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Mesoscale Discussion 2116 |
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Mesoscale Discussion 2116
NWS Storm Prediction Center Norman OK
1252 PM CDT Thu Sep 26 2024
Areas affected...portions of eastern/southeastern Georgia
Concerning...Tornado Watch 684...685...
Valid 261752Z - 261845Z
The severe weather threat for Tornado Watch 684, 685 continues.
SUMMARY...Low-topped supercells have shown increased low-level
rotation over the last few hours across southeastern/eastern GA. The
air mass in place is not overly favorable for tornadoes in the short
term casting some uncertainty on the longevity of the tornado
threat. A greater tornado risk should develop later today as Helene
approaches.
DISCUSSION...As of 1745 UTC, regional radar imagery shows a broad
area of stratiform precipitation and embedded convective elements
ongoing near a stationary front across potions of southern/eastern
GA. North of the primary outer bands of TC Helene, substantial
precipitation has been ongoing over the past 24. Despite strong
low-level warm air advection, the precipitation has severely limited
diurnal destabilization this far inland. With Buoyancy less than 250
J/kg of MUCAPE on SPC mesoanalysis, most of the convection is very
low-topped and weak. Still, low-level hodographs have enlarged (and
will continue to do so) through the day. This is supporting some
tornado risk with the more robust cells in several weak bands.
Eventually, a higher-theta E air mass should move in as the core of
Helene approaches from the south later this afternoon/evening. This
could support more buoyancy and a greater tornado risk.
The primary uncertainty remains the limited buoyancy through the
next several hours north of and west of Tornado Watch #685 and #684
respectively. A local extension of the active watches could be
required to cover the more uncertain short-term tornado risk.
However, the approach of Helene will eventually support a
longer-fused tornado threat as low-level wind fields and buoyancy
increase substantially. For now, the risk of tornadoes appears
lower, though trends will continue to be monitored.
..Lyons/Mosier.. 09/26/2024
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CHS...CAE...JAX...FFC...TAE...
LAT...LON 31638231 31748395 31968427 32928364 33298289 33408240
33218227 32108210 31928211 31638231
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