834
ACUS01 KWNS 190553
SWODY1
SPC AC 190552

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

$$