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Severe WX February 8th - 12th deep south severe threat.

Usually with bombing out low pressure systems that southeast quadrant promotes height falls and better instability, so a triple whammy with moisture starting to pull in from the elongated broad pressure midnight the night before, peak daytime heating arrival and a favorable spot for synoptically enhancing lift and instability.

This in all rights is a similar BUT weaker system than the coastal one before. But this one will make it further inland to about possible the Tennessee state line in terms of quality moisture.
 
A similar event that I can think of in recent memory which is similar to the placement of the surface low and 500mb trough in terms of a correlation to positioning, (not that this will be like those events) is the Mayfield event and Midwest 2013 tornado event. With the impact area on the nose of the 500mb stream.

Just me rambling, doubt this will be anything like those events. But I am starting to get a wee bit worried on potential for some nasty storms across Mississippi
 
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Not really sure how clear the 00z GFS Can make it, semi isolated linear supercells lol.

GFS now forecasting mid to upper 60 dewpoints into portions of south central and central Alabama /missippi.
Mainly the western half of alabama.
Screenshot_2023-02-04-22-13-39-95_40deb401b9ffe8e1df2f1cc5ba480b12.jpgScreenshot_2023-02-04-22-12-42-37_40deb401b9ffe8e1df2f1cc5ba480b12.jpg
 
By the looks of the 12z guidance today and the CIPS analog match of March 9th, 2006 this could be a strongly forced line with a robust damaging wind threat and an isolated tornado risk.

The 00z GFS run shows there are still problems with run to run consistency. Hopefully, after the energy moves onshore tomorrow we can see improved consistency by tomorrow night’s runs.
 
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06z nam is considerably slower with the system. About 24 hours.

This could either ..

A: give it more time to build up moisture if the shortwave is slow enough to come through around midday the following day.

B. Be a sloppy mess with extremely low instability and a line run by dynamics.
 
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12z nam sped back up, better parameter space than the globals somebody in missippi will have a decent chance for bad weather. but still inconstancy in ejecting and weather it starts rapidly dropping pressure or where.
 
Instability is not a question at this point, it seems or at least with the 12z nam. Just evolution of the surface low, which will correlate with better shear which models have been showing. But it did not with the last two nam runs.

Will note that it. Seems the 12z nam keeps the trough positively tilted.Screenshot_2023-02-05-08-47-15-23_40deb401b9ffe8e1df2f1cc5ba480b12.jpg
 
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Just a hot take here , but I think they're could be a semi robust tornado/severe event in missippi if things come together. Wouldn't surprise me to see upper 60s dewpoints into north central missippi. I really wish the ejection and progression of the low would solidify, but, you could probably have excess of 2000j of sbcape into central missippi if things go as planned. The 18z and 00z name runs later today will really help if it gets on board more with the globals progression and ejection with the current thermodynamics of the mesoscale models. A semi robust event will take place. Especially due in part to some of the isolated convection that models indicate initiating near the Arkansas/ Louisiana/ Mississippi State line.

Some things are bound to change and I'm probably not seeing the big picture well. But definitely something I'm keeping a eye on. The inconstancy has really hindered SPC from issuing a outlook the past couple of days.

Random sounding from central Mississippi 2023020512_NAM_078_32.36,-90.13_severe_ml.png
 
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CheeselandSkies said:
NAM is definitely much more aggressive than the GFS with instability up to about the I-22 corridor, perhaps it has less cloud cover over the warm sector?
Click to expand...
The nams warm sector and some of the globals synoptics keep me toying with the thought of a low end severe/tornado regional outbreak over mississippi.. I'll keep quiet on that possibility until more runs.
 
JBishopwx said:
Click to expand...

Good link, that's why I've been toying with the idea in my head of a low end regional outbreak, too early to say it or forecast it, but Wednesday definitely has my eyes. This event should have had a risk outline on day 5. But model inconsistency with instability (mainly) and low pressure evolution have kept the guys at SPC holding it in there bag. Good decision on there part really.
 
One thing I like to state is that you don't need a whole lot of SRH helicity to have tornado producing supercells more so a factor I like to think of is the stream wise vorticity. low shear but critical angles of around 70+ with isolated convection heck thats pretty darn good.
 
RadarSPC.jpg

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
MISSISSIPPI VALLEY AND TENNESSEE VALLEY...

CORRECTED FOR TYPO

...SUMMARY...
At least isolated severe thunderstorms are expected Wednesday and
Wednesday night across the Lower Mississippi Valley and Tennessee
Valley.

...ArkLaTex to Tennessee Valley including LA/AR/MS/AL/TN...
Severe-weather potential is expected to increase into Wednesday
across the region. This will be as a shortwave trough/polar jet
spread northeastward from the south-central Plains/Ozarks toward the
Midwest and interface with an increasingly moist air mass across the
Lower Mississippi Valley/Tennessee Valley.

However, numerical guidance timing/spatial variability and the
likelihood of early day convection, as well as modest overall
destabilization, cast uncertainty regarding the potential and
placement of somewhat higher severe probabilities (such as a Slight
Risk) at this time. Recent NAM runs continue to be much more
east-northeastward progressive as compared to recent ECMWF/GFS
guidance.

Early day cloud cover and scattered thunderstorms will likely be
semi-persistent factors ahead of the cold front on Wednesday,
although most global guidance has trended slightly more unstable
with respect to the warm/moist sector over the prior 24-36 hr of
guidance runs. Regardless, currently thinking is the warm sector
will at least modestly destabilize Wednesday across portions of
Louisiana into Arkansas/Mississippi. At least an isolated
severe-weather potential should increase accordingly, including
damaging wind/tornado risks. This severe potential should reach
portions of Alabama/Tennessee Wednesday night.

An upgrade to a categorical Slight Risk could be warranted for
portions of the region into the Day 2 time frame as forecast details
become clearer.

...Lower Ohio Valley/Midwest...
Steady northeastward ejection of the shortwave trough and related
deepening phase of the northeastward-advancing surface cyclone from
the Ozarks to the Midwest could influence a strongly forced
low-topped convective line across the region Wednesday night, even
in the presence of minimal instability with northward extent. Given
a pronounced strengthening of deep-layer winds, along with
steepening lapse rates atop residual but eroding boundary layer
stability, at least low wind-related severe probabilities may be
warranted in future outlooks, even with thermodynamic
uncertainties/potential limitations.
Click to expand...
 
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