Hail and Damaging Winds in Montana, July 8, 2019

Area Forecast Discussion
National Weather Service Billings MT
127 PM MDT Mon Jul 8 2019

.SHORT TERM...valid for Tue and Wed...

Potential exists for severe thunderstorms and flash flooding this
evening. BE PREPARED!

Convection already developing over the Beartooth Absarokas at 1140
am. Latest mesoanalysis shows capping across our lower elevations,
but since this morning's activity we've had a few hours of sun
which is helping to destabilize our air mass. We are already
seeing temps in the 70s, with dew points mainly in the 50s, except
low 60s in our far east. Recent HRRR runs show convection
initiating in our southwest at 19-20z, but this is too late given
what we are seeing now. Water vapor imagery shows a seasonally
strong shortwave lifting thru the great basin, and this will
provide plenty of large scale ascent for today's convection.

Ingredients are all coming together for a risk of both severe
storms (mainly hail/wind) and flash flooding (pwats over an inch)
this afternoon and evening. CAMs show a couple rounds of storms
moving thru, and this seems reasonable given the ascent. Moisture
will be greatest east of Yellowstone County, an area that has seen
significant rainfall over the past several days. Storms will be
moving, but any heavy rain (or multiple rounds of heavy rain) on
top of saturated soil could produce flash flooding. The potential
for severe weather will last til around midnight in our far east.
For Billings, 3-9 pm seems to be the prime time.

Cooler air will surge in tonight behind a cold front, and the
upper trof axis will finally shift east early tomorrow. We will
see hints of a trowal as the low deepens to our northeast, and
looks like a good chance of showers even in the morning on
Tuesday. Low will pull away later in the day but with enough
diurnal instability under the NW flow aloft to keep scattered
showers going thru the afternoon and early evening. Freezing
levels will be quite a bit lower under the upper trof, the GFS
shows wet bulb zero heights around 7kft agl, so expect small hail
with any modest thunderstorm that develops.

Tuesday high temps will be only in the low-mid 70s. After a
relatively chilly night, upper level ridge will build in for drier
and warmer conditions on Wednesday. We should see highs get
closer to normal and in the 80s.

JKL

.LONG TERM...valid for Thu...Fri...Sat...Sun...Mon...

Upper ridge over the area on Thursday gets flattened with a
shortwave moving through the region. Some late day showers and
thunderstorms are possible over western areas. Ridging builds back
over the region Friday and through much of the weekend, with moisture
and energy advecting into the area, undercutting the ridge.
Showers and thunderstorms look possible most afternoons/evenings
in this monsoonal pattern. High temperatures look to range from
the middle to upper 80s most days, with low temperatures mainly in
the 50s. STP

&&

.AVIATION...

Thunderstorms will move off the higher terrain this afternoon and
push off onto the plains and move east into this evening. Some
thunderstorms will be strong to severe with large hail, damaging
winds and heavy rainfall. The best locations for severe storms,
especially with flash flooding will be east of a KBIL-KSHR line.
MVFR/IFR conditions will be likely with any thunderstorm.
Otherwise, VFR conditions will prevail. The mountains will be
obscured at times into the evening. STP

&&

.PRELIMINARY POINT TEMP/POPS...

    Tue     Wed     Thu     Fri     Sat     Sun     Mon
-----------------------------------------------------------
BIL 056/073 054/085 062/087 061/085 062/089 063/091 063/088
    96/T    20/B    02/T    21/U    11/B    21/U    11/U
LVM 049/074 047/084 055/086 055/085 055/087 057/088 057/086
    85/T    00/B    12/T    22/T    22/T    23/T    22/T
HDN 056/072 052/085 059/086 060/084 061/089 062/091 062/087
    96/T    20/B    01/U    11/B    11/B    20/U    11/U
MLS 058/070 051/081 059/087 060/084 061/088 063/090 062/087
    +8/T    30/U    00/U    11/U    21/U    21/U    11/U
4BQ 057/071 050/081 059/087 060/084 061/087 062/090 062/087
    +8/T    30/U    01/U    12/T    22/T    21/U    11/U
BHK 057/068 049/078 057/085 059/082 060/086 061/088 062/086
    +9/T    50/U    01/U    11/U    21/U    21/U    21/U
SHR 052/072 047/085 057/088 057/084 057/087 059/091 059/087
    96/T    20/U    02/T    24/T    33/T    31/U    22/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Severe Thunderstorm Watch 499 in effect until 9 PM MDT this
      evening FOR ZONES 29>39-41-42-56>58-63-66>68.
     Flash Flood Watch in effect through late tonight FOR ZONES
      30>33-36>38-57-58.
WY...Severe Thunderstorm Watch 499 in effect until 9 PM MDT this
      evening FOR ZONES 98-99.

&&

weather.gov/billings

<!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>