614
ACUS48 KWNS 040854
SWOD48
SPC AC 040852

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0352 AM CDT Thu Jun 04 2026

Valid 071200Z - 121200Z

...DISCUSSION...
...Day4/Sunday...

A short-wave trough initially from the lee of the Canadian Rockies
into the northern Rockies is forecast to lift northeast into central
Canada, while a lower-latitude wave moves through the central and
southern Plains toward the MS Valley. Elsewhere, a short-wave trough
will traverse the Northeast and Mid-Atlantic. At the surface, a cold
front will slowly advance across the northern Plains, while a
separate cold front moves south through the Mid-Atlantic.

The strongest mid/upper-level winds and associated vertical shear
will lag the northern Plains cold front to the west; however, the
presence of moderate to strong instability within the warm sector
may compensate, yielding the potential for an organized
severe-weather event Sunday afternoon and evening. Elsewhere,
isolated to widely scattered severe storms appear possible along the
Mid-Atlantic cold front, as well as across lower elevations of
central and southern Plains into Ozark Plateau, in association with
the mid-level trough.


...Day5/Monday...

Ensemble mean and deterministic model solutions are in good
agreement in suggesting that a mid-level trough will move onto the
West Coast, with a downstream belt of stronger winds remaining
confined to the Interior West. At the surface, a cold front
initially from the ND-MN Red River Valley into central High Plains
will weaken through the day in response to falling pressures over
the Rockies. Isolated severe storms appear possible along the
segment of the front immediately east of a surface low over western
KS where strong instability is forecast. However, generally weak
forcing for ascent and marginal vertical shear may limit the
potential for an organized severe-weather episode.


...Day6/Tuesday...

The ensemble mean and deterministic model solutions remain in
relatively good agreement in depicting the continued amplification
of the mid-level trough over the western U.S., with a belt of
stronger winds aloft overspreading the northern Plains. At the
surface, there is reasonably good ensemble clustering in the
location of a deepening lee cyclone over the northern High Plains,
with a lee trough extending through the central into southern High
Plains. While large-scale forcing for ascent remains somewhat
nebulous, low-level convergence in the vicinity of the surface low
and lee trough should be sufficient to initiate afternoon/evening
thunderstorms within an environment favoring the potential for a
concentrated area of severe weather.


...Day7-8/Wednesday and Thursday...

The ensemble mean solutions suggest the main trough becoming
quasi-stationary over the Interior West. There is considerably more
spread in the deterministic models, especially by Thursday, in the
location and geometry of the mid-level trough, as well as any
smaller-scale disturbances embedded within it. At the surface, there
is fairly large spread in ensemble member low pressure positions,
and the location of any associated boundaries. In general, it
appears that some severe-weather threat will continue across the
northern Plains; however, confidence in a more specific details is
currently too low to delineate an area.

..Mead.. 06/04/2026