SPC Jun 16, 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
1113 AM CDT Tue Jun 16 2026

Valid 161630Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING ACROSS PARTS OF INDIANA AND LOWER MICHIGAN...AND TONIGHT
OVER PARTS OF IOWA....

...SUMMARY...
Severe thunderstorms are possible this afternoon and tonight across
multiple parts of the Midwest, as well as on a more isolated basis
across the Gulf Coast, south-central Plains and northern Plains.

...IN/Lower MI...
Morning water vapor loop shows a strong and progressive Clipper
system tracking southeastward across MN/WI. A band of clouds and
isolated thunderstorms precedes this system, extending from southern
Lower MI into central IL. While a few strong storms are possible to
develop in this band, the greater risk for severe storms appears to
be associated with a period of heating in the wake of these clouds.
Steep lapse rates and cold temperatures aloft will combine with
dewpoints around 60F to result in sufficient afternoon/evening CAPE
for widely scattered strong/severe storm development. Large hail
will be the initial main concern, along with some risk of a tornado
or two. By early evening, damaging winds will be the main concern.

...IA Overnight...
The next in a series of fast-moving upper-level features will move
across the Dakotas tonight, with large-scale forcing for ascent
spreading into parts of MN/IA before 12z. This ascent will begin
interacting with a plume of returning moisture, leading to scattered
thunderstorm development in the pre-dawn hours. Elevated supercells
capable of large hail will be the main risk through 12z.

...MT/ND...
The aforementioned upper feature will affect northeast MT and the
Dakotas this afternoon and evening. A deeply-mixed boundary layer
will develop over this area with temperatures in the 80s and 35-45F
t-td spreads. CAPE will be rather weak, which should limit overall
convective organization. Nevertheless, fast-moving high-based
showers and thunderstorms capable of gusty and occasionally severe
wind gusts are expected.

...Gulf Coast...
The tropical system (PTC 1) along the south TX coast is expected to
slowly organize today, with widespread showers and thunderstorms
from east TX into the central Gulf coast. Low-level winds are not
particularly strong and forecast hodographs are only marginally
favorable for updraft rotation. Nevertheless with such a broad area
of risk, a tornado or two is certainly possible this afternoon
through tonight.

..Hart/Lyons.. 06/16/2026


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SPC Jun 16, 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
0758 AM CDT Tue Jun 16 2026

Valid 161300Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MIDWEST...

...SUMMARY...
Severe thunderstorms are possible today and tonight across multiple
parts of the Midwest, as well as on a more isolated basis across the
Gulf Coast, south-central Plains and northern Plains.

...Midwest/Great Lakes...
A low amplitude shortwave trough will amplify and spread
east-southeastward over the Great Lakes today. While overall
moisture content will remain modest, steady low-level moistening is
expected ahead of a surface low/cold front, and south of a
north/northeastward-shifting warm front. This moistening and
insolation beneath a developing mid-level dry slot should support a
corridor of modest destabilization as the mid-level cold pool
(including 500 mb temperatures around -18 to -20C) overspreads the
region this afternoon. This environment should become sufficient for
a developing broken band of strong/severe low-topped storms
including supercells, posing a risk for severe hail/damaging winds
and possibly a couple of tornadoes from mid-afternoon through early
evening.

...Iowa/Upper Midwest late tonight...
A categorical Slight Risk has been introduced for what should be a
steadily increasing late-night/pre-dawn potential for large hail, at
least on isolated basis. This potential should tend to focus across
parts of central/eastern Iowa. Exact details of timing/spatial
extent of cap erosion are a bit uncertain, but will defer to a
significantly strengthening southwesterly low-level jet and
east/southeastward-advecting elevated mixed layer and ample
source-region elevated buoyancy regarding concern for large hail.
This will be as robust warm/moist advection develops and initial
height falls arrive into the region early Wednesday with increasing
elevated convection probable.

...South-central Plains...
Near/ahead of the stalling front, boundary-layer moistening may
support CAPE on the order of 1000-2000 J/kg across parts of southern
Kansas into southwestern Missouri, where mid-level inhibition may
remain weak enough through late afternoon/early evening to allow for
isolated/widely scattered thunderstorm development. Sufficient
vertical shear could support supercell development. Additional
severe storm development, at least on an isolated basis, is
plausible farther west-southwest later in the afternoon/early
evening across northern Oklahoma/southern Kansas into the Texas
Panhandle.

...Northern Great Plains into Midwest...
Models suggest that a corridor of fairly deep boundary-layer mixing
will precede the vigorous short wave trough digging across and
east-southeast of the Canadian/northern U.S. Rockies. Associated
mid-level forcing for ascent will contribute to sufficient
destabilization to support scattered thunderstorm development with
potential to produce some hail and scattered strong to severe
surface gusts late this afternoon into evening.

