Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1252 AM CDT Thu Jun 19 2025

Valid 191200Z - 201200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
MIDDLE ATLANTIC...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY...

...SUMMARY...
Severe thunderstorms are expected across much of the Middle Atlantic
region, and to a lesser extent into the Carolinas and over portions
of New England. Severe wind gusts are the primary concern. Isolated
hail and wind threat is expected across the northern Plains into
Minnesota, primarily during the evening/overnight.

...Eastern U.S...

Seasonally strong upper trough is currently located over IL and
should advance into the OH Valley by 18z as stronger 500mb flow
develops across western PA/NY. With time, 50+kt flow should
translate into the Middle Atlantic, coincident/just ahead of the
primary synoptic front. Latest model guidance suggests modest 0-3km
lapse rates will develop by mid day as the boundary layer warms
ahead of the wind shift, especially from the Carolinas into Upstate
NY. In fact, much of the I-95 corridor over the Middle Atlantic will
warm quickly through the 80s to near 90F, effectively removing any
inhibition. As a result, convection should readily develop within a
very moist environment (PWs 1.75-2 inches) characterized by MLCAPE
in excess of 2000 J/kg. Forecast soundings exhibit deep
west-southwesterly flow with 0-6km bulk shear around 30kt. These
profiles favor organized line segments and clusters, and severe wind
gusts will likely be noted with the most robust activity. Convection
should spread off the Middle Atlantic Coast during the evening
hours.

...Northern Plains/Upper MS Valley...

Latest water-vapor imagery depicts a short-wave trough over
southeast BC. This feature will suppress heights across southern
AB/SK early in the period, and a secondary disturbance will eject
across southern SK during the evening. These features are expected
to encourage convective development along the cool side of a
boundary that will be draped from the upper MS Valley-central
ND-southern SK. Low-level warm advection should aid bouts of
elevated convection, but the primary concern is with thunderstorms
that evolve during the early evening. Storms that form over
southeastern SK and southwestern MB will spread southeast toward a
region of increasing low-level warm advection. LLJ is forecast to
increase across eastern SD into southwest MN during the late
evening. Elevated supercells should develop ahead of the Canadian
convection as the LLJ strengthens into the upper Red River Valley.
An MCS may ultimately evolve over the upper MS Valley late in the
period as the LLJ shifts into southeast MN/southwestern WI. Hail and
wind are the primary concern with this activity.

..Darrow/Weinman.. 06/19/2025

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
0100 AM CDT Thu Jun 19 2025

Valid 201200Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS INTO THE UPPER MIDWEST/GREAT LAKES...

...SUMMARY...
Severe thunderstorms may develop Friday into Friday night across
parts of the northern Plains and upper Midwest. Significant severe
weather is possible.

...Synopsis...
A seasonably deep mid/upper-level cyclone will move across the
Pacific Northwest on Friday, as the attendant large-scale trough
begins to impinge on the central/northern Great Plains. Downstream,
an upper ridge will gradually shift eastward from the southern
Plains toward the lower MS Valley. 

A surface low will deepen across the northern High Plains, with
increasing low-level moisture expected near and east of the low and
trailing dryline/surface trough, and also near/north of a warm front
that will extend east/northeast of the low. 

...Dakotas into the Upper Midwest/Great Lakes...
Strong to extreme buoyancy will develop Friday afternoon across much
of the central/northern Plains into the Upper Midwest. Warming
temperatures aloft will result in substantial capping across the
warm sector, and coverage/location of storms within an otherwise
volatile environment remains very uncertain. 

Most guidance suggests a mid/upper-level shortwave will emerge from
the western trough and move across the northern Plains sometime
during the afternoon/evening, though differences remain regarding
the timing and amplitude of this shortwave. This shortwave trough
could aid in isolated storm development by late afternoon/early
evening, primarily near or north of the surface low and warm front.
Veering wind profiles will support supercells, with a conditional
threat for very large hail, isolated severe gusts, and also some
tornado potential if any supercells can become surface-based. 

Some increase in storm coverage is expected Friday evening into the
overnight, in response to a nocturnally strengthening low-level jet.
Initial development within this regime could be supercellular, with
potential for upscale growth with time. An intense MCS capable of
producing significant severe gusts could evolve with time. Even if
this does not occur, one or more smaller clusters may develop and
track east-southeastward north of the warm front, with very large
buoyancy and sufficient deep-layer shear supporting a threat of
large to very large hail and severe gusts. 

Greater severe probabilities may be needed if confidence increases
regarding a sufficient coverage of supercells, and/or development of
an intense MCS. 

...Montana...
Low-level easterly flow will support some moistening across much of
MT on Friday, though guidance continues to vary regarding the
magnitude of destabilization during the afternoon and evening.
Large-scale ascent associated with the approaching mid/upper-level
trough will support scattered storm development across western MT
during the afternoon, with sufficient deep-layer shear for some
storm organization. Depending on the extent of downstream
destabilization, some threat for strong to potentially severe storms
may spread into parts of central/eastern MT Friday evening. Greater
severe probabilities may be needed into parts of western/central MT
depending on trends regarding destabilization.  

...South-central High Plains...
High-based convection may develop Friday afternoon across parts of
CO/NM, within a very warm and well-mixed environment. While this
convection should generally be disorganized, localized severe gusts
could accompany this convection before it subsides during the
evening.  

...Lower Great Lakes...
A northwesterly flow regime will become established across the lower
Great Lakes vicinity on Friday. While large-scale ascent will remain
rather nebulous, and destabilization is expected to be rather
modest, elongated hodographs will conditionally support some storm
organization. A few strong storms capable of locally gusty winds and
perhaps marginal hail cannot be ruled out during the afternoon and
evening.

..Dean.. 06/19/2025

Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0206 AM CDT Thu Jun 19 2025

Valid 191200Z - 201200Z

...CRITICAL FIRE WEATHER AREA FOR NORTHWESTERN NEVADA...
...CRITICAL FIRE WEATHER AREA FOR PARTS OF EASTERN NEVADA...WESTERN
UTAH...AND FAR NORTHWESTERN ARIZONA...

...Synopsis...
Within the base of a large-scale trough moving into the western
CONUS, a swath of moderate-strong deep-layer southwesterly flow will
overspread central CA into the Great Basin today. In response,
surface low pressure will deepen over the northern Great Basin and
separately over the Lower CO River Valley. 

...Great Basin...
Deep boundary-layer mixing is expected across the Great Basin during
the afternoon, with surface temperatures climbing into the 90s to
100 F and RH falling into the single digits. The deep boundary-layer
mixing into the strong flow aloft, coupled with a tightening
regional pressure gradient, will contribute to an expansive area of
20-25 mph sustained southwesterly surface winds (with higher gusts).
The greatest overlap of these strong surface winds and low RH is
expected over northwestern NV and western UT into eastern NV and far
northwestern AZ. Given dry/receptive fuels over these areas,
critical fire-weather conditions are expected.

...San Joaquin Valley and vicinity...
Hot and dry conditions will combine with 15-20 mph sustained
northwesterly surface winds during the afternoon into the evening.
This will promote elevated fire-weather conditions where fuels are
receptive to fire spread.

...Dry Thunderstorms...
Large-scale forcing for ascent preceding the midlevel trough will
favor isolated dry thunderstorms across parts of southeastern OR
into central ID during the evening hours. However, current
indications are that fuels are only modestly receptive to
lightning-induced ignitions -- precluding Dry Thunderstorm
highlights at this time.

..Weinman.. 06/19/2025

...Please see www.spc.noaa.gov/fire for graphic product...