558
ACUS03 KWNS 121928
SWODY3
SPC AC 121927

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0227 PM CDT Fri Jun 12 2026

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SUNDAY ACROSS MUCH
OF THE NORTHERN MID ATLANTIC COAST STATES...

...SUMMARY...
Severe thunderstorms are possible across the lower Great Lakes and
upper Ohio Valley vicinity through much of the northern Mid Atlantic
Sunday.

...Discussion...
Downstream of initially amplified mid-level ridging offshore of the
Pacific coast, models indicate that flow will continue to trend
cyclonic east of the Rockies through the Atlantic Seaboard, to the
south of a broadening vortex centered near southern Hudson Bay.
Within this regime, it appears that notable short wave troughing
will pivot east of the Upper Midwest through the southeastern
Canadian provinces and Northeast by late Sunday night, accompanied
by cyclogenesis across the lower Great Lakes through St. Lawrence
Valley vicinity.  It appears that this may be preceded by the
remnants of an initially fairly notable mesoscale convective vortex,
within strengthening westerly flow across the Allegheny/Cumberland
Plateau through the northern Mid Atlantic by early Sunday evening.

...Northeast...
There remains considerable spread within the latest model output
concerning the extent of convective potential for this period.
Mostly this appears related pre-frontal low-level moisture return
and destabilization across the upper Ohio Valley into the lee of the
lower Great Lakes, which could be slowed or impeded by the influence
of preceding convective outflow.  However, guidance generally
suggests that destabilization prior to the arrival of the MCV and
belt of enhanced lower/mid-tropospheric wind fields (30-40+ kt) will
be sufficient to support potential for organized severe convection
east of the Allegheny Mountains through the northern Mid Atlantic by
late Sunday afternoon.  More substantive strengthening of mid-level
wind fields and forcing for ascent appear likely to overspread the
pre-frontal environment across parts of the upper Ohio Valley into
the lee of the lower Great Lakes region, where it appears increasing
model output is now suggesting that the evolving warm sector may
become sufficiently unstable to support a risk for organized severe
storm development.

Damaging wind gusts accompanying organizing lines and/or clusters
appear the primary severe hazard, but there also appears at least
some potential for a few tornadoes.  It is still possible that
severe weather probabilities will need to be increased further in
later outlook updates for this period.

..Kerr.. 06/12/2026

$$