Alert archive / Iowa / Special Weather Statements in 2018

Special Weather Statement, NWS La Crosse, WI

May 2, 20184 counties in Iowa

NWS La Crosse, WI issued this special weather statement at May 2, 2018, 4:42 PM CDT for 4 counties in Iowa. It was in force for 63 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 2, 2018, 4:42 PM CDT (21:42 UTC)
Expired: May 2, 2018, 5:45 PM CDT
In force: 63 min
Issued by: NWS La Crosse, WI

Counties Chickasaw County, IA, Fayette County, IA, Howard County, IA, Winneshiek County, IA

The radar

The La Crosse radar (KARX), 113 km from the middle of the area, began a volume at 21:45 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

Davenport, (KDVN), launched 12:00Z, 9.7 hours before the alert went out and 225 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1837 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 151 m²/s²
0-3 km storm-relative helicity: 243 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

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

NWS La Crosse, WI wrote its last area forecast discussion before this special weather statement went out at May 2, 2:48 PM CDT, 1 hour 54 minutes earlier.

Area forecast discussion, May 2, 2:48 PM CDT, 1 hour 54 minutes before

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<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.
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        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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Hazardous weather outlook, May 2, 4:03 AM CDT, 12 hours 39 minutes before

Hazardous Weather Outlook
National Weather Service La Crosse WI
403 AM CDT Wed May 2 2018

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-031200-
Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette-
Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston-
Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe-Juneau-
Adams-Vernon-Crawford-Richland-Grant-
403 AM CDT Wed May 2 2018

This Hazardous Weather Outlook is for portions of southeast
Minnesota, northeast Iowa, and southwest into central Wisconsin.

.DAY ONE...Today and Tonight

Thunderstorms will be possible along and south of Interstate 90
from late this afternoon into the evening. A few of these storms
may produce isolated large hail across parts of northeast Iowa and
southwest Wisconsin.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Thunderstorms will be possible Thursday afternoon into Thursday
night, and again Saturday night. At this time, there is a small
risk of severe storms south of Interstate 90 on Thursday afternoon
and evening.

Water levels will continue to rise along the Mississippi River
through the weekend, with minor flooding expected in some areas.
Please visit water.weather.gov for the latest river forecast
information.

.SPOTTER INFORMATION STATEMENT...

Rainfall reports are appreciated.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

Boyne

In the hours before

Special weather statement, May 2, 4:42 PM CDT, 0 minutes before

Special Weather Statement
National Weather Service La Crosse WI
442 PM CDT WED MAY 2 2018

IAZ009-010-019-029-MNZ094-022245-
Winneshiek-Chickasaw-Howard-Fayette-Mower-
442 PM CDT WED MAY 2 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT HOWARD...FAYETTE...
WINNESHIEK...CHICKASAW AND SOUTHEASTERN MOWER COUNTIES...

At 439 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Le Roy to near Charles City to near
Allison. Movement was east at 60 mph.

Half inch hail is possible with these storms.

Locations impacted include...
Decorah, Oelwein, Cresco, New Hampton, West Union, Nashua, Fayette,
Fairbank, Calmar, Fredericksburg, Le Roy, Ossian, Riceville, Elgin,
Clermont, Elma, Maynard, Lime Springs, Hawkeye and Lawler.

Torrential rainfall is also occurring with these storms, and may
cause localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4264 9208 4291 9208 4291 9255 4350 9255
      4350 9271 4355 9270 4356 9245 4350 9244
      4350 9161 4264 9161
TIME...MOT...LOC 2139Z 271DEG 43KT 4347 9256 4305 9257 4269 9278

JAM

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 1, 7:21 PM CDT	Special Weather Statement	ARX	Crawford, Grant, La Crosse, Vernon	54 min
May 2, 9:32 AM CDT	River Flood Warning	ARX	Vernon	5 days
May 2, 11:12 AM CDT	River Flood Warning	ARX	Richland, Vernon	4 days
May 2, 5:31 PM CDT	Special Weather Statement	ARX	Crawford, Grant, Richland	74 min
May 1, 8:38 PM CDT	Special Weather Statement	ARX	Clayton	37 min

Nearby

Special Weather Statements in Iowa, 2018 Every special weather statement 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.