Mesoscale Discussion 2058
NWS Storm Prediction Center Norman OK
0152 PM CDT Tue Aug 29 2023
Areas affected…southwestern through west central Florida coastal
Concerning…Severe potential…Watch possible
Valid 291852Z – 292145Z
Probability of Watch Issuance…40 percent
SUMMARY…Potential for an isolated, brief tornado may not be
completely negligible in the near term, but still appears generally
low, and may not increase appreciably until at least this evening
closer to the Fort Myers into Tampa Bay vicinity.
DISCUSSION…After migrating north-northwestward for at least a
period late this morning, the motion of Idalia has trended a bit
more to the north across the southeastern Gulf of Mexico. This is
200+ miles offshore of southwestern through west central Florida
coastal areas, which have been increasingly impacted by the far
outer eastern convective bands.
The arrival of the lead convective band, and some preceding discrete
cells, appears to have coincided with some strengthening of
south-southeasterly flow to 30-40+ in the 850-700 mb layer.
However, based on NAM and Rapid Refresh forecast soundings, and VWP
data, speed shear dominates the low-level hodograph, with weak
turning with height limited to a shallow near-surface layer. These
type of hodographs may not change appreciably until near/after
00-02Z this evening, near the Fort Myers into Tampa Bay vicinity,
where/when forecast soundings indicate a period of some increase in
turning with height and increasing speed in the lower to mid-levels
(and enlarging clockwise curved hodographs), with the continued
northward progression and closer approach of the circulation center
to the coast.
…Please see www.spc.noaa.gov for graphic product…
LAT…LON 28048273 27468228 26768189 26008147 25728167 25958194
26488220 26968255 27398274 28048273