SPC May 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
1120 AM CDT Wed May 13 2026

Valid 131630Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL MT
SOUTHWARD INTO NORTHERN UT...

...SUMMARY...
Scattered thunderstorms capable of damaging wind gusts are possible
from the Great Basin into northern Rockies this afternoon and
evening. Other areas of isolated severe wind/hail risk may occur
over the upper Ohio Valley and the Texas Panhandle.

...WV/PA/NY...
Recent surface analysis places a low over northern Lake
Huron/central Ontario, with a cold front extending back
southwestward through western OH and western KY. Current satellite
shows the associated shortwave trough extending from central Ontario
into the Mid MS Valley. This imagery also shows two embedded
vorticity maxima, one near the surface low over central Ontario and
the other farther southwest over IL/IN. This shortwave is expected
to mature throughout the day, trending towards a more neutral tilt
by this evening, while also gradually shifting eastward. The
associated cold front is forecast to shift quickly eastward as well.

At least scattered clouds will likely persist throughout the day,
somewhat tempering the overall daytime heating. Even so, modest
low-level moisture (i.e. dewpoints in the low/mid 50s) ahead of the
cold front will support a corridor of sufficient buoyancy for
thunderstorm development ahead of the front from western PA and WV
eastward across PA and into southern/central NY. Linear forcing
along the front and relatively modest deep-layer shear will favor a
multicellular line segment mode. Potential exists for a few deeper
updrafts capable of damaging gusts, but the limited heating ahead of
the front, modest buoyancy, and displacement south and east of the
stronger low to mid-level flow should keep the overall severe
potential isolated. A few isolated instances of hail are possible
early in the convective cycle before the more linear structures
dominate.

Recently issued MCD #0710 addresses this area as well.

...Great Basin into the northern Rockies...
Current satellite imagery shows a well-defined, negatively tilted
shortwave trough progressing across the Pacific Northwest. This wave
is forecast to continue eastward through ID and MT today. Strong
heating and deep boundary-layer mixing is expected ahead of this
wave from the Great Basin into the northern Rockies. At the same
time, mid-level moisture associated with the wave will advect
eastward/northeastward, resulting in large area of deep inverted-v
thermodynamic profiles that are also buoyant enough to support
convection and isolated lightning. Strong mid-level flow will
accompany the shortwave, with moderate mid-level flow extending
southward from the primary wave through UT and far western CO.

Scattered convection is expected as lift associated with the wave
begins to interact with this destabilizing airmass, likely starting
around 20/21Z from western MT into northern UT. This convection,
which should include lightning-producing updrafts, will then spread
eastward/northeastward with time. Strong to severe gusts are
possible across this entire region, with the highest likelihood for
severe gusts from central/southern ID into central MT where the
strongest mid-level flow is expected.

...TX Panhandle...
Deep boundary-layer mixing is anticipated across the TX Panhandle
today, with temperatures climbing into the 90s. Low-level moisture
advection should result in higher dewpoints across the eastern
Panhandle, with the resultant dryline acting as a focus for
convergence and attempts at convective initiation. The overall
environment does not look conducive for initiation and majority of
the CAMs do not show storm development. However, any storm that can
persist in this environment would conditionally pose a threat of
damaging wind gusts and large hail.

..Mosier/Chalmers.. 05/13/2026


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SPC May 13, 2026 1300 UTC Day 1 Convective Outlook

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


Day 1 Convective Outlook RESENT 1
NWS Storm Prediction Center Norman OK
0714 AM CDT Wed May 13 2026

Valid 131300Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL MT
SOUTHWARD INTO NORTHERN UT...

...SUMMARY...
Scattered thunderstorms capable of damaging wind gusts are possible
across portions of the northern High Plains and Great Basin this
afternoon and evening. Other areas of isolated severe wind/hail
risk occur over the upper Ohio Valley and the Texas Panhandle.

