SPC May 19, 2026 2000 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... 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.


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SPC May 19, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... 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


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SPC May 19, 2026 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 AM CDT Tue May 19 2026

Valid 191300Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
PLAINS INTO THE LOWER MISSISSIPPI VALLEY/MID-SOUTH...OHIO
VALLEY...AND LOWER GREAT LAKES...

...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.

...Southern Plains into the Lower Mississippi Valley...
Numerous thunderstorms are ongoing this morning across
central/eastern OK into northwest AR and southern MO. Most of this
activity is occurring along and north of a southward-moving cold
front, and should therefore pose a limited severe risk in the short
term. Eventual regeneration along the cold front and/or
strengthening of ongoing activity should occur later today across TX
into the lower MS Valley/Mid-South. Mid-level flow is forecast to
remain fairly modest, and deep-layer shear for most areas will tend
to be marginal. Still, filtered daytime heating of a moist low-level
airmass will support moderate to strong instability along/ahead of
the front by early afternoon. Scattered severe/damaging winds should
be the main threat with loosely organized clusters and bowing line
segments. This wind threat may continue to the TX/LA Coast this
evening/overnight. Some potential for supercells should also exist
across parts of west-central TX and vicinity, where steeper
mid-level lapse rates and greater instability is forecast to be in
place. Large hail appears possible with any supercells that can be
sustained, and isolated 2+ inch diameter hail may occur. With time
this evening, this convection may also grow upscale into a bowing
cluster and pose a greater severe wind risk.

...Ohio Valley into the Lower Great Lakes and Northeast...
Modestly enhanced mid-level southwesterly flow will be present today
over the OH Valley and lower Great Lakes regions, as a positively
tilted mid/upper-level trough moves from the Upper Midwest into
eastern Canada. Isolated to scattered thunderstorms should develop
along/ahead of a surface cold front this afternoon as the
pre-frontal airmass gradually destabilizes. Stronger instability
should be present this afternoon across the OH Valley, but greater
deep-layer shear may tend to remain mostly displaced farther north.
Even so, some thunderstorm organization should occur, with
multicells and bowing line segments possible. Scattered
severe/damaging winds should be the main threat, although isolated
hail could occur with the strongest cores. This convection should
spread into the lower Great Lakes by mid to late evening, before
eventually weakening across the Northeast late tonight. A separate
area of convection may develop this afternoon across parts of New
England, and also pose a threat for mainly occasional damaging
winds.

..Gleason/Marsh.. 05/19/2026


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SPC May 19, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0805 PM CDT Mon May 18 2026

Valid 190100Z - 191200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
FAR NORTHERN OKLAHOMA...SOUTHERN AND EASTERN KANSAS INTO NORTHWEST
MISSOURI...FAR SOUTHEAST NEBRASKA AND SOUTH-CENTRAL IOWA...

...SUMMARY...
Numerous severe thunderstorms are expected this evening from the
southern and central Plains into the mid Missouri Valley. Supercells
and bowing line segments capable of producing severe wind gusts,
tornadoes and large hail remain likely from eastern and southern
Kansas into far southeast Nebraska, Iowa and northwest Missouri.

...Southern and Central Plains/Mid Missouri Valley...
At the synoptic level, multiple shortwave troughs are ejecting
northeastward across the central U.S. early this evening. A 50 to 70
knot mid-level jet is translating northeastward across the central
Plains, with a 40 to 50 knot low-level jet in place from northern
Oklahoma into eastern Kansas and western Missouri. A squall-line is
ongoing along the western edge of the low-level jet, and this line
will move east-southeastward across the remainder of eastern Kansas
into western Missouri this evening into tonight. Ahead of the line,
strong instability is analyzed by the RAP with MLCAPE in the 3000 to
4000 J/kg range. This, combined with strong large-scale ascent to
the southeast of the mid-level jet, and moderate deep-layer shear
evident on regional WSR-88D VWPs, will continue to support a severe
threat with this line for the remainder of the evening. Severe wind
gusts with be likely along the leading edge of the line. Large hail
and tornadoes will also be possible with rotating elements embedded
in the line.

Further north-northeast into northeast Kansas, northwest Missouri
and south-central Iowa, several semi-discrete supercells are
ongoing. The Kansas City WSR-88D has 0-3 km storm-relative helicity
near 475 ms/s2, which appears representative of the environment
ahead of these storms. For this reason, a potential will continue
for strong tornadoes over the next few hours. These supercells will
also be capable of producing large hail and severe wind gusts.

The squall-line will gradually move east-southeastward into the
lower Missouri Valley and Ozarks from late this evening into the
overnight period. The severe threat will become less widespread as
relatively weaker instability is encountered later tonight.

...Southern Plains...
At the surface, a 997 mb low is located over far northwestern
Oklahoma, with a dryline extending southward across far western
Oklahoma into west Texas. To the east of the dryline, the RAP has
MLCAPE in the 3000 to 4000 J/kg range. Near the axis of the
strongest instability, a few storms are ongoing across southwest
Oklahoma, but weakening has recently occurred. Redevelopment will be
possible later this evening. The strong instability combined with
moderate deep-layer shear and steep low to mid-level lapse rates
would support a threat for large hail and severe wind gusts, if
cells can re-intensify. An isolated tornado threat will also be
possible if a supercell could develop. Thunderstorms are expected to
increase in coverage over much of Oklahoma during the overnight
period, as a cold front moves southward. However, the severe threat
should become more isolated tonight as instability gradually
decreases across the region.

..Broyles.. 05/19/2026


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