Alert archive / Florida / Mesoscale Discussions in 2021
Mesoscale Discussion 219
The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2021, 4:28 AM CDT for 5 counties in Alabama; 6 counties in Florida; Clay County, Early County, Seminole County, Georgia. It was in force for 92 min.
The area
The outline as issued.
The facts
- Issued
- Mar 18, 2021, 4:28 AM CDT (09:28 UTC)
- Expired
- Mar 18, 2021, 6:00 AM CDT
- In force
- 92 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 38
Counties Coffee County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Bay County, FL, Calhoun County, FL, Holmes County, FL, Jackson County, FL, Walton County, FL, Washington County, FL, Clay County, GA, Early County, GA, Seminole County, GA
The radar
The Eglin Afb radar (KEVX), 43 km from the middle of the area, began a volume at 09:28 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Tallahassee Rgnl, FL (KTLH), launched 00:00Z, 9.5 hours before the alert went out and 163 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1019 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 126 m²/s²
- 0-3 km storm-relative helicity
- 171 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
036
ACUS11 KWNS 180929
SWOMCD
SPC MCD 180928
GAZ000-FLZ000-ALZ000-181100-
Mesoscale Discussion 0219
NWS Storm Prediction Center Norman OK
0428 AM CDT Thu Mar 18 2021
Areas affected...Portions of the FL Panhandle...southeastern
AL...and far southwestern GA
Concerning...Tornado Watch 38...
Valid 180928Z - 181100Z
The severe weather threat for Tornado Watch 38 continues.
SUMMARY...An isolated severe threat continues across parts of the
Florida Panhandle and southeastern Alabama.
DISCUSSION...Storms have struggled to intensify over the past couple
of hours as they move eastward across the FL Panhandle and
southeastern AL. A brief low-level circulation in Crenshaw County AL
has since weakened. Even though low-level and deep-layer shear
remain favorable for organized storms, it appears that the lack of
better large-scale forcing and weak mid-level lapse rates are
limiting updraft strength. Even so, a 30-40 kt low-level jet and
enhanced hodograph will conditionally support tornado potential with
any stronger cells that can develop within the broken line of
storms. Isolated strong/gusty downdraft winds also remain a
possibility given the strength of the low-level flow. Given radar
trends over the past few hours, it is not clear whether another
watch will be needed past the scheduled 11Z expiration time of
Tornado Watch 38.
..Gleason.. 03/18/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TAE...BMX...MOB...
LAT...LON 30398655 30688646 30998631 31348620 31738608 31828542
31798487 31058473 29968538 30298608 30398655SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 17, 7:07 PM CDT | Tornado Watch | SPC | Colbert, Cullman, Franklin, Lauderdale, Lawrence, Limestone and 3 more | 3 hr |
| Mar 17, 9:16 PM CDT | Mesoscale Discussion | SPC | Cullman, DeKalb, Jackson, Limestone, Madison, Marshall and 1 more | 89 min |
| Mar 17, 10:15 PM CDT | Mesoscale Discussion | SPC | Baldwin, Barbour, Bullock, Calhoun, Chambers, Cherokee and 18 more | 90 min |
| Mar 17, 11:02 PM CDT | Tornado Watch | SPC | Coffee, Covington, Dale, Geneva, Henry, Houston | 9 hr |
| Mar 18, 1:52 AM CDT | Mesoscale Discussion | SPC | Barbour, Coffee, Covington, Dale, Geneva, Henry and 2 more | 83 min |
| Mar 18, 6:32 AM CDT | Mesoscale Discussion | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Jackson and 6 more | 58 min |
| Mar 18, 6:53 AM CDT | Tornado Watch | SPC | Dixie, Franklin, Gadsden, Gulf, Jefferson, Lafayette and 5 more | 5 hr |
| Mar 18, 10:05 AM CDT | Mesoscale Discussion | SPC | Columbia, Dixie, Hamilton, Jefferson, Lafayette, Madison and 2 more | 115 min |
| Mar 18, 10:42 AM CDT | Tornado Watch | SPC | Alachua, Baker, Bradford, Clay, Columbia, Duval and 7 more | 6 hr |
| Mar 18, 9:34 AM CDT | Mesoscale Discussion | SPC | Banks, Barrow, Clarke, Elbert, Franklin, Habersham and 5 more | 2 hr |
| Mar 18, 1:08 PM CDT | Tornado Watch | SPC | Elbert, Lincoln | 4 hr |
| Mar 18, 2:10 PM CDT | Mesoscale Discussion | SPC | Elbert | 3 hr |
Nearby
Mesoscale Discussions in Florida, 2021Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Georgia, 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.