Alert archive / Florida / Mesoscale Discussions in 2021
Mesoscale Discussion 114
The Storm Prediction Center issued this mesoscale discussion at Feb 17, 2021, 10:18 PM CST for 8 counties in Florida. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 17, 2021, 10:18 PM CST (04:18 UTC)
- Expired
- Feb 18, 2021, 12:45 AM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
Counties Bay County, FL, Calhoun County, FL, Escambia County, FL, Gulf County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL
The radar
The Eglin Afb radar (KEVX), 108 km from the middle of the area, began a volume at 04:18 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, 4.3 hours before the alert went out and 254 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
- 1835 m above ground
- 0-6 km bulk shear
- 63 kt
- 0-1 km storm-relative helicity
- 238 m²/s²
- 0-3 km storm-relative helicity
- 546 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
440
ACUS11 KWNS 180418
SWOMCD
SPC MCD 180418
FLZ000-ALZ000-MSZ000-180645-
Mesoscale Discussion 0114
NWS Storm Prediction Center Norman OK
1018 PM CST Wed Feb 17 2021
Areas affected...Coastal Mississippi...Alabama...and the western
Florida Panhandle
Concerning...Severe potential...Watch possible
Valid 180418Z - 180645Z
Probability of Watch Issuance...40 percent
SUMMARY...Isolated storms may intensify along and just off the coast
in the next few hours as the warm front approaches. Uncertainty
remains how far inland the risk will extend. A WW remains possible.
DISCUSSION...Latest surface analysis shows a low south of Gulfport,
MS, with a warm front extending east-southeastward into the northern
Gulf of Mexico. Evening CAM solutions continue to indicate that the
low will move ashore west of Pensacola in the next few hours,
allowing a marginally unstable air mass to affect coastal areas of
AL and the western FL Panhandle. Forecast soundings suggest that
surface dewpoints in the mid 60s are needed to result in
surface-based parcels, greatly limiting the areal extent of the risk
to the immediate coast. Shear profiles are quite strong, and given
the presence of the warm front, a conditional risk of tornadoes and
damaging winds will be present with any storms in this small area
tonight.
Thus far, convection has struggled to intensify near the low.
However, a few cells have begun to form in the warm sector. A
tornado watch may be needed if/when this activity approaches land.
..Hart.. 02/18/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TAE...MOB...LIX...
LAT...LON 30718741 30818628 30428509 29608504 29568565 29738689
29688793 29698891 30268860 30718741SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 18, 1:49 AM CST | Tornado Watch | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 7 more | 6 hr |
| Feb 18, 4:54 AM CST | Mesoscale Discussion | SPC | Bay, Gulf | 2 hr |
| Feb 18, 7:09 AM CST | Mesoscale Discussion | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Jackson and 4 more | 2 hr |
| Feb 18, 7:45 AM CST | Tornado Watch | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Jackson and 6 more | 7 hr |
| Feb 18, 10:35 AM CST | Mesoscale Discussion | SPC | Gadsden, Jefferson, Leon, Liberty, Wakulla | 115 min |
| Feb 18, 12:43 PM CST | Mesoscale Discussion | SPC | Jefferson, Madison, Taylor | 92 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.