MD 1831 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PORTIONS OF THE FL KEYS
Mesoscale Discussion 1831
NWS Storm Prediction Center Norman OK
0118 AM CDT Tue Sep 27 2022
Areas affected...Portions of the FL Keys
Concerning...Severe potential...Watch possible
Valid 270618Z - 270845Z
Probability of Watch Issuance...40 percent
SUMMARY...A threat for waterspouts and perhaps a brief tornado or
two should gradually increase through the early morning. Watch
issuance is possible, with observational trends being closely
monitored.
DISCUSSION...Outer rain bands associated with Hurricane Ian are
ongoing over the FL Straits early this morning. The low-level flow
estimated by recent KBYX/KAMX VWPs is not overly strong at the
moment. But, further strengthening of the east-southeasterly
low-level winds will occur over the next couple of hours as the
hurricane moves slowly northward over western Cuba. As this occurs,
hodographs should gradually increase, especially in the 0-3 km
layer. Any low-topped showers/thunderstorms that can maintain a more
northerly motion compared to northwesterly should have access to
marginally favorable effective SRH around 100 m2/s2.
One such low-topped supercell that occurred earlier between Key West
and Marathon FL briefly had an enhanced rotational velocity
signature from KBYX before quickly weakening. Other cells occurring
offshore and to the southeast of Key Largo FL have also shown
occasional low-level rotation. An isolated threat for waterspouts
and perhaps a brief tornado or two should persist this morning given
the presence of rich low-level moisture/sufficient instability, and
a gradually improving kinematic environment. Watch issuance appears
possible, especially if observational trends show multiple low-level
supercells developing offshore.
..Gleason/Guyer.. 09/27/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...KEY...
LAT...LON 24158324 24718301 24928196 25058107 25168040 25007967
24687953 24287988 24038030 23738187 23808285 24158324
