SPC Apr 11, 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
0742 AM CDT Sat Apr 11 2026

Valid 111300Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHERN HIGH PLAINS...

...SUMMARY...
Scattered thunderstorms producing hail and strong wind gusts are
possible across portions of the southern High Plains this afternoon
and evening. More isolated strong to severe thunderstorms are
expected across parts of the central Rockies, central Plains, upper
Mississippi Valley, and portions of the California coast.

...Southern High Plains...
Thunderstorm development is likely by mid/late-afternoon across
southwest Texas and eastern New Mexico as increase forcing for
ascent overspreads modest but increasing low-level moisture.
Initially discrete cells are likely and will pose a threat for large
hail given adequate deep-layer wind shear /generally 30-40 kt/.
However, weak capping and strong ascent should promote upscale
growth by early evening into several linear clusters. As this
transition occurs, strong to severe wind gust potential will
increase and become the predominant hazard, though an embedded
circulation or two may occur with a tornado possible.

...Central Plains to the Upper Mississippi Valley...
Low-level warm air advection will likely become increasingly focused
through the day and into the overnight hours from the central Plains
into the upper Mississippi Valley. 850 mb winds are forecast to
steadily strengthen to 40-60 kt by this evening and will support
moistening in the lowest 1-2 km under a plume of 7-7.5 C/km
mid-level lapse rates. Forecast soundings suggest that this
environment will be weakly capped and should support isolated to
widely scattered thunderstorms during the afternoon hours across the
central Plains before spreading/re-developing northeastward into the
upper Mississippi Valley late tonight. While deep-layer wind shear
will not be overly strong (around 30 kt), it should be sufficient
for a few organized cells capable of severe hail.

A more conditional supercell potential may materialize by mid/late
afternoon through early evening across portions of the middle/lower
Missouri Valley near/just south of the northward-shifting surface
warm front, which may augmented by residual cloud cover/weakening
storms across northeast Kansas/far southeast Nebraska in the
pre-dawn hours. Forecast soundings from this region suggest a weakly
capped, but moderately buoyant airmass, with notably strong
low-level/deep-layer wind profiles that would conditionally support
supercells including some tornado risk.

...Central/northern Rockies...
A northeast-ejecting shortwave trough, along with steep mid-level
lapse rates and modest mid-level moisture, will likely support
additional thunderstorms across the central to northern Rockies this
afternoon as diurnal heating occurs. A combination of modest
deep-layer wind shear and well-mixed boundary layers will support
potential for strong to severe downburst winds.

...Northern/central California Coast...
A progressive upper wave will continue eastward and reach the
northern California coast tonight. As this occurs, ascent within
the left-exit region of an attendant upper jet, coupled with cool
mid-level temperatures near the center of the upper low, will
support isolated thunderstorms across northern/central California.
Winds within the lowest 1-2 km AGL should increase to around 40 kt
as the wave moves onshore, which will contribute to the potential
for convective downdrafts to produce a few locally damaging wind
gusts.

..Guyer/Broyles.. 04/11/2026


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SPC Apr 11, 2026 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1242 AM CDT Sat Apr 11 2026

Valid 111200Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE SOUTHERN HIGH PLAINS...

...SUMMARY...
Scattered thunderstorms producing hail and strong wind gusts will be
possible across portions of the southern High Plains this afternoon
and evening. More isolated strong to severe thunderstorms are
expected across parts of the central Rockies, central Plains, upper
Mississippi Valley, and portions of the California coast.

...Synopsis...
An upper trough is evident in early-morning water-vapor imagery off
the California Coast. This wave will gradually de-amplify over the
next 24 hours as it progresses northeastward into the northern
Rockies. Further south, a lower-amplitude upper disturbance is noted
off the coast of Baja CA, and will migrate northeast into southwest
TX through this evening. Ahead of these features, modest lee
troughing along the High Plains and the southeastward shift of
surface high from the Midwest into the upper OH Valley will yield an
extended fetch of southerly low-level flow from the TX coast into
the upper MS Valley, resulting in northward moisture return as well
as a broad zone of isentropic ascent from the Plains into the upper
MS Valley.

