787
ACUS02 KWNS 280501
SWODY2
SPC AC 280459

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1159 PM CDT Mon May 27 2024

Valid 291200Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY
AFTERNOON AND EVENING ACROSS PARTS OF EASTERN MONTANA...WYOMING AND
COLORADO INTO WESTERN PORTIONS OF THE DAKOTAS...NEBRASKA AND
KANSAS...

...SUMMARY...
Scattered strong storms posing a risk for severe hail and wind
appear probable across the northern and central High Plains vicinity
late Wednesday afternoon and evening.

...Synopsis...
Stronger westerlies, with at least a couple of modestly amplified
embedded short waves are forecast to persist across the northern
mid-latitudes of the Pacific into western North America through this
period.  Near the leading edge of this regime, large-scale mid-level
troughing appears likely to remain slowly progressive across the
Canadian Prairies and northern U.S. Rockies.

Farther east, a blocking anticyclonic circulation may attempt to
form within larger-scale ridging across the southern Manitoba into
northwestern Ontario/northern Minnesota vicinity, with little
eastward progression of downstream amplified, positively tilted
troughing inland of the Atlantic Seaboard.

In the southern mid- and subtropical latitudes, ridging, initially
centered over central Mexico before retrograding into the Pacific to
the south of Baja, will remain suppressed as low-amplitude mid/upper
troughing advances inland across California/northern Baja into the
Southwest.

Beneath this regime, it still appears that a notable reinforcing
cold front will advance into the Southeast, while stalling and
weakening across the eastern Great Plains.  At the same time,
weakening conglomerate convective outflow may be in the process of
overspreading lower Texas coastal areas and the lower Rio Grande at
the outset of the period.

Within deepening surface troughing across the High Plains, further
boundary-layer moistening is expected, but it still appears that
this will be modest for the time of year across the northern High
Plains.

...Lee of the northern Rockies and Front Range...
Through peak daytime heating, and into Wednesday evening, deep-layer
shear downstream of the mid-level troughing progressing into/across
the northern Rockies is forecast to remain modest to weak. However,
even with the limited boundary-layer moistening (including surface
dew points only reaching mid/upper 50s F), steep
lower/mid-tropospheric lapse rates may contribute to CAPE on the
order of 1000-2000 J/kg, in a narrow corridor along the lee surface
trough with daytime heating.

After storms initiate off the higher terrain, aided by mid/upper
forcing for ascent, they probably will continue to intensify as they
encounter this environment.  Consolidating cold pools may support
upscale growing clusters, aided by strengthening southerly 850 mb
flow (in excess of 30 kt) by early evening.  This may be accompanied
by increasing potential for strong to severe surface gusts, before
convection weakens in a more stable/stabilizing environment deeper
into the Great Plains later Wednesday evening.

...Texas...
Convective potential for this period remains unclear.  Moderate to
strong potential instability may again develop with daytime heating
across the Pecos Valley and Davis Mountains vicinity into the
Edwards Plateau, in the presence of sufficient shear for supercells.
Forcing for ascent, however, remains uncertain, and initiation
through late afternoon may be confined to near the Davis Mountains,
before one or two storms propagate east-southeastward off the higher
terrain.  This activity will probably weaken during the evening as
inhibition increases with the loss of daytime heating, but a period
of renewed development might be possible aided by low-level warm
advection across the Edwards Plateau vicinity Wednesday evening.

..Kerr.. 05/28/2024

$$