SPC MD 500

SPC MD 500


Mesoscale Discussion 0500
NWS Storm Prediction Center Norman OK
0145 PM CDT Sat Apr 20 2024

Areas affected…Northern South Carolina into southern North

Concerning…Severe potential…Watch unlikely

Valid 201845Z – 202045Z

Probability of Watch Issuance…20 percent

SUMMARY…Thunderstorm development is anticipated within the next
hour. A few strong/severe cells, including the potential for a
supercell or two, will pose a severe hail/wind threat to parts of
the Carolinas this afternoon and evening. This threat should remain
fairly localized; watch issuance is not anticipated.

DISCUSSION…Steady growth of multiple cumulus congestus has been
noted in GOES imagery over the past 30-60 minutes along a cold front
and in the vicinity of a weak surface low across parts of the
Carolinas. Glaciation is noted in a few of the deeper towers,
suggesting that thunderstorm initiation is probable within the next
hour or so. Discrete to semi-discrete cells that emerge from within
the growing cumulus field will likely propagate off the slow-moving
cold front into an increasingly buoyant air mass downstream into the
eastern Carolinas (where MLCAPE is increasing to around 1500 J/kg).
Within the past hour regional VWPs sampled weak winds through the
lowest few kilometers, but a nearly uni-directional wind profile
with 40-50 knot flow between 5-6 km. This is yielding 0-6 km BWD
values on the order of 30-40 knots with a wind profile favorable for
splitting cells. Consequently, this environment appears supportive
of supercells with an attendant large hail (0.75 to 1.25 inch in
diameter) and severe wind risk. The hail risk might be regionally
maximized across parts of NC to the north of a differential heating
boundary where muted diurnal mixing is supporting higher buoyancy.
Conversely, areas to the south of this boundary may see a higher
damaging wind threat given steeper low-level lapse rates.
Regardless, it remains unclear how many cells will emerge from the
cumulus field and evolve into mature supercells given the weak
forcing for ascent. Latest CAM guidance also suggests storm coverage
may be limited, which lends credence to the idea that the overall
severe threat should remain sufficiently localized to preclude the
need for a watch.

..Moore/Goss.. 04/20/2024

…Please see www.spc.noaa.gov for graphic product…


LAT…LON 33607884 33637921 34248114 34508152 34848145 35258111
35438081 35598018 35497859 35367780 35217705 34747706
34457730 34257759 33957784 33837798 33797836 33677863

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