Alert archive / North Carolina / Mesoscale Discussions in 2021
Mesoscale Discussion 1395
The Storm Prediction Center issued this mesoscale discussion at Jul 30, 2021, 2:46 PM EDT for 19 counties in North Carolina. It was in force for 119 min.
The area
The outline as issued.
The facts
- Issued
- Jul 30, 2021, 2:46 PM EDT (18:46 UTC)
- Expired
- Jul 30, 2021, 4:45 PM EDT
- In force
- 119 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Beaufort County, NC, Bertie County, NC, Camden County, NC, Chowan County, NC, Craven County, NC, Currituck County, NC, Edgecombe County, NC, Greene County, NC, Johnston County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Pasquotank County, NC, Perquimans County, NC, Pitt County, NC, Tyrrell County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC
The radar
The Raleigh/Durham radar (KRAX), 98 km from the middle of the area, began a volume at 18:47 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, 6.8 hours before the alert went out and 113 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
- 2048 J/kg
- Mixed-layer CIN
- -42 J/kg
- Mixed-layer LCL
- 793 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- 159 m²/s²
- 0-3 km storm-relative helicity
- 154 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
353
ACUS11 KWNS 301847
SWOMCD
SPC MCD 301846
NCZ000-302045-
Mesoscale Discussion 1395
NWS Storm Prediction Center Norman OK
0146 PM CDT Fri Jul 30 2021
Areas affected...Parts of eastern North Carolina
Concerning...Severe potential...Watch unlikely
Valid 301846Z - 302045Z
Probability of Watch Issuance...5 percent
SUMMARY...A few strong thunderstorms are likely to continue to
develop through late afternoon. An organizing small cluster or two
of storms is possible, posing at least some risk for locally strong
downbursts and damaging surface gusts.
DISCUSSION...Thunderstorms have recently initiated to the south of
Rocky Mount, along weakly confluent flow within pre-frontal surface
troughing. This appears to coincide with the leading edge of weak
cooling and moistening around 850 mb, in the presence of at least
modest deep-layer shear beneath 30-35+ kt northwesterly flow around
500 mb.
Aided by inflow of very moist boundary-layer air with surface dew
points in the mid/upper 70s, and characterized by sizable CAPE in
excess of 2000 J/kg, vigorous convective development may persist
this afternoon, largely supported by lift along convectively
generated cold pools. Given the the favorable shear, a supercell
structure or two is possible, and at least some upscale convective
growth might not be out of the question.
Warm mid-level temperatures seem likely to limit the potential for
large hail, and low-level shear appears generally weak. However,
with further insolation and steepening of low-level lapse rates, the
environment should become conducive to a few downbursts aided by
heavy precipitation loading.
..Kerr/Grams.. 07/30/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...MHX...RAH...
LAT...LON 35977797 36187687 36447590 35697566 35037719 34977816
35347851 35757845 35977797Nearby
Mesoscale Discussions in North 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.