SPC Sep 14, 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
0746 AM CDT Mon Sep 14 2026

Valid 141300Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
EASTERN NEBRASKA INTO WESTERN/CENTRAL IOWA...

...SUMMARY...
Scattered strong to severe thunderstorms should occur across parts
of eastern Nebraska into western/central Iowa this afternoon and
evening. Large hail, severe gusts, and a few tornadoes all appear
possible.

...Central Plains into Iowa...
A seasonably strong mid-level shortwave trough with 50-70+ kt
mid-level jet will advance quickly east-northeastward across the
northern Plains and south-central Canada today. Mid/upper-level
ridging will remain prominent over much of the Southeast and OH
Valley. Between these two features, a belt of around 30-50 kt
mid-level west-southwesterlies will persist across the central
Plains into the lower/mid MO Valley. The primary surface low over
the northern Plains this morning will develop into southern
Saskatchewan/Manitoba by this evening, with a secondary surface low
likely to form along/near the NE/SD border by late afternoon.
Greater low-level moisture across KS will attempt to lift northward
along a warm front today across the central Plains ahead of a cold
front that will sweep southeastward across the northern/central
Plains through the period.

Ongoing convection this morning across the central Plains/mid MO
Valley is being aided by warm/moist advection associated with a
strong south-southwesterly low-level jet. This activity should tend
to remain elevated and sub-severe as it tracks quickly
east-northeastward through the late morning before eventually
weakening. In its wake, destabilization is forecast to rapidly occur
across eastern NE/western IA as rich low-level moisture quickly
streams northward. There is still some variability in short-term
guidance with the degree and northward extent of low-level moisture
return through late afternoon across this region, which introduces a
fair amount of uncertainty regarding how unstable the warm sector
will become. Even so, a narrow corridor of moderate to strong
instability (MLCAPE 2000-3000+ J/kg) appears plausible across
eastern NE/western IA and vicinity by 21-00Z, assuming surface
temperatures can warm into at least the low to mid 80s.

Robust thunderstorms should develop along or just ahead of the cold
front by late afternoon/early evening across eastern NE, with
strengthening/favorable deep-layer shear for supercells initially.
Large hail may occur, but modest lapse rates aloft and a quick mode
transition to mainly clusters/line segments will probably limit the
spatial/temporal extent of the hail threat. Nearly all guidance
continues to show a favorable environment for tornadoes across
eastern NE/western IA as the supercells/clusters spread quickly
eastward this evening, with a 40-50 kt low-level jet aiding the
development of ample effective SRH. But, various RAP forecast
soundings across this region show lingering low-level inhibition,
and it remains unclear whether convection will be able to fully take
advantage of the strong low-level shear. Even with this uncertainty,
a sustained surface-based supercell in this environment would
conditionally be capable of producing a strong tornado.

Otherwise, severe/damaging winds should become an increasing concern
as clusters develop and spread east-northeastward. Weak instability
with eastward extent in eastern IA and vicinity should limit the
severe risk tonight. While deep-layer shear will be somewhat weaker
with southward extent across the central Plains, at least isolated
severe gusts may also occur with high-based/loosely organized
convection that develops this afternoon from eastern CO into
western/northern KS along a surface trough. Confidence remains too
low in a more focused corridor of severe wind potential across this
region to include greater probabilities with this update.

...Northern Plains...
A band of elevated thunderstorms is occurring this morning across
the Dakotas as large-scale ascent preceding the shortwave trough
overspreads the northern Plains in tandem with strong low-level warm
advection. Latest surface observations and recent RAP forecast
soundings across this region show cool and stable conditions in the
boundary layer, which limits confidence in an isolated severe wind
threat this morning as convection moves quickly northeastward.
Still, small hail and gusty winds may occur given the enhanced
background/gradient wind field and sufficient MUCAPE present, with
some convective enhancement possible.

...Southwest/Four Corners...
Scattered thunderstorm development will occur later today from
western CO and southeast UT into parts of AZ/NM as a fairly moist
low-level airmass gradually destabilizes. Modestly enhanced
mid-level westerly flow should be present this afternoon over parts
of UT/CO, though it is uncertain if diurnal heating and related
instability will be sufficient for an organized severe risk. Still,
isolated gusty winds and small to perhaps near-severe hail could
occur with the strongest thunderstorms. Farther south, flow will be
weaker across AZ, resulting in mostly disorganized convection. Even
so, localized strong gusts appear possible, especially where
stronger heating occurs and steeper low-level lapse rates develop
during the afternoon. Overall, confidence in an organized severe
risk is too low to include 5% hail/wind probabilities at this time.

