Alert archive / Florida / Mesoscale Discussions in 2021

Mesoscale Discussion 94

February 15, 2021Houston County, Alabama; 24 counties in Florida; 19 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Feb 15, 2021, 3:08 PM CST for Houston County, Alabama; 24 counties in Florida; 19 counties in Georgia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Feb 15, 2021, 3:08 PM CST (21:08 UTC)
Expired
Feb 15, 2021, 5:15 PM CST
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Tornado watch 7...8
All 44 counties

Houston County, AL, Alachua County, FL, Baker County, FL, Bradford County, FL, Calhoun County, FL, Clay County, FL, Columbia County, FL, Dixie County, FL, Franklin County, FL, Gadsden County, FL, Gilchrist County, FL, Gulf County, FL, Hamilton County, FL, Jackson County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Levy County, FL, Liberty County, FL, Madison County, FL, Putnam County, FL, Suwannee County, FL, Taylor County, FL, Union County, FL, Wakulla County, FL, Baker County, GA, Berrien County, GA, Brooks County, GA, Calhoun County, GA, Charlton County, GA, Clinch County, GA, Colquitt County, GA, Cook County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Echols County, GA, Grady County, GA, Lanier County, GA, Lowndes County, GA, Miller County, GA, Mitchell County, GA, Seminole County, GA, Thomas County, GA

The radar

The Tallahassee radar (KTLH), 45 km from the middle of the area, began a volume at 21:13 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 9.1 hours before the alert went out and 42 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, Tallahassee Rgnl, FL at 12:00Z on 2021-02-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Tallahassee Rgnl, FL at 12:00Z on 2021-02-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 252 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
468 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
252 m²/s²
0-3 km storm-relative helicity
303 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

447 
ACUS11 KWNS 152109
SWOMCD
SPC MCD 152108 
FLZ000-GAZ000-ALZ000-152315-

Mesoscale Discussion 0094
NWS Storm Prediction Center Norman OK
0308 PM CST Mon Feb 15 2021

Areas affected...the eastern half of the Florida Panhandle into
adjacent southern Georgia and northern Florida

Concerning...Tornado Watch 7...8...

Valid 152108Z - 152315Z

The severe weather threat for Tornado Watch 7, 8 continues.

SUMMARY...Widespread storms, and local severe weather threat,
continues within Tornado Watches 007 and 008.

DISCUSSION...Latest radar loop shows a band of strong storms
crossing central portions of the Florida Panhandle, and far
southeastern Alabama near the Alabama/Georgia border -- within WW
007.  Other/more isolated storms continue farther east, into
northern portions of the Florida Peninsula -- within WW 008.

The boundary layer across WW 007 has been slow to destabilize
northward, and with increasingly widespread precipitation
moving/spreading across the remainder of the WW area, little
additional surface-based destabilization is expected before storms
exit the watch over the next hour to hour and a half.  Until then,
damaging winds will remain the primary severe risk, with a tornado
or two still possible.

Meanwhile, a much more favorable thermodynamic environment persists
across roughly the southern half of WW 008, but flow -- though
gradually increasing -- remains weaker than areas farther west. 
Still, gusty/damaging winds and a tornado or two remain possible,
with risk to begin diminishing gradually into early evening beyond
the diurnal instability peak.

..Goss.. 02/15/2021

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

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

LAT...LON   29978546 30618541 31368533 31658434 31228282 30738202
            30098154 29498164 29078318 29538537 29978546

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 15, 3:09 AM CSTMesoscale DiscussionSPCFayette, Franklin, Lamar, Marion, Pickens6 hr
Feb 15, 9:28 AM CSTMesoscale DiscussionSPCColbert, Fayette, Franklin, Greene, Lamar, Lauderdale and 6 more6 hr
Feb 15, 11:24 AM CSTMesoscale DiscussionSPCCoffee, Dale, Geneva, Henry, Houston66 min
Feb 15, 11:55 AM CSTTornado WatchSPCCoffee, Covington, Dale, Geneva, Henry, Houston5 hr
Feb 15, 1:38 PM CSTMesoscale DiscussionSPCBay, Calhoun, Franklin, Gadsden, Gulf, Liberty97 min
Feb 15, 1:47 PM CSTMesoscale DiscussionSPCAlachua, Baker, Bradford, Citrus, Clay, Columbia and 17 more118 min
Feb 15, 2:02 PM CSTTornado WatchSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 13 more7 hr
Feb 15, 5:32 PM CSTMesoscale DiscussionSPCBrevard, Indian River, Osceola, Seminole118 min

Nearby

Mesoscale Discussions in Florida, 2021Mesoscale Discussions in Georgia, 2021Mesoscale Discussions in Alabama, 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.