SPC Sep 27, 2024 2000 UTC Day 1 Convective Outlook
[html]SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0247 PM CDT Fri Sep 27 2024
Valid 272000Z - 281200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
CENTRAL AND SOUTHERN VIRGINIA INTO FAR EASTERN NORTH CAROLINA...
CORRECTED FOR GEN THUNDER LINE/NDFD GRAPHIC
...SUMMARY...
A couple of tornadoes remain possible this afternoon across parts of
North Carolina into Virginia.
...20Z Update...
Tornado probabilities have been trimmed to areas preceding the
primary convective rainband associated with the remnants of Helene.
Tornado probabilities were also adjusted over southwestern VA to
account for intensifying convection closer to the center of Helene,
where insolation has destabilized the low-level airmass amid strong
low-level shear. In both of the aforementioned regimes, at least a
couple of tornadoes remain possible with the stronger storms until
they either outpace available buoyancy, or nocturnal cooling
supports boundary-layer stabilization. Please see MCD 2126 for more
short-term details of the ongoing tornado threat.
..Squitieri.. 09/27/2024
.PREV DISCUSSION... /ISSUED 1112 AM CDT Fri Sep 27 2024/
...Synopsis...
The center of Helene is tracking quickly northward across the
mountains over western NC/east TN, with a band of strong convection
to the east of the low extending from southern VA into eastern NC.
Local VAD profiles, surface observations, and model guidance
indicate a continuing very favorable environment for transient
rotating updrafts along this line and the risk of a few tornadoes.
Guidance suggests that low-level wind shear will slowly weaken this
afternoon throughout the northeastern quadrant of the system, with
the line of convection lifting northeastward into a progressively
less moist air mass. Little diurnal heating is expected ahead of
the line, limiting destabilization. These trends would suggest the
overall risk of tornadoes will also slowly weaken by evening.
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Source: SPC Sep 27, 2024 2000 UTC Day 1 Convective Outlook (http://ht**://www.spc.noaa.gov/products/outlook/day1otlk_2000.html)