SPC Apr 5, 2025 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0259 PM CDT Sat Apr 05 2025

Valid 052000Z - 061200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR NORTHERN
MISSISSIPPI INTO WESTERN TENNESSEE...

...SUMMARY...
Severe storms, capable of producing damaging wind gusts, large hail
and several tornadoes are still expected from the Sabine River
Valley northeastward into the Mid-South and lower Mississippi and
Ohio Valleys. Strong tornadoes, very large hail, and severe wind
gusts are all possible.

...20Z Update...
The primary changes made to the 20Z Convective Outlook Update were
to trim severe probabilities from the west to account for the
passage of the ongoing QLCS over the Mid-South into the Lower MS
Valley region. Severe hail may still accompany the stronger storms
along southern extent of or immediately ahead of the QLCS.
Otherwise, strong to severe surface gusts and tornadoes (a couple of
which may be strong) may occur with embedded mesovortices and LEWPs
within the QLCS, as well as with any storms ahead of the line. See
the previous outlook (below) for more details.

..Squitieri.. 04/05/2025

.PREV DISCUSSION... /ISSUED 1140 AM CDT Sat Apr 05 2025/

...East TX/ArkLaTex to Lower Mississippi Valley...
Severe storms continue to increase through late morning into midday
especially across parts of Arkansas, with the upscale-growing
MCS/bow echo near/northeast of the Little Rock area as of 1130 CDT.
A 60 kt wind gust was recently measured at KLRF/North Little Rock.
This bowing MCS should continue to favor the zone near/immediately
north of the effective boundary that precedes it (roughly parallel
to I-40), likely taking it into western Tennessee this afternoon,
potentially near the Memphis metro vicinity. See Mesoscale
Discussion 411 for additional details. A Moderate Risk upgrade has
been introduced for this scenario, as well as potential
semi-discrete warm-sector development later this afternoon to its
south.

Within the axis of a strong low-level jet (south-southwesterly 50-60
kt across the ArkLaTex and ArkLaMiss), supercell longevity/tornado
potential will be maximized with any diurnal warm-sector development
that occurs away from (east-southeast of) the outflow-reinforced
effective front, although the extent of that my tend to be somewhat
curbed by persistent cloud cover and semi-mild mid-level
temperatures (-9 or -10C at 500mb) into the warm sector.
Additionally, deep-layer shear vectors will be largely parallel to
the effective front regionally, suggestive of a mixed convective
mode including HP supercells/smaller-scale bows in close proximity
to the convectively modified effective front. The front will become
more east/southeastward-progressive later this afternoon and tonight
across east/southeast Texas, southern Arkansas, and Louisiana.
Overall, some tornadoes are expected regionally, a few of which
could be strong, aside from damaging winds and isolated large hail.

...Mid-South into the TN/OH Valleys...
Farther north, the boundary will be less progressive throughout the
morning/early afternoon, particularly north of a weak low currently
over northeast Texas. The boundary will likely sharpen during this
time, before then becoming more progressive once again as the
convectively augmented shortwave trough currently moving into
western Oklahoma progresses into the region. This will likely result
in a bowing line segment with damaging gusts as the primary severe
risk. However, given the strength of the low-level flow, some
embedded tornado potential exists as well.

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