RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1119 AM CDT Tue May 19 2026
Valid 191630Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
OVER PART OF THE OHIO VALLEY INTO NEW YORK...AND THROUGH TONIGHT
OVER PARTS OF TEXAS....
...SUMMARY...
Scattered severe thunderstorms will be possible today from the
southern Plains into the lower Mississippi Valley/Mid-South, Ohio
Valley, and lower Great Lakes. Damaging winds and hail will be the
primary threats. A greater threat for large to very large hail
should exist across parts of west-central Texas.
...OH Valley and Lower Great Lakes...
Deep southwesterly flow is present today from southern IL into much
of the OH Valley and NY. Visible satellite imagery shows mostly
clear skies in the region, allowing strong destabilization and
steepening low-level lapse rates. The result will be a rather large
zone of favorable environment for strong/damaging wind gusts this
afternoon with any organized convection. Given the continued trend
in morning model guidance of scattered clusters of storms in this
corridor, the SLGT risk area has been maintained.
...South-central TX...
A warm/moist and unstable air mass will develop this afternoon
across parts of west-central TX. Scattered thunderstorm development
is expected along a cold front sagging into the region. with weak
supercells structures possible. These storms will track
southeastward through the late afternoon/evening with a large hail
threat. Eventual upscale growth into bowing structures may extend
the severe risk overnight into south-central TX.
...East TX/LA/AR...
Widespread overnight convection continues to build southeastward
across southeast OK and western AR. This activity will persist much
of the day and spread across much of AR/East TX/northern LA, in a
region of relatively weak vertical shear and poor lapse rates.
Storms may occasionally pose a risk of gusty/damaging winds, but the
overall threat appears marginal.
..Hart/Halbert.. 05/19/2026
Read more
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0253 PM CDT Tue May 19 2026
Valid 192000Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
OHIO VALLEY INTO THE LOWER GREAT LAKES...AND PARTS OF CENTRAL/SOUTH
TEXAS...
...SUMMARY...
Scattered severe thunderstorms will be possible today from the
southern Plains into the lower Mississippi Valley/Mid-South, Ohio
Valley, and lower Great Lakes. Damaging winds and hail will be the
primary threats. A greater threat for large to very large hail
should exist across parts of west-central Texas.
...20Z Update...
The primary change to the forecast was to increase wind
probabilities in parts of South Texas. Convection within the Rolling
Plains should continue to develop this afternoon along a slowly
moving cold front. Given the moisture surge ahead of this activity,
it seems plausible that cold pool development will be robust enough
to support continued development southward into the overnight.
Recent HRRR guidance and the ECMWF support this possibility.
Elsewhere, only minor changes where made based on current
observations.
..Wendt.. 05/19/2026
.PREV DISCUSSION... /ISSUED 1119 AM CDT Tue May 19 2026/
...OH Valley and Lower Great Lakes...
Deep southwesterly flow is present today from southern IL into much
of the OH Valley and NY. Visible satellite imagery shows mostly
clear skies in the region, allowing strong destabilization and
steepening low-level lapse rates. The result will be a rather large
zone of favorable environment for strong/damaging wind gusts this
afternoon with any organized convection. Given the continued trend
in morning model guidance of scattered clusters of storms in this
corridor, the SLGT risk area has been maintained.
...South-central TX...
A warm/moist and unstable air mass will develop this afternoon
across parts of west-central TX. Scattered thunderstorm development
is expected along a cold front sagging into the region. with weak
supercells structures possible. These storms will track
southeastward through the late afternoon/evening with a large hail
threat. Eventual upscale growth into bowing structures may extend
the severe risk overnight into south-central TX.
...East TX/LA/AR...
Widespread overnight convection continues to build southeastward
across southeast OK and western AR. This activity will persist much
of the day and spread across much of AR/East TX/northern LA, in a
region of relatively weak vertical shear and poor lapse rates.
Storms may occasionally pose a risk of gusty/damaging winds, but the
overall threat appears marginal.
Read more
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1218 PM CDT Tue May 19 2026
Valid 201200Z - 211200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
SOUTHWEST TEXAS...
...SUMMARY...
Isolated to widely scattered severe storms are expected Wednesday
afternoon into night across portions of southwest Texas into eastern
New Mexico. Large hail --potentially in excess of two inches-- will
be the predominant severe-weather hazard. Isolated occurrences of
severe wind and/or marginally severe hail are expected Wednesday
afternoon into early evening from the Cumberland Plateau into
Mid-Atlantic and southern New England.