...Delmarva/coastal Mid-Atlantic...
Some strong/locally severe thunderstorms could occur tonight as
convection develop near/north of a near-coastal/offshore surface low
and northward-advancing warm front. Storms will tend to be elevated
inland, but modest buoyancy and strong unidirectional shear through
the cloud-bearing layer could yield some hail and/or gusty winds.

...Gulf Coast...
Strengthening westerly flow, including 20-40 kt in the 850-500 mb
layer, is anticipated regionally coincident with a moist boundary
layer. As diurnal heating/destabilization occurs, this may support
modestly organizing convection, perhaps transient supercell
structures, posing a risk for damaging wind gusts and perhaps a
brief tornado or two.

..Guyer/Broyles.. 06/16/2026


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SPC Jun 16, 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
1250 AM CDT Tue Jun 16 2026

Valid 161200Z - 171200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TODAY THROUGH
TONIGHT ACROSS PARTS OF THE NORTHERN GREAT PLAINS INTO MIDWEST AND
NEAR THE GULF COAST...

...SUMMARY...
Areas of mainly widely scattered strong thunderstorm development,
accompanied by at least some risk for severe weather, are possible
across parts of the northern Great Plains into Midwest and near the
Gulf Coast vicinity today through tonight.

...Discussion...
Higher latitude blocking appears likely to maintain a broad area of
cyclonic mid-level flow with anomalously low heights to the lee of
the northern Rockies through the northern and middle Atlantic
Seaboard. Within this regime, models suggest that an initially
vigorous short wave trough (now digging into the Upper Midwest) may
maintain strength into and across the Lake Michigan vicinity, before
undergoing considerable deformation while turning eastward and
northeastward, to the southeast of a mid-level becoming centered
near the northern Manitoba/northwestern Ontario border. After
rounding the crest of mid-level ridging centered over the northern
mid-latitude eastern Pacific, it appears that another significant
short wave perturbation will dig through the broadly confluent
regime to the southwest of the low, across the northern Rockies
through northern Great Plains by late tonight.

In lower latitudes, mid/upper ridging emanating from the subtropical
Atlantic may maintain considerable influence across the Florida
peninsula today, while weak troughing, perhaps with a developing
mid-level cyclonic circulation, slowly pivots across the lower Texas
and Mexican Gulf coast.

In lower levels, seasonably high boundary-layer moisture content has
generally been maintained across much of the Gulf coastal plain. It
appears that strengthening southerly low-level flow may support more
substantive moisture return to the southeast of deepening surface
troughing across the northern into central Great Plains by late
tonight.

...Midwest/Great Lakes...
Weak convection accompanying forcing for ascent associated with the
lead short wave trough appears likely to persist and perhaps
increase across the Upper Midwest through Great Lakes and Ohio
Valley during the day. Coinciding low-level cooling is likely to at
least slow, if not inhibit, boundary layer warming in the wake of
this activity. However, various model output suggests that
associated low-level moistening, coupled with a period of insolation
beneath a developing mid-level dry slot, may be sufficient to
support a corridor of modest destabilization as the mid-level cold
pool (including 500 mb temperatures around -18 to -20C) overspreads
the southern Lake Michigan vicinity late this afternoon. This
environment might become sufficient for a developing broken band of
vigorous convection, perhaps including supercells, posing a risk for
severe hail/wind and possibly a tornado or two, before weakening
later this evening.

...Central Great Plains...
Forcing for ascent to support convective development along the
stalling cold front, trailing the short wave trough progressing into
the Great Lakes/Ohio Valley, remains unclear. However, there
appears a general consensus within model output that boundary-layer
moistening may support CAPE on the order of 1000-2000 J/kg across
parts of southern Kansas into southwestern Missouri, where mid-level
inhibition may remain weak enough through late afternoon/early
evening to allow for isolated/widely scattered thunderstorm
initiation. If this occurs, guidance indicates sufficient shear for
supercell development, before increasing inhibition suppresses
convection later this evening.

...Gulf Coast...
Models indicate modest strengthening of westerly flow (including
20-40 kt in the 850-500 mb layer) in a belt across the north central
through northeastern Gulf coast vicinity today. Coinciding with
destabilization driven by daytime heating of the seasonably moist
boundary layer, this may support modestly organizing convection,
perhaps transient supercell structures, posing a risk for damaging
wind gusts and perhaps an isolated tornado or two.

