Alert archive / Florida / Mesoscale Discussions in 2021

Mesoscale Discussion 1176

July 7, 202116 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Jul 7, 2021, 7:06 AM EDT for 16 counties in Florida. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Jul 7, 2021, 7:06 AM EDT (11:06 UTC)
Expired
Jul 7, 2021, 8:00 AM EDT
In force
54 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 340

Counties Charlotte County, FL, Citrus County, FL, DeSoto County, FL, Hardee County, FL, Hernando County, FL, Highlands County, FL, Hillsborough County, FL, Lake County, FL, Lee County, FL, Levy County, FL, Manatee County, FL, Pasco County, FL, Pinellas County, FL, Polk County, FL, Sarasota County, FL, Sumter County, FL

The radar

The Tampa radar (KTBW), 27 km from the middle of the area, began a volume at 11:09 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

Tampa Bay, FL (KTBW), launched 00:00Z, 11.1 hours before the alert went out and 27 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.

Skew-T log-pSkew-T log-p diagram, Tampa Bay, FL at 00:00Z on 2021-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 46 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tampa Bay, FL at 00:00Z on 2021-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
46 J/kg
Mixed-layer CIN
-60 J/kg
Mixed-layer LCL
1020 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
266 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

691 
ACUS11 KWNS 071106
SWOMCD
SPC MCD 071106 
FLZ000-071200-

Mesoscale Discussion 1176
NWS Storm Prediction Center Norman OK
0606 AM CDT Wed Jul 07 2021

Areas affected...western and central Florida

Concerning...Tornado Watch 340...

Valid 071106Z - 071200Z

The severe weather threat for Tornado Watch 340 continues.

SUMMARY...Tornado risk has diminished a bit over the past 1 to 2
hours.  With WW 340 set to expire at 07/12Z, a replacement WW may
not be required.

DISCUSSION...As Tropical Storm Elsa continues shifting slowly
northward, weakening of the primary convective band east of the
center has occurred, over the Peninsula.  Accordingly, low-level
circulations have become less numerous and weaker over the past hour
or so.

While tornado risk will remain non-zero, particularly near and north
of the Tampa area with a secondary band of convection east/southeast
of the center of circulation where low-level flow remains more
backed, at this time it appears that a replacement WW -- south of
newly issued Tornado Watch 341 over northern Florida -- may not be
required.

..Goss.. 07/07/2021

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

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

LAT...LON   29278319 29408267 29058170 27938136 26798131 25788166
            25738230 27708293 28468294 29278319

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 6, 10:37 PM EDTTornado WatchSPCAlachua, Charlotte, Citrus, Collier, DeSoto, Gilchrist and 22 more9 hr
Jul 6, 11:59 PM EDTMesoscale DiscussionSPCCharlotte, DeSoto, Hardee, Hillsborough2 hr
Jul 7, 3:03 AM EDTMesoscale DiscussionSPCCharlotte, Citrus, DeSoto, Hardee, Hernando, Hillsborough and 5 more117 min
Jul 7, 5:42 AM EDTMesoscale DiscussionSPCAlachua, Bradford, Charlotte, Citrus, Columbia, DeSoto and 19 more2 hr
Jul 7, 6:46 AM EDTTornado WatchSPCBaker, Bradford, Clay, Columbia, Duval, Hamilton and 4 more6 hr
Jul 7, 10:30 AM EDTMesoscale DiscussionSPCBaker, Bradford, Clay, Columbia, Duval, Hamilton and 3 more2 hr
Jul 7, 12:28 PM EDTMesoscale DiscussionSPCBaker, Bradford, Clay, Columbia, Duval, Nassau and 1 more2 hr
Jul 7, 1:04 PM EDTTornado WatchSPCBaker, Bradford, Clay, Columbia, Duval, Hamilton and 3 more7 hr
Jul 7, 4:47 PM EDTMesoscale DiscussionSPCBaker, Clay, Columbia, Duval, Nassau, Saint Johns and 1 more118 min

Nearby

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.