SPC Jul 19, 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
0746 AM CDT Sun Jul 19 2026

Valid 191300Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTH GEORGIA
INTO SOUTHERN VIRGINIA AND ACROSS THE DAKOTAS INTO WESTERN
MINNESOTA...

...SUMMARY...
Scattered damaging wind gusts are possible this afternoon over
portions of the Southeast. Scattered severe thunderstorms capable
of severe wind gusts and large hail are possible late this afternoon
through the evening across parts of the Upper Midwest.

... Southeast ...
Water-vapor imagery this morning shows a mid-level trough over the
Gulf of St. Lawrence and the Northeast U.S. moving east towards the
western Atlantic. A seasonably strong cold front over the OH Valley
eastward into the northern Mid-Atlantic states, will push south
before weakening over VA. A very moist airmass evident in 12 UTC
area raobs (14-15 g/kg lowest 100-mb mean mixing ratios) will
heat/destabilize across VA into the southern Appalachians.
Scattered thunderstorms will likely develop by midday into the early
afternoon both over the higher terrain and near the front. Slightly
stronger westerly flow over VA into the northern half of NC will
favor eastward-moving clusters this afternoon. High PW and
steepened low-level lapse rates will likely favor water-loading
within the stronger downdrafts. Scattered 50-60 mph gusts capable
of wind damage will be the primary hazard. Farther southwest over
GA into AL, a couple of bands of storms may yield wind-damage
potential with the stronger downdrafts. Isolated severe gusts are
also possible across parts of the central FL Peninsula northward
into southern GA.

...Upper Midwest...
A mid-level anticyclone will remain centered over the central
Rockies as an upper speed max intensifies and overspreads MT
eastward into MN. An associated mid-level trough initially over
Alberta will pivot east-southeast into Manitoba and adjacent
portions of ND-MN. Southerly low-level flow will advect richer
moisture northward into the Dakotas/MN region during the day.
Models show a relatively narrow tongue of 60s to near 70 F dewpoints
to the east of lee trough. In between a southeastward-moving cool
front and the lee trough, deep boundary layer mixing is expected.
Models generally show 1500-3000 J/kg MLCAPE over the Dakotas by mid
afternoon beneath 70 to 90-kt westerly 200-mb flow. Widely
scattered thunderstorms are expected to develop across the Dakotas
by mid to late afternoon as convective inhibition erodes.
Elongated, straight hodographs and effective shear around 40 kt will
support an initial supercell mode. Very large hail (1 to 3.5 inches
in diameter) is possible with a few of these supercells. As
additional storms develop towards the early evening, convective
outflow and additional storm mergers may lead to upscale growth of a
severe-wind producing linear cluster (most probable over the eastern
ND into adjacent SD-MN). Peak gusts with this activity are forecast
in the 60-85 mph range. These storms will move east into parts of
the eastern Dakotas and western MN before eventually weakening
overnight.

..Smith/Broyles.. 07/19/2026


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SPC Jul 19, 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
0100 AM CDT Sun Jul 19 2026

Valid 191200Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTH GEORGIA
INTO SOUTHERN VIRGINIA AND ACROSS THE DAKOTAS INTO WESTERN
MINNESOTA...

...SUMMARY...
Severe thunderstorms capable of damaging winds will be possible from
parts of north Georgia, across the Carolinas, and into southern
Virginia this afternoon. Additional severe thunderstorms capable of
damaging winds and large hail will be possible this afternoon and
evening across parts of the Dakotas and western Minnesota.

... Synopsis ...

The base-state mid-level pattern today will feature a western US
ridge and eastern US trough, with a weak closed low over the
northeast Gulf. Within this background flow field, a short-wave
trough will be exiting the Northeast US and a closed low across the
Canadian Prairies will crest the western ridge before digging
southeast late in the day toward the Upper Midwest.

At the surface, a large anticyclone will settle into the Great Lakes
region during the day. On the periphery of this anticyclone, a cold
front will be draped from coastal Virginia to the west-southwest,
before arcing northwest into the Mid-Mississippi Valley and then
into the Upper Midwest. This front will sag south across the eastern
US, while beginning to lift north and east across the Mississippi
Valley and Upper-Midwest. The front will act to delineate a very
warm/hot and moist airmass to the south and west from a cooler/dryer
airmass to the north and east.

... Georgia into southern Virginia and the greater Southeast ...

To the south of the advancing surface front, temperatures will warm
into the low-to-mid-90Fs from northern Georgia into southern
Virginia. At the same time, surface dewpoints of the upper-60Fs and
low-70Fs will be maintained. The result will be an strongly unstable
environment with HREF ensemble mean MUCAPE between 1500-2000 J/kg
across the region. Forecast soundings show precipitable water
greater than 1.75 inches across much of the area, with a band of
precipitable water in excess of 2 inches. This, coupled with steep
sub-cloud layer lapse rates (approaching 8 C/km) which will support
wind damage potential with any sustained thunderstorm updraft.

Surrounding this area, more scattered thunderstorm development is
expected within the moist and unstable environment. At this time, it
appears a corridor of higher likelihood for thunderstorm development
will extend from southeast Louisiana northeast toward northern
Georgia. This increased thunderstorm activity appears to be
associated with a band of modest convergence in the 850-700 millibar
layer to the north of a weak low across the northeast Gulf. Damaging
wind gusts will be possible with some of these storms.

