Mesoscale Discussion 1931

Issued

Nov 5, 2021, 10:09 AM EDT (14:09 UTC)

Expired

Nov 5, 2021, 12:15 PM EDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

Counties Collier County, FL, Miami-Dade County, FL, Monroe County, FL

The Miami radar (KAMX), 55 km from the middle of the area, began a volume at 14:11 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

128 
ACUS11 KWNS 051409
SWOMCD
SPC MCD 051409 
FLZ000-051615-

Mesoscale Discussion 1931
NWS Storm Prediction Center Norman OK
0909 AM CDT Fri Nov 05 2021

Areas affected...Portions of far southern Florida

Concerning...Severe potential...Watch unlikely 

Valid 051409Z - 051615Z

Probability of Watch Issuance...20 percent

SUMMARY...A damaging gust or brief tornado are possible over the
next couple of hours. A WW issuance is not expected given the brief,
spatially confined nature of the severe threat.

DISCUSSION...While widespread precipitation/thunderstorms have
hampered destabilization thus far across much of the FL peninsula,
the 12Z MFL sounding and some of the latest METAR observations
suggest that a warm front is gradually advancing northward into
Monroe and Miami-Dade Counties. Modifying the 12Z observed MFL
sounding for the KHST or KTMB METAR surface temperatures/dewpoints
(both in the mid 70s) suggests that over 2000/1000 J/kg SB/MLCAPE is
present across extreme southern Florida. Both the observed sounding
and AMX VWPs within the past hour show a modestly curved hodograph
with nearly 200 m2/s2 effective SRH, indicative of some potential
for storms to organize and perhaps demonstrate occasions of
low-level rotation.

At the moment, some convective cells are attempting to organize
offshore Monroe County and are expected to move onshore within the
hour. Given the aforementioned kinematics/thermodynamics in place.
The more organized storms will have the potential to support a
threat for a damaging gust or perhaps a brief tornado. However,
since the severe threat is expected to be marginal and constrained
primarily to Monroe/Miami-Dade Counties (perhaps southern
Collier/Broward Counties) in the near-term, a WW issuance is not
anticipated.

..Squitieri/Goss.. 11/05/2021

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

ATTN...WFO...MFL...KEY...

LAT...LON   25868213 26128161 26228070 26138011 25818000 25488013
            25188027 24998050 24908083 24918125 25048184 25868213

Mesoscale Discussions in Florida, 2021Every mesoscale discussion in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.