ACUS01 KWNS 012019
SWODY1
SPC AC 012017

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0317 PM CDT Mon Apr 01 2024

Valid 012000Z - 021200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL
AND NORTHEASTERN OKLAHOMA...AND INTO FAR NORTH-CENTRAL TEXAS...

...SUMMARY...
Severe thunderstorms with very large hail (2-3 inch diameter or
greater), damaging gusts (60-80 mph) and a few tornadoes
(potentially up to EF2) are expected this afternoon into tonight
from north Texas and Oklahoma into the lower Ohio River Valley.

...Discussion...
Current forecast reasoning and outlook areas remains generally in
line with prior outlooks, with widespread/all-hazards severe risk
from the southern Plains into the Ohio Valley.

The main change in the current outlook update is a westward
adjustment of thunder/severe probability lines across the Big
Country and Concho Valley of Texas, where storms have initiated
along a developing dryline a bit earlier, and farther west, than
previously anticipated.

Otherwise, the outlook remains largely unchanged at this time, aside
from minor line tweaks to account for current convective
evolution/development.

..Goss.. 04/01/2024

.PREV DISCUSSION... /ISSUED 1128 AM CDT Mon Apr 01 2024/

...Synopsis...
Embedded speed maxima (90-100+ kt 500 mb) from southern NM/far west
TX to northwest Mexico will eject northeastward to OK this evening
and MO overnight. An associated lee cyclone will deepen this
afternoon across the TX South Plains and then progress into
northwest OK this evening and the mid MS Valley by the end of the
period. A broad/moist warm sector is in place from the southern
Plains to the mid MS/lower OH Valleys, beneath a warm elevated mixed
layer with 8-9 C/km midlevel lapse rates. The cap will weaken
through the afternoon from the west, with thunderstorm initiation
becoming likely by mid afternoon along a surface front from KS into
MO/IL, and mid-late afternoon along the dryline from western/central
OK into northwest TX.

...KS/MO/IL/IN through tonight...
Scattered thunderstorm development is likely starting mid afternoon
along the baroclinic zone from KS into MO, and storms will
subsequently spread eastward along the warm front from MO into
IL/IN. The environment will favor supercells capable of producing
very large hail (2-3 inches in diameter) and a few tornadoes, with
an isolated strong tornado possible. Storm mode will become messier
into the overnight hours with upscale growth into clusters/line
segments, with an increase in the threat for damaging winds (60-80
mph), and a continued threat for tornadoes (possibly up to EF2) with embedded/QLCS circulations.

...OK/TX this afternoon into early tonight...
The elevated mixed layer and associated cap, along with widespread
clouds, will tend to delay surface-based storm development until
mid-late afternoon, when forcing for ascent increases from the
southwest with the approach of the mid-upper jet streak. By about
21z, scattered thunderstorm development is expected along the
dryline from northwest TX into western OK, and storms will spread
quickly northeastward into central/eastern OK through this
evening/early tonight. Steep midlevel lapse rates and
boundary-layer dewpoints in the mid-upper 60s will contribute to
MLCAPE of 2000-3000 J/kg, in an environment with very strong
deep-layer shear/long hodographs favorable for multiple supercells
with very large hail (3 inches in diameter or greater). The
magnitude of the tornado threat is a bit less certain, given a
weakness in the low-level shear until a more consolidated low-level
jet response begins by late evening, when storm mergers and upscale
growth become more probable into eastern OK/northwest AR/southwest
MO early tonight. However, given the very strong flow and
seasonably rich low-level moisture, there will be the potential for
a couple of strong (roughly EF2) tornadoes late this afternoon into
tonight.

$$
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ACUS01 KWNS 022003
SWODY1
SPC AC 022001

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0301 PM CDT Tue Apr 02 2024

Valid 022000Z - 031200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM
SOUTHEASTERN INDIANA AND SOUTHWESTERN OHIO INTO CENTRAL KENTUCKY...

...SUMMARY...
A local severe weather outbreak remains possible through this
evening primarily across the Mid-Ohio Valley area, with the broader
severe weather risk extending east to the upper Ohio Valley, and
south to the Gulf Coast. Strong tornadoes remain most likely from
southern Indiana to central Ohio and southward into the Mid South.
A threat for strong tornadoes may focus this evening into tonight
across parts of Alabama and Georgia.

...Discussion...
Previous forecast reasoning largely remains on track, though
adjustments to the outlook areas -- including trimming the MDT risk
on the eastern fringe -- have been implemented.

Multiple rounds of prior convection have hindered warm-sector
recovery into the moderate-risk area, but clearing evident in
visible imagery from western Kentucky to central Ohio has occurred
ahead of the front. This corridor remains the focus for significant
severe weather, including potential for strong tornadoes.

Elsewhere, earlier reasoning remains valid, with a broad area of
severe weather potential still evident from the Ohio Valley to the
Gulf Coast.

..Goss.. 04/02/2024

.PREV DISCUSSION... /ISSUED 1122 AM CDT Tue Apr 02 2024/

...OH/TN Valley area through this evening...
Complex scenario late this morning with ongoing convection across
WV, trailing outflow to the west across KY, and another cluster of
storms moving into the trailing outflow zone across TN/KY. The lead
storms have produced damaging winds (up to 92 mph measured), though
this line of storms should weaken near or just after midday as it
encounters the remnant cool air wedge close to the WV/VA border.
The storms farther west will move along the remnant outflow zone,
where surface temperatures are in the low-mid 70s with dewpoints of
65-70 F. A couple of the storms will likely become persistent
supercells capable of producing tornadoes (some of which could be
strong/EF2-3) given the already strong wind profiles/long hodographs
with effective SRH of 200-300 m2/s2.

Uncertainty is relatively high for areas north of the ongoing
TN-KY-WV convection. The storms approaching middle TN and southern
KY will tend to reinforce the earlier outflow, which will likely
interfere with/limit destabilization this afternoon toward parts of
OH (especially eastern OH). The corridor of richer low-level
moisture from northeast AR into southeast MO (immediately west of
the TN storms) suggests that air mass recovery will occur toward
southern IL and southern/central IN by late morning into early
afternoon, and southwest OH this afternoon. Strong deep-layer
shear/long hodographs associated with an amplifying midlevel
trough/jet and a deepening surface cyclone will support the
potential for fast-moving supercells capable of all severe hazards,
including strong tornadoes where sufficient low-level
warming/moistening occurs in the wake of the morning convection. As
previously mentioned, the northeastern extent of the primary severe
threat into OH is more uncertain given the ongoing convection to the
south, but will trim the northeast edge of the MDT risk area and
expand south some to account for the outflow corridor enhancing the
tornado threat on the mesoscale across KY.

...Eastern AL/western GA overnight...
In response to the amplifying midlevel trough/deepening cyclone over
the MS/OH Valleys, deep-layer flow and low-level moisture advection
will increase tonight across AL/GA. A surge of upper 60s
boundary-layer dewpoints and strengthening low-level shear both
appear supportive of supercells/tornadoes overnight in a broken band
ahead of the synoptic cold front. An isolated strong tornado or two
will be possible.

$$
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