SPC Mar 4, 2024 2000 UTC Day 1 Convective Outlook

[NorthGeorgiaWX]

SPC 2000Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0159 PM CST Mon Mar 04 2024

Valid 042000Z - 051200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A LARGE
AREA FROM CENTRAL/EAST TEXAS INTO MOST OF THE MISSISSIPPI VALLEY...

...SUMMARY...
Isolated strong to severe thunderstorms will be possible this
afternoon into tonight from parts of central Texas into the lower
Mississippi Valley, as well as from the Ozarks into the Midwest.
Large hail is expected to be the main threat, but strong/gusty winds
and even a tornado may also occur.

...20Z Update...

...Eastern IA/Northern MO/Northern IL...
Recent surface analysis places a low just south of the IL/WI/MO
border intersection. A cold front extends southwestward from this
low across northern MO and eastern KS, while a warm front extends
eastward across northern IL and then arcs sharply northeastward over
southern Lake Michigan. A few elevated storms have been noted near
the surface low, with some deepening warm sector cumulus also
ongoing from central MO into northern/central IL. As mentioned in
MCD #0189, additional thunderstorm development is still expected
along and just ahead of cold front from far eastern IA into
northwest Illinois and northeast Missouri in the next 1-3 hours.
Front-parallel orientation to the deep-layer vertical shear will
likely lead to an undercutting of these storms, with a predominantly
elevated storm mode anticipated. Even so, steep lapse rates will
support some stronger updrafts capable of hail. Some damaging gusts
are possible as well, particularly as cells interact with the cold
front.

...East TX/LA/Western MS this afternoon and evening...
Scattered thunderstorms are currently ongoing from East TX across
much of LA, supported by southwesterly flow aloft and resultant
warm-air advection. General expectation is for these storms to
gradually shift northeastward into more of western MS over time, in
tandem with the zone of most favorable warm-air advection. Modest
vertical shear remains favorable for transient supercell structures
and the threat for hail and damaging gusts.

...Eastern OK into Mid MS Valley this evening and overnight...
Thunderstorm development along the front later this evening along
the from southern MO into eastern OK remains uncertain, given the
potential for warm mid-level temperatures and resulting capping.
Additionally, vertical shear will be modest, with a resultant
potential for the front to undercutting development. Even so, the
warm and moist low-levels combined with steep mid-level lapse rates
will support a conditional risk for severe hail.

..Mosier.. 03/04/2024

.PREV DISCUSSION... /ISSUED 1000 AM CST Mon Mar 04 2024/

...East TX/LA/Western MS Today...
Moderately strong southern-stream mid-level flow is present today
across the southern states, with several weak perturbations
affecting the area.  A warm and moist surface air mass is in place
across east TX into LA, where dewpoints in the upper 60s and 70s
will yield afternoon MLCAPE of 1500-2000 J/kg.  Weak low-level warm
advection is expected to result in increasing thunderstorm
development this morning through the afternoon as storms spread
eastward toward southwest MS.  Deep-layer shear is sufficient for at
least transient supercell structures, but relatively weak low-level
winds suggest the main threats will be hail and gusty winds with the
strongest cells.

...Eastern IA/Northern MO/Northern IL...
A strong surface cold front is sagging southeastward across IA this
morning into a marginally moist and unstable air mass.  All 12z
model guidance agrees on the development of showers and
thunderstorms along the front by early afternoon, although many
solutions suggest most of the activity will be behind the front and
slightly elevated.  Nevertheless, cool temperatures aloft and steep
mid-level lapse rates will promote hail in the stronger cores. 
Storms that can form and persist ahead of the front would have some
marginal concern for gusty winds and perhaps a brief tornado as
well.

...Eastern OK into Mid MS Valley...
Morning model guidance is quite diverse in the development of
thunderstorms across this region, with low confidence in any
particular area.  Will maintain the ongoing MRGL area as a
conditional risk if storms can form - mainly due to unseasonably
warm and moist conditions and sufficient CAPE for some risk of hail.
 However, considerably uncertainty exists.

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