Alert archive / Florida / Mesoscale Discussions in 2021
Mesoscale Discussion 1031
The Storm Prediction Center issued this mesoscale discussion at Jun 20, 2021, 11:01 AM EDT for Alachua County, Bradford County, Clay County, Florida. It was in force for 119 min.
The area
The outline as issued.
The facts
- Issued
- Jun 20, 2021, 11:01 AM EDT (15:01 UTC)
- Expired
- Jun 20, 2021, 1:00 PM EDT
- In force
- 119 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Alachua County, FL, Bradford County, FL, Clay County, FL
The radar
The Jacksonville radar (KJAX), 105 km from the middle of the area, began a volume at 15:05 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
Jacksonville, FL (KJAX), launched 12:00Z, 3.0 hours before the alert went out and 107 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
- 1078 J/kg
- Mixed-layer CIN
- -61 J/kg
- Mixed-layer LCL
- 938 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 170 m²/s²
- 0-3 km storm-relative helicity
- 197 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 9.6
The text
As transmitted.
548
ACUS11 KWNS 201502
SWOMCD
SPC MCD 201501
FLZ000-201700-
Mesoscale Discussion 1031
NWS Storm Prediction Center Norman OK
1001 AM CDT Sun Jun 20 2021
Areas affected...north FL
Concerning...Severe potential...Watch unlikely
Valid 201501Z - 201700Z
Probability of Watch Issuance...20 percent
SUMMARY...A couple of strong to locally severe thunderstorms are
possible across north FL late this morning into the midday hours.
Expected coverage/magnitude of a potential severe risk will likely
remain too low to warrant a watch issuance.
DISCUSSION...Radar mosaic late this morning shows a cluster of
intensifying storms on the southeastern periphery of Claudette's
circulation. A very moist airmass is located over north FL with
upper 70s deg F dewpoints at multiple observation sites.
Jacksonville's 88D VAD data shows some veering and strengthening of
flow in the lowest 1km, which has led to some hodograph enlargement.
Additionally, RAP forecast soundings also show this modest hodograph
enlargement. However, the relatively moist and poor lapse rate
profile will limit overall updraft strength and downdraft potential.
The severe risk with these storms could include a low possibility
for a weak/brief tornado or a strong gust or two. Given this
expected threat in terms of the magnitude and its confined spatial
extent, a watch issuance is unlikely.
..Smith/Hart.. 06/20/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TBW...JAX...
LAT...LON 29438269 30028221 29998180 29788168 29588175 29288259
29438269SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 19, 8:00 PM EDT | Tornado Watch | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 9 more | 13 hr |
| Jun 20, 12:58 AM EDT | Mesoscale Discussion | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 9 more | 2 hr |
| Jun 20, 6:00 AM EDT | Mesoscale Discussion | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Hamilton and 9 more | 2 hr |
| Jun 20, 8:40 AM EDT | Mesoscale Discussion | SPC | Baker, Columbia, Duval, Hamilton, Madison, Nassau and 1 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.