Alert archive / Florida / Mesoscale Discussions in 2021
Mesoscale Discussion 1930
The Storm Prediction Center issued this mesoscale discussion at Nov 5, 2021, 4:29 AM EDT for Miami-Dade County, Monroe County, Florida. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Nov 5, 2021, 4:29 AM EDT (08:29 UTC)
- Expired
- Nov 5, 2021, 7:00 AM EDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Miami-Dade County, FL, Monroe County, FL
The radar
The Miami radar (KAMX), 67 km from the middle of the area, began a volume at 08:32 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.
The nearest sounding before it
Miami, FL (KMFL), launched 00:00Z, 8.5 hours before the alert went out and 88 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 612 J/kg
- Mixed-layer CIN
- -5 J/kg
- Mixed-layer LCL
- 925 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 16 m²/s²
- 0-3 km storm-relative helicity
- 60 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
391
ACUS11 KWNS 050830
SWOMCD
SPC MCD 050829
FLZ000-051100-
Mesoscale Discussion 1930
NWS Storm Prediction Center Norman OK
0329 AM CDT Fri Nov 05 2021
Areas affected...South Florida
Concerning...Severe potential...Watch unlikely
Valid 050829Z - 051100Z
Probability of Watch Issuance...20 percent
SUMMARY...A marginal tornado and hail threat is expected to develop
across parts of south Florida early this morning. The threat should
be too isolated for weather watch issuance.
DISCUSSION...The latest radar imagery from Key West shows scattered
thunderstorms across the the southern Florida Peninsula with several
discrete cells located in the Florida Keys. A rotating storm was
located just to the northeast of Key West. The cells in the Florida
Keys will continue to move north-northeastward over the next few
hours. The RAP is estimating MLCAPE across the Florida Keys in the
1000 to 1200 J/kg range with slightly weaker instability across the
southern Florida Peninsula. The WSR-88D VWP at Miami has 0-6 km
shear near 45 knots and 0-3 km storm relative helicity has risen to
near 180 m2/s2 over the last hour. This wind profile will support
weak supercell structures along with a marginal tornado threat.The
strongest of cores should be capable of producing hail. The marginal
tornado and hail threat is expected to continue through daybreak as
the more discrete storms move across the eastern Florida Keys and
into areas to the southwest of Miami.
..Broyles/Grams.. 11/05/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MFL...KEY...
LAT...LON 24748091 24968033 25448008 25818013 25928040 25908091
25928149 25818172 25608188 25168195 24798172 24748091SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 5, 10:09 AM EDT | Mesoscale Discussion | SPC | Collier, Miami-Dade, Monroe | 2 hr |
| Nov 5, 6:56 PM EDT | Mesoscale Discussion | SPC | Brevard, Charlotte, DeSoto, Glades, Hardee, Highlands and 6 more | 3 hr |
Nearby
Mesoscale Discussions in Florida, 2021Every mesoscale discussion in 2021
Sources
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.