Alert archive / Iowa / Winter Storm Watches in 2018

Winter Storm Watch 3, NWS Sioux Falls, SD

February 22, 20188 counties in South Dakota; 11 counties in Iowa; 8 counties in Minnesota

NWS Sioux Falls, SD issued this winter storm watch at Feb 22, 2018, 3:56 PM CST for 8 counties in South Dakota; 11 counties in Iowa; 8 counties in Minnesota. It took effect at Feb 24, 2018, 6:00 AM CST. It was in force for .

The area

The counties it named.

The facts

Issued
Feb 22, 2018, 3:56 PM CST (21:56 UTC)
In effect from
Feb 24, 2018, 6:00 AM CST
Expired
Feb 23, 2018, 3:00 PM CST
In force
Issued by
NWS Sioux Falls, SD
All 27 counties

Buena Vista County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Ida County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Cottonwood County, MN, Jackson County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Bon Homme County, SD, Clay County, SD, Lincoln County, SD, Minnehaha County, SD, Moody County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 56 km from the middle of the area, began a volume at 21:58 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 9.9 hours before the alert went out and 262 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2018-02-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2018-02-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 204 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1937 m above ground
0-6 km bulk shear
74 kt
0-1 km storm-relative helicity
204 m²/s²
0-3 km storm-relative helicity
131 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this winter storm watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Sioux Falls, SD wrote its last area forecast discussion before this winter storm watch went out at Feb 22, 3:25 PM CST, 31 minutes earlier.

Area forecast discussion, Feb 22, 3:25 PM CST, 31 minutes before
<!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>
Hazardous weather outlook, Feb 22, 4:38 AM CST, 11 hours 18 minutes before
Hazardous Weather Outlook
National Weather Service Sioux Falls SD
438 AM CST Thu Feb 22 2018

IAZ002-003-012>014-020>022-031-032-MNZ090-NEZ013-014-SDZ070-071-
231045-
Osceola-Dickinson-Sioux-O'Brien-Clay IA-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Jackson-Dixon-Dakota-Clay SD-Union-
438 AM CST Thu Feb 22 2018

This Hazardous Weather Outlook is for portions of northwest Iowa,
west central Iowa, southwest Minnesota, northeast Nebraska, and
southeast South Dakota.

.DAY ONE...Today and Tonight

A wintry mix of freezing drizzle, freezing rain and snow will be
found across the area today and tonight. There may even be a bit
of sleet late this afternoon and early evening. Most of the
accumulating snow is expected Thursday evening. Before hand on
Thursday, light freezing precipitation will periodically accompany
areas of light snow. Total ice accumulations are expected to
remain below a tenth of an inch. Snow accumulations will average
generally one and a half to two and a half inches. A winter
weather advisory is in effect.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

There is another chance for snow on Saturday. Details with the
storm track could certainly change, but at this time, moderate
snow accumulations are possible. This forecast will be updated in
the future to pin down snow amounts.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

IAZ001-MNZ080-081-089-098-SDZ062-066-067-231045-
Lyon IA-Murray-Cottonwood-Nobles-Rock-Minnehaha-Turner-Lincoln SD-
438 AM CST Thu Feb 22 2018

This Hazardous Weather Outlook is for portions of northwest Iowa,
southwest Minnesota, and southeast South Dakota.

.DAY ONE...Today and Tonight

Snow is expected to occur today and tonight. Areas of light snow
today may be accompanied by light freezing drizzle. Accumulating
snow will occur from west to east from mid afternoon through the
evening hours. Total ice accumulations will be minor, generally a
few hundredths of an inch or less. Snow accumulations are expected
to be near 2 to around 3 inches. A winter weather advisory is in
effect.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

There is another chance for snow on Saturday. Details with the
storm track could certainly change, but at this time, moderate
snow accumulations are possible. This forecast will be updated in
the future to pin down snow amounts.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

MNZ071-072-097-SDZ038>040-050-052>061-063>065-068-069-231045-
Lincoln MN-Lyon MN-Pipestone-Beadle-Kingsbury-Brookings-Gregory-
Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-
McCook-Charles Mix-Douglas-Hutchinson-Bon Homme-Yankton-
438 AM CST Thu Feb 22 2018

This Hazardous Weather Outlook is for portions of southwest
Minnesota, central South Dakota, east central South Dakota, south
central South Dakota, and southeast South Dakota.

.DAY ONE...Today and Tonight

Snow will occur today and this evening. Most of the snow
accumulation will occur this afternoon and evening. Three to four
inches of snow is expected. However closer to the Nebraska border,
snow amounts may stay closer to two inches but combined with a
threat for some light freezing drizzle today. A winter weather
advisory is in effect.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

There is another chance for snow on Saturday. Details with the
storm track could certainly change, but at this time, moderate
snow accumulations are possible, especially from southeast South
Dakota to southwest Minnesota. East central South Dakota may see
lighter amounts. This forecast will be updated in the future to
pin down snow amounts.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

Nearby

Winter Storm Watches in Iowa, 2018Winter Storm Watches in South Dakota, 2018Winter Storm Watches in Minnesota, 2018Every winter storm watch in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.