148
ACUS48 KWNS 030846
SWOD48
SPC AC 030845

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0345 AM CDT Wed Jun 03 2026

Valid 061200Z - 111200Z

...DISCUSSION...
...Day 4/Saturday...

Model guidance is in good agreement in the progression of a
short-wave trough from the Great Lakes into Northeast, with a strong
upstream system moving through the Canada Rockies and Pacific
Northwest into the northern Rockies. Elsewhere, a mid-level low will
track through the southern and central Plains. In the low levels, a
cold front is forecast to move through the Great Lakes into the OH
Valley and Northeast, while a lee cyclone deepens over the northern
High Plains along a separate cold front emerging from the northern
Rockies.

The most probable location for organized severe thunderstorm
development appears to be in the vicinity of the lee cyclone and
front in portions of eastern MT and western ND Saturday afternoon
and evening. There, steep lapse rates and moderate instability will
coincide with steadily strengthening deep-layer shear. Elsewhere, at
least isolated severe storms appear possible along the cold front
from portions of the Great Lakes into the OH Valley and the
Northeast, as well as in parts of TX, to the southeast of the upper
low.


...Day5/Sunday...

A short-wave trough will continue through the Northeast and
Mid-Atlantic, while the bulk of ensemble guidance suggests the
northern Rockies disturbance will lift northeast into the Canadian
Prairie Provinces. Meanwhile, the central/southern Plains low is
forecast to evolve into an open wave while moving into the mid/lower
MO Valley and Ozark Plateau. The models indicate the potential for
moderate to strong instability to develop across the northern Plains
warm sector on Sunday afternoon. However, there is some signal that
the strongest vertical shear will be displaced to the west of the
cold front. Furthermore, given that the strongest forcing for ascent
is expected to lift north of the International Border, residual
capping across the warm sector may limit storm coverage. Given these
concerns, no probabilities will be included in this forecast.

Elsewhere, at least isolated severe storms appears possible along
the cold front in portions of the Northeast into Mid-Atlantic Sunday
afternoon.


...Day 6-8/Monday through Wednesday...

Ensemble guidance is suggestive that mid-level troughing will evolve
along the West Coast early next week, with that feature slowly
advancing through the Interior West. Considerably more spread is
evident in the deterministic models, with low confidence in any one
solution. In general, it appears that the stronger mid-level flow
associated with the western U.S. trough may begin to overspread
portions of the northern and central High Plains by Tuesday and/or
Wednesday, where a moist and unstable air mass is expected to
reside. Should confidence increase in the finer-scale details of the
pattern, unconditional 15% probabilities may need to be included
during this time frame.

..Mead.. 06/03/2026