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000
ACUS02 KWNS 130542
SWODY2
SPC AC 130540

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Sat Apr 13 2024

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF PA TO
EAST OH...

...SUMMARY...
Isolated to scattered severe thunderstorms are possible from late
afternoon into the evening on Sunday, across eastern Indiana into
the Northeast States. Damaging winds should be the primary hazard,
but a tornado or two and large hail are also possible.

...Northeast States to eastern IN...
A mid-level jetlet attendant to a low-amplitude shortwave impulse
should progress across the northern Great Lakes and Ontario into New
England by Sunday evening. Weak cyclogenesis should occur with the
surface low tracking east across parts of NY. An attendant cold
front should arc westward and progress southeastward.

A pronounced elevated mixed layer across the Midwest and southern
Great Lakes will shift southeastward into the Mid-Atlantic and
Southeast States. This elevated mixed layer will likely cap
surface-based convection until near/after peak heating along the
west/east-oriented cold front. 00Z RRFS/NAM soundings appear
relatively reasonable with this evolution as modified low-level
moisture return emanating from the southern Great Plains struggles
to reduce MLCIN until cooling aloft advects in from the
west-northwest. Other guidance may be too moist within the boundary
layer given upstream observations and 36 hours of air mass
modification remaining. Still, a corridor of MLCAPE reaching
1000-1500 J/kg will probably develop in IN/OH given the initially
steep mid-level lapse rates. This buoyancy plume will subside with
eastern extent towards the DE Valley.

Hodographs across the region should be dominated by low-level
curvature enlargement, especially with eastern extent. However, weak
speed and directional shear components are expected above that
within the buoyancy layer. Maturing cells will attempt to form
supercell structures, but given the nearly parallel orientation of
the front with respect to the deep-layer westerly flow regime,
convective mode should favor west/east-oriented clusters. These
should largely progress south-southeast amid the undercutting nature
of the composite front and emerging convective outflows. Due to the
initially steep mid-level lapse rates and enlarged low-level
hodographs, there is concern for a brief supercell tornado and
isolated hail threat. Though with the limiting factors, it appears
damaging winds should be the primary hazard during the evening
before convection wanes with southern extent overnight.

..Grams.. 04/13/2024

$$