MIL-OSI USA: SPC Jun 28, 2025 Day 4-8 Severe Weather Outlook

Source: US National Oceanic and Atmospheric Administration

Day 4-8 Severe Weather Outlook Issued on Jun 28, 2025

Updated: Sat Jun 28 08:02:03 UTC 2025

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D4
Tue, Jul 01, 2025 – Wed, Jul 02, 2025
D7
Fri, Jul 04, 2025 – Sat, Jul 05, 2025

D5
Wed, Jul 02, 2025 – Thu, Jul 03, 2025
D8
Sat, Jul 05, 2025 – Sun, Jul 06, 2025

D6
Thu, Jul 03, 2025 – Fri, Jul 04, 2025
(All days are valid from 12 UTC – 12 UTC the following day)

Note: A severe weather area depicted in the Day 4-8 period indicates 15%, 30% or higher probability for severe thunderstorms within 25 miles of any point.

PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.

POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears unlikely (i.e., less than 15%) for the forecast day.

 Forecast Discussion

ZCZC SPCSWOD48 ALL
ACUS48 KWNS 280800
SPC AC 280800

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 AM CDT Sat Jun 28 2025

Valid 011200Z – 061200Z

…DISCUSSION…
A mid-level trough will move from the Great Lakes to the Northeast
on Day 4/Tuesday. At the surface, a cold front will move east
through the period. Moderate instability is expected along this
front and some severe weather may be possible from the Mid-Atlantic
to the Northeast. Slight risk (15%) probabilities may eventually be
needed within this zone, but there is potential for
cloudcover/thunderstorm activity from Monday evening to impact
destabilization. Therefore, confidence is not high enough for
probabilities at this time.

Beyond Day 4, a relative lull in severe weather potential is
expected. Multiple reinforcing mid-level troughs will amplify the
larger-scale trough across the eastern CONUS. As this occurs, the
surface cold front will move south, potentially to the Gulf Coast
and into the western Atlantic. This will eliminate the very moist
airmass which resulted in moderate to strong instability across much
of the eastern CONUS for the past few weeks.

The greater low-level moisture is expected to remain and perhaps
advect north across the central Plains beneath a large-scale ridge.
This could result in some thunderstorm activity, but shear is
expected to be very weak, and the building ridge aloft may suppress
convection on D5/Wednesday to D6/Thursday.

By next weekend, this ridge is expected to flatten with some
stronger mid-level flow moving across the northern Plains. The exact
evolution of the upper-pattern remains uncertain and therefore,
confidence is low, but severe weather chances may increase across
the northern Plains by next weekend.

..Bentley.. 06/28/2025

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