...Northern Great Plains into Midwest...
Models suggest that a corridor of fairly deep boundary-layer mixing
will precede the vigorous short wave trough digging across and
east-southeast of the Canadian/northern U.S. Rockies. It appears
that associated mid-level forcing for ascent will contribute to
sufficient destabilization to support scattered thunderstorm
development with potential to produce some hail and scattered strong
to severe surface gusts late this afternoon into evening.

Within strengthening downstream warm advection, forcing for ascent
may begin to interact with better elevated moisture return to
support increasing strong thunderstorm development with potential to
producing severe hail by late tonight, across parts of eastern Iowa
and adjacent portions of the Midwest.

..Kerr/Weinman.. 06/16/2026


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SPC Jun 15, 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
0243 PM CDT Mon Jun 15 2026

Valid 152000Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHERN HIGH PLAINS AND FROM THE CENTRAL DAKOTAS TO CENTRAL
MINNESOTA...

...SUMMARY...
Isolated large hail and severe thunderstorm winds may occur across
the southern High Plains and Dakotas/Upper Midwest this afternoon
and evening.

...20z Update...
No appreciable forecast changes were required. Based on latest
analyses, the highest severe wind threat remains across the eastern
Dakotas/western Minnesota where low-level lapse rates have increased
to near dry adiabatic ahead of approaching convection attendant to a
low-level vorticity maximum. A few recent severe wind gusts have
accompanied some of this convection as it moves into the plume of
steep low-level lapse rates. However, based on latest guidance
thunderstorm coverage should remain widely scattered through early
evening, suggesting that 5% wind probabilities remain the most
appropriate characterization of the risk.

Across the southern High Plains, convective initiation is underway
within the southern Rockies. Per MRMS vertical ice trends, some
large hail may accompany some of this initial activity before it
spreads east through the evening. Based on latest model trends, a
convective cluster will likely materialize out of the scattered
thunderstorms north of the Albuquerque area and will pose a severe
wind threat downstream across east-central NM later this evening. As
with the northern Plains, this threat should be sufficiently
isolated to maintain only 5% wind probabilities. See the previous
discussion below and MCDs #1149 and #1150 for additional forecast
details.

..Moore.. 06/15/2026

.PREV DISCUSSION... /ISSUED 1111 AM CDT Mon Jun 15 2026/

...Southern High Plains...
Northwesterly flow aloft will support a sharpening lee trough across
the southern High Plains today, with lee cyclogenesis yielding a
surface low over southeast CO by the late afternoon. Mass response
to the deepening lee trough and developing surface low will result
in moist low-level southeasterly/southerly flow across much of the
southern High Plains. This moistening will help offset mixing via
diurnal heating, keeping dewpoints in the 50s through the afternoon.
Steep mid-level lapse rates will be in place as well, with the
combination of low-level moisture and steep mid-level lapse rates
supporting airmass destabilization and moderate buoyancy by this
afternoon.

Thunderstorm development is initially expected over the high terrain
of south-central CO and central NM during the afternoon. Moderate
deep-layer westerly flow will take these storms into the lower
elevations of the southern High Plains during the late afternoon and
evening. Moderate buoyancy combined with 30 to 40 kt of effective
shear will support the potential for a few supercells and sustained
multicells, with potential consolidation into small organizing
southeastward-moving clusters. Hail is possible early in the
convective cycle, with a trend towards more damaging gusts within
any forward-propagating clusters during the late afternoon and
evening.

...Dakotas/Minnesota...
Morning satellite imagery shows a well-defined shortwave trough
dropping southeastward into the northern Plains within the western
periphery of a broad upper trough that extends over much of the
central and eastern CONUS. Surface moisture will be limited ahead of
this wave, but low to mid-level moisture attendant to the shortwave
and cold temperatures aloft will still support modest buoyancy
across the region this afternoon. This buoyancy coupled with ascent
from the shortwave will result in isolated to widely scattered
high-based thunderstorms. Additionally, strengthening
west-northwesterly flow attendant to the shortwave could yield some
strong/locally severe wind gusts this afternoon through around
sunset.

...Gulf Coast/Coastal Southeast...
A very moist airmass is in place in the vicinity of a weak frontal
zone that extends from the TX Coast northeastward through the
central Gulf Coast and southern GA. Numerous to widespread showers
and thunderstorms are anticipated across much of this region. The
airmass is weakly sheared, favoring a slow-moving, disorganized
storm evolution with heavy rain as the primary risk (as noted in the
Day 1 WPC Excessive Rainfall Outlook). However, a few damaging gusts
from water-loaded downbursts are still possible. Overall coverage is
expected to remain less than 5%.


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