SPC Sep 10, 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
0740 PM CDT Wed Sep 09 2026

Valid 100100Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS A PORTION OF THE
UPPER OHIO VALLEY...

...SUMMARY...
Isolated severe storms capable of mainly damaging wind gusts will
remain possible through late evening from the upper Ohio Valley into
the southern Plains.

...Upper Ohio Valley/Lower Great Lakes...

Scattered thunderstorms are ongoing this evening along and ahead of
a cold front from north-central PA into central OH within a moist
air mass with the 00Z Pittsburgh sounding indicating MLCAPE of
around 1000 J/kg. Moreover, the corresponding wind profile exhibited
relatively strong low-level and deep-layer shear with effective SRH
of around 250 m2/s2 and effective bulk shear of around 40 kt. So,
while lapse rates and resultant instability are expected to weaken
with the loss of daytime heating, the kinematic environment will
remain supportive of transient supercell and bowing structures
capable of locally damaging wind gusts and perhaps a tornado for the
next couple of hours.

...Southern Plains into the Ozarks...

A thunderstorm complex ongoing southeast of Kansas City this evening
is located to the north of the synoptic front that stretches from
central MO through far southeast KS and northwest OK into the TX
Panhandle. Some cold pool organization is present per KEAX base
velocity data, with recent reports of wind damage and wind gusts up
to 59 mph. The air mass ahead of the storms has been slightly
modified by convective outflow but still remains sufficiently
buoyant to sustain the ongoing storms with a continued risk for
isolated severe wind gusts through the remainder of the evening.

Over the southern Plains, widely scattered thunderstorms continue
this evening along and in the immediate wake of the front. The air
mass ahead of the front remains hot with a deep, well-mixed boundary
layer, which will remain supportive of locally severe wind gusts for
the next hour or two.

..Mead.. 09/10/2026


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SPC Sep 9, 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
1127 AM CDT Wed Sep 09 2026

Valid 091630Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM CENTRAL OHIO INTO NORTHWEST PENNSYLVANIA AND WESTERN
NEW YORK....

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley today.

...OH/PA/NY...
A fast-moving shortwave trough now over WI/IL will track eastward
today across the Great Lakes region. At the surface, the primary
baroclinic currently extends from Lake Erie into OH/IN and will move
eastward and be the focus for scattered afternoon thunderstorms.
Strong heating and dewpoints in the 70s across much of OH and
western PA will result in moderate CAPE values and steep low-level
lapse rates. Sufficient deep-layer shear will promote organized
storms with some bowing structures expected, capable of locally
damaging wind gusts. This activity will spread into western
NY/northwest PA by early evening before weakening.

...IN/IL/MO...
The storms that form over OH will zipper southwestward along the
boundary into a pocket of ample CAPE/moisture over parts of southern
IN/IL into southern MO. Winds aloft in this area will be weaker,
with less overall organization of storms. Nevertheless, a few
storms may occasionally produce damaging wind gusts.

...TX/OK/KS...
Widely scattered slow-moving afternoon thunderstorms will pose a
risk of gusty/damaging winds in a hot/humid surface air mass.

..Hart/Guyer.. 09/09/2026


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SPC Sep 9, 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
0741 AM CDT Wed Sep 09 2026

Valid 091300Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL OHIO
FROM WESTERN NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley today. A more organized
severe weather threat is expected from eastern Ohio to western New
York.

...Synopsis...
Early-morning satellite imagery show broad upper troughing from the
Pacific Northwest/British Columbia through the Upper Great Lakes and
Ontario. Several shortwave troughs are embedded within this larger
upper troughing, including one moving into northern MN and another
farther north across far northwestern Ontario. A belt of moderate to
strong mid-level westerly/southwesterly flow extends between the
base of these two waves. Expectation is the southern wave to move
quickly eastward through the Upper Great Lakes and Ontario,
accompanied by mid-level jet max.

Surface analysis places a occluded low over far northwestern
Ontario, with a cold front extending southward into western Upper MI
and then back southwestward through central NE. An outflow-augmented
pre-frontal trough precedes this front, extending from a low in
southwest Lower MI to another low over northeast KS to another over
far southwest KS/far southeast CO. Both the cold front and
pre-frontal trough are expected to progress modestly
southward/southeastward today. Two corridors of relatively higher
thunderstorm coverage are anticipated this afternoon/evening, one
from eastern OH into western PA/western NY and the other farther
southwest from the Lower MO Valley into the TX/OK Panhandles.

