Alert archive / Florida / Mesoscale Discussions in 2021
Mesoscale Discussion 1920
The Storm Prediction Center issued this mesoscale discussion at Oct 27, 2021, 10:22 PM CDT for 4 counties in Florida. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 27, 2021, 10:22 PM CDT (03:22 UTC)
- Expired
- Oct 28, 2021, 12:45 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
Counties Bay County, FL, Franklin County, FL, Gulf County, FL, Walton County, FL
The radar
The Eglin Afb radar (KEVX), 57 km from the middle of the area, began a volume at 03:24 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, 3.4 hours before the alert went out and 130 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
- 2227 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 20 m²/s²
- 0-3 km storm-relative helicity
- 53 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
398
ACUS11 KWNS 280322
SWOMCD
SPC MCD 280322
FLZ000-280545-
Mesoscale Discussion 1920
NWS Storm Prediction Center Norman OK
1022 PM CDT Wed Oct 27 2021
Areas affected...parts of the coastal Florida Panhandle
Concerning...Severe potential...Watch possible
Valid 280322Z - 280545Z
Probability of Watch Issuance...40 percent
SUMMARY...Isolated severe storms may eventually impact coastal
counties of the Florida Panhandle.
DISCUSSION...An expanding batch of thunderstorms continues to move
eastward across southern AL and into the western FL Panhandle, with
the bulk of the activity offshore. A warm front currently extends
from the Mobile/Pensacola area east/southeastward over the Gulf of
Mexico, with only low to mid 60s F dewpoints toward Panama City FL
as of 03Z.
Warm advection aided by 30-40 kt southwesterly flow at 850 mb will
result in a gradual increase in instability across the coastal
counties of the FL Panhandle, coincident with the arrival of 70s F
dewpoints. Shear will favor supercells, and perhaps a brief tornado,
but the overall threat will depend on the degree of boundary-layer
destabilization over land. As such, an additional watch could be
needed later tonight east of WW 543.
..Jewell/Grams.. 10/28/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TAE...MOB...
LAT...LON 30668638 30608604 30438567 29958433 29758461 29628484
29548502 29668540 29898549 30258607 30278632 30398642
30668638SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 27, 7:21 PM CDT | Tornado Watch | SPC | Escambia, Okaloosa, Santa Rosa | 7 hr |
| Oct 27, 9:08 PM CDT | Mesoscale Discussion | SPC | Escambia, Okaloosa, Santa Rosa | 97 min |
| Oct 27, 11:21 PM CDT | Tornado Watch | SPC | Bay, Calhoun, Franklin, Gulf, Liberty, Wakulla and 2 more | 6 hr |
| Oct 28, 7:12 AM CDT | Mesoscale Discussion | SPC | Alachua, Bradford, Citrus, Dixie, Gilchrist, Hernando and 7 more | 2 hr |
| Oct 28, 8:00 AM CDT | Tornado Watch | SPC | Alachua, Baker, Bradford, Brevard, Charlotte, Citrus and 35 more | 10 hr |
| Oct 28, 10:51 AM CDT | Mesoscale Discussion | SPC | Charlotte, DeSoto, Flagler, Hardee, Highlands, Hillsborough and 11 more | 114 min |
| Oct 28, 1:08 PM CDT | Mesoscale Discussion | SPC | Charlotte, DeSoto, Flagler, Hardee, Lake, Manatee and 3 more | 97 min |
| Oct 28, 3:11 PM CDT | Mesoscale Discussion | SPC | Brevard, Charlotte, DeSoto, Glades, Highlands, Indian River and 2 more | 94 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.