563
ACUS03 KWNS 300727
SWODY3
SPC AC 300726

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0226 AM CDT Thu May 30 2024

Valid 011200Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SATURDAY
AFTERNOON AND EVENING ACROSS PARTS OF EASTERN COLORADO...WESTERN AND
CENTRAL NEBRASKA AND WESTERN KANSAS...

...SUMMARY...
Scattered strong storms, including a few supercells, may develop to
the east of the Front Range Saturday afternoon, before evolving into
organizing clusters while spreading into the adjacent Great Plains
through Saturday evening.  These may pose a risk for severe wind,
hail and perhaps a couple of brief tornadoes.

...Synopsis...
In the wake of amplified mid/upper troughing forecast to continue
slowly shifting away from the Atlantic Seaboard, stronger westerlies
across the northern tier of the U.S. may trend more zonal Saturday
through Saturday night.  As ridging across the subtropics remains
suppressed, weak zonal flow appears likely to persist across the
southern tier of the U.S., gradually developing into and across the
southern Atlantic Seaboard.

Beneath this regime, seasonably high moisture content air will
likely remain confined to the lee of the southern Rockies, but
gradually continue advecting eastward across and east of the lower
Mississippi Valley, in the wake of a lead low-amplitude short wave
forecast to approach the southern Appalachians.

Downstream of troughing advancing inland of the Pacific coast within
both streams, models indicate at least one initially subtle
perturbation may undergo amplification, perhaps enhanced by
convective development, as it progresses to the east of the Front
Range Saturday afternoon and evening.  It is possible that another
wave may similarly impact the Pecos Valley/Texas Big Bend vicinity,
but this potential appears more uncertain due to greater model
differences.

...Front Range into adjacent Great Plains...
It appears that large-scale mid/upper forcing for ascent will become
conducive thunderstorm initiation off the higher terrain Saturday
afternoon.  This activity is expected to intensify as it propagates
into slowly deepening lee surface troughing, where boundary-layer
moistening may become sufficient to support CAPE on the order of
1000-2000 J/kg.  Veering wind profiles with height beneath modest
westerly mid-level flow probably will contribute to sufficient shear
for a few supercells, initially, posing a risk for severe hail and
perhaps a couple of brief tornadoes.

It appears that this convection will gradually grow upscale in the
presence of forcing aided by lower/mid-tropospheric warm advection,
with evolving clusters posing increasing potential for strong to
severe wind gusts deeper into the plains, before weakening by late
Saturday evening.

...Lower Mississippi Valley into Southwest Texas...
Potential storm coverage remains uncertain in the wake of the lead
short wave perturbation progressing to the east of the lower
Mississippi Valley.  Mid-level heights may tend to rise during the
day.  However, mid-level inhibition might not be prohibitive to
thunderstorm initiation, at least initially, particularly across
parts of southeast Texas into the lower Mississippi Valley.
Deep-layer mean wind fields and shear probably will remain modest to
weak, but destabilization and approach of convective temperatures
with insolation may support widely scattered to scattered storms
posing at least some risk for severe wind and hail.

..Kerr.. 05/30/2024

$$