Alert archive / North Carolina / Mesoscale Discussions in 2017
Mesoscale Discussion 929
The Storm Prediction Center issued this mesoscale discussion at May 31, 2017, 2:33 PM EDT for 23 counties in North Carolina. It was in force for 117 min.
The area
The outline as issued.
The facts
- Issued
- May 31, 2017, 2:33 PM EDT (18:33 UTC)
- Expired
- May 31, 2017, 4:30 PM EDT
- In force
- 117 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 23 counties
Bertie County, NC, Cumberland County, NC, Duplin County, NC, Edgecombe County, NC, Franklin County, NC, Greene County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Johnston County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Moore County, NC, Nash County, NC, Pitt County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC, Wake County, NC, Wayne County, NC, Wilson County, NC
The radar
The Raleigh/Durham radar (KRAX), 40 km from the middle of the area, began a volume at 18:34 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
Newport, NC (KMHX), launched 12:00Z, 6.6 hours before the alert went out and 137 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.
- Mixed-layer CAPE
- 629 J/kg
- Mixed-layer CIN
- -77 J/kg
- Mixed-layer LCL
- 1151 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 30 m²/s²
- 0-3 km storm-relative helicity
- 17 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.7
The text
As transmitted.
922
ACUS11 KWNS 311833
SWOMCD
SPC MCD 311833
NCZ000-SCZ000-312030-
Mesoscale Discussion 0929
NWS Storm Prediction Center Norman OK
0133 PM CDT Wed May 31 2017
Areas affected...Central and Eastern NC
Concerning...Severe potential...Watch unlikely
Valid 311833Z - 312030Z
Probability of Watch Issuance...20 percent
SUMMARY...Isolated damaging wind gusts and/or hail are possible over
the next several hours across portions of central and eastern NC.
DISCUSSION...Recent radar imagery showed quick storm development
across central NC over the past hour. Impetus for this development
is likely a fast-moving, low-amplitude shortwave trough embedded
within the enhanced cyclonic flow extending from the TN valley into
the mid-Atlantic. Daytime heating amidst ample low-level moisture
has contributed to modest instability over the region, with recent
mesoanalysis estimating MLCAPE near 1000 J/kg. The stronger
mid-level flow is displaced north of region across the Northeast but
enough mid-level flow (i.e. around 40 kt at 500) and shear (i.e.
effective shear around 40-45 kt) still exists to support rotating
updrafts and modest storm organization. As a result, some hail
and/or damaging wind gusts are possible with the stronger storms.
Limited severe coverage is currently expected to preclude watch
issuance but convective trends across the region will be monitored
closely.
..Mosier/Hart.. 05/31/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...MHX...RAH...ILM...
LAT...LON 36057662 35297713 34877776 34577914 34767964 35177983
35767918 36357795 36437691 36057662Nearby
Mesoscale Discussions in North 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.