Alert archive / North Carolina / Mesoscale Discussions in 2021
Mesoscale Discussion 1780
The Storm Prediction Center issued this mesoscale discussion at Sep 22, 2021, 9:04 PM EDT for 9 counties in North Carolina; Marlboro County, South Carolina. It was in force for 56 min.
The area
The outline as issued.
The facts
- Issued
- Sep 22, 2021, 9:04 PM EDT (01:04 UTC)
- Expired
- Sep 22, 2021, 10:00 PM EDT
- In force
- 56 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Anson County, NC, Cumberland County, NC, Harnett County, NC, Hoke County, NC, Lee County, NC, Montgomery County, NC, Moore County, NC, Richmond County, NC, Scotland County, NC, Marlboro County, SC
The radar
The Raleigh/Durham radar (KRAX), 123 km from the middle of the area, began a volume at 01:03 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
Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 1.1 hours before the alert went out and 126 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
- 30 J/kg
- Mixed-layer CIN
- -124 J/kg
- Mixed-layer LCL
- 547 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 2 m²/s²
- 0-3 km storm-relative helicity
- 81 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.4
The text
As transmitted.
183
ACUS11 KWNS 230105
SWOMCD
SPC MCD 230104
NCZ000-SCZ000-230200-
Mesoscale Discussion 1780
NWS Storm Prediction Center Norman OK
0804 PM CDT Wed Sep 22 2021
Areas affected...South-central North Carolina
Concerning...Severe potential...Watch unlikely
Valid 230104Z - 230200Z
Probability of Watch Issuance...5 percent
SUMMARY...Sporadic strong to severe winds are possible with an
organizing line of storms. However, this threat should remain
limited spatially and temporally. A watch is not anticipated.
DISCUSSION...Latest reflectivity and velocity data from KRAX show a
line of storms across south-central NC beginning to show some signs
of organization, including a broad book-end vortex developing on the
northern end of the line. This hint at intensification is
corroborated by a recent uptick in lightning activity and cooling
cloud tops in GOES IR imagery. Although deep-layer shear is modest
(at around 20-30 knots), it is aligned roughly orthogonal to the
developing line, which will aid in organization. Decaying convection
downstream across central NC produced a 60 mph wind report at KSCR
within the past hour, so despite diurnal cooling, the thermodynamic
environment appears supportive of strong to severe winds given a
sufficiently strong downdraft. As such, sporadic strong to severe
winds may accompany this line in the near term. The duration of this
threat is uncertain, but given steady stabilizing trends the
probability for a prolonged threat appears low.
..Moore/Grams.. 09/23/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...RAH...ILM...CAE...
LAT...LON 35108017 35367990 35657958 35577894 35297864 35017877
34697908 34457949 34387984 34428011 34768005 35108017Nearby
Mesoscale Discussions in North Carolina, 2021Mesoscale Discussions in South Carolina, 2021Every mesoscale discussion in 2021
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.