ACUS02 KWNS 240556
SPC AC 240555
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Mon Jun 24 2019
Valid 251200Z - 261200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
KANSAS AND SOUTHEAST NEBRASKA INTO WESTERN ILLINOIS...
At least isolated severe thunderstorms producing hail and wind are
possible from the southern High Plains northeastward into Iowa and
Illinois, as well as across the Arklatex.
A shortwave trough will eject northeast from the Great Lakes into
Canada with weakly rising heights across the Plains. Meanwhile, an
upper low will drop south along the coastal Pacific Northwest,
resulting in shortwave ridging over the northern Rockies.
At the surface, high pressure will be situated over Deep South, with
southerly winds across the Plains. Here, a weak trough will develop
from the NM/TX border toward southern NE and IA, with a moist and
unstable air mass to the east. This zone will support isolated cells
or small clusters of storms, capable of wind or hail during the
afternoon and evening.
...NM/TX border northeastward into IA and IL...
Despite the height rises, cool midlevel temperatures (-10 to -12 C)
will remain over the central states. Heating will then result in
steep lapse rates, with widespread 60s to low 70s F dewpoints
contributing to an extensive area of strong instability. MUCAPE in
excess of 3000 J/kg is possible from west TX into IA, with higher
values across OK, KS, and western MO.
Strong heating will occur near the surface trough, with little if
any CIN. Storms are likely to form by 21Z with slow-moving cells
across TX, OK, and KS. Some of these storms may become small
clusters with accelerating outflows late in the day.
Farther north, winds aloft will be stronger from NE into IL and may
better support an organized severe threat with an MCS. Initiation
appears most likely on the nose of the low-level jet after 21Z over
NE/KS, developing across MO, IA, and into IL during the evening.
Hail is also possible with strong instability and cool temperatures
...Arklatex and southeast OK...
Several models including the NAM and ECMWF suggest an early day MCS
affecting southeast OK, developing toward the Arklatex. This is a
plausible scenario given ample moisture, instability, and sufficient
lift via low-level warm advection. Another possible instigator may
be antecedent outflow boundaries, which are difficult to forecast.
Thus, low severe probabilities appear justified mainly for strong
...MAXIMUM RISK BY HAZARD...
Tornado: 2% - Marginal
Wind: 15% - Slight
Hail: 5% - Marginal