...Eastern North Carolina...
A cold front will move southward across NC today. Large-scale ascent
will generally be weak, though isolated convective development may
occur as the front encounters greater low-level moisture and sea
breeze boundaries over coastal/eastern NC. Deep-layer shear within a
northwesterly mid-level flow regime will be sufficient for organized
thunderstorms, but poor mid-level lapse rates should tend to limit
updraft intensity and the overall severe threat. Regardless, any
thunderstorms that can develop and be sustained in this regime could
produce locally gusty winds and small hail.

..Gleason/Lyons.. 09/14/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TVTDRw

SPC Sep 14, 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 Mon Sep 14 2026

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN NE
AND WESTERN IA...

...SUMMARY...
Scattered strong to severe thunderstorms are possible across parts
of eastern Nebraska into western Iowa late this afternoon and
evening.

...Eastern NE/western IA...
A strong mid/upper-level trough will move eastward from the northern
Plains into the Upper Great Lakes through tonight. A deepening
surface low will move across the Canadian Prairies, while a
secondary low may develop along a trailing cold front/surface trough
across the central High Plains. This system will be accompanied by
strengthening deep-layer flow from the central Plains into the Upper
Midwest.

Extensive elevated convection will likely be ongoing at the start of
the period from the mid Missouri Valley northward into the Dakotas
and western MN. In the wake of this early-day convection, rich
low-level moisture (with dewpoints in the 70s F) is forecast to
stream northward into eastern NE and western IA. This moistening
combined with relatively steep midlevel lapse rates will support
moderate to strong destabilization by late afternoon, while
low-level and deep-layer shear will become increasingly favorable
with time. The resulting environment will become conditionally
favorable for supercells capable of all severe hazards.

The strongest large-scale ascent will become focused north of the
region by afternoon, and it remains uncertain if heating in the wake
of morning convection will be sufficient to remove CINH within the
most favorable environment. If a supercell can become established
and move through this environment during the late afternoon/early
evening, then large to very large hail, localized damaging gusts,
and tornadoes will all be possible. While most guidance depicts
storm development by early evening, 00Z CAM guidance continues to
vary regarding the potential for sustained supercells, with
relatively quick clustering possible. Even in the absence of
sustained supercell development, the environment will be favorable
for severe hail and damaging wind with any persistent clusters into
the evening.

...Western/north-central KS...
Strong heating is expected near/south of a surface trough across
parts of western/central KS this afternoon. Scattered storm
development is expected by late afternoon from western into
north-central KS. Deep-layer shear will be weaker with southwest
extent, but steep low-level lapse rates and 25-35 kt of flow in the
850-500 mb layer will support potential for one or more loosely
organized clusters with at least localized severe-wind potential.

...Four Corners region into AZ...
Scattered storm development is expected later today from western CO
and southeast UT into parts of AZ/NM, within an anomalously moist
environment. The strongest mid/upper-level flow and deep-layer shear
within this region is expected over parts of UT/CO, though it is
uncertain if diurnal heating/destabilization will be sufficient for
an organized severe threat in this area. Some threat for strong
gusts and small to near-severe hail could evolve with the strongest
storms.

Farther south, flow will be weaker across AZ, resulting in generally
disorganized storms. Localized strong gusts will be possible,
especially in areas where stronger pre-storm heating occurs during
the afternoon.

...Coastal NC...
A cold front will move southward across NC through the day today.
Large-scale ascent will generally be weak, though isolated storm
development will be possible as the front encounters richer moisture
and any sea breeze boundaries near the coast. Deep-layer shear
within a northwesterly flow regime will be sufficient for organized
convection, but poor midlevel lapse rates may limit updraft
intensity and potential for an organized severe threat. Any
sustained storms within this regime could produce locally gusty
winds and small hail.

..Dean/Halbert.. 09/14/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TVSxQd

SPC Sep 14, 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
0759 PM CDT Sun Sep 13 2026

Valid 140100Z - 141200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The organized-severe threat appears low for the remainder of
tonight, though occasional strong storms will be possible this
evening across the central and northern High Plains, and overnight
into parts of the mid Missouri Valley.

