SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1245 AM CDT Mon Mar 31 2025
Valid 311200Z - 011200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TODAY ACROSS
PARTS OF SERN MS...CNTRL/SRN AL...THE FL PNHDL...MUCH OF
GA...SC...AND CNTRL NC...
...SUMMARY...
One or two organized thunderstorm clusters may overspread much of
the Southeast today, accompanied by swaths of strong to severe wind
gusts and perhaps a few tornadoes.
...Discussion...
After a period of deepening across southern Ontario into Quebec,
models indicate that a modest surface cyclone will migrate across
the St. Lawrence Valley into the Canadian Maritimes during this
period, in advance of a significant mid-level trough gradually
turning east of northwestern Ontario. As this occurs, a lower
amplitude mid-level perturbation of mid-latitude Pacific origins is
forecast to accelerate east of the south central Great Plains
through the Mid South, southern Appalachians and Mid Atlantic coast
vicinity by late tonight.
Upstream, a seasonably strong mid/upper jet is forecast to continue
digging inland of the California coast through the southern Rockies,
as flow undergoes amplification across the southern mid- and
subtropical latitudes of the eastern Pacific. It appears that this
will be accompanied by cyclogenesis to the lee of the Colorado
Rockies by late tonight. However, through daybreak Tuesday,
appreciable low-level moisture return may be confined to a narrow
plume west of the lower Rio Grande Valley into portions of the Texas
South Plains, beneath warm elevated mixed-layer air, in the wake of
a stalling cold front near or just inland of the Gulf into southern
Mid Atlantic coasts.
Prior to this frontal passage, mid 60s to near 70F surface dew
points may linger across parts of the lower Mississippi Valley at
the outset of the period, while advecting east-northeastward across
parts of the eastern Gulf into south Atlantic coast states, beneath
the remnants of a plume of elevated mixed-layer air emanating from
the Great Plains.
...Eastern Gulf/South Atlantic Coast states...
Associated with the low amplitude short wave emerging from the south
central Great Plains, there remains a considerable signal, within
model output, that forcing for ascent within the moderately unstable
(including 1000-2000+ J/kg CAPE) pre-frontal environment will be
sufficient to contribute to the evolution of an organized cluster of
convection across Mississippi and Louisiana by 12Z this morning. It
appears that destabilization ahead of this activity will be
sufficient to maintain or support renewed intensification across
Alabama/Georgia and adjacent portions of Florida, into the
Carolinas, by late afternoon or early this evening. Aided by
ambient flow associated with a progressive 30-50+ kt jet in the
850-500 mb layer, at least some convection-allowing guidance and
other model output is suggestive that convectively augmented
rear-inflow may support one or more swaths of damaging wind gusts.
...Northern Mid Atlantic...
Although stronger low-level wind fields will tend to shift northeast
of the region early today with the progression of the Canadian
cyclone, deep-layer shear will remain sufficiently strong to support
a risk for severe convection. It appears that low-level moistening
and daytime heating will contribute to at least a narrow corridor of
weak to moderate boundary-layer destabilization along the
pre-frontal surface troughing by late this afternoon. This may
provide the focus for increasing thunderstorm development,
particularly as the instability axis is overtaken by the cold front
by this evening. Isolated supercells are possible initially, posing
a risk for severe hail, and at least some risk for a tornado, before
locally damaging wind gusts become the more prominent potential
severe hazard as convection increases in coverage.
..Kerr/Weinman.. 03/31/2025
Read more
