SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0641 AM CST Thu Mar 10 2022
Valid 101300Z - 111200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
CENTRAL AND NORTHERN FLORIDA...
...SUMMARY...
Isolated damaging thunderstorm winds are possible over parts of
central and northern Florida.
...Synopsis...
Broadly cyclonic mid/upper-level flow, around a substantial longwave
trough, will cover much of the CONUS through the period. An
extensive fetch of west-southwest to southwest flow aloft will cover
the Southeast -- ahead of a strengthening, positively tilted
shortwave trough digging southeastward over the Great Basin, Four
Corners and parts of AZ/NM. In that flow belt, a leading, low-
amplitude shortwave trough -- evident in moisture-channel imagery
over MS -- will weaken and eject northeastward to near the Delmarva
Peninsula by 00Z, then out to the Atlantic thereafter.
Surface analysis at 11Z showed a quasistationary, synoptic frontal
zone over southern portions of SC/GA, southwestward across the AAF
area and the north-central Gulf. This front will drift erratically
on the mesoscale but exhibit no substantial motion through the
period, bring beneath nearly parallel flow aloft. To its south, an
outflow boundary was drawn across the FL Peninsula near a DAB-LEE-
PIE line, also quasistationary. This boundary generally should
move/redevelop erratically northward today and tonight, once the
associated swath of convection and precip along and just to its
north weakens and moves eastward to the Atlantic. A more-distant
synoptic cold front was drawn from southern ON to southern portions
of IL/MO, northern/western OK, through a weak frontal wave over
northwest TX, to southeastern and north-central NM. This boundary
will sag slowly southward through the period, reaching the lower
Ohio Valley, central AR, the Edwards Plateau, and far west TX by 12Z
tomorrow.
...FL...
Widely scattered to scattered thunderstorms should both move
eastward off the Gulf, and develop over the peninsula, during the
day. This will occur as the inland boundary layer destabilizes
today along and south of the outflow boundary. Organized multicells
in bands and clusters, and perhaps isolated/transient supercells,
are possible. Isolated damaging gusts will be the main concern, and
large hail may occur in the most intense cores as well, even north
of the boundary along the Gulf Coast of the eastern Panhandle to the
coastal bend. Tornado potential is non-zero but very conditional on
localized, mesobeta- to storm-scale processes and storm/boundary
interactions, given the modest ambient low-level hodographs/shear
values progged.
Though the leading shortwave trough will pass well poleward of the
outflow boundary over FL, subtle tightening of midtropospheric
height gradients related to the shortwave trough, and associated
low/middle-level mass response, should extend far enough south to
influence organized convective potential today. Effective-shear
magnitudes around 40-45 kt should be common (locally/briefly
higher). Where sufficient diurnal surface heating can occur into
the afternoon, behind morning clouds/precip, surface dew points from
the upper 60s to low 70s F may support MLCAPE in the 1500-2000 J/kg
range. During the evening, boundary-layer stabilization and
decreasing deep-layer flow both are expected, resulting in reduced
convective coverage and dwindling of severe potential over the bulk
of the peninsula.
A separate round of thunderstorms -- developing tonight over the
north-central/northeastern Gulf and predominantly affecting the
inland parts of the region on day 2 -- may reach coastal portions of
the central/eastern FL Panhandle during the last few hours of the
period (i.e., 09-12Z). At this time, forecast low-level
thermodynamic profiles appear too stable for surface-based
convection before 12Z, and unconditional severe wind and tornado
potential appears too minimal to stretch those outlook lines
westward toward the AAF area.
..Edwards/Mosier.. 03/10/2022
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