SPC AC 131950
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0250 PM CDT Sun Jul 13 2025
Valid 132000Z - 141200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHEAST
ARIZONA...CENTRAL PENNSYLVANIA INTO NORTHERN NEW YORK...
...SUMMARY...
Isolated severe thunderstorms are possible today through early
tonight in the Upper Midwest, Mid-Atlantic/Northeast, Southwest,
south-central Texas to the Lower Ohio Valley, and Florida.
...20Z Update...
Adjustments were made to the general thunderstorm area based on
current observations. The forecast is otherwise unchanged. See the
previous forecast for additional details.
..Wendt.. 07/13/2025
.PREV DISCUSSION... /ISSUED 1128 AM CDT Sun Jul 13 2025/
...Northeast/Mid-Atlantic States...
Moist low-level convergence, orographic effects, and glancing ascent
from an exiting shortwave trough will combine to support widespread
thunderstorm development from western/central NY southward into
central VA today. Shear is weak across much of the region, with a
generally disorganized multicellular mode anticipated. As such,
water-loaded downbursts will be the primary risk. However, modestly
stronger mid-level southwesterlies could support some sustained
multicells from central/northern NY into central PA. Consequently,
there is corridor of greater severe potential across this region
where storm clustering and linear segments appear more likely.
...Southwest...
Modest northerly flow aloft is forecast across northern NM, turning
more northeasterly over southeast AZ. Widespread storms are expected
to develop off the higher terrain and then progress
southward/southwestward from mid-afternoon to mid-evening. Given
moderate northeasterly flow, the potential for strong gusts exists,
particularly across southeast AZ, where high-based storms coming off
the higher terrain will move into a deeply mixed airmass.
...Upper Midwest...
Satellite imagery shows some modest drying over far southern MB and
western ND associated with a low-amplitude shortwave trough embedded
within the northwesterly flow aloft. Modest large-scale ascent
attendant to this wave will augment convergence along a surface
trough progressing through the region to support thunderstorms
during the late afternoon/early evening. Strengthening mid-level
northwesterly flow will result in hodographs supportive of potential
discrete supercells and large hail production. However, relatively
warm profiles (i.e. modest mid-level lapse rates) and lingering
convective inhibition should limit overall storm intensity/coverage.
Isolated large hail/severe gusts from a few widely spaced supercells
seem plausible from late afternoon until around sunset.
...TX Hill Country into South-Central/East Texas...
Morning radar and satellite imagery show a well-defined MCV centered
over the Concho/McCulloch/Menard county vicinity. This MCV is not
expected to move much today as it drifts slowly south/southeastward.
However, outflow associated with thunderstorms generated by this MCV
is pushing eastward/southeastward into the very moist and buoyant
airmass downstream. Primary threat with this system is likely flash
flooding (see WPC EROs/MPDs for details), but a few water-loaded
downbursts capable of wind damage are possible as the composite
outflow pushes into more of south-central/east TX this afternoon and
evening.
...Mid-South/Lower Ohio Valley...
A pair of convectively enhanced vorticity maxima are apparent across
the region on recent radar and satellite imagery. The southernmost
vorticity max is currently moving eastward across the central OK/AR
border, while the northernmost max is moving through central MO.
Both of these features are expected to progress
eastward/northeastward today, interacting with the moist and buoyant
airmass downstream to promote widespread thunderstorms from the
Lower OH Valley into the Mid-South vicinity. Modest but deep
southwesterly flow will be in place, which could potentially support
some clustering/upscale growth along a northeastward-progressing
cold pool, particularly from the MO Bootheel vicinity into western
KY and southern IN where the highest storm coverage is expected.
Some risk for damaging gusts could accompany this cluster.
...Lower MS Valley...
A few water-loaded downbursts are possible within the very moist
(i.e. PWAT greater than 2") and strongly buoyant (i.e. MLCAPE over
2500 J/kg) airmass over the region this afternoon. Updraft longevity
will be limited by weak shear but new development is likely on any
outflow boundaries.
...Florida...
A modest mid-level cyclone will drift closer to the Southeast coast
today. Mid-level northerly/northwesterly flow around the western
periphery of this cyclone is expected across the northern and
central FL Peninsula today. Even though it will be relatively modest
(i.e. 20 to 25 kt at 500 mb), it should still be enough to foster
some long-lived updrafts within the very moist and unstable airmass
that is in place. As a result, damaging gusts will be possible
within wet microbursts from mid-afternoon to early evening.
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
SPC AC 131731
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1231 PM CDT Sun Jul 13 2025
Valid 141200Z - 151200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN
NEW ENGLAND TO THE MID ATLANTIC AND THE NORTHERN ROCKIES/PLAINS...
...SUMMARY...
Isolated strong to severe thunderstorms are possible across portions
of the northern Plains/Rockies and across the Mid Atlantic and
Southern New England Monday.
...Mid Atlantic to southern New England...
