ACUS01 KWNS 080610
SWODY1
SPC AC 080609

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0109 AM CDT Tue Jul 08 2025

Valid 081200Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDDLE
ATLANTIC...

CORRECTED FOR REGIONAL HEADER

...SUMMARY...
Scattered severe thunderstorms are expected across the Mid Atlantic.
More isolated activity is expected across portions of the Plains
into the Mid Mississippi Valley.

...Middle Atlantic...

Early-morning water-vapor imagery depicts a notable short-wave
trough over the upper MS Valley, shifting east in line with latest
model guidance. This feature is forecast to advance into the central
Great Lakes region by the end of the period. As the short wave
advances east, a corridor of higher PW (currently extending from AR
into the upper OH Valley) will be shunted downstream as a
low-amplitude disturbance ejects toward the Mid Atlantic. While some suppression of the height field can be expected late, it appears the
weak disturbance should be the primary mechanism for encouraging
somewhat stronger southwesterly flow which would extend as far south
as central VA. Even so, 0-6km bulk shear is only expected to be on
the order of 20-25kt, but favorably oriented for clusters and short
line segments. Forecast soundings exhibit poor lapse rates, but
high-water content suggests damaging downbursts are likely,
especially with any organized clusters. Convective temperatures will
be breached by 17-18z as readings climb into the mid 80s, and
scattered thunderstorms should readily develop from central PA into
central VA. This activity will then propagate toward the Mid
Atlantic Coast with an attendant risk for damaging winds.

...Plains...

Upper ridge is forecast to hold across the southwestern U.S. through
the day1 period; although, northwesterly flow is expected to
increase a bit along the eastern periphery of this feature over the
High Plains. As a result, high-level diffluent flow will be noted
across the southern Plains into southern MO. At the surface,
low-level boundaries/convergence will prove weak, and left-over
convective debris will likely prove influential in late-afternoon
development. Early this morning, an MCS was propagating south across
eastern NE/southwest IA. This complex will likely advance into
southeast KS/southwest MO by sunrise. It's not entirely clear how
organized this cluster will be at the start of the period, but
convective outflow will likely contribute to additional development
later in the day. Strong boundary-layer heating will also aid
isolated thunderstorm development across the High Plains of eastern
WY/CO/NM. This activity will spread southeast during the evening
with a risk for hail/wind.

..Darrow/Weinman.. 07/08/2025

$$

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ACUS01 KWNS 110622
SWODY1
SPC AC 110621

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0121 AM CDT Fri Jul 11 2025

Valid 111200Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING ACROSS PARTS OF NORTHEASTERN KANSAS...MUCH OF NORTHERN MISSOURI...SOUTHEASTERN IOWA...NORTHERN ILLINOIS...ADJACENT SOUTHERN
WISCONSIN AND NORTHWESTERN INDIANA...AND PARTS OF SOUTHWESTERN LOWER MICHIGAN...

CORRECTED FOR TYPOS

...SUMMARY...
Strong thunderstorms are likely to impact a corridor from the lower
Missouri Valley into southern portions of the Great Lakes region
this afternoon and evening, accompanied by a risk for damaging wind
gusts, a few tornadoes and some hail.

...Discussion...
While mid/upper ridging across the subtropical into southern
mid-latitudes remains at least a bit suppressed for the time of
year, models indicate that the stronger westerlies will remain
confined to the higher latitudes. It does appear that one notable
short wave trough, now digging to the lee of the Canadian and
northern U.S. Rockies, will progress eastward along the central
Canadian/U.S. border vicinity today through tonight, and gradually
pivot from a positive to neutral tilt. As it does, preceding weak
mid-level troughing, and at least a couple of embedded convective perturbations, are forecast to accelerate northeastward within weak
to modest ambient flow backing to a southwesterly component across
the lower Missouri Valley vicinity into the Great Lakes region.

At the same time, northwesterly mid-level flow will be maintained
with weak height falls across the southern Rockies into adjacent
Great Plains, while gradual mid-level height rises are forecast
across the Appalachians into Atlantic Seaboard.

In lower-levels, the primary short wave trough may support a modest
developing surface low across northwestern Ontario, with cooler and
drier air in its wake overspreading much of the northern Great
Plains by 12Z Saturday. Another low emerging from the central Great
Plains is forecast to migrate northeast of the lower Missouri Valley
toward the upper Great Lakes, along an initially diffuse low-level
baroclinic zone.

...Lower Missouri Valley into Great Lakes...
The low-level baroclinic zone may still be a focus for weakening
convective development at the outset of the period. However, as the
convection dissipates further, models suggest that the boundary will
become better defined with strengthening differential heating.
Surface dew points near and above 70F, beneath modestly steep
mid-level lapse rates, are forecast to contribute to CAPE on the
order of 2000-3000 J/kg along and south of the boundary, gradually
tapering to the north, beneath a lingering belt of convectively
augmented mid-level flow (on the order of 30-50 kt in the 700-500 mb
layer). Coupled with modest, clockwise-curved low-level hodographs
developing in advance of the migratory low, the environment may
become conducive to supercell structures posing a risk for a few
tornadoes across parts of northern Missouri and southeastern Iowa
into northern Illinois, before damaging wind gusts become the more
predominant potential hazard as convection tends to grow upscale
into clusters through this evening.

