Alert archive / North Carolina / Mesoscale Discussions in 2017

Mesoscale Discussion 1609

September 1, 201719 counties in North Carolina; 8 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Sep 1, 2017, 1:07 PM EDT for 19 counties in North Carolina; 8 counties in South Carolina. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Sep 1, 2017, 1:07 PM EDT (17:07 UTC)
Expired
Sep 1, 2017, 3:00 PM EDT
In force
113 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 27 counties

Alamance County, NC, Anson County, NC, Cabarrus County, NC, Catawba County, NC, Chatham County, NC, Cleveland County, NC, Davidson County, NC, Gaston County, NC, Iredell County, NC, Lee County, NC, Lincoln County, NC, Mecklenburg County, NC, Montgomery County, NC, Moore County, NC, Randolph County, NC, Richmond County, NC, Rowan County, NC, Stanly County, NC, Union County, NC, Cherokee County, SC, Chester County, SC, Chesterfield County, SC, Fairfield County, SC, Lancaster County, SC, Spartanburg County, SC, Union County, SC, York County, SC

The radar

The Greer radar (KGSP), 134 km from the middle of the area, began a volume at 17:08 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 5.1 hours before the alert went out and 133 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, Greensboro/Hi Pt, NC at 12:00Z on 2017-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 208 joules per kilogram.LCLLFCEL10008507005003002001001 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, Greensboro/Hi Pt, NC at 12:00Z on 2017-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 86 square meters per square second.19395878Sfc1 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
208 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
585 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
86 m²/s²
0-3 km storm-relative helicity
143 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 1, 1:49 PM EDTTornado WatchSPCAlexander, Anson, Bladen, Burke, Cabarrus, Caldwell and 27 more8 hr
Sep 1, 4:44 PM EDTMesoscale DiscussionSPCAlamance, Anson, Cabarrus, Chatham, Cumberland, Davidson and 22 more91 min
Sep 1, 7:23 PM EDTMesoscale DiscussionSPCAlexander, Anson, Bladen, Burke, Cabarrus, Caldwell and 25 more97 min
Sep 1, 3:06 PM EDTMesoscale DiscussionSPCAiken, Allendale, Bamberg, Barnwell, Beaufort, Berkeley and 18 more2 hr

Nearby

Mesoscale Discussions in North Carolina, 2017Mesoscale Discussions in South Carolina, 2017Every mesoscale discussion in 2017

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.