Interesting discussion by The NWS office out of Jackson.
The forecast and messaging for impacts related to a powerful
trough moving into the Mississippi Valley region Tuesday are
holding steady with severe weather timing mostly locked in for the
afternoon to early evening hours. With that said, instability
continues to be a question mark, and it is something we will
likely not have a good handle on right up until the onset of the
event in our area. Past historical analogs (e.g., SLU CIPS) with
less dynamics/shear have produced more significant severe weather
than we expect with tomorrow`s event, but those events had
considerably more boundary layer moisture and instability to work
with. This will be a fast-evolving scenario and we`ll be
monitoring the guidance/obs as we get closer, so stay tuned for
any adjustments.
In any case, we still expect very strong winds aloft to be
juxtaposed with whatever surface warm sector develops, and this
will support organized storms ahead of a strong cold front, and
perhaps the possibility of a few discrete supercells ahead of the
more organized convective system over the central LA to southwest/
central MS area. The extreme shear and synoptic pattern remain
highly favorable for severe weather, so there should at least be
low-end wind damage even if updraft intensity is not impressive.
It will just be a question about how significant the severe
weather and tornado threat will be. Aside from the severe
weather, the strong pressure falls and tightening pressure
gradient will result in strong surface gradient winds, and a wind
advisory will remain in effect.
