LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri May 19 2023
Valid 191200Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
SOUTHERN PLAINS INTO WESTERN ARKANSAS...
...SUMMARY...
Strong/locally severe storms are expected this afternoon and evening
from parts of the southern Plains eastward into parts of Arkansas.
...Synopsis...
A rather deep mid/upper-level cyclone is forecast to move across the
Great Lakes region today, as an associated cold front moves
southward through parts of the central/southern Plains, lower/mid MS
Valley, and OH Valley. An upper ridge is expected to remain in place
over parts of the Great Basin. A weak mid/upper-level trough is
expected to move northeastward near the Carolina coast, with
development of a surface low possible along the coastal front later
today into tonight.
...North TX into central/southeast OK and western AR...
An overnight MCS is expected to weaken later this morning across
parts of OK. The evolution of the associated MCV and any outflow
boundaries remain somewhat uncertain, but in general, moderate
destabilization is expected along/south of the cold front this
afternoon from parts of OK into the ArkLaTex region and much of TX.
The cold front will likely be the primary focus for scattered
thunderstorm development by late afternoon, though initiation will
also be possible near any remnant outflow boundary, and some
guidance suggests development near a prefrontal trough across parts
of north TX.
Deep-layer flow will not be particularly strong, but some modest
enhancement to midlevel westerlies associated with the MCV may
support effective shear of 30-35 kt across parts of OK into north
TX, supporting the potential for strong multicell clusters and
perhaps a couple of supercells. Guidance varies somewhat regarding
the strength of low-level flow/shear across the warm sector, but a
tornado or two cannot be ruled out if supercells can be sustained.
...Southeast NM into parts of west-central/southwest TX...
A surface trough and associated wind shift is expected to move
southward into parts of southeast NM/west TX during the afternoon,
well in advance of the relatively cold/stable airmass moving
southward across the Great Plains. Isolated to widely scattered
thunderstorm development will be possible along/north of this
surface trough, within a warm/well-mixed environment.
North/northeasterly surface winds veering to modest westerlies aloft
will support effective shear of 30-40 kt, and a few organized
cells/clusters capable of hail and isolated severe gusts will be
possible. A loosely organized MCS may develop and spread southward
across the Edwards plateau later tonight, with a continued risk of
at least isolated severe wind/hail.
...OH Valley into the lower Great Lakes...
Modest heating/moistening may support weak convection along the cold
front this afternoon/evening across parts of the OH Valley and lower
Great Lakes region. While wind profiles will be somewhat supportive
of organized storms, very weak buoyancy is expected to limit the
overall severe risk.
...Arizona...
Scattered to widespread thunderstorms are expected across parts of
AZ this afternoon and evening, within an anomalously moist
environment. Weak northeasterly midlevel flow may support an
outflow-driven storm cluster moving into the lower elevations with
gusty wind potential, though any severe wind risk remains uncertain
at this time.
..Dean/Thornton.. 05/19/2023
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