Mesoscale Discussion 393

Issued

Apr 16, 2021, 4:08 PM EDT (20:08 UTC)

Expired

Apr 16, 2021, 6:15 PM EDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

Counties Brevard County, FL, Lake County, FL, Orange County, FL, Seminole County, FL, Sumter County, FL

The Melbourne radar (KMLB), 113 km from the middle of the area, began a volume at 20:09 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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753 
ACUS11 KWNS 162008
SWOMCD
SPC MCD 162008 
FLZ000-162215-

Mesoscale Discussion 0393
NWS Storm Prediction Center Norman OK
0308 PM CDT Fri Apr 16 2021

Areas affected...Parts of the central Florida Peninsula

Concerning...Severe potential...Watch unlikely 

Valid 162008Z - 162215Z

Probability of Watch Issuance...20 percent

SUMMARY...A couple of strong to severe thunderstorms, posing a risk
for large hail and locally strong surface gusts, are possible late
this afternoon, and could impact the Greater Orlando Metropolitan
area into the Space Coast by 6-7 PM EDT.  While a severe weather
watch is not currently anticipated, trends will be monitored.

DISCUSSION...At least weak large-scale ascent appears ongoing, in
response to warm advection along a broad east-west oriented
lower/mid tropospheric baroclinic across the Florida peninsula. 
This appears to be coming focused across central portions of the
peninsula, perhaps in advance of a subtle mid-level perturbation,
generally just to the northeast of warmer and more strongly capping
mid-level air.  Beneath this regime, latest mesoanalysis suggests
that boundary-layer convergence is becoming enhanced northeast/north
of Tampa and Lakeland, through the Orlando/Kissimmee and Melbourne
area, where daytime heating appears to be contributing to
mixed-layer CAPE in excess of 1000 J/kg.

In response to this destabilization and lift, deepening convective
development appears underway along this corridor (particularly
currently to the north-northeast of Tampa), and the initiation of at
least a few storms appears possible through 22-23Z.  Although
low-level flow is generally light and west-southwesterly,
deeper-layer vertical shear is strong, beneath 40-50 kt westerly
flow around the 500 mb level.  This should contribute to
organization of sustained thunderstorm development, with the
evolution of an isolated supercell structure or two possible. 
Forecast soundings are suggestive that this activity could pose a
risk for large hail, and perhaps localized strong surface gusts,
before diminishing by early this evening.

..Kerr/Guyer.. 04/16/2021

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

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

LAT...LON   28968217 28998102 28108048 28278229 28968217

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.