SPC Apr 21, 2026 0100 UTC Day 1 Convective Outlook

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


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 PM CDT Mon Apr 20 2026

Valid 210100Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected through tonight.

...Discussion...
Scattered thunderstorms persist across central and southern TX this
evening, where southerly 850 mb winds are aiding lift/warm advection
atop the relatively cool boundary layer. In addition, a weak wave
aloft is moving across the southern Plains. As such, storms may
increase in coverage through tonight, expanding into northern and
eastern TX. Effective shear will remain weak especially over
northern areas, and severe storms are not expected.

Elsewhere, showers will generally decrease over far southern FL with
the loss of heating. Farther west, an isolated lightning flash
cannot be ruled out over parts of the WA/OR Cascades as an offshore
upper trough slowly pushes east.

..Jewell.. 04/21/2026


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SPC Apr 20, 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
0246 PM CDT Mon Apr 20 2026

Valid 202000Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected today.

...20Z Update...
The TSTM area over the coast of southern New England and the
Mid-Atlantic was removed, as large-scale forcing for ascent and
related thunderstorm activity has shifted offshore. Elsewhere, the
previous forecast remains on track.

..Weinman.. 04/20/2026

.PREV DISCUSSION... /ISSUED 1052 AM CDT Mon Apr 20 2026/

...Synopsis...
An upper impulse will continue to pose a risk of scattered
thunderstorms over parts of NM and south/west TX through the
afternoon, with activity spreading into north-central TX late
tonight.

Other thunderstorms are possible this afternoon and evening over
south FL in a moist and marginally unstable air mass, along the
coast of southern New England, and over portions of OR/WA. In all
areas, weak instability will preclude the risk of organized severe
storms.


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SPC Apr 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
1052 AM CDT Mon Apr 20 2026

Valid 201630Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected today.

...Synopsis...
An upper impulse will continue to pose a risk of scattered
thunderstorms over parts of NM and south/west TX through the
afternoon, with activity spreading into north-central TX late
tonight.

Other thunderstorms are possible this afternoon and evening over
south FL in a moist and marginally unstable air mass, along the
coast of southern New England, and over portions of OR/WA. In all
areas, weak instability will preclude the risk of organized severe
storms.

..Hart/Flournoy.. 04/20/2026


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SPC Apr 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
1118 PM CDT Sun Apr 19 2026

Valid 201200Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected today.

...Synopsis...
An upper trough will exit the northeastern states today, with
northwest flow aloft extending from the northern Plains to the East
Coast. Upper ridging will occur over the Rockies, while a large
upper trough slowly approaches the West Coast.

At the surface, high pressure will result in relatively stable
conditions for much of the central and eastern CONUS, with centers
over the Mid Atlantic and near the northern Gulf Coast.

In the wake of the eastern trough, winds just off the surface will
maintain a zone of elevated moisture and instability over much of
TX, where scattered showers and storms will be most likely. Weak
instability will preclude any severe storm chances there.

To the west, cooling aloft with the approaching upper trough will
support weak instability into parts of OR and WA, with isolated late
day thunderstorms possible over portions of the Cascades.
Small/non-severe hail cannot be ruled out, along with locally gusty
winds mainly in the 00-03Z time frame.

..Jewell/Chalmers.. 04/20/2026


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