SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Wed Jul 27 2022
Valid 291200Z - 301200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
OZARKS/MID-SOUTH TO PARTS OF THE MID-ATLANTIC REGION...
...SUMMARY...
Isolated damaging thunderstorm gusts may occur from the
Ozarks/Mid-South to parts of the Mid-Atlantic region.
...Synopsis...
The predominantly influential mid/upper-level feature for day 3 will
continue to be progressive troughing over eastern Canada, extending
into parts of the Great Lakes and Northeastern CONUS. A broad/
complex cyclone will move from its day-2 position over ON eastward
across QC, with a trailing, positively tilted trough moving from the
Upper Great Lakes across the Lower Great Lakes and parts of OH/PA
during this period. At 30/00Z, the trough should extend from
north-central QC southwestward over parts of Lake Huron and Lower
MI, to eastern/central MO. The associated surface cold front is
forecast by 30/00Z to reach parts of ME, Southern New England, to
near or just south of the Ohio River, becoming quasistationary over
the eastern/southern Ozarks, parts of OK and the TX Panhandle.
Meanwhile, mid/upper-level ridging and associated weak flow aloft
will cover the Southeast, southern Plains and southern Rockies,
northwestward to the Pacific Northwest.
...Ozarks region to Mid-Atlantic/Northeast...
Scattered to widely scattered thunderstorms are expected to develop
near the front, as well as along any outflow/differential-heating
boundaries left to its south by convection from day 2 into early
this period. Damaging to isolated severe gusts will be the main
concern.
With the mid/upper trough moving away from most of the region, weak
height rises are forecast aloft, albeit under flow that still should
be gently cyclonic in curvature through the 500-250-mb layer. A
swath of rich low-level moisture -- with PW around 2 inches or
greater, as well as surface dew points commonly in the upper 60s to
mid 70s F -- will combine with near-frontal lift, diurnal heating
and accompanying CINH erosion, to promote multicellular clusters
with sporadic damaging, wet downbursts. A series of small vorticity
maxima -- some convectively induced/enhanced from day 2 -- may be
moving roughly eastward along this corridor and over the surface
baroclinic zone between the south-central Plains and Tidewater,
aiding convective potential in mesoscale nodes. However, location
specifics are too uncertain and low in predictability three days out
to pinpoint denser concentrations within this lengthy corridor.
Stronger flow aloft will remain over NY and New England, which still
will be ahead of the positively tilted mid/upper trough and near the
frontal zone, but likely with weaker moisture/instability than the
previous day. While some strong convection may develop over this
region, severe potential is too uncertain at this time to extend the
unconditional 5%/MRGL probabilities farther north.
...Central High Plains...
North of the front, the persistent easterly low-level flow component
will advect moisture westward across the south-central Plains and
into this region, supporting mainly afternoon/evening thunderstorm
potential. Though low/middle-level flow will be weak, a well-mixed
subcloud layer and the southwestern fringe of stronger upper/
anvil-level flow may aid in convective organization. At this time,
lack of both greater flow and better-focused forcing precludes an
unconditional threat area.
..Edwards.. 07/27/2022
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