ACUS48 KWNS 010911
SPC AC 010909

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0409 AM CDT Mon Jun 01 2020

Valid 041200Z - 091200Z

An upper ridge will initially be centered over the Four Corners area
and southern High Plains during the middle of the week.
Semi-progressive westerlies will remain across the northern tier of
the CONUS and Canada. An amplification of the large-scale pattern
will likely occur into Day 5/Friday and Day 6/Saturday as the upper
ridge builds over the Plains ahead of an upper trough ejecting
northeastward over the Southwest States/central Rockies.

For Day 4/Thursday, at least isolated severe thunderstorms can be
expected near the southward-shifting front from the Ozarks to the
Tennessee Valley and central/southern Appalachians and Mid-Atlantic
region. While severe thunderstorms can be expected, modest
westerlies aloft and mesoscale uncertainties related to prior-day
convection preclude a 15% percent graphical delineation. Across the
north-central Plains, severe thunderstorms including a risk for
supercells currently appears most probable across eastern South
Dakota/northeast Nebraska into northwest Iowa/southwest Minnesota
within an unstable environment near a west/east-oriented front.

On Day 5/Friday, the building upper ridge across the Plains leads to
some uncertainty, but isolated strong/severe thunderstorms could
occur across the Lower Missouri Valley to Tennessee Valley and
southern Appalachians. Some severe risk may also exist across parts
of Montana and the adjacent northern High Plains. 

Severe weather-potential may further increase across the
northern/central High Plains on Day 6/Saturday.

..Guyer.. 06/01/2020