Source: US National Oceanic and Atmospheric Administration
SPC AC 051950
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0150 PM CST Wed Mar 05 2025
Valid 052000Z – 061200Z
…THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST
VIRGINIA AND THE EASTERN CAROLINAS…
…SUMMARY…
Severe thunderstorms capable of producing scattered damaging-wind
gusts and a few tornadoes are possible today across parts of the
eastern Carolinas into southeast Virginia. Other strong to severe
storms may occur from the Allegheny Plateau into the Mid Atlantic.
…20z Update…
The previous forecast remains on track with no substantial changes
required beyond clearing probabilities behind a broken squall line
currently traversing the Carolinas and Virginia. Damaging gusts
continue to be observed with portions of the line, and transient
embedded circulations have been noted within the line per KAKQ
velocity imagery. Within the past 30 minutes, GOES IR imagery shows
cooling cloud top temperatures across southern NC, indicative of a
gradual strengthening trend that is likely the result of peak
daytime heating within the narrow warm sector ahead of the line.
Recent forecast guidance has captured this trend well and suggests
that the intensifying convection across southern NC will spread
northeast into northeastern NC/southeast VA through early evening.
Given these trends, the Enhanced risk has been maintained, though
convection will likely begin moving off the Mid-Atlantic coast
between 23-01z. See MCD #152 for additional short-term details
regarding the severe threat across the Mid-Atlantic, and MCD #153
for forecast concerns regarding the upper OH River Valley.
..Moore.. 03/05/2025
.PREV DISCUSSION… /ISSUED 1028 AM CST Wed Mar 05 2025/
…VA and the Carolinas…
A strongly forced convective line continues to push eastward across
the central Carolinas and south-central VA. Thus far, updraft depth
has been limited by modest buoyancy, as evidenced by the lack of
lightning within the line. However, the downstream airmass is
expected to undergo modification as low 60s dewpoints advect
northward just ahead of the line. This increased moisture should
lead to greater buoyancy, and the potential for deeper, more
persistent updrafts within the line. As storms deepen, the very
strong low to deep-layer shear (i.e. 0-1 km bulk shear over 50 kt
and 0-6 km bulk shear over 70 kt) in place over the region will
support storm organization mainly in the form of bowing
structures/mesovortices. An attendant threat for tornadoes will
probably develop with the more persistent/long-lived embedded
circulations in addition to wind damage focused near inflections and
bowing segments of the convective line.
Additional details for this region can be found in recently issued
MCD #0149.
…Upper OH Valley/PA vicinity…
Recent surface analysis places a deep, occluded low (i.e. 980 mb)
over southern Lake Michigan. An occluded front extends
east-southeastward from this low to a triple point in the western WV
Panhandle/northern VA vicinity. A cold front also extends
south-southeastward from this low across western IN before arcing
more southerly across the TN Valley. Visible satellite indicates
that a mid-level dry-slot has contributed to some clearing over OH,
in the vicinity of the occluded front. This should allow for some
modest daytime heating, with the resultant steepening of the
low-level lapse rates. This will occur beneath cold mid-level
temperatures, contributing to fairly steep lapse rates profile
throughout much of the troposphere. Some low to mid-level moistening
is also possible as large-scale forcing for ascent attendant to the
approaching upper low persists, resulting in modest buoyancy (i.e.
MLCAPE less than 500 J/kg) across the region ahead of the cold
front. Thunderstorm development appears possible as the front
interacts with this airmass, and vertically veering wind profiles
with effective shear values near 40 kt will support the potential
isolated low-topped transient supercells and perhaps bowing linear
segments.
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