...Southern Rockies into the Great Plains...
Thermodynamic profiles characterized by modest low-level moisture,
but with generally steep lapse rates, including fairly deep
boundary-layer mixing, may become conducive to scattered
thunderstorm clusters posing a risk for severe wind and hail late
this afternoon and evening. This may be aided by modest shear
beneath the northwesterly mid-level flow, with thunderstorm activity
mostly initiating off the higher terrain of the Front Range through
Sangre de Cristo Mountains. However, low-level convergence within
surface troughing across southern Kansas through the Oklahoma/Texas
Panhandle vicinity may also become sufficient for thunderstorm
initiation during the peak late afternoon heating.

..Kerr/Thornton.. 07/11/2025

$$

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ACUS01 KWNS 141636
SWODY1
SPC AC 141635

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1135 AM CDT Mon Jul 14 2025

Valid 141630Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
MID-ATLANTIC AS WELL AS FAR EAST-CENTRAL WYOMING...SOUTHWEST SOUTH
DAKOTA...AND THE FAR NORTHERN NEBRASKA PANHANDLE...

CORRECTED FOR INCORRECT GEOGRAPHIC DESCRIPTION IN HEADLINE

...SUMMARY...
Strong to severe thunderstorms are possible across parts of the
northern Plains as well as the Mid-Atlantic States this afternoon
into tonight. Isolated strong to severe thunderstorms are possible
across the Mid-South, southeast Arizona, and Florida.

...Mid-Atlantic into the Northeast...
A belt of stronger mid-level flow extends from the north-central CONUS/south-central Canadian Prairies through the Northeast, with
some modest cyclonic curvature. A more defined shortwave trough is
currently progressing into the Upper OH Valley/central Appalachians,
along the southern periphery of the belt of stronger, broadly
cyclonic flow. Showers and isolated thunderstorms are currently
ongoing just ahead of this shortwave.

Expectation is for this shortwave trough to continue
eastward/northeastward throughout the day, with the modest upper
troughing farther north shifting eastward as well. A reservoir of
ample low-level moisture (i.e. dewpoints in the low to mid 70s) is
in place ahead of this shortwave. This low-level moisture will
support airmass destabilization and moderate buoyancy this afternoon
despite widespread cloudiness and tempered daytime heating.
Thunderstorm development is anticipated as large-scale ascent
attendant to the approaching shortwave (and larger upper trough)
moves into the region. Additionally, recent surface analysis places
a trough axis from the northern NY/VT border southwestward through
central PA. Low-level convergence along this axis could augment the
large-scale ascent. All of these factors will act to support
scattered to numerous thunderstorms this afternoon.

While mid-level flow and related deep-layer shear are both expected
to remain fairly modest, some of this convection could congeal into
multiple loosely organized clusters. Steepened low-level lapse rates
and water loaded downdrafts could support isolated strong to
damaging winds as thunderstorms spread generally eastward through
the afternoon and evening. Highest thunderstorm coverage and
greatest relative chance for damaging gusts is expected from eastern
PA through central VA.

...Northern Plains to Northern Minnesota...
Satellite imagery shows a vorticity maximum drifting slowly across
the central Intermountain West. Large-scale ascent attendant to this
vorticity maximum will augment low-level convergence along a
sharpening lee trough, likely resulting in enough lift to promote
thunderstorm development across eastern WY during the late
afternoon. This area is on the southern periphery of a belt of
stronger westerlies, and there appears to be just enough westerly
flow aloft for updraft organization and persistence into the better
moisture and buoyancy farther east. As such, there is a risk for
strong to severe gusts within this deeply mixed airmass throughout
the afternoon and evening.

Thunderstorm development also appears possible along a surface
trough that arcs from western MT to a low in southwest SD. A
conditional severe risk exists with any storms that develop near the
surface low over ND this afternoon, but the greater thunderstorm
coverage is anticipated later this evening and overnight as warm-air
advection across the frontal zone strengthens. Elevated
thunderstorms are also expected tonight as an
upper trough overspreads the northern Rockies. Given ample shear and
buoyancy, isolated hail is possible in both of these regions
tonight.

...Eastern GA into the FL Peninsula...
Ample low-level moisture and robust diurnal heating will result in
strong buoyancy from eastern GA southward across the entire FL
Peninsula this afternoon. A modest cyclone drifting westward towards
the GA/FL coast will interact with this airmass, contributing to
widespread thunderstorm development this afternoon. Convection
should develop along/near the Atlantic Coast before spreading south-southwestward and inland across much of the FL Peninsula this afternoon/evening. Several clusters capable of producing isolated
strong to severe winds are possible.

...AZ...
High pressure over the southern Great Basin will contribute to
around 20-25 kt of northeasterly mid-level flow across southern AZ
this afternoon. This mid-level flow will take storms that develop
across the higher terrain southwestward into the deeply mixed
boundary layer over southeast AZ. A few strong to severe gusts are
possible, but overall coverage will likely be sparse.

...South-Central/Southeast TX into the Mid-South...
A trio of MCVs is apparent on radar and satellite imagery this
morning. One is centered over Real and Uvalde Counties in the TX
Hill Country, with another over Denton and Collin Counties in north
TX, and the third farther north over northeast AR. At least
scattered thunderstorms are possible this afternoon/evening with
each of these MCVs as they progress eastward/northeastward. Vertical
shear will be weak, but discrete storm propagation along the
stronger outflows could result in occasionally strong/damaging
downbursts.

..Mosier.. 07/14/2025

$$

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