...Southern High Plains...
Thunderstorm development appears likely by mid-afternoon across
southwest TX as ascent associated with the upper disturbance off the
coast of Baja CA migrates out of northern Mexico and overspreads
returning moisture. Initially discrete cells are likely and will
pose a threat for large hail given adequate deep-layer wind shear.
However, weak capping and strong ascent should promote upscale
growth by early evening into one or more convective lines. As this
transition occurs, strong to severe wind gusts will become the
predominant hazard, though an embedded circulation or two may be
possible. Based on latest guidance, the wind/tornado threat may be
maximized along and south of the I-20 corridor where the signal for
clustering/banding is greatest in latest CAM and ensemble guidance.

...Central Plains to the Upper MS Valley...
Low-level warm air advection will likely become increasingly focused
through the day and into the overnight hours from the central Plains
into the upper MS Valley. 850 mb winds are forecast to strengthen to
40-50 knots by this evening and will support steady moistening in
the lowest 1-2 km under a plume of 7-7.5 C/km mid-level lapse rates.
Forecast soundings suggest that this environment will be weakly
capped and should support isolated to scattered thunderstorms during
the afternoon hours across the central Plains before
spreading/re-developing northeastward into the upper MS Valley late
tonight. While deep-layer wind shear will not be overly strong
(around 30 knots), it should be sufficient for a few transient
organized cells capable of large hail.

A more conditional supercell threat may materialize across portions
of the lower MO valley where some CAM guidance depicts convection
developing late afternoon along the surface warm front. Forecast
soundings from this region suggest a weakly capped, but moderately
buoyant and strongly sheared environment may be in place that could
support a well-organized supercell. However, poor ensemble consensus
limits confidence in this scenario.

...Central to northern Rockies...
00z RAOBs from the Great Basin/Four Corners region sampled steep
mid-level lapse rates with modest mid-level moisture. While fairly
dry, this environment was sufficient for convection yesterday and
will likely support additional thunderstorms across the central to
northern Rockies this afternoon as diurnal heating erodes inhibition
and maximizes surface-based buoyancy. Ascent ahead of the decaying
upper wave will likely support isolated to scattered thunderstorms,
and a combination of modest deep-layer wind shear and deep,
well-mixed boundary layers will promote strong to severe downburst
winds. A fairly strong wind signal in latest HREF guidance
co-located with transient UH streaks lent enough confidence to
expand 5% wind probabilities northwestward to address this concern.

...CA Coast...
A progressive upper wave will move into northern CA late this
afternoon into the overnight hours. As this occurs, ascent within
the left-exit region of an attendant upper jet, coupled with cool
mid-level temperatures near the center of the upper low, should
support isolated thunderstorms across northern CA. Winds within the
lowest 1-2 km should increase to around 40 knots as the wave moves
onshore, which may be augmented by convective downdrafts to yield a
few damaging gusts along the coast.

..Moore/Halbert.. 04/11/2026


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SPC Apr 11, 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
0758 PM CDT Fri Apr 10 2026

Valid 110100Z - 111200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Isolated to scattered thunderstorms remain possible during the late
evening hours across parts of the southern Plains and Great Basin;
however, the overall severe risk appears limited.

...Southern Plains...
Latest MRMS imagery depicts steady weakening of convection across
northeast NM and across northern OK with the onset of nocturnal
cooling and expanding convective outflows. While a couple of
stronger storms are noted across far eastern NM and southwest TX,
weak deep-layer wind shear and diminishing buoyancy should favor a
weakening trend heading into the late evening hours.