...WV/PA/NY...
A large upper trough is deepening as it tracks southeastward across
the Great Lakes and Midwest into the Upper Ohio Valley. The
associated surface cold front is sweeping across OH, and will extend
from central NY into western PA and northern WV later today. Clouds
are currently prevalent across this region, but some
clearing/heating is expected as low-level moisture is transported
into the area. The result will be narrow corridor of sufficient
CAPE for thunderstorm development along the front from NY into WV.
Given the strength of the upper trough and winds aloft, there is
concern for a few severe storms capable of damaging winds and
perhaps hail...mainly in the 18-00z period.

...Great Basin...
A second strong and progressive upper trough has moved ashore over
OR/WA and will spread mid-level height falls and large scale ascent
across much of the Great Basin and Rockies today and tonight.
Low-level moisture is very sparse ahead of the system, but pockets
of strong heating from northern UT into eastern ID/western WY and
central MT will result in inverted-v profiles and sufficient CAPE
for isolated charge separation and robust updrafts. CAM solutions
suggest a risk of high-based fast-moving showers and occasional
thunderstorms affecting the region, with the risk of severe wind
gusts.

...TX Panhandle...
A surface dryline will become established over the TX panhandle
later today, where temperatures will climb well into the 90s.
Forecast soundings show only modest CAPE and limited risk of
convective initiation over this area. However, any storm that can
persist in this environment would conditionally pose a threat of
damaging wind gusts and large hail. Will maintain the ongoing MRGL
risk for this conditional risk.

..Hart/Wendt.. 05/13/2026


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SPC May 13, 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
0108 AM CDT Wed May 13 2026

Valid 131200Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHERN UTAH
NORTHWARD ACROSS EASTERN IDAHO...WESTERN WYOMING...AND PORTIONS OF
WESTERN MONTANA...

...SUMMARY...
Scattered severe thunderstorms are possible across portions of the
northern High Plains Wednesday afternoon and evening. Severe wind
gusts are the primary hazard.

... Synopsis ...

An amplified, yet progressive, midlevel pattern will exist across
the US on Wednesday. A vigorous shortwave trough will move east
across the northern Rockies as a Mexico-to-Canada midlevel ridge
moves into the central US. Downstream from the ridge, an amplified
trough will deepen further, developing into a closed low over the
northern Mid-Atlantic and southern New England region.

... Portions of the Great Basin and the Central and Northern Rockies
...

As the potent midlevel shortwave trough moves across the northern
Rockies an attendant 80-90 knot midlevel jet streak will overspread
northern portions of the area during the afternoon and evening
hours. At the same time, a cold front will push east across the
region leading to scattered convection by mid-to-late afternoon.
Forecast soundings continue to exhibit inverted-V thermodynamic
profiles and increasing cloud-layer shear. The result will be fast
moving storms capable of transporting momentum downward to the
surface. Additionally, the dry sub-cloud layer will support the
potential for some dry microburst potential.

... Ohio Valley and Central Appalachians ...

A surface low will move east from Lower Michigan toward northern New
York, dragging a cold front eastward across the Ohio Valley and
central Appalachians before ending up near the Atlantic Coast.
Toward the end of the forecast period, the northern New York surface
low will redevelop farther southeast along the front near the
Atlantic Coast.

Ahead of the front, surface dewpoints should rise into
low-to-mid-50Fs contributing to weak instability with diurnal
heating. Thunderstorms should develop across the area during the
afternoon along the front, with additional thunderstorms possible
across terrain favored areas across the central Appalachians.
Sufficient vertical shear beneath a 50 knot midlevel jet and modest
low-level lapse rates would support a marginal wind threat.

... Texas Panhandle into the High Plains of Southern Colorado ...

Strong diurnal heating beneath the midlevel ridge may be sufficient
for convective inhibition to erode and isolated thunderstorms to
develop across terrain favored areas. Very steep lapse rates will
support a hail and wind threat.

..Marsh/Weinman.. 05/13/2026


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SPC May 12, 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
0254 PM CDT Tue May 12 2026

Valid 122000Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE GREAT LAKES...CENTRAL PLAINS AND FLORIDA...