...Central Ohio into western New York...
Moist low-levels are already in place from the OH Valley into
western PA and NY, with recent surface analysis sampling upper 60s
dewpoints in central OH decreasing to the low/mid 60s across western
PA and western NY. This moist airmass is expected to destabilize
amid modest low-level moisture advection and filtered insolation,
ahead of a convectively augmented vorticity maximum. With the cold
front still well to the northwest, this vorticity maximum will be
the primary impetus for thunderstorm development, augmenting the
weak low-level confluence along the weak pre-frontal trough. A
predominately linear/clustered storm mode is anticipated, but
strengthening mid-level flow will support effective bulk shear from
30 to 40 kt, which could support some more persist/organized line
segments. Damaging gusts are the primary risk with any of these more
organized segments. Low-level hodographs do show some notable
curative, particularly from western PA into western NY after 00Z,
amid a strengthening low-level jet. As such, there is a
low-probability tornado risk is these areas.

...Lower OH and MO Valleys into the TX/OK Panhandles...
Thunderstorm coverage is gradually expected to increase across the
region this afternoon and evening, beginning near a surface low move
across the Lower MO Valley before expanding back southwestward along
the southward-progressing front. The stronger vertical shear will be
displace north of the front, and a largely disorganized,
outflow-dominant storm mode is anticipated. Slightly better flow
aloft may favor a more focused cluster across the Mid-Mississippi
Valley into western Kentucky/Tennessee. Steep low-level lapse rates
and high cloud bases could support strong gusts from the Lower MO
Valley into the TX/OK Panhandles.

...Southern AZ...
Afternoon thunderstorms are expected over the higher terrain near
the southern AZ/NM border. There is some potential this activity
progresses westward into the lower elevations of southern AZ.
However, upper ridging will be centered over this region and
vertical shear will be weak, resulting in slow storm motion and
disorganized, outflow-dominant structures. A few strong gusts could
result from any more persistent updrafts.

..Mosier/Lyons.. 09/09/2026


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SPC Sep 9, 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
1241 AM CDT Wed Sep 09 2026

Valid 091200Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO
INTO WESTERN NEW YORK...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the central Plains to the Ohio Valley on Wednesday. A more
organized severe weather threat is expected from eastern Ohio to
western New York.

...Synopsis...
A belt of enhanced mid-level flow will move through the broad
upper-level trough across Ontario, overspreading the Great Lakes
into Upstate New York and Quebec. A cold front will extend from a
deep surface low across northern Ontario south through the Upper
Midwest and into the central High Plains. Isolated to widely
scattered thunderstorm activity is expected near the surface trough
across the Ohio Valley into the Northeast and along the front from
the Midwest to the central High Plains.

...Eastern Ohio into western New York...
Across the eastern Ohio Valley into portions of the Northeast,
strengthening mid-level flow will overspread the region with
thunderstorms developing along the cold front and pre-frontal
surface trough. Upper 60s to 70s dew points and filtered daytime
heating will yield moderate instability amid ample deep layer shear
for organization. Mode will likely be a mix of multi-cell clusters
and transient supercells, with potential for damaging wind.
Generally weak lapse rate profiles and quick mode transition to
clusters/linear segments should limit hail and tornado potential.
Nonetheless, as the low-level jet increases into the afternoon and
clockwise curvature increases in hodographs a tornado may be
possible.

...Ohio Valley to the Midwest and the central Plains...
Morning convection will be likely across much of the
Midwest/Mid-Missouri Valley into the northwestern Ohio Valley.
Remnant shower activity/cloud cover will likely limit severe
potential with northern extent. Nonetheless, isolated to widely
scattered thunderstorm activity is expected to develop by the
afternoon along the front and remnant outflow from the eastern Ohio
Valley through portions of the Midwest and into the central Plains.
Flow will be fairly weak across the central Plains, with generally a
marginal damaging wind threat with multi-cell clusters as daytime
heating steepens low-level lapse rates amid deeply mixed profiles.
Slightly better flow aloft may favor a more focused cluster across
the Mid-Mississippi Valley into western Kentucky/Tennessee.

..Thornton/Chalmers.. 09/09/2026


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