SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0248 PM CDT Fri Aug 19 2022
Valid 192000Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE LOWER MISSOURI VALLEY INTO THE MIDDLE MISSISSIPPI VALLEY...
...SUMMARY...
Isolated large hail and strong gusts are possible across parts of
the Lower Missouri into the Middle Mississippi Valley through this
evening.
...20z Update - Lower MO Valley Vicinity...
The Marginal and Slight risk areas have been expanded across
portions of southeast NE/southwest IA/northwest MO/northeast KS to
account for ongoing convective trends. Strong to severe storms are
ongoing along the cold front and have produced up to golf ball sized
hail over parts of IA. A similar environment extends westward along
the front toward the MO Valley, and large hail will be the main
concern with storms through early evening. For information regarding
short term severe potential across parts of Kansas reference MCD
1697, and MCD 1698 across parts of Iowa.
..Leitman.. 08/19/2022
.PREV DISCUSSION... /ISSUED 1122 AM CDT Fri Aug 19 2022/
...IA/MO/IL vicinity...
To the south and southeast of a vertically stacked low over
southwest MN, pockets of greater boundary-layer heating are evident
across parts of IA into MO and IL. Amid cool mid-level temperatures
around -12 C at 500 mb, moderate buoyancy with MLCAPE of 1000-2000
J/kg should become common by late afternoon. A scattering of
thunderstorms is expected during this time frame into the evening,
focused along the primary surface cold front and confluence bands
ahead of it. While stronger deep-layer shear will be found in the
southwest quadrant of the broader cyclone, a swath of moderate
mid-level westerlies should extend east towards the IA/MO/IL border
area yielding effective bulk shear of 25-35 kts. This area should be
most favored for a few lower-end supercells and small multicell
clusters mainly producing isolated severe hail and damaging wind
until convection wanes later this evening.
...KS...
In the wake of ongoing elevated convection, a corridor of
destabilization is expected near and behind the surface cold front
drifting south from southern NE/northwest KS. Buoyancy will remain
limited and mid-level lapse rates were relatively modest in upstream
12Z soundings from North Platte and Rapid City. Nevertheless, the
presence of 30-40 kt mid-level west-northwesterlies to the southwest
of the vertically stacked low in southern MN will support a threat
for a few cells producing isolated severe hail and wind during the
late afternoon to early evening.
...Eastern GA/coastal Carolinas...
Generally stratiform rain with isolated deeper convection has been
slowly drifting east over southern NC and far eastern SC. This has
convectively reinforced a weak baroclinic zone across the region
with a 1017-mb mesolow over eastern SC. This minor cyclone should
drift north towards central NC through tonight. A rather localized
corridor of enhanced low-level SRH near the track of this low
conditionally supports a threat for a brief tornado. Otherwise,
locally damaging winds will be possible with scattered multicell
clusters that emanate out of GA later this afternoon.
...Central/western AZ...
A few strong storms with locally gusty winds may materialize during
the late afternoon and early evening across the region within a very
moist air mass. Potential for organized severe storms appears
limited owing to weak deep-layer shear/mid-level lapse rates.
Read more CHECK UPDATE ZOOM GRAPHIC
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