...SUMMARY...
Severe storms remain possible across parts of the Florida Peninsula
today, and potentially from southeast Kansas into parts of the Great
Lakes late this afternoon and early evening.

...20z Update Great Lakes...
Afternoon visible imagery shows the cold core of an upper-level
trough beginning to impinging on modest low-level moisture south of
a stalled front near the MI/WI border. While moisture and resulting
buoyancy remain very limited (200-300 J/kg MUCAPE), steep mid-level
lapse rates and continued heating should support enough
destabilization for a few storms this afternoon and evening. Hail is
possible, especially with any storms elevated above the surface
given fairly strong mid-level flow. Have adjusted 5% hail
probabilities northward toward the warm front across the MI/WI
border.

...FL...
Numerous storms are ongoing this afternoon south of an east-west
oriented baroclinic zone across the FL Peninsula. To the south, the
environment remains moderately unstable and sheared, which has
supported a few organized clusters and supercells so far. Hail,
damaging winds, and a brief tornado remain possible with the
strongest storms as the boundary is forecast to sag southward
through tonight. Have removed severe probabilities and trimmed
thunder behind the boundary where the air mass has stabilized.

Otherwise, the prior outlooks remains valid with only minor
adjustments. See the previous discussion for more information.

..Lyons.. 05/12/2026

.PREV DISCUSSION... /ISSUED 1127 AM CDT Tue May 12 2026/

...Florida...
A very moist airmass is in place across the FL Peninsula today, with
surface observations showing dewpoints in the low to mid 70s.
Mesoanalysis estimates MLCAPE is at or above 1500 J/kg for much of
the peninsula already. A shortwave trough is currently moving into
the central Gulf Coast vicinity, with continued
eastward/southeastward progress expected throughout the day. The
prevailing buoyancy coupled with ascent attendant to this wave will
result in scattered to numerous thunderstorms. Low-level flow is
generally weak, but the shift from low-level easterly winds to
moderate southwesterly aloft is supporting moderate deep-layer
vertical shear. Some increased shear is possible in the vicinity of
the east-coast sea-breeze, with the strongest storms anticipated
near this boundary as a result. The overall expectation is for some
organized multicells and a few supercells, posing a risk of damaging
wind gusts and hail, particularly across the east-central portions
of the peninsula.

...Upper Midwest through the Mid MO Valley into southeast
KS/northeast OK...
Recent satellite imagery shows a well-defined shortwave trough
moving through the Upper Midwest towards the Upper Great Lakes.
Surface analysis places the low associated with this shortwave over
the northern MN/WI border vicinity, with an attendant cold front
extending back southwestward through northwest IA,
southeast/south-central NE, and far northwest KS. A modest
pre-frontal trough is in place just ahead of this cold front. The
shortwave trough is forecast to continue eastward, while the cold
front progresses eastward/southeastward. Northern portion of this
front (closer to the surface low and parent shortwave) will make
notably more eastward/southeastward progress than the
southern/western portion, which will move more gradually
southeastward.

Low-level moisture advection is anticipated ahead of the front, but
with mid 50s dewpoints currently in central OK, the extent and
quality of this moisture will likely be somewhat limited. Filtered
heating and mixing could also reduce dewpoints. Even so, dewpoints
will likely still reach at least the mid 40s across southern WI,
gradually increasing into the mid 50s across southeast KS/southwest
MO/northeast OK. This is expected to be enough moisture to support a
narrow corridor of modest buoyancy. Strongest ascent will be near
the surface low and shortwave trough across the Upper/Mid MS Valley,
supporting higher storm coverage than areas farther southwest. A few
high-based storms capable of wind damage and isolated hail are
possible.

Farther southwest, lower storm coverage is expected, particularly
from west-central IL into southeast KS. Thunderstorm chances across
much of this area appear low enough to remove severe probabilities.
The only exception is over the southeast KS/southwest MO vicinity.
Here, greater low to mid-level moisture could still support a storm
or two. Shear is strong enough to support hail with any storms that
mature.


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