SPC AC 290602
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0102 AM CDT Tue Apr 29 2025
Valid 291200Z - 301200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
WEST TX INTO SOUTHWEST OK...AND FOR PARTS OF THE OHIO VALLEY AND
LOWER GREAT LAKES...
...SUMMARY...
Scattered severe thunderstorms are possible within a broad swath
from the Lower Great Lakes to the southern High Plains, mainly
during the afternoon to evening on Tuesday. Corridors of greater
threat are expected over the Upper Ohio Valley/Lower Great Lakes and
in parts of west Texas into southwest Oklahoma.
...Synopsis...
A deep mid/upper-level shortwave trough will move eastward across
the Great Lakes into southeast Canada today. A deepening surface low
will move across Quebec during the day, as an attendant cold front
moves across the Great Lakes, Ohio Valley, and Northeast. To the
west, a mid/upper-level trough and embedded midlevel cyclone will
move very slowly eastward across the Four Corners/Southwest. A weak
surface low is expected to remain nearly stationary near the TX
Trans-Pecos region. A cold front initially moving southward into the
southern Plains will tend to slow down with time, with its position
becoming modulated by repeated rounds of convection.
...Ohio Valley into the Lower Great Lakes...
Some uncertainty remains regarding the evolution of overnight
convection into the start of the D1/Tuesday period. However, most
guidance suggests that, despite weakening midlevel lapse rates,
moderate buoyancy will develop along/ahead of the front from the
Ohio Valley into parts of the Lower Great Lakes. Any ongoing morning
convection may intensify as it moves east-northeastward, with
additional development expected along/ahead of the front this
afternoon.
Strong low/midlevel flow will support development of organized storm
clusters, along with some potential for discrete or embedded
supercells. Scattered damaging winds will be possible, with some
potential for swaths of more concentrated wind damage if any
organized clusters or linear segments develop. 35-50 kt in the
850-700 mb layer will support sufficient low-level shear for some
supercell and/or line-embedded tornado threat. Isolated hail could
also accompany any persistent supercell structures.
...West TX into the Ozarks...
Multiple rounds of thunderstorms are expected across the southern
Plains in the vicinity of the surface front, with widely scattered
diurnal development also possible along the southward trailing
dryline into the Permian Basin vicinity. Strong midlevel flow east
of the Southwest trough will provide sufficient deep-layer shear for
storm organization, within a moderate to strongly unstable
environment near/south of the front. Occasional supercells will be
possible, with a threat of large to very large hail, severe gusts,
and a few tornadoes. One or more clusters are likely to develop and
spread eastward, which could provide localized swaths of more
concentrated strong/severe gusts. The favored corridor of any such
clusters remains somewhat uncertain, with the front expected to
gradually sag south with time.
..Dean/Weinman.. 04/29/2025
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
SPC AC 290552
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1252 AM CDT Tue Apr 29 2025
Valid 301200Z - 011200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS NORTH-CENTRAL
TEXAS...SOUTHEASTERN OKLAHOMA...WESTERN/CENTRAL ARKANSAS...
...SUMMARY...
Scattered severe thunderstorms are possible on Wednesday, centered
on central Texas to eastern Oklahoma and western Arkansas. Large
hail, damaging wind, and a few tornadoes will be possible with
thunderstorm activity.
...Synopsis...
A shortwave trough is expected to move eastward across the Southern
Plains on Wednesday, with multiple rounds of thunderstorm activity
possible across portions of Texas and Oklahoma. At the start of the
period Wednesday morning, convection should be ongoing across
western Oklahoma into northern Texas near the surface low. This
activity will continue to track eastward through the period and
intensify through the afternoon/evening, as the surface low moves
north and eastward. Additional thunderstorm development is expected
along the southern fringe near the dryline in north-central Texas.
A warm front extending across portions of Missouri, southern
Indiana, southern Illinois into northern Kentucky may be the focus
of strong to severe thunderstorm development Wednesday afternoon.
...Southern Plains into the Lower Mississippi Valley...
The aforementioned thunderstorm activity early in the period
Wednesday morning is expected to intensify through the afternoon, as
daytime heating and increasing moisture leads to destabilization
downstream in the warm sector. By the afternoon, the dryline across
central Texas will be the focus of new development as upper level
forcing overspreads the region. With multiple rounds of convection
expected across the Texas Panhandle into western Oklahoma and north
Texas in the D1 period, there is some uncertainty on where all the
mesoscale features will be as this occurs. Nonetheless, it appears
that ahead of the dryline the environment will be characterized by
steep lapse rates, modest MLCAPE, and strong deep layer shear. This
will support potential for a few supercells initially capable of
very large hail. Should the mode remain favorable, the tornado risk
will increase through the afternoon as the low-level jet strengthens
and low-level curvature of hodographs increases. A more favorable
corridor for tornadoes may exist near the Red River across
southeastern Oklahoma/northern Texas. Upscale growth will promote
potential for damaging wind, especially across eastern Oklahoma into
western Arkansas. However, shear will also support potential for
line embedded circulations.
Additional thunderstorms may re-develop further west across the
Texas Panhandle Wednesday afternoon, with potential for large hail.
At this time, it is uncertain how much recovery can happen from
multiple rounds of convection late D1 into D2 across this region.
...Lower MO/OH Valleys...
Along the warm front from southern Indiana into southern Illinois
and northern Kentucky, thunderstorm development is possible
Wednesday afternoon. Forcing remains weaker across this region, with
the shortwave back in the southern Plains. However, profiles would
be supportive of a supercell or two in this region, given the plume
of steep low to mid-level lapse rates, buoyancy, and sufficient
shear. These would be capable of hail, severe wind, and potentially
a tornado. For now, some uncertainty on coverage keeps probabilities
low.
..Thornton/Bentley.. 04/29/2025
WUUS02 PTSDY2
SPC AC 290717
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0217 AM CDT Tue Apr 29 2025
Valid 011200Z - 021200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
TEXAS INTO THE MISSISSIPPI/OHIO VALLEY AND NORTHWARD TO THE GREAT
LAKES...
...SUMMARY...
Scattered thunderstorm development is expected from central Texas
into the Mississippi and Ohio Valleys northward to the Great Lakes.
Thunderstorms will pose a risk for strong to severe winds and hail.
...Discussion...
A mid-level trough will eject across the Midwest into the
Mississippi and Ohio Valleys region on Thursday, with a broad area
of enhanced southwesterly flow extending from the lower Mississippi
Valley into the Great Lakes region. A cold front will sag southward
through this region, with potential for scattered thunderstorm
development throughout the day Thursday across a broad region. A
primarily marginal risk for wind and hail will be possible with this
activity. This overall risk is limited by displacement of better
shear northward through time with respect to the more favorable air
mass across Tennessee southward into northern MS/AR/northern LA.
Nonetheless, dew points in the mid 50s to 60s will extend as far
north as the Great Lakes, where stronger deep layer shear is
forecast which supports bringing the probabilities into this region.
Early in the D3/Thursday period, a line of thunderstorms may be
ongoing across northeastern Texas into central Arkansas. Some
re-intensification of this activity will be possible through the
afternoon as the air mass downstream warms and becomes favorably
unstable. Weaker shear profiles and forcing gradually shifting
northward through the afternoon/evening will likely keep this threat
lower. Nonetheless, potential for damaging wind will be possible.
Further west across the dryline in central Texas, deep layer flow
will remain modest enough to support potential for some thunderstorm
development by the late afternoon. While low level shear will be
weak, deep layer flow will support potential for instances of severe
hail, given steep low to mid-level lapse rates.
..Thornton/Bentley.. 04/29/2025
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z
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