Weak troughing at the northern periphery of the subtropical ridge
will shift northward across parts of the Northeast Monday. At the
surface, a wind shift/weak front will move from the eastern Great
Lakes into the upper OH/St Lawrence Valley by early afternoon. A
very warm and humid air mass is in place east of the front with
dewpoints in the 70s F expected. Despite some lingering cloud cover,
diurnal heating should support moderate destabilization over much of
the Northeast. Widespread thunderstorm activity is expected along
and ahead of the surface boundary from northern VA into southern NY.
Slight enhancement of the flow aloft to near 20 kt from the
approaching shortwave could be enough to foster some longer-lived
clusters with damaging gust potential from northern VA into southern
NY. Elsewhere across the East, confidence in storm coverage/damaging
wind potential is lower, but any stronger storms will remain cable
of damaging outflow gusts from heavily water-loaded downdrafts.
...Northern Rockies and Plains...
An upper trough, forecast to emanate from southern Canada, will move
eastward over the northern Rockies/Plains Monday and Monday night.
Ascent from this feature will overspread a weak cold front and lee
trough/low, that will serve as a focus for scattered thunderstorms
through afternoon and evening. Along the southern fringes of
enhanced westerly flow aloft, a mix of multicells and transient
supercells is expected. Modest surface moisture and deep
boundary-layer mixing will support moderate buoyancy atop inverted-v
structures favorable for damaging gusts and some hail with storms
from northern WY into the western Dakotas.
Late in the evening and into the overnight hours, low-level warm
advection and continued ascent from the upper trough are expected to
intensify along and north of the cold front from eastern MT into ND.
A belt of strong mid-level flow (35-50 kt) will overlap with
elevated destabilization north of the front. While not overly
robust, sufficient buoyancy (MUCAPE ~1000 J/kg) and elongated
hodographs should support a few organized elevated storms (including
supercell structures) capable of isolated hail.
...Southeast States...
A seasonably warm and moist air mass will again reside across much
of the southeastern US beneath broad subtropical ridging aloft.
Scattered to numerous storms expected Monday afternoon and evening
amid strong diurnal heating and weak background ascent. With PWATs
near or exceeding two inches and moderate buoyancy, a few stronger
thunderstorm clusters may develop. With weak vertical shear below 15
kt, organized storms on a widespread basis are not expected. Still,
sporadic damaging gusts from wet microbursts are possible.
..Lyons.. 07/13/2025
WUUS02 PTSDY2
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z
SPC AC 131939
Day 3 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0239 PM CDT Sun Jul 13 2025
Valid 151200Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
MIDWEST TO THE CENTRAL HIGH PLAINS AND ACROSS THE MID MISSISSIPPI
VALLEY...
CORRECTED FOR NDFD FILL ERROR
...SUMMARY...
Isolated strong to severe thunderstorms are possible Tuesday
afternoon and evening across portions of the central Plains to Upper
Midwest and Mid Mississippi Valley.
...Northern/Central Plains to the Upper Midwest...
A broad upper trough and multiple convectively enhanced shortwave
perturbations moving out of southern Canada should move
east/southeastward over the Northern Rockies Tuesday. A belt of
enhanced mid-level flow (30-40 kt) will also spread eastward,
overlapping with a sagging cold front from the western Great Lakes,
across the northern Plains and into the Rockies. Along and south of
the front, rich low-level moisture is expected with dewpoints in the
upper 60s to low 70s F contributing to 2500-3000 J/kg of MLCAPE.
Ascent from the approach trough and flow aloft will aid in deepening
a lee low across the central High Plains at the junction of the
front and a prominent lee trough. Convergence along these features,
should support scattered thunderstorms Tuesday afternoon and
evening.
With deep-layer shear increasing to 30-35 kt, scattered
thunderstorms organized into multicell clusters or supercell
structures is possible along the cold front from the eastern Dakotas
to the western Great Lakes and within the broader warm sector across
southern SD to central NE. More isolated storms will also be
possible along and east of the lee trough trailing the surface low
to the south. Steep low mid-level lapse rates of 8+ C/km will be
more than sufficient for isolated severe storms capable of damaging
gusts and some hail. Consideration was given to higher severe
probabilities given large forecast buoyancy and more focused forcing
along the front/triple point. However, variability in the timing of
the front and overnight convective influences at this range lend low
confidence to any one solution.
At least an isolated severe risk should also extend westward within
the post-front upslope regime across far southern MT and into
eastern WY and western SD. While buoyancy will be reduced, low-level
moist advection and upslope flow behind the front will support
isolated to widely scattered storms within enhanced mid-level flow.
Hail and isolated damaging gusts are possible.
...Mid MS Valley...
Multiple model solutions show a rather well-defined MCV moving out
of the southern Plains and Ozarks into the mid MS Valley by Tuesday
morning. A very warm and humid air mass will remain in place ahead
of this feature supporting sufficient buoyancy for scattered
thunderstorms. The exact placement and intensity of this feature
remains very uncertain owing to different mesoscale
solutions/convective influence in the coming days. Still, some
enhancement of the low/mid-level flow field could support some
organized clusters capable of damaging gusts.
..Lyons.. 07/13/2025
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z
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