LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Sun Jul 16 2023
Valid 162000Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM KANSAS INTO
MISSOURI...AND OVER NORTHERN LOUISIANA...
...SUMMARY...
A brief/weak tornado will be possible across portions of the
Northeast this afternoon, while scattered large hail and severe wind
will be possible across the Central Plains and portions of the
Midwest.
...Northeast...
Low-level shear continues to decrease over New England, though
instability remains. As such have reduced tornado probabilities,
although heating over NY/VT may yield a few strong cells in the
weaker shear area. The strong low-level shear has shifted primarily
northeast of where the more favorable instability resides.
...Sabine Valley into the mid MS Valley...
A corridor of strong instability exists ahead of ongoing strong to
severe storms now near the AR/LA border. These may pose a damaging
wind threat as they likely persist today, traveling southeastward
across northern LA. For more information see mesoscale discussion
1578.
Farther north, scattered strong cells persist over east-central MO,
where strong outflow winds have been observed. The air mass remains
unstable eastward into IL, and both strong gusts and marginal hail
may occur with MLCAPE to 2000 J/kg and around 30 kt effective shear.
...Central/Northern Plains...
Strong heating continues over the region, with increasing CU noted
on satellite near the boundary in KS. Convection is also growing
over the Black Hills area, through storm coverage should remain
isolated there. Favorable 50 kt effective shear will conditionally
favor hail cells. The greatest threat area continues to be over KS
where heating continues and the air mass is most unstable south of
the front. For more information see mesoscale discussion 1579.
..Jewell.. 07/16/2023
.PREV DISCUSSION... /ISSUED 1137 AM CDT Sun Jul 16 2023/
...Northeast/Southern New England and Mid-Atlantic States...
Widespread precipitation, with embedded stronger convective
elements, continues across eastern portions of the mid-Atlantic
region northeast into New England at 16z. Widespread cloud
cover/limited heating has tempered destabilization of a very moist
air mass (PW in excess of 2 inches), however weak MLCAPE (500 to
locally near 1000 J/kg) is expected through this afternoon, which
will remain sufficient for a few stronger storms to persist.
Low-level shear will also remain supportive of mostly transient
low-level rotation and some continued tornado risk through mid
afternoon.
...Central Plains/Midwest...
A persistent low-level jet will continue to provide a moist/unstable
inflow into the MCS over eastern KS/western MO, and diurnal heating
downstream over central MO will result in moderate/strong MLCAPE as
this MCS continues moving east-southeast over the next few hours.
Mid-level flow of 30-40 kts will provide sufficient shear to
maintain some degree of organization with at least some risk for
damaging winds this afternoon.
The Marginal Risk has been expanded northwest towards the Black
Hills Region of SD, where isolated thunderstorms may develop this
afternoon/evening. Northwesterly mid-level flow of 40-50 kts will
support supercell potential with a risk for severe hail and strong
wind gusts.
...North Texas/Southern Oklahoma to ArkLaTex/Middle Gulf Coast...
A persistent MCS continues along the Red River late this morning,
with isolated severe winds reported over the past hour. Daytime
heating of an exceptionally moist air mass will contribute to
strong/locally extreme instability by afternoon downstream towards
the Arklatex, and despite marginal shear this convective system will
likely maintain its structure while moving southeast this afternoon.
At least isolated damaging winds will be possible with this MCS
through the afternoon, and also with additional storms/clusters that
may develop towards the middle Gulf Coast within an uncapped air
mass.
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