Alert archive / Florida / Mesoscale Discussions in 2024
Mesoscale Discussion 1237
The Storm Prediction Center issued this mesoscale discussion at Jun 12, 2024, 11:09 AM EDT for 9 counties in Florida. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 12, 2024, 11:09 AM EDT (15:09 UTC)
- Expired
- Jun 12, 2024, 1:15 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Broward County, FL, Collier County, FL, Glades County, FL, Hendry County, FL, Lee County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Palm Beach County, FL
The radar
The Miami radar (KAMX), 83 km from the middle of the area, began a volume at 15:08 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, 3.2 hours before the alert went out and 85 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
- 789 J/kg
- Mixed-layer CIN
- -52 J/kg
- Mixed-layer LCL
- 913 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- 53 m²/s²
- 0-3 km storm-relative helicity
- 127 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
The text
As transmitted.
731
ACUS11 KWNS 121509
SWOMCD
SPC MCD 121509
FLZ000-121715-
Mesoscale Discussion 1237
NWS Storm Prediction Center Norman OK
1009 AM CDT Wed Jun 12 2024
Areas affected...South FL
Concerning...Severe potential...Watch unlikely
Valid 121509Z - 121715Z
Probability of Watch Issuance...20 percent
SUMMARY...Brief tornadoes and isolated damaging gusts are possible
across south Florida for the next several hours.
DISCUSSION...Recent radar imagery has revealed low-level rotation
within some of the shallow, more cellular convection across southern
FL, particularly near the intersection of Collier, Broward, and
Miami-Dade counties. These showers and thunderstorms are being
initiated by warm-air advection, but are quickly becoming surface
based with the very moist and uncapped airmass across the region.
Buoyancy is modest (i.e. around 1500-2000 J/kg of MLCAPE), promoted
by shallow but vertically deep thermodynamic profiles. This buoyancy
is more than sufficient for deep updrafts capable of lightning.
Additionally, the AMX VAD profiles show notable low-level veering,
with 20 to 25 kt of 0-1 km storm-relative helicity sampled recently.
There may also be some ambient vertical vorticity within the
low-level environment, given the presence of storm outflow and
low-level convergence that is occurring, particularly to the south
of the main precipitation shield. As result, there is likely a
mesoscale corridor of greater tornado potential across from Mainland
Monroe County northeastward into southern Palm Beach County.
Water-loaded downbursts are also possible across much of south FL.
..Mosier/Goss.. 06/12/2024
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MFL...MLB...KEY...TBW...
LAT...LON 25138100 25568138 25868172 26208222 26718212 27158120
27238021 26157992 24998038 25138100Nearby
Mesoscale Discussions in Florida, 2024Every mesoscale discussion in 2024
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.