377
ACUS03 KWNS 260731
SWODY3
SPC AC 260730

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Sun May 26 2024

Valid 281200Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TUESDAY
AFTERNOON AND EVENING ACROSS PARTS OF THE TEXAS EDWARDS PLATEAU INTO
EASTERN NEW MEXICO AND ACROSS PARTS OF NORTHEASTERN
OREGON....CENTRAL AND NORTHERN IDAHO...AND WESTERN MONTANA...

...SUMMARY...
Strong thunderstorms may impact parts of the Texas Edwards Plateau
and Permian Basin into eastern New Mexico, as well as portions of
the northern Rockies, Tuesday afternoon into Tuesday evening,
accompanied by at least some risk for severe weather.

...Synopsis...
Mid/upper flow across the northern mid-latitudes of the Pacific into
western North America is forecast to remain modestly amplified and
slowly progressive into and through this period.  This appears
likely to include larger-scale troughing migrating inland of the
Pacific coast through the northern Rockies, and downstream ridging
shifting eastward across the eastern Canadian Prairies and northern
U.S. Great Plains.  Downstream troughing, across and east of the
upper Mississippi Valley, may be a bit slower, with one notable
embedded short wave impulse forecast to dig southeast of the Upper
Midwest into the lower Ohio Valley, but another notable impulse may
accelerate east-northeast of the lower Great Lakes through the St.
Lawrence Valley.  This will be accompanied by a weakening surface
cyclone and trailing reinforcing surges of cooler/drier air into the
Northeast and across the Ohio Valley into the Southeast.

Cooler and drier air may also advance southward through the southern
Great Plains, beneath ridging within weaker westerlies across the
southern mid- into subtropical latitudes.

Seasonably high boundary-layer moisture may be in the process of
shifting offshore of the southern Atlantic coast at the beginning of
the period, and becoming confined to parts of the Edwards Plateau,
Permian Basin and adjacent Rio Grande Valley.  However, there is
notable spread among the model output concerning this and other
synoptic/sub-synoptic details.

...Southwest Texas into Eastern New Mexico...
It currently appears that the dryline within weak lingering surface
troughing across parts of eastern New Mexico through the Permian
Basin/Edwards Plateau vicinity will become the focus for strong
thunderstorm development Tuesday afternoon.  It is possible that
this may be aided by forcing for ascent associated with a weak
perturbation progressing through the larger-scale ridging aloft.  In
the presence of steep lapse rates, it appears that the low-level
moisture to the east of the dryline may be sufficient for moderate
to large CAPE with daytime heating, with deep-layer shear, aided by
veering winds with height in lower through mid-levels, conducive to
the evolution of a few supercells.  It is possible that severe
probabilities could be increased further in later outlooks for this
period.

...Northern Intermountain Region/Rockies...
Models suggest that weak destabilization ahead of the inland
advancing mid-level trough will support increasing thunderstorm
development Tuesday afternoon and evening.  The latest NAM, in
particular, suggests 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.. 05/26/2024

$$