Mesoscale Discussion 1921

Issued

Oct 28, 2021, 8:12 AM EDT (12:12 UTC)

Expired

Oct 28, 2021, 10:15 AM EDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

60%

Counties Alachua County, FL, Bradford County, FL, Citrus County, FL, Dixie County, FL, Gilchrist County, FL, Hernando County, FL, Lafayette County, FL, Levy County, FL, Marion County, FL, Putnam County, FL, Suwannee County, FL, Taylor County, FL, Union County, FL

The Moody AFB radar (KVAX), 146 km from the middle of the area, began a volume at 12:12 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.

• Tornado Watch 545Oct 28, 9:00 AM EDT

357 
ACUS11 KWNS 281212
SWOMCD
SPC MCD 281212 
FLZ000-281415-

Mesoscale Discussion 1921
NWS Storm Prediction Center Norman OK
0712 AM CDT Thu Oct 28 2021

Areas affected...Parts of northern and central Florida

Concerning...Severe potential...Watch possible 

Valid 281212Z - 281415Z

Probability of Watch Issuance...60 percent

SUMMARY...Intensifying thunderstorm development may pose increasing
potential to produce tornadoes inland of coastal areas, across much
of northern and central Florida, perhaps as far west as Tallahassee,
by 10 AM to Noon EDT.  Trends are being monitored for the
possibility of a watch issuance.

DISCUSSION...To the southeast of a broad, deep occluded lower/mid
tropospheric cyclone centered over the Ozark Plateau vicinity, the
surface cold front is advancing eastward through the Florida
Panhandle.  The front is preceded by the weak northern flank of a
more extensive squall line (now extending across the northeast into
south central Gulf of Mexico), which is advancing through Big Bend
vicinity.  As the front and convective boundary continue eastward,
beneath difluent and increasingly cyclonic mid/upper flow, latest
model output suggests that the moist warm sector will begin
advancing inland of Gulf coast areas through much of northern into
central Florida by 14-16Z.

It appears that boundary-layer dew points will increase through the
lower 70s and possibly contribute to mixed-layer CAPE in excess of
1000 J/kg, despite the continuing presence of weak lapse rates
associated with warm layer aloft.  Boundary-layer warming may also
be inhibited by considerable cloud cover, but clockwise-curved
low-level hodographs are forecast to enlarge beneath southerly 850
mb flow strengthening to 30-40+ kt.

This environment may become increasingly conducive to the inland
development of discrete thunderstorm development, as well as
intensification of thunderstorms along the pre-frontal convective
line, including evolving supercell structures which may pose a risk
for tornadoes and locally strong surface gusts.

..Kerr/Guyer.. 10/28/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MLB...TBW...JAX...TAE...

LAT...LON   29898412 30418390 30108214 29458137 28368273 28888284
            29658379 29898412

Mesoscale Discussions in Florida, 2021Every mesoscale discussion in 2021

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.