783
ACUS02 KWNS 270506
SWODY2
SPC AC 270505

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1205 AM CDT Mon May 27 2024

Valid 281200Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO
TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO
SOUTHEASTERN NEW MEXICO....

...SUMMARY...
Strong thunderstorms, perhaps including a few supercells and a
couple of organizing clusters posing a risk for severe wind and
hail, are possible across much of central into western Texas and
southeastern New Mexico Tuesday afternoon into Tuesday evening.

...Synopsis...
The westerlies are forecast to remain modestly amplified and
progressive across the northern mid-latitudes of the Pacific into
western North America through this period.  Within this regime,
models indicate that large-scale mid-level troughing will shift
inland of the British Columbia and Pacific Northwest coast through
the Canadian and northern U.S. Rockies, while downstream ridging
overspreads the eastern Canadian Prairies and northern U.S. Great
Plains.  Farther east, the progression of larger-scale troughing
east of the upper Mississippi Valley may be slower, as one notable
embedded short wave digs southeast of the Upper Midwest toward the
lower Ohio Valley, but a preceding impulse may accelerate
east-northeast of the lower Great Lakes region into the St. Lawrence
Valley.  This likely will be accompanied by a weakening surface
cyclone, and trailing reinforcing surges of cooler/drier air through
much of the Northeast, Mid Atlantic and Ohio into middle Mississippi
Valleys.

An initial surge of cooler and drier air likely will advance across
the remainder of the Southeast, into the Florida Peninsula and north
central Gulf coast, and later, beneath ridging within weaker
westerlies across the southern mid- and subtropical latitudes,
through the southern Great Plains.

...Texas and portions of adjacent states...
Latest model output, including the NAM in particular, suggests that
the southern Great Plains portion of the lead cold front may become
reinforced by outflow from convection as it spreads across and south
of the Red River Valley early Tuesday.  This convection likely will
be initially rooted within lower/mid-tropospheric warm advection,
aided by forcing for ascent associated with at least one mid/upper
perturbation progressing through the larger-scale ridging.

Beneath warm and capping elevated mixed-layer air, daytime heating
to the south of the front will contribute to strengthening
differential heating across the front/outflow, with residual
seasonably moist air to the south of this boundary becoming
characterized by large mixed-layer CAPE on the order of 2000-4000
J/kg.  As the initial convection increasingly acquires inflow of
this air, substantive further intensification is probable as it
propagates southward toward the upper Texas/Louisiana coastal plain,
accompanied by potential damaging wind gusts.

Upstream, it appears that a trailing perturbation may support
renewed thunderstorm development across parts of the Texas South
Plains and Big Country by mid to late afternoon.  Although
lower/mid-tropospheric wind fields may be modest in strength,
turning with height beneath stronger flow aloft may be supportive of
supercells initially, accompanied by potential to produce large hail
before consolidating and growing upscale.  It appears that this
activity may tend to track southeastward along outflow trailing the
initial convection, accompanied by substantive further
intensification.  This may include an evolving mesoscale convective
vortex, strengthening rear-inflow, and cold pool with potentially
sustained strong to severe surface gusts propagating southeastward
and southward toward the Texas Hill Country and through the Edwards
Plateau into Tuesday evening.

It is possible severe wind probabilities may need to be increased a
bit further in later outlooks, as model spread decreases and
potential convective evolution becomes a bit clearer.

Otherwise, isolated supercell storms remain a possibility near the
dryline initially across parts of the Permian Basin.

...Northern Intermountain Region/Rockies...
Models indicate that weak destabilization ahead of the inland
advancing mid-level trough will support increasing thunderstorm
development Tuesday afternoon and evening.  The NAM, in particular,
continues to suggest that activity may consolidate across the
mountains of central Idaho into western Montana, where evaporative
cooling within a well-mixed sub-cloud boundary layer may contribute
to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric
flow and a strengthening cold pool.  It is possible that strong to
severe surface gusts may spread east of the continental divide
Tuesday evening, even as more weakly unstable inflow begins to
weaken convection.

..Kerr.. 05/27/2024

$$