Additional elevated thunderstorms are anticipated well north of the
stalled surface boundary along the OK/KS border with recent CAM
guidance suggesting multi-cell clusters developing across portions
of central to northeast KS after 03 UTC. The recent 00z DDC RAOB
likely sampled the environment this convection will develop in, and
hints that at least a small hail threat may materialize with
initially discrete cells prior to upscale growth within the first
couple of hours after initiation.

...Great Basin...
Similar to the southern Plains, convective trends have largely shown
signs of weakening over the past hour across central to northern NV
where surface temperatures are quickly cooling into the 60s. The
combination of rain-cooled air/outflows and the onset of nocturnal
cooling should further reduce any remaining mixed-layer buoyancy
(which was already fairly marginal per regional 00z RAOBs).
Consequently, the thermodynamic environment no longer appears
supportive of intense convection, though a strong storm or two may
persist for the next hour as the boundary layer continues to
stabilize.

..Moore.. 04/11/2026


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SPC Apr 10, 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
1130 AM CDT Fri Apr 10 2026

Valid 101630Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTH-CENTRAL PLAINS/OZARKS...NORTHERN CALIFORNIA/GREAT
BASIN...AND WESTERN OREGON...

...SUMMARY...
Thunderstorms with isolated large hail and severe gusts are possible
this afternoon and evening across parts of the south-central Plains
to the Ozarks. Strong to locally severe storms may also occur from
western/northern Nevada into southeast Oregon and southwest Idaho,
and also across parts of north-central California.

...Southern High Plains/South-central Plains into the Ozarks...
Recent surface analysis places a low over the western TX Panhandle,
with a cold front extending east-northeastward from this low across
northwest and north-central OK, and far southeast KS, before
becoming oriented more northeastward across southern and central MO.
Showers and thunderstorms are ongoing in the vicinity of this
boundary, as well modest southeastward-progressing outflow, across
far southern KS and northern OK.

The cold front is forecast to trend more stationary throughout the
day as heights rise across the Plains and southerly low-level flow
persists across the southern Plains, with the outflow following this
trend as well. After 06Z, this stationary boundary will likely begin
shifting back northward into southern KS as warm front. Additional
thunderstorm development is possible amid low-level convergence near
both the stationary front and outflow as the airmass modestly
destabilizes this afternoon. Isolated damaging gusts and/or
marginally severe hail is possible with the strongest storms, but
modest shear and buoyancy suggests most storms will be sub-severe.

Farther west, low-level convergence along a sharpening lee trough
may contribute to late afternoon thunderstorm development across the
southern High Plain, particularly northeast NM. High cloud bases and
steep low-level lapse rates support the potential for strong
downbursts with any deep/more persistent updrafts. Some interaction
with the western extent of the frontal zone is possible as well,
which could briefly enhance updrafts, contributing to a continued
potential for damaging gusts as well as isolated hail.

...North-central CA/western OR into the northern Great Basin...
Upper low currently centered just off the northern/central CA coast
is forecast to become more progressive and negatively tilted
throughout the day today. Mid-level moisture and ascent attendant to
this wave will support scattered thunderstorm development this
afternoon from central/northern CA and western OR into the northern
Great Basin and interior Northwest. Cold temperatures aloft (i.e.
-20 deg C at 500 mb) and strong diurnal heating will result in steep
low/mid-level lapse rates and at least modest buoyancy across much
of the region.

A few areas (interior valley of central CA, Willamette Valley in OR,
and northern NV/southwest OR/southern ID) appear to have a slightly
higher potential for isolated strong to severe storms, largely a
result of more diurnal heating/higher afternoon temperatures.
Greater buoyancy combined with moderate/strong deep-layer shear will
support semi-organized cells/clusters, and perhaps even a few
supercells, may develop with an attendant threat of hail and
localized severe wind gusts. Deep-layer shear will be a bit weaker
across the interior valley of central CA but still sufficient for a
few organized storms. The steep lapse rate environment and local
terrain influences could also support transient cell rotation and
possibly funnels, or even a brief tornado.

..Mosier/Squitieri.. 04/10/2026


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