SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0134 AM CDT Tue Sep 06 2022
Valid 081200Z - 091200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THURSDAY
AFTERNOON AND EVENING...
...SUMMARY...
Strong thunderstorms may impact parts of the upper Great Lakes
vicinity late Thursday afternoon and evening, posing at least some
risk for severe weather.
...Synopsis...
Remnants of mid-level troughing emerging from the northern
mid-latitude Pacific, likely reaching the eastern Canadian Prairies
by 12Z Thursday, may gradually become absorbed within flow around a
deep mid-level low forecast to turn westward and southward to the
northwest of Hudson Bay through daybreak Friday. It appears that
this will be accompanied by the northeastward migration of a surface
cyclone from central Manitoba through southern Hudson Bay. In the
wake of this feature, models indicate that a cold front will advance
southeastward into the upper Great Lakes vicinity and northern Great
Plains, as trailing mid-level troughing digs into the northern
Rockies, in advance of amplified troughing/ridging across Alaska and
the northeastern Pacific into the far western Canadian provinces.
Coinciding with these developments, substantive further suppression
of the Great Basin mid-level high is forecast, while Kay migrates
northwestward off the southern Baja coast, and a broad low become
better developed within weak flow centered near the Louisiana coast.
Weak mid-level troughing is also forecast to shift off the
northern/mid Atlantic coast, with an associated front stalling and
weakening across the southern Mid Atlantic coast into Tennessee
Valley and Mid South vicinity.
...Upper Great Lakes vicinity...
Although the northward return of seasonably high moisture content
will be impeded, a corridor of modest moisture is currently present
ahead of surface troughing across parts of the middle Missouri
Valley and northern Great Plains. Beneath a plume of very warm and
capping elevated mixed-layer air, which is forecast to advect as far
east-northeast as the Lake Superior vicinity before becoming cut
off, a narrow pre-frontal corridor of mixed-layer CAPE on the order
of 500-1000+ J/kg may develop across parts of northeastern Minnesota
by late Thursday afternoon. While this is fairly modest, the steep
lapse rates, coupled with sufficient vertical shear near the
southern periphery of stronger lower/mid-tropospheric forcing for
ascent, may contribute to an environment at least marginally
conducive to organized severe convection. This may initially
include a supercell or two, with severe hail and wind the primary
potential hazards.
..Kerr.. 09/06/2022
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/SXrbg7
