Mesoscale Discussion 78

Issued

Feb 14, 2021, 12:38 AM EST (05:38 UTC)

Expired

Feb 14, 2021, 2:45 AM EST

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

Counties Charlotte County, FL, Collier County, FL, DeSoto County, FL, Lee County, FL, Manatee County, FL, Sarasota County, FL

The Tampa radar (KTBW), 126 km from the middle of the area, began a volume at 05:41 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.

887 
ACUS11 KWNS 140539
SWOMCD
SPC MCD 140538 
FLZ000-140745-

Mesoscale Discussion 0078
NWS Storm Prediction Center Norman OK
1138 PM CST Sat Feb 13 2021

Areas affected...Florida Gulf coastal areas near and to the south of
Tampa

Concerning...Severe potential...Watch unlikely 

Valid 140538Z - 140745Z

Probability of Watch Issuance...20 percent

SUMMARY...Strong storms may spread across and inland of Florida
coastal areas near and to the southwest of Tampa through 2-4 AM EST,
perhaps accompanied by at least some risk for potentially damaging
wind gusts.

DISCUSSION...There has been some recent increase in number of
thunderstorms and intensity offshore of the Florida Peninsula Gulf
coast.  This is to the south of the stalled surface frontal zone,
which extends inland across the peninsula, near/north of the Tampa
and Daytona Beach areas.  It appears supported by a northeastward
migrating short wave perturbation, which is beginning to progress
into anticyclonic, and increasingly confluent, mid/upper flow on the
northwestern periphery of a strengthening southwestern Atlantic
subtropical ridge.

This also appears aided by inflow of moderately unstable air over
the southeastern Gulf of Mexico, with at least some further boundary
destabilization inland across the coastal waters into the Florida
Peninsula overnight.  This may coincide with modest strengthening of
southerly 850 mb flow (to 30+ kt), which is forecast by models
across and inland of coastal areas to the south of Tampa during the
06-09Z time frame.  As this occurs, the ongoing vigorous
thunderstorm development will probably spread inland.

It remains unclear whether convective development will be able to
consolidate into a growing cluster of storms, but deep-layer shear
beneath a belt of 50+ kt south-southwesterly mid-level flow (around
500 mb) provides potential for organization.  With low-level wind
profiles generally modest/unidirectional, the primary potential
severe hazard appears damaging wind gusts where heavy precipitation
loading may become a factor.

..Kerr/Guyer.. 02/14/2021

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

ATTN...WFO...MFL...TBW...

LAT...LON   27798249 27298152 26058100 25378126 25438198 26848276
            27798249

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.