RSS Mesoscale Discussions from Storm Prediction Center
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0749 AM CDT Fri May 22 2026
Valid 221300Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE TEXAS
PANHANDLE AND NORTHWEST TEXAS INTO SOUTHWEST OKLAHOMA...
...SUMMARY...
Thunderstorms with large to very large hail and severe gusts are
possible late this afternoon into the evening in parts of the
southern High Plains.
...Southern High Plains...
Modest cyclonic mid-level flow will extend from the Interior West
through the base of the trough over the south-central U.S.
Water-vapor imagery shows a weak disturbance migrating east across
the Permian Basin this morning. A seasonably moist airmass
maintained via southeasterly low-level flow will heat and become
moderately to strongly unstable by mid afternoon.
Model forecast soundings show relatively cool 500-mb temperatures
(near -14 deg C) with steep low- to mid-level lapse rates later this
afternoon. Strong heating will locally erode appreciable remaining
convective inhibition and widely scattered thunderstorms will likely
develop by late afternoon. Although westerly flow will likely
remain modest (20 kt from 600 to 200 mb), strongly veering flow will
result in 25-30 kt effective shear, supporting supercells initially.
Large to very large hail will be possible with the more intense
updrafts. Increasing storm coverage during the evening will tend to
promote some upscale growth into a linear cluster with severe gusts
becoming more prevalent. The risk for severe gusts (60-80 mph) may
focus during the 00-03 UTC period before a gradual waning in
coverage/intensity by late evening.
...Central Gulf Coast States/Ohio and Tennessee Valleys...
Water-vapor imagery shows a disturbance moving northeastward across
the ArkLaMiss this morning and moving towards western portions of
TN/KY and the lower OH Valley. Surface analysis indicates a moist
airmass featuring dewpoints ranging from the upper 60s over TN to
the lower 70s over the central Gulf Coast. Despite widespread cloud
cover, some thinning of the cloud shield is expected as temperatures
slowly warm through the early afternoon. Models generally show weak
buoyancy (500-1000 J/kg MLCAPE) and skinny CAPE profiles and
tempered lapse rates (reference the Nashville and Birmingham 12 UTC
raobs). However, models show some enhancement/strengthening of
925-500 mb flow moving northeastward across MS/AL into TN through
the mid-late afternoon. As a result, some enlargement of hodographs
will likely occur during the diurnal heating cycle and a few weak
supercell structures will probably develop. Yet, the ongoing
thunderstorm band over eastern MS may be ill timed as it moves
northeastward across western/northern AL through midday.
Nonetheless, an isolated risk for a tornado seems possible over much
of this general region. A risk for isolated damaging gusts may also
accompany some of the stronger thunderstorms before this activity
wanes by the early evening.
...Mid Missouri Valley...
An upper-level trough and an associated mid-level jet streak will
move northeastward today across the north-central U.S. At the
surface, an axis of low-level moisture will be in place from eastern
Kansas northward into eastern Nebraska. Ahead of the trough,
scattered thunderstorms will develop in the afternoon along and near
the moist axis. Surface dewpoints in the lower to mid 60s F will
contribute to weak instability with MLCAPE likely peaking in the 500
to 1000 J/kg range across eastern Nebraska. RAP forecast soundings
near Omaha suggest that 0-6 km shear will reach 35 knots as the
trough approaches this afternoon, which would support the
development of low-topped supercells capable of isolated severe wind
gusts and hail. The severe threat is expected to persist into the
early evening.
..Smith/Weinman.. 05/22/2026
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