...Synopsis...
A low-amplitude short-wave trough will move through the base of an
eastern Canada trough, with a belt of strong mid/upper-level winds
overspreading New England. Elsewhere, a short-wave trough initially
near the Four Corners will weaken Wednesday while moving into
confluent flow over the central High Plains. There is some model
signal for a lower-latitude impulse to move through northern Mexico
into NM and western TX Wednesday afternoon and evening.
In the low levels, a cold front will move south through New England
and the Mid-Atlantic with the western extension of the boundary
weakening through the forecast period across TX.
...Eastern New Mexico into southwest Texas and the Edwards
Plateau...
Boundary-layer dewpoints in the mid 50s to low 60s will combine with
steep mid-level lapse rates to yield a moderately unstable air mass
by afternoon with MLCAPE increasing to 1500-2000 J/kg across
portions of southwest TX into the Edwards Plateau. Instability is
expected to decrease with northward extent in the immediate lee of
the Guadalupe, Sacramento, and Sangre De Cristo mountains, due to
limited boundary-layer moisture content.
Isolated to widely scattered thunderstorm development is anticipated
by mid/late afternoon along favored terrain, with initiation
potentially being aided by the mid-level disturbance mentioned in
the synopsis. A slight enhancement of the mid-level flow is forecast
across the area in association with the disturbance, which will
contribute to 35-45 kt of effective bulk shear across the
instability axis. As such, supercell storm modes appear likely,
especially across southwest TX where the strongest instability is
expected to reside. Large hail potentially in excess of 2" will be
the predominant hazard with the afternoon and early evening storms.
A number of the 12z models suggest that the daytime storms will grow
upscale into an MCS across portions of the Permian Basin and Concho
Valley into Edwards Plateau Wednesday evening into night with a risk
for locally damaging wind gusts and large hail.
Given the above considerations, a level 2/Slight Risk has been added
where confidence is highest in longer-lived supercell potential.
...Cumberland Plateau into Mid-Atlantic and southern New England...
A hot and a moist air mass is forecast to develop ahead of the front
Wednesday afternoon with MLCAPE increasing to 1000-2000 J/kg with
minimal capping. Convergence along the front along with terrain
influences are expected to foster a gradual increase in thunderstorm
coverage and intensity Wednesday afternoon from northern parts of
the Cumberland Plateau into the Mid-Atlantic and southern New
England. The strongest vertical shear is expected to reside to the
north of the surface warm sector, which coupled with poor mid-level
lapse rates, should limit the potential for organized storm modes.
Nonetheless, model soundings indicate the presence of 1.0-1.5 km
deep, well-mixed boundary-layers, which will be supportive of
locally damaging downburst winds through the afternoon into early
evening. Isolated occurrences of marginally severe hail are also
possible.
..Mead.. 05/19/2026
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0207 PM CDT Tue May 19 2026
Valid 211200Z - 221200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE CENTRAL AND SOUTHERN HIGH PLAINS...
...SUMMARY...
Isolated severe storms are possible across parts of the central and
southern High Plains Thursday afternoon and evening.
...Synopsis...
A short-wave trough and associated mid-level jet streak initially
over the northern Rockies Thursday morning will translate southeast
into the central Rockies, within the base of a mid/upper-level low
situated over southern Saskatchewan. Elsewhere, a vorticity maximum,
possibly of convective origins, is forecast to progress from the
southern Plains toward the mid/lower MS and TN Valleys.
At the surface, a frontal system tied to the northern and central
Rockies trough is forecast to move through the northern High Plains,
while a front remains quasi-stationary from NC through the TN Valley
into Ozark Plateau.
...Central and Southern High Plains...
In the absence of appreciable boundary-layer moisture content, the
presence of steep low/mid-level lapse rates will support MLCAPE of
500-1000 J/kg from south of I-70 in the lee of the CO Front Range to
the Raton Mesa and points south. Low-level upslope flow coupled with
increased forcing for ascent downstream from the approaching
vorticity maximum are expected to foster isolated to widely
scattered thunderstorm development along the favored terrain
Thursday afternoon into evening. The presence of 30-40 kt deep-layer
shear will support the potential for some storm organization with an
attendant large-hail threat.
...Northern High Plains...
Diurnally enhanced thunderstorm development is expected to occur
across eastern parts of MT and WY into the western Dakotas, along
the surface front, and ahead of the mid-level trough. Limited
instability and vertical shear are expected to limited
severe-weather potential.
..Mead.. 05/19/2026
Read more
