Special Weather Statement, NWS Riverton, WY

Area Forecast Discussion
National Weather Service Riverton WY
159 PM MDT Tue Aug 14 2018

.SHORT TERM...This afternoon through Wednesday
Issued at 1036 AM MDT Tue Aug 14 2018

This afternoon through evening will feature the most active
convective weather for the next few days. The flow will become
increasingly difluent ahead of the approaching trough. the trough
axis is progged to push through the area Wednesday morning. Our
zones north and east of the Divide today will have very
substantial cape to work with. The interstate 25 corridor, the Big
Horn Mountains, and the Big Horn Basin are under a marginal risk.
Small hail and locally heavy rainfall are a good bet in this area
for the remainder of today. A weak mid level circulation will
track east across Northern Wyoming which will enhance the
lift/wind directional shear as well. In fact, lifted indices are
progged to be down to minus 7 in Northern WY today. On Wednesday,
the northeast zones will still have the potential for convection
in the morning before the drier and more stable air moves in from
the west behind the trough as the trough axis pushes on through.
In Fact, as far as fire weather is concerned, the dry punch can
already easily be seen punching in from the west on the wv loop
nosing into Northwest Wyoming into YNP and the Absarokas as the
dry air wraps around the base of the trough. As this dry air moves
into the area, there is a good chance we could see critical fire
weather conditions for our southwest fire weather zones Wednesday.
For now,we have an SPS addressing the borderline fire weather
conditions expected for Southwest Wyoming for this afternoon. A
fire weather watch may be needed for our southwestern fire weather
zones for Wednesday, albeit winds will be marginal but RH values
could drop to 10 percent in these zones.

.LONG TERM...Wednesday night through Tuesday
Issued at 1036 AM MDT Tue Aug 14 2018

On Thursday, some moisture will return to the west and could bring
 a few showers and thunderstorms. With the lack of a trigger
though, coverage looks rather sparse so we kept the POPS in the
slight chance category and kept most of the activity across the
west and the adjacent foothills.

Medium range models are in decent agreement with A low-amplitude
trough over the Pacific Northwest/N. California at 12Z Friday.
This system is expected to push into the Intermountain West Friday
night, and then across the Northern Rockies Saturday/Saturday
night. The associated cold front is expected to push across the
area in the Saturday/Saturday night time frame. Synoptic forcing
from this system will begin to overspread the far west late
Friday, and then spread across the entire area Friday night and
Saturday. Chances of convection will be mainly over the west
Friday spreading east to include all of the area late Friday
night/Saturday morning. The best chances of convection will be
Saturday afternoon into Saturday night east of the Divide as the
cold front begins to slide across the area. Despite the main
forcing exiting the area Saturday night, decent chances of
precipitation will continue east of the Divide through Saturday
night into Sunday especially over the far east from a potential
combination of low-level northerly upslope, wrap around moisture
and/or a trailing shortwave. There could be enough cold air for
the northern mountains (Absaroka/Bighorn) to see rain changing to
snow above 10.5/11 KFT MSL Saturday night/Sunday.

For Monday and Tuesday there is quite a bit of spread between
models and their ensembles. They are showing a potential shortwave
in the northwest flow or a transitory ridge building into the
area, and how they handle a disturbance in the Pacific that could
impact the area Tuesday. For now will go for a warming trend with
a mainly dry forecast.

&&

.AVIATION...For the 00Z TAFS through 00Z Wednesday evening
Issued at 1036 AM MDT Tue Aug 14 2018

The west (KJAC, KRKS, KBPI, KPNA) will remain dry with possibly
some restrictions in visibility in FU from vcnty KJAC and north
through 12z Wednesday.

East of the Continental Divide, scattered thunderstorms are expected
to develop along and east of the Bighorn Range and south to vicinity
KCPR 20z today-02Z Wednesday. Isolated thunderstorms could be
strong to severe with large hail and wind gusts over 50kts.
Showers and storms will be more widely scattered further west,
vicinity KCOD and KWRL, but more isolated KRIW and KLND this
afternoon and early evening. Some lower MVFR ceilings may push
into KCPR after 06z Wednesday, but confidence is too low at this
time to go beyond SCT015.

&&

.FIRE WEATHER...
Issued AT 129 PM MDT Tue Aug 14 2018

...FIRE WEATHER WATCH FOR ZONE 277 WEDNESDAY FROM 1PM TO 8PM...

A weather system will continue across the area this afternoon.
Across many areas East of the Divide, isolated to widely scattered
showers and thunderstorms are possible into the evening, some could
be strong especially east of a Greybull to Riverton line with strong
wind gusts and hail. RH recoveries will be good east of the
Continental Divide and poor to the west. A Fire Weather Watch has
been issued for Fire Zone 277 for Wednesday afternoon, while near
critical fire weather is expected across the other areas southern
Wyoming due to very dry conditions but only moderately gusty
winds.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Wednesday afternoon through Wednesday
evening for WYZ277.

&&

SHORT TERM...Lipson
LONG TERM...Hulme
AVIATION...Lipson
FIRE WEATHER...Hulme

Hazardous Weather Outlook
National Weather Service Riverton WY
206 AM MDT Tue Aug 14 2018

WYZ001>020-022>030-151300-
Yellowstone National Park-Absaroka Mountains-Cody Foothills-
North Big Horn Basin-Southwest Big Horn Basin-
Southeast Big Horn Basin-Owl Creek and Bridger Mountains-
Bighorn Mountains West-Bighorn Mountains Southeast-
Northeast Johnson County-Southeast Johnson County-
Teton and Gros Ventre Mountains-Jackson Hole-
Wind River Mountains West-Wind River Mountains East-
Upper Wind River Basin-Wind River Basin-Lander Foothills-
Green Mountains and Rattlesnake Range-
Natrona County Lower Elevations-Casper Mountain-Star Valley-
Salt River and Wyoming Ranges-Upper Green River Basin Foothills-
Upper Green River Basin-South Lincoln County-
Rock Springs and Green River-Flaming Gorge-East Sweetwater County-
206 AM MDT Tue Aug 14 2018

This Hazardous Weather Outlook is for Western and Central Wyoming.

.DAY ONE...Today and Tonight

Isolated to widely scattered afternoon and evening thunderstorms,
mainly East of the Divide. Strong to severe thunderstorms are
possible mainly east of a Greybull to Riverton line.

Near critical fire weather this afternoon across southern and
portions of western Wyoming.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Wednesday...Critical fire weather possible in southern Wyoming.

Thursday through Sunday...Isolated to locally scattered
thunderstorms. The best chance of showers and thunderstorms will
occur east of the Continental Divide Saturday and Sunday.

.SPOTTER INFORMATION STATEMENT...

Spotters are urged to report wind gusts past 45 mph and hail.
Thank you.

<!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>

<!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>

<!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>

<!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>

<!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>

<!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>