LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Tue Aug 08 2023
Valid 081630Z - 091200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
CENTRAL HIGH PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
PLAINS AND SOUTHEAST...
...SUMMARY...
Scattered severe thunderstorms are expected across parts of the
central Plains during the late afternoon into tonight. Large to very
large hail, severe gusts, and a tornado or two are possible.
Scattered damaging winds and isolated severe hail will also be
possible through early evening across parts of the Southeast.
...Wyoming/northern Colorado to Central Plains...
A prominent summertime shortwave trough will continue to advance
southeastward over southeast Idaho/northern Utah into Wyoming today,
with downstream height falls influencing the High Plains by evening.
This scenario will enhance lee troughing, aiding a
north-northwestward surge of low-level moisture through late
afternoon/evening toward much of the Colorado Front Range and
southeast Wyoming/Nebraska Panhandle.
Initial high-based thunderstorm development is expected over the
mountains/higher terrain of northern Colorado/southern Wyoming by
mid-afternoon, with a subsequent increase/eastward spread, along
with additional development into the larger buoyancy environment
across the central High Plains including northeast
Colorado/southwest Nebraska/northwest Kansas.
Strengthening late-day westerlies (35-45 kt) will contribute to
elongated, nearly-straight hodographs, while buoyancy with 2500-3000
J/kg MLCAPE should be maximized across northeast Colorado and
southwest Nebraska. Splitting supercells are expected with a
north/south-oriented cluster likely evolving relatively quickly as
outflows consolidate towards the Colorado/Nebraska/Kansas border
vicinity. The potential for a longer-track discrete supercell or two
appears greatest along the southern periphery of convective
development owing to lack of interference from other storms. Very
large hail, significant severe wind gusts, and a tornado or two are
all possible.
A strengthening nocturnal low-level jet and enhanced warm/moist
advection near/above the surface could help maintain or even
reinvigorate the MCS east-southeastward into central/eastern Kansas
overnight, with damaging wind potential and possibly some hail risk.
...Lower Mississippi Valley/Southeast...
The leading edge of a residual MCS is ongoing across the Lower
Mississippi Valley at late morning, with a considerable amount of
trailing stratiform precipitation. Much of this MCS will continue to
interface with the cooler/more stable side of the front that arcs
roughly west-to-east across Louisiana/Mississippi/Alabama and
Georgia, with some of the MCS-related cloud canopy extending across
the downstream warm sector.
But even a glancing influence of the MCS/any MCV and related
outflows should contribute to at least isolated/widely scattered
thunderstorm development near the front this afternoon as the
boundary layer becomes moderately to strongly unstable, with upper
70s F warm-sector surface dewpoints common. Upstream WSR-88D VWP
data (such as Fort Smith AR and Little Rock this morning) does
sample a seasonally strong 50+ kt belt of westerlies between 3-8 km
AGL, with the stronger winds grazing the frontal zone/adjacent warm
sector. This is likely to support sustained/relatively organized
multicellular clusters with scattered damaging winds as the most
common hazard.
...New England...
A relatively short duration severe risk may briefly linger early
this afternoon across coastal southeast New England in association
with a narrow warm/moist sector ahead of a secondary surface low,
including the possibly of a localized wind damage and/or a brief
tornado. Otherwise, convective development this afternoon is
anticipated over western New England where deep-layer shear will be
weak in closer proximity to the trough axis, with the potential for
organized severe thunderstorm development expected to remain low.
...Northern Minnesota/eastern North Dakota...
A shortwave trough over northern Manitoba and northwest Ontario will
continue to dig southeastward, with a cold front settling southward
across North Dakota/northern Minnesota through tonight.
Thunderstorms should be focused along the front particularly late
this afternoon through early evening. An adequate combination of
deep-layer shear and instability should support an isolated severe
wind/hail risk.
..Guyer/Squitieri.. 08/08/2023
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