spc ac 051928
day 3 convective outlook
nws storm prediction center norman ok
0128 pm cst thu mar 05 2026
valid 071200z - 081200z
...there is a slight risk of severe thunderstorms from tx to lower
ms valley and the upper oh valley to lower great lakes...
...summary...
isolated to scattered severe thunderstorms are possible from
saturday morning into the evening across a broad swath of the
southern great plains to the lower great lakes. isolated very large
hail may occur in parts of texas.
...synopsis...
an upper trough consisting of multiple embedded shortwave impulses
will move east from the upper midwest to the great lakes. a closed
low over the lower co valley will further retrograde to west of baja
ca. a surface cyclone over eastern upper mi at 12z saturday will
deepen as it rapidly progresses into qc. a full-latitude cold front
will arc southwestward, crossing the eastern great lakes and midwest
on saturday. the trailing portion will slow its southern movement
over tx and likely be modulated by convective outflows.
...tx to the lower ms valley...
primary changes are to add a cig1 area for very large hail potential
in tx, and shift/expand the cat 2-slgt risk north-northeast per
latest guidance.
while tx will largely remain within a flat to low-amplitude
mid-level ridge between the aforementioned troughs/lows well to its
north and west, seasonably rich low-level moisture atop an
undercutting cold front should support regenerative convection
through much of the period. with the west-southwesterly mid-level
flow regime, steep mid-level lapse rates will be maintained over the
pre-convective warm sector. low-level flow will become increasingly
weak and diffluent, yielding a favorable deep-layer wind profile for
hail growth. primary uncertainty is the degree of surface-based
development towards late afternoon/early evening along the composite
front/outflow. current indications are that cig2-type giant hail
potential might evolve with more discrete/isolated convection in the
south-central tx vicinity. for now, will incrementally add a cig1
and defer to later outlooks for a possible categorical upgrade.
farther east-northeast across the lower ms valley, clusters may be
consolidating into line segments by mid-late morning saturday. these
may yield an increase in mainly damaging wind and brief tornado
potential as the warm/moist sector destabilizes downstream. an
extensive swath of widespread convection is anticipated during the
afternoon. but this should become increasingly aligned with the
deep-layer shear vector. in conjunction with decreasing low-level
hodograph curvature, setup may only favor sporadic damaging winds
before storm intensities wane after sunset.
...oh valley to the lower great lakes...
no adjustment has been made to the level 2-slgt risk area. at least
scattered convection should be ongoing upstream over parts of the
midwest and mid-south along/ahead of the aforementioned cold front.
this activity may not entirely decay, with renewed storm development
possible along the large-scale outflow that will probably remain
displaced appreciably east of the front. where adequate insolation
can occur amid steep mid-level lapse rates, an uptick in storm
intensity should occur midday into the afternoon. overall amplitudes
still seem to favor non-significant severe, but a scattering of
damaging winds, a couple tornadoes, and isolated marginally severe
hail all appear plausible. these threats should wane after sunset
and with eastern extent towards the appalachians.
..grams.. 03/05/2026
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note: the next day 3 outlook is scheduled by 0830z