Alert archive / Florida / Mesoscale Discussions in 2021
Mesoscale Discussion 97
The Storm Prediction Center issued this mesoscale discussion at Feb 15, 2021, 7:38 PM EST for 7 counties in Florida. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 15, 2021, 7:38 PM EST (00:38 UTC)
- Expired
- Feb 15, 2021, 9:45 PM EST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 8
Counties Alachua County, FL, Bradford County, FL, Citrus County, FL, Clay County, FL, Duval County, FL, Hernando County, FL, Marion County, FL
The radar
The Jacksonville radar (KJAX), 141 km from the middle of the area, began a volume at 00:41 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 00:00Z, 0.6 hours before the alert went out and 143 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
- 1374 J/kg
- Mixed-layer CIN
- -50 J/kg
- Mixed-layer LCL
- 678 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- 322 m²/s²
- 0-3 km storm-relative helicity
- 422 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 11.6
The text
As transmitted.
675
ACUS11 KWNS 160038
SWOMCD
SPC MCD 160038
FLZ000-GAZ000-160245-
Mesoscale Discussion 0097
NWS Storm Prediction Center Norman OK
0638 PM CST Mon Feb 15 2021
Areas affected...Florida coastal areas north of Tampa into
northeastern Florida
Concerning...Tornado Watch 8...
Valid 160038Z - 160245Z
The severe weather threat for Tornado Watch 8 continues.
SUMMARY...Intensification of inland advancing thunderstorms is
possible across interior northern Florida, near and northeast of the
Gainesville and Ocala vicinities, by 8-9 PM EST. This may pose the
risk for a couple of tornadoes and damaging wind gusts.
Destabilization along coastal areas closer to Tampa is being
monitored. It is possible that a severe weather watch may be
needed, but not yet certain.
DISCUSSION...Aided by advection within broadly cyclonic, 40-50 kt
south-southwesterly deep-layer mean flow, a broken pre-frontal
squall line continues to gradually progress inland of coastal areas
to the northwest of Cedar Key. Nearly coincident with a 40-50 kt
southerly 850 mb jet, low-level shear is contributing to the
evolution of small-scale mesovortices within a number of embedded
organized convective structures. However, based on objective
analyses, activity is progressing across a weakly unstable to stable
boundary-layer, across the coastal waters into coastal areas. This
may tend to limit the severe weather potential; but, as activity
encounters the remnants of a heated and lingering unstable
boundary-layer over interior northern Florida, there appears
potential for intensification of activity near and north-northeast
of the Gainesville and Ocala vicinities by 01-02Z.
To the southwest, low-level moistening off the eastern Gulf of
Mexico may contribute to increasing destabilization along coastal
areas closer to Tampa by 02-04Z. This could be accompanied by the
inland progression of vigorous convection, including a supercell
structure or two which could pose a risk for damaging wind gusts
and/or a tornado.
..Kerr.. 02/16/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TBW...JAX...
LAT...LON 29958240 30628192 30578151 29108199 27878289 28088344
28928293 29958240Nearby
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.