saturday. Strong to severe thunderstorms
producing large hail and strong gusty winds will be possible
along and east of the Interstate 25 corridor Wednesday; an
isolated tornado cannot be ruled out.

.Spotter information statement...

Spotter activation may be needed this afternoon and Wednesday
afternoon along and east of the I-25 corridor.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>