SPC Mar 20, 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
1115 AM CDT Fri Mar 20 2026

Valid 201630Z - 211200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER OHIO VALLEY INTO THE CENTRAL APPALACHIANS...

...SUMMARY...
Strong to locally severe thunderstorms are possible across parts of
the Upper Ohio Valley and central Appalachians, mainly late this
afternoon into the evening.

...Upper Ohio Valley into the Central Appalachians...
Midday water-vapor imagery indicates a mid-level shortwave trough
over Lower Michigan as a belt of strong west-northwesterly flow is
maintained across the north-central U.S. eastward to the
Mid-Atlantic and New England coastal vicinity. This disturbance is
forecast to quickly move to the Delmarva/NJ by midnight.

The northern extent of a moisture plume, and an airmass still
undergoing modification over the Gulf Basin, will protrude northeast
into the upper OH Valley by late afternoon. Forecast guidance shows
surface dewpoints perhaps reaching near 50 deg F near the OH-WV-PA
border region towards 00z. Cold 500-mb temperatures and diurnal
heating will act to partially compensate for modest moisture and
contribute to weak buoyancy. Isolated to widely scattered
low-topped thunderstorms will probably develop along a
southeastward-moving cold front during the evening. Elongated
hodographs support updraft organization but the overall limited
moisture will act to constrain otherwise greater storm coverage.
Marginally severe hail and perhaps a couple of damaging gusts are
the primary hazards with the stronger storms.

..Smith/Mosier.. 03/20/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TRcB4X

SPC Mar 20, 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
1230 AM CDT Fri Mar 20 2026

Valid 201200Z - 211200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
OHIO VALLEY REGION...

...SUMMARY...
Strong to locally severe thunderstorms are possible across parts of
the Upper Ohio Valley, mainly late this afternoon into the evening.

...Upper Ohio Valley...

Dominant upper ridge will hold across the southwestern parts of the
CONUS through the day1 period, but this feature will influence most
of the western US by forcing stronger westerlies to near the
international border/Great Lakes region. Latest model guidance
suggests a weak shortwave trough will top the ridge and dig
southeast across the Great Lakes into the upper OH Valley by 21/00z.
As this occurs weak midlevel height falls will be noted across
eastern OH/PA as a surface cold front settles across western
NY-northern OH-central IN by late afternoon.

Early this morning, boundary-layer moisture is quite dry across much
of the OH Valley with only upper 30s/lower 40s surface dew points
observed. Deepening westerly flow suggests low-level moisture across
southeast MO/northern AR will advect toward the upper OH Valley,
possibly arriving prior to the frontal passage. Even so, dew points
within this source region are only in the mid 40s to lower 50s.
Forecast soundings for mid afternoon suggest modest boundary-layer
heating such that 0-3km lapse rates should be on the order of 7 C/km
with MUCAPE around 500-700 J/kg. Current thinking is scattered
convection will develop along/ahead of the cold front by late
afternoon, then spread southeast before weakening with loss of
daytime heating. Strong deep-layer shear favors organized updrafts
and the greatest risk should be gusty winds with marginally severe
hail.

..Darrow/Chalmers.. 03/20/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TRbZ9X

SPC Mar 19, 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
0300 PM CDT Thu Mar 19 2026

Valid 192000Z - 201200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunderstorms are not forecast across the U.S. today or tonight.

...20Z Update...
The previous forecast (see below) remains unchanged.

..Squitieri.. 03/19/2026

.PREV DISCUSSION... /ISSUED 1049 AM CDT Thu Mar 19 2026/

...Synopsis...

Surface high pressure over the Southeast and a dry airmass over the
Gulf Basin will result in a persistent stable environment east of
the Rockies, precluding thunderstorm activity. A drier airmass is
also expected across south FL compared to previous days. Offshore
thunderstorms may approach the east-central FL coast tonight.
However, meager instability and nebulous forcing will likely limit
any thunderstorm coverage on land to less than 10 percent.


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TRbQR4

SPC Mar 19, 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
1049 AM CDT Thu Mar 19 2026

Valid 191630Z - 201200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunderstorms are not forecast across the U.S. today or tonight.

...Synopsis...

Surface high pressure over the Southeast and a dry airmass over the
Gulf Basin will result in a persistent stable environment east of
the Rockies, precluding thunderstorm activity. A drier airmass is
also expected across south FL compared to previous days. Offshore
thunderstorms may approach the east-central FL coast tonight.
However, meager instability and nebulous forcing will likely limit
any thunderstorm coverage on land to less than 10 percent.

..Leitman.. 03/19/2026


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/TRb8sR