422
ACUS02 KWNS 131725
SWODY2
SPC AC 131724

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1224 PM CDT Thu Jun 13 2024

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF
CO/KS/NE AND THE NORTHEAST STATES...

...SUMMARY...
Scattered severe storms with large hail and wind gusts of 60-80 mph
will be possible from mid-afternoon through the evening on Friday
along the Front Range to the central Great Plains. Scattered strong
storms with sporadic damaging winds and isolated hail will be
possible across the Northeast States during the afternoon to early
evening.

...CO/KS/NE...
Primary categorical change this cycle is to expand the level 2-SLGT
risk southward into the more deeply mixed air with thunderstorms
expected to develop off the Raton Mesa/Sangre de Cristo Mountains.
This includes expansion of the significant severe wind highlight for
gusts to around 80 mph.

A southern-stream shortwave trough currently off the northern Baja
CA coast will reach the Four Corners area by Friday afternoon and
progress towards the central High Plains through early Saturday.
This feature will likely dampen during the D2 period. The bulk of
mid to upper-flow enhancement will be confined along the southern
arc of the trough, near/ahead of substantial warming within the
southwest quadrant of the trough. As such, the overall kinematic
profile will be relatively modest by typical central High Plains
standards. But the large-scale forcing for ascent attendant to the
approaching trough will support scattered to widespread thunderstorm
development during the afternoon off the higher terrain onto the
adjacent plains.

A quasi-stationary front, modulated by D1 convection, should be
draped from the Ozark Plateau west-northwest into the central High
Plains. Moderate uncertainty exists with regard to placement of the
front in western KS/eastern CO by peak heating, with hot
temperatures expected within the deeply mixed air mass to its south.
A confined plume of enhanced low-level moisture will be present
along and just north of the front emanating west-northwest from the
Ozarks. This should support a corridor of MLCAPE from 1500-2500 J/kg
amid initially steep mid-level lapse rates.

Given the modest deep-layer shear profiles and pervasive convective
coverage, a cluster mode should dominate as storms spread onto the
High Plains. As they impinge on the greater buoyancy plume/frontal
zone, a bowing structure or two may develop as a modestly organized
QLCS moves east-northeast into western parts of KS/NE. Scattered
severe wind swaths and some hail will be possible, peaking in the
late afternoon to dusk. The north and east extent of the threat
should slowly wane in both intensity/coverage Friday night.

...New England to the central Appalachians...
A series of shortwave impulses embedded within a broader mid/upper
trough over ON/QC and the Great Lakes will shift east across the
Northeast States through Friday Night. One of these impulses should
amplify somewhat as it tracks from the southern Great Plains into
NY/PA. A surface cold front should extend from New England
southwestward into the OH Valley on Friday afternoon, with a lee
trough east of the Appalachians.

Mid-level lapse rates will be relatively steeper with northern
extent into New England and weaker with southern extent into the
Mid-Atlantic States and the central Appalachians. However, deeper
boundary-layer warming/mixing is anticipated with southern extent. A
broad plume of modest buoyancy with MLCAPE of 500-1500 J/kg is
anticipated. Scattered thunderstorms are expected along and ahead of
the surface cold front during the afternoon. While the bulk of
strong mid to upper-level southwesterly flow should lag behind the
boundary and largely parallel it as well, vertical shear will be
sufficient for organized cells capable of isolated severe hail and
damaging winds across New England. With southern extent, strong
gusts within multicell clusters should yield sporadic wind damage.
The level 2-SLGT risk corridor in the Northeast represents the
relatively more favorable potential for cells/clusters to produce
scattered damaging winds and marginally severe hail.

..Grams.. 06/13/2024

$$