...Parts of the Ohio Valley and Northeast...
A broken band of thunderstorms is ongoing this evening from parts of
the Upper Ohio Valley into the Northeast. Despite the presence of
moderate deep-layer flow/shear, longevity of organized storms within
this corridor has been limited by poor midlevel lapse rates and
generally modest buoyancy. Sporadic damaging winds have been
reported with the strongest of these storms, but a general weakening
trend is expected to continue through the evening. Localized wind
damage cannot be ruled out with any remaining vigorous storms,
though longevity of the remaining threat appears too limited to
maintain severe probabilities.

...Central/northern Plains into the Mid Missouri Valley...
Isolated strong storms are ongoing near the NE/WY/SD border region
this evening. While deep-layer shear and midlevel lapse rates are
favorable, generally modest low-level moisture and buoyancy have
limited the severe threat thus far. The time window for any
remaining diurnal convection to intensify appears limited, though
isolated hail cannot be entirely ruled out into late evening.

Late this evening, elevated convection is expected to increase in
coverage across the northern High Plains, and also in a separate
band into parts of the mid Missouri Valley. Relatively favorable
lapse rates and buoyancy may allow this convection to briefly
approach severe limits, but generally modest deep-layer shear and a
tendency for storm interference may tend to limit the
organized-severe threat. Confidence in more than brief elevated hail
potential is too low to include probabilities.

...Parts of central MT...
Isolated small but relatively organized cells have recently
developed to the east and south of Great Falls, in advance of a
mid/upper-level low/trough approaching the northern Rockies. While
favorable shear will continue to support occasional storm
organization, very weak buoyancy is expected to limit organized
severe potential through the evening. Small hail and localized
strong gusts may occur with the strongest storms.

..Dean.. 09/14/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TVSmPj

SPC Sep 13, 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
1139 AM CDT Sun Sep 13 2026

Valid 131630Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHEAST...

...SUMMARY...
Isolated to widely scattered severe thunderstorms will be possible
across parts of the upper Ohio Valley into the Northeast this
afternoon and evening. Isolated strong to severe thunderstorms may
also occur across parts of the central and northern High Plains.

...Northeast and upper/middle Ohio Valley...
Have upgraded portions of the region to a categorical Slight Risk
with expectations of a semi-focused regional corridor of wind damage
later this afternoon through early evening. Within large-scale upper
troughing over eastern Canada, a strong west-southwesterly mid-level
jet will overspread the Great Lakes into the Ohio Valley and
Northeast later today into tonight. A surface cold front will
likewise track eastward across these regions through tonight. A
seasonably moist low-level airmass will be in place ahead of the
cold front, but poor lapse rates aloft (around 6-6.5 C/km) and cloud
cover should limit the degree of destabilization that can occur this
afternoon, although cloud cover has tended to thin/abate since early
this morning across the upper Ohio Valley. While the main influence
of the upstream upper-level trough will not arrive until this
evening, strengthening mid-level flow through the day will support
35-45 kt of deep-layer shear and the potential for organized bands
of convection.

At least widely scattered thunderstorms are expected to develop
along/ahead of the front by mid afternoon (around 19-22Z) from parts
of Ohio into western New York, and then spread quickly eastward
across the upper Ohio Valley into the Northeast. The deep-layer
shear will be strong enough for some supercells initially, with
perhaps a marginal/isolated hail threat even with the poor lapse
rates present aloft. But, clusters/bowing segments with an isolated
damaging wind threat should quickly develop given the linear forcing
of the front. This convection is forecast to weaken with eastward
extent this evening with the onset of nocturnal cooling, and as it
encounters a less unstable airmass.

...Wyoming and central/northern High Plains to Missouri Valley...
A closed mid/upper-level low over the Pacific Northwest this morning
will move eastward to the northern Rockies/High Plains through the
period. Diurnal destabilization will generally be limited ahead of
this low, though a narrow zone of weak instability may develop by
late afternoon across southern Wyoming, and across northeast
Colorado into the Nebraska Panhandle in a modest low-level upslope
flow regime. Isolated thunderstorm development is expected with
sufficient wind profiles for isolated severe hail/wind potential.

Elevated thunderstorms should again increase in coverage across
western/central South Dakota towards the mid Missouri Valley late
tonight into early Monday morning. Moderate MUCAPE and sufficient
cloud-layer shear could support an isolated hail threat with the
initial development across western/southern South Dakota, though
mergers/interactions and weakening buoyancy will likely limit the
longevity and eastward extent of this threat into the mid Missouri
Valley.

..Guyer/Weinman.. 09/13/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TVSfbn