Alert archive / Florida / Mesoscale Discussions in 2021
Mesoscale Discussion 1061
The Storm Prediction Center issued this mesoscale discussion at Jun 22, 2021, 12:58 PM EDT for 15 counties in Florida. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 22, 2021, 12:58 PM EDT (16:58 UTC)
- Expired
- Jun 22, 2021, 3:00 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Alachua County, FL, Bradford County, FL, Citrus County, FL, Clay County, FL, Flagler County, FL, Gilchrist County, FL, Hernando County, FL, Lake County, FL, Levy County, FL, Marion County, FL, Pasco County, FL, Putnam County, FL, Saint Johns County, FL, Sumter County, FL, Union County, FL
The radar
The Jacksonville radar (KJAX), 132 km from the middle of the area, began a volume at 16:58 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, 5.0 hours before the alert went out and 134 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
- 591 J/kg
- Mixed-layer CIN
- -95 J/kg
- Mixed-layer LCL
- 1014 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 136 m²/s²
- 0-3 km storm-relative helicity
- 176 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.5
The text
As transmitted.
011
ACUS11 KWNS 221659
SWOMCD
SPC MCD 221658
FLZ000-221900-
Mesoscale Discussion 1061
NWS Storm Prediction Center Norman OK
1158 AM CDT Tue Jun 22 2021
Areas affected...Northern FL
Concerning...Severe potential...Watch unlikely
Valid 221658Z - 221900Z
Probability of Watch Issuance...20 percent
SUMMARY...A few damaging wind gusts are possible with the strongest
storms this afternoon.
DISCUSSION...Recent surface analysis shows a convectively enhanced
outflow boundary moving across northern FL. This boundary is well
ahead of the cold front, which is currently moving through central
GA. Given the buoyancy downstream, expectation is for the ongoing
activity to continue. Thus far, updrafts have been relatively
short-lived, likely as a result of poor vertical shear and
progressive nature of the outflow boundary undercutting ongoing
storms.
Surface analysis and visible satellite imagery also show the west
coast sea-breeze, which is delineated fairly well by the 88 deg F
isotherm. Storms have begun developing along the sea-breeze. Weakly
sheared environment suggests a short life cycle with most updrafts.
Even so, ample moisture exists for water loading, and a few stronger
downdrafts are possible. Additionally, storms along the
southward-moving outflow could merge with those developing along the
sea breeze, augmented updrafts/downdrafts. Limited
severe coverage is currently anticipated, but overall convective
trends will be monitored closely.
..Mosier/Hart.. 06/22/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MLB...TBW...JAX...TAE...
LAT...LON 29618302 30218224 30338150 30058126 29598113 28898125
28368179 28148269 28818258 29258285 29618302Nearby
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.