Alert archive / Florida / Mesoscale Discussions in 2021
Mesoscale Discussion 1813
The Storm Prediction Center issued this mesoscale discussion at Oct 9, 2021, 1:24 PM EDT for 7 counties in Florida. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- Oct 9, 2021, 1:24 PM EDT (17:24 UTC)
- Expired
- Oct 9, 2021, 3:00 PM EDT
- In force
- 96 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Broward County, FL, Hendry County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Palm Beach County, FL, Saint Lucie County, FL
The radar
The Miami radar (KAMX), 67 km from the middle of the area, began a volume at 17:26 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 12:00Z, 5.4 hours before the alert went out and 47 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
- 103 J/kg
- Mixed-layer CIN
- -279 J/kg
- Mixed-layer LCL
- 1522 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 9 m²/s²
- 0-3 km storm-relative helicity
- 78 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
679
ACUS11 KWNS 091724
SWOMCD
SPC MCD 091724
FLZ000-091900-
Mesoscale Discussion 1813
NWS Storm Prediction Center Norman OK
1224 PM CDT Sat Oct 09 2021
Areas affected...portions of south Florida
Concerning...Severe potential...Watch unlikely
Valid 091724Z - 091900Z
Probability of Watch Issuance...5 percent
SUMMARY...Scattered thunderstorms may produce isolated damaging wind
gusts this afternoon. A weather watch is unlikely.
DISCUSSION...As of 1715 UTC, widespread thunderstorms were
developing across the southern tip of the Florida Peninsula in
response to strong heating and lift along the backside of a weak
trough across the southeast. Continued heating of a moisture airmass
with dewpoints in the 70s F is support moderate destabilization with
2000-3000 J/kg of MLCAPE across south Florida. Mid-level flow is not
overly strong, but 20-30 kts of shear may support a few organized
multi-cell clusters through the afternoon. As storms continue to
develop and move southeast, they should gradually coalesce into
several clusters. Stronger cold pools may support isolated instances
of damaging winds.
Overall severe coverage is expected to remain low, but widespread
storms suggests some low-end damaging wind potential across much of
south Florida this afternoon/evening. The relative greatest severe
potential appears to be along the southeastern Coast within the next
couple of hours with storms approaching from the northwest. However,
overall confidence in severe coverage is low. Given the overall
uncertainty, a watch is unlikely.
..Lyons/Hart.. 10/09/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MFL...MLB...KEY...TBW...
LAT...LON 27458029 26957986 26127990 25518004 25158031 24928058
24918072 25848118 26708123 27268091 27458029Nearby
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.