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

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1156 PM CDT Sun Sep 13 2026

Valid 151200Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TUESDAY
AFTERNOON AND EVENING IN A CORRIDOR SOUTH/SOUTHWEST OF THE GREAT
LAKES THROUGH PORTIONS OF THE CENTRAL GREAT PLAINS...

...SUMMARY...
Scattered strong thunderstorms may impact a corridor south to
southwest of the Great Lakes through the lower Missouri Valley
Tuesday afternoon and evening, accompanied by at least some risk for
locally damaging wind gusts.

...Discussion...
Latest model output appears in better agreement concerning digging
mid-level troughing along the Pacific coast through this period,
downstream of a still notable mid-level high centered across the
northern mid-latitude eastern Pacific.  Coincident with this
upstream amplification, initially prominent mid-level ridging
centered over the Southeast is forecast to build northwestward
across much of the northern Great Plains through Great Lakes region.
As this occurs, a deamplifying short wave trough and associated
surface cyclone are forecast to continue an east-northeastward
migration across the remainder of northwestern Ontario through much
of northern Quebec by late Tuesday night.  

It appears that a cold front trailing the cyclone will gradually
overtake a preceding low-level baroclinic zone, reinforced by
considerable ongoing convection and initially slowly advancing
across and southeast of the southern Lower Michigan through southern
Iowa and northern Kansas vicinity at 12Z Tuesday.  A gradual
southward progression into the Ohio Valley and across the lower
Missouri Valley may proceed Tuesday into Tuesday night, beneath the
building mid-level ridge. 

...Southern Great Lakes through central Great Plains...
Particularly from portions of the southern Great Lakes region into
the lower Missouri Valley, it appears that the southward progression
of the convective outflow reinforced boundary will be initially slow
enough to allow for substantive destabilization in close proximity
to the modest southern fringe of the westerlies.  With surface dew
points increasing to near 70 F, steepening low-level lapse rates
with insolation may support the development of moderate mixed-layer
CAPE on the order of 2000 J/kg.  Although mid/upper heights may be
tending to slowly rise, it appears that mid-level inhibition may
remain weak enough to allow for the initiation of increasing,
scattered thunderstorm development through the mid to late
afternoon.  Warm profiles, in general (if not a developing warm
layer aloft), may tend to suppress large hail, but thermodynamic
profiles characterized by steep lapse rates of potential wet-bulb
temperature in lower/mid-levels could contribute to a few downbursts
and developing cold pools with a few strong gusts into Tuesday
evening.

..Kerr.. 09/14/2026

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0225 AM CDT Mon Sep 14 2026

Valid 161200Z - 171200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The risk for severe thunderstorms appears negligible (i.e, less than
5 percent probabilities) across the U.S. Wednesday through Wednesday
night.

...Discussion...
It appears that an initially digging short wave trough along the
Pacific coast will contribute to the evolution of a mid/upper low
centered across northern California by or shortly after the
beginning of this period.  There it is forecast to generally remain,
cut off from the stronger westerlies confined to the northern
mid-latitudes.  

A couple of notable short wave perturbations will remain progressive
within a stronger confluent mid/upper regime across the eastern
Canadian Provinces through northern mid-latitude Atlantic, including
one forecast to translate east of Newfoundland and Labrador and
another digging through northern Manitoba and northwestern Ontario.

In lower latitudes, mid-level ridging likely will remain prominent
across much of the central and southern Great Plains through
northern Mid Atlantic.  More uncertainty exists concerning an
easterly wave approaching the Florida Peninsula and a possible
mid-level perturbation suppressing the ridging across parts of the
lower Great Lakes/upper Ohio Valley vicinity.

Based on current model output, a remnant surface frontal zone across
the Ohio into lower Missouri Valleys will remain a focus for higher
boundary layer moisture content and the development of moderate CAPE
with insolation.  However, there is spread concerning the degree to
which this front remains quasi-stationary, or begins to return
northward toward at least a bit more of a favorably sheared regime
for organized convection.  Given this uncertainty, and the otherwise
marginal/isolated nature of the anticipated severe weather
potential, severe probabilities for Wednesday through Wednesday
night appear less than 5 percent at this time.

..Kerr.. 09/14/2026