Alert archive / New Hampshire / Mesoscale Discussions in 2018

Mesoscale Discussion 357

May 4, 2018Cumberland County, Oxford County, York County, Maine; 5 counties in New Hampshire

The Storm Prediction Center issued this mesoscale discussion at May 4, 2018, 7:54 PM EDT for Cumberland County, Oxford County, York County, Maine; 5 counties in New Hampshire. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: May 4, 2018, 7:54 PM EDT (23:54 UTC)
Expired: May 4, 2018, 10:30 PM EDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Cumberland County, ME, Oxford County, ME, York County, ME, Belknap County, NH, Carroll County, NH, Coos County, NH, Grafton County, NH, Strafford County, NH

The radar

The Portland,ME radar (KGYX), 81 km from the middle of the area, began a volume at 23:57 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

Gray, ME (KGYX), launched 12:00Z, 11.9 hours before the alert went out and 80 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: 898 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 21 m²/s²
0-3 km storm-relative helicity: 83 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

<!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>

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 4, 2:18 PM EDT	Mesoscale Discussion	SPC	Belknap, Carroll, Cheshire, Coos, Grafton, Merrimack and 1 more	87 min
May 4, 5:52 PM EDT	Mesoscale Discussion	SPC	Cheshire, Hillsborough	83 min
May 4, 6:20 PM EDT	Severe Thunderstorm Watch	SPC	Belknap, Cheshire, Coos, Grafton, Hillsborough, Merrimack and 1 more	4 hr
May 4, 6:48 PM EDT	Mesoscale Discussion	SPC	Coos, Grafton	117 min

Nearby

Mesoscale Discussions in New Hampshire, 2018 Mesoscale Discussions in Maine, 2018 Every mesoscale discussion 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.