854
ACUS11 KWNS 260847
SWOMCD
SPC MCD 260846
FLZ000-261115-

Mesoscale Discussion 2109
NWS Storm Prediction Center Norman OK
0346 AM CDT Thu Sep 26 2024

Areas affected...South Florida

Concerning...Severe potential...Watch possible

Valid 260846Z - 261115Z

Probability of Watch Issuance...40 percent

SUMMARY...An isolated tornado threat will continue across parts of
south Florida over the next few hours. Weather watch will be
possible at some point this morning.

DISCUSSION...Hurricane Helene is currently located over the eastern
Gulf of Mexico, with the outer rain bands extending to near the west
coast of south Florida. The latest hi-resolution radar imagery from
Miami shows widely spaced discrete storms ongoing along and near the
Florida Gulf Coast. The WSR-88D VWP at Miami has 0-6 km shear around
35 knots, with 0-3 storm-relative helicity near 275 m2/s2, which is
pretty similar to what was evident on the 06Z sounding at Miami.
This will be favorable for storm rotation and potentially tornado
development within the cells that obtain supercell structure. RAP
forecast soundings across south Florida slowly strengthen low-level
shear this morning, and have a gradual increase in instability. This
suggests that the tornado threat will be maintained across south
Florida. Additionally, a band of storms has developed to the south
of the Florida Keys over the last couple of hours. As this band of
storms spreads northward into south Florida this morning, the
tornado threat may increase.

..Broyles/Gleason.. 09/26/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MFL...MLB...KEY...TBW...

LAT...LON   25708005 26147999 26528003 26928031 27178098 27108143
            26878182 26488202 25838192 25228197 24738201 24518184
            24498160 24588130 24798075 25138027 25708005