Another potential area of damaging wind gusts will be across
north-central Florida into far south-central Georgia. Here, HREF
guidance shows an east-northeast expanding band of thunderstorms
emanating from the low over the northeast Gulf.

... Dakotas into western Montana ...

Temperatures are expected to warm into the upper-90Fs to the
low-100Fs during the afternoon to the east of a low-level trough
axis developing in the lee of the Rockies in the northern High
Plains. To the east of this trough axis, HREF ensemble mean
dewpoints in the mid-to-upper-60Fs will combine with those hot
afternoon temperatures to support a very unstable environment, with
HREF ensemble mean MUCAPE values between 1500-2000 J/kg across the
Dakotas and individual members considerably higher (3000-4000 J/kg).

Scattered thunderstorms are expected to develop across the Dakotas
by mid afternoon as convective temperatures are approached and
modest height falls overspread the area. Long, straight hodographs
and effective-layer shear around 40-knots will support supercellular
structures, including storm splits, early in the thunderstorm
convective life cycle. Large hail, potentially in excess of 2
inches, will be possible with these initial storms. However, dry
sub-cloud layers and low-level lapse rates around 9 C/km will
support strong convective outflows that will tend to favor upscale
growth, especially in regions where storm splits interact with one
another. One or more convective clusters will move east-southeast
during the late afternoon and evening continuing the threat for
damaging winds, before eventually weakening overnight.

..Marsh/Weinman.. 07/19/2026


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SPC Jul 19, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0809 PM CDT Sat Jul 18 2026

Valid 190100Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ...

CORRECTED FOR INCORRECT CATEGORICAL LINES

...SUMMARY...
Storms capable of wind damage may continue for another hour or so
across central Pennsylvania before dissipating. Additional
strong-to-severe thunderstorms capable of damaging winds and hail
will be likely across portions western Montana

... 01Z Update ...

Overall thunderstorm intensity continues to wane across much of the
northeast with the loss of daytime heating and multiple rounds of
thunderstorms acting to stabilize the airmass. However, a few
damaging thunderstorm wind gusts will be possible from far eastern
Ohio into southern New England for perhaps another hour or two. The
most likely area for wind damage is across central Pennsylvania
where the most intense thunderstorms are currently found. These
storms should weaken further in the next couple of hours, bringing
an end to the organized severe threat.

Across western Montana, sufficient buoyancy is in place to support
ongoing convection, some of which has produced severe wind gusts
this afternoon. Steep lapse rates coupled with gradually
strengthening mid-level flow will support an ongoing severe threat,
including a couple of outflow-driven convective clusters. Please see
MCD #1656 for more details.

..Marsh.. 07/19/2026


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SPC Jul 18, 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 Sat Jul 18 2026

Valid 181630Z - 191200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
THROUGH LATE EVENING FROM THE LOWER GREAT LAKES INTO THE
MID-ATLANTIC...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON EVENING FOR PARTS OF WESTERN MONTANA...

...SUMMARY...
Severe thunderstorms are expected across portions of the Ohio Valley
and Lower Great Lakes into the Mid-Atlantic and Northeast this
afternoon and evening. Damaging gusts will be the primary threat,
but a few tornadoes are possible, including perhaps a strong
tornado.

...Mid-Atlantic to the lower Great Lakes this afternoon/evening...
Ongoing convection across central PA/NY will continue to spread
eastward through early afternoon within a warm advection zone along
and north of a surface warm front. The warm front will move
northward today in advance of a surface cyclone and associated
midlevel trough now in the vicinity of Lake Huron. In the wake of
the ongoing convection, destabilization will occur as boundary-layer
dewpoints rise to near 70 F and surface temperatures into the 80s,
resulting in moderate buoyancy in the warm sector. Destabilization
will occur earlier immediately south-through-west of the ongoing
storms across eastern PA/NJ, and a little later this afternoon into
central NY.

Additional thunderstorm development is beginning in southwest PA and
vicinity as of 16z and a continued increase in storms is expected
into early-mid afternoon along a cold front and along pre-frontal
confluence zones/lake-enhanced boundaries. A mixed convective mode
(line segments and clusters) is expected, with embedded bowing
segments and a chance for pre-frontal supercells in PA/NY/NJ where
vertical shear and hodograph curvature will be larger along the warm
front. Wind damage will be the primary severe threat with both the
frontal convection and pre-frontal storms, with a few tornadoes
possible with supercell structures and/or embedded mesovortices.

...Northern Rockies late this afternoon/evening...
Scattered thunderstorm development is expected later this
afternoon/evening across western MT and vicinity, within the
northwest fringe of the midlevel ridge and monsoonal moisture plume.
Midlevel flow will be somewhat enhanced to the immediate southeast
of a midlevel trough moving over southeast BC, thus some organized
storm structures will be possible with faster storm motions compared
to yesterday. Occasional severe outflow gusts and large hail up to
1.5 inches in diameter will be the main threats.

..Thompson/Bunting.. 07/18/2026


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