118
ACUS48 KWNS 140855
SWOD48
SPC AC 140853

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0353 AM CDT Wed May 14 2025

Valid 171200Z - 221200Z

...DISCUSSION...
An active period of severe weather remains likely through the
weekend and into early next week for portions of the central CONUS.
A weakening upper trough is forecast to migrate across the Northeast
late this weekend as a second upper wave begins to amplify over the
western states. This upper regime will favor surface pressure falls
across the High Plains that will promote south/southeasterly return
flow into the southern/central Plains through early next week.
Severe thunderstorm chances will increase as preceding upper
disturbances and the primary upper wave eject into the Plains over
the warm sector. While severe weather chances are anticipated most
days through the extended period, confidence in more focused,
synoptically-driven corridors is currently greatest on D5/Sunday and
D6/Monday across the southern Plains.

...D5/Sunday to D6/Monday...
Increasing southwesterly flow aloft over the southern/central
Rockies will promote lee cyclogenesis across the central High Plains
beginning D4/Saturday through D7/Monday. This will foster moisture
return into northern TX, OK, and southern KS as a warm front lifts
north. Long-range ensemble guidance suggests dewpoints ranging from
the mid 60s to low 70s are likely by Sunday afternoon across the
southern High Plains to the east of a sharpening dryline. Recent
GFS/GEFS solutions have come into better alignment with ECMWF/EPS
runs that depict a leading impulse within the subtropical jet
overspreading the southern High Plains late Sunday afternoon.
Enhanced westerly low- to mid-level flow coupled with ascent
associated with the upper feature should promote eastward mixing of
the dryline with attendant chances for thunderstorm development
within a buoyant and strongly sheared environment.

The ejection of the primary trough axis on D6/Monday should result
in more widespread 50+ knot mid-level flow overspreading much of
OK/KS. The eastward migration of the surface low and trailing
dryline through the day should provide adequate forcing for ascent
for thunderstorm development within a buoyant and strongly sheared
environment, which should promote an organized, and potentially more
widespread, severe threat.

More specific mesoscale details for both days remain unclear at this
range, but the general alignment of global deterministic/ensemble
guidance regarding the overall synoptic regime and convective
environment, combined with a consistent QPF signal on both days,
suggests predictability is high enough to introduce risk
probabilities.

...D4/Saturday...
A residual cold front associated with a weakening surface low over
the northern CONUS is expected to be draped from the southern
Appalachians southwestward into the mid-MS Valley/Ozark Plateau
region. Sufficient buoyancy and strong zonal flow aloft will likely
support organized convection along the frontal zone. While some
severe threat is anticipated, mid-level ridging and lingering
convection at the start of the day limit confidence/predictability
in where the better mesoscale corridors for severe convection will
become established.

...D7/Tuesday...
Some severe threat is expected to persist into Tuesday as a surface
low and attendant trough/dryline migrate east towards the Midwest.
Ensemble guidance hints at strong/severe thunderstorm potential
across parts of AR, MO, and the lower OH Valley, but spread among
deterministic solutions and the potential for lingering convection
from D6/Monday limits confidence at this range.

..Moore.. 05/14/2025