SPC AC 041241
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0741 AM CDT Wed Jun 04 2025
Valid 041300Z - 051200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN NEW
MEXICO INTO THE TX PANHANDLE...
...SUMMARY...
Isolated severe thunderstorms are possible later this afternoon into
the evening across portions of the southern High Plains. Hail and
wind are the primary concerns. Locally damaging winds may accompany
convection that develops from the lower Great Lakes into eastern
Texas.
...Synopsis...
Upper troughing that currently extends across much of the western
and central CONUS is forecast to remain in place throughout the day.
Western periphery of expansive subtropical ridging will remain over
the East Coast as well. Despite little change in the large-scale
upper pattern, multiple shortwave troughs progressing within these
larger features will contribute to convectively active day, with
thunderstorms anticipated from the southern Great Basin and
Southwest into the High Plains as well as from Lower MI into
east/southeast TX. Numerous thunderstorms are anticipated from the
northern Rockies into the northern Plains, and the Southeast and
Florida as well.
...Southern Rockies into the southern High Plains...
The showers and isolated thunderstorm ongoing across the region are
expected to continue northeastward while weakening over the next
several hours. Much of this region is currently under a cool and dry
post-frontal regime, but southerly flow should return this
afternoon, contributing to quick airmass modification ahead of a
shortwave trough moving across the Southwest states. Showers and
thunderstorms are anticipated ahead of this shortwave from the Four
Corners eastward into the southern High Plains. The strongest storms
are expected during the late afternoon/early evening across
east-central NM, where the leading edge of the better low-level
moisture return interacts with storms moving off the higher terrain
of central NM ahead of the approaching shortwave trough.
Enhanced mid-level flow will extend through this region as well,
resulting in environmental conditions supportive of supercells.
Large hail is favored initially, but high cloud bases and strong
outflow will likely result in a transition to a more linear/bowing
mode tonight. Despite nocturnal cooling and resultant low-level
stabilization, some strong gusts are still possible as these storms
continue into the western TX Panhandle this evening and tonight. A
low-probability tornado threat exists as these storms move towards
the TX Panhandle, where better low-level moisture and stronger
southeasterly winds are possible. However, the anticipated linear
storm mode and stabilizing nocturnal cooling should keep the tornado
threat low.
...Lower MI southward through the OH Valley and Ozarks into East
TX...
A weakening cold front currently extends from northern Lower MI into
central TX. Much of this front is expected to make modest
eastward/southeastward progress throughout the day, before becoming
increasingly stationary tonight. A moist airmass precedes this
front, and afternoon dewpoints from the mid 60s to low 70s will
support moderate buoyancy and scattered to numerous thunderstorms.
Moderate 0-6 km (i.e. 30-35 kt) shear suggests a few robust storms
could evolve that would pose at least some risk for gusty winds.
Greatest risk for damaging winds will be during the afternoon when
buoyancy is maximized.
..Mosier/Broyles.. 06/04/2025
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
SPC AC 040547
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1247 AM CDT Wed Jun 04 2025
Valid 051200Z - 061200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN THE SOUTHERN
HIGH PLAINS AND OK TO SOUTH KS...
...SUMMARY...
Scattered severe thunderstorms are anticipated, mainly from late
afternoon Thursday into Thursday night from the southern High Plains
across southern Kansas and Oklahoma. A few tornadoes, large to
isolated very large hail, and severe gusts are possible.
...Southern High Plains to southern KS and OK...
A cluster of thunderstorms will likely be ongoing at 12Z Thursday
across a portion of northwest TX within a low-level warm theta-e
advection regime. As the low-level jet diurnally subsides, this
activity is expected to diminish. The intensity and areal extent of
this convection will likely impact later-day frontal location and
the degree of destabilization to its northeast. The 00Z NAM is much
more aggressive than guidance consensus at limiting diurnal
destabilization across KS/OK. To the west of this morning activity,
robust destabilization is expected across the southern High Plains
from both increased boundary-layer moisture combined with an
expansion of steep mid-level lapse rates. A plume of large buoyancy
with MLCAPE of 2000-3000 J/kg is expected by afternoon.
With generally neutral mid-level height change, isolated to
scattered convective development is most likely to focus off the
higher terrain of the Trans-Pecos and the Raton Mesa during the late
afternoon to early evening. A few storms are possible in between
these corridors along the eastern NM dryline, but confidence is low.
Deep-layer shear profiles will favor discrete supercells where
convection is sustained. Large hail and damaging winds are possible,
with tornado potential increasing into early evening as the
low-level jet strengthens. Long-track supercell potential is evident
off the Raton Mesa, near the surface warm front, where greater
hodograph elongation is anticipated. This could support a swath of
very large hail. Widespread convection is expected within this
similar zone later into the evening through Thursday night amid
strengthening warm advection. This should result in a
forward-propagating MCS to the east-southeast from parts of the TX
Panhandle to southern KS and OK through early morning Friday. The
amplitude of severe wind potential will likely be modulated by the
degree of surface-based instability. Given the likelihood of
below-normal temperatures Thursday, low confidence exists to warrant
greater probabilities.
...Mid-South to New England...
A weak cold front will aid in isolated to scattered afternoon
thunderstorms across a broad swath of the central to northeastern
states. Large buoyancy will likely be confined to the Mid-South,
with weak to moderate MLCAPE extending northeastward. This front
will remain on the periphery of modest mid-level southwesterlies.
Multicell clusters are expected to dominate in this setup with
sporadic damaging winds as the primary hazard. Slightly greater
effective bulk shear in the Mid-South and Northeast should also
offer a threat for isolated severe hail.
..Grams.. 06/04/2025
WUUS02 PTSDY2
SPC AC 040730
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Wed Jun 04 2025
Valid 061200Z - 071200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
HIGH PLAINS TO THE TN/LOWER OH VALLEYS...
...SUMMARY...
Scattered severe thunderstorms are expected from the southern High
Plains to the Tennessee and Lower Ohio Valleys on Friday into Friday
night.
...Southern High Plains to the TN/Lower OH Valleys...
Enhanced zonal mid-level flow within the southern stream will
overlap a richly moist and unstable air mass across the southern
Great Plains to the TN Valley on Friday. An MCS is expected to be
initially ongoing in the OK vicinity at 12Z Friday. Guidance
generally suggests that the remnant MCV will track east-northeast
across the Mid-South and OH Valley through the period. This should
enhance 700-mb winds and support scattered damaging wind swaths
downstream through at least Friday evening. Have broadened the 15
percent severe area eastward through much of KY south to northern
AL/GA, with still much uncertainty on how far south/east remnant MCS
outflow(s) will reach.
Farther west across the southern High Plains to OK vicinity, the
overall setup from the convective-parameterized guidance appears
conditionally more favorable relative to D2. A broader plume of
large buoyancy is progged across OK/TX by Friday afternoon. In
addition, a northern-stream shortwave impulse is progged to dig into
the central Great Plains by Friday evening/night. This would further
enhance the belt of mid/upper-level westerlies to its south. A
similar evolution of supercells developing off the Raton Mesa
vicinity and growing upscale into a nocturnal MCS seems plausible.
The primary limiting factor to a categorical upgrade is with the
potential impact of the late D2/early D3 MCS on instability and
southern extent of convective outflows, which parameterized guidance
are notoriously underdone with. In addition, there is potential for
that MCS to be more intense/widespread than currently forecast. For
now, have opted to maintain a level 2-SLGT, with potential for
upgrades in later outlooks as limiting impacts of the early-period
MCS are likely better resolved.
..Grams.. 06/04/2025
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z
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