Alert archive / Mississippi / Mesoscale Discussions in 2021

Mesoscale Discussion 1006

June 19, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Jun 19, 2021, 1:08 AM CDT for 4 states. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jun 19, 2021, 1:08 AM CDT (06:08 UTC)
Expired
Jun 19, 2021, 3:45 AM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch possible
Chance of a watch
60%

Counties Baldwin County, AL, Escambia County, AL, Mobile County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, Saint Bernard Parish, LA, George County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Stone County, MS

The radar

The Mobile radar (KMOB), 35 km from the middle of the area, began a volume at 06:12 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

Slidell Radar S, LA (KSIL), launched 00:00Z, 6.1 hours before the alert went out and 144 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, Slidell Radar S, LA at 00:00Z on 2021-06-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 174 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, Slidell Radar S, LA at 00:00Z on 2021-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 108 square meters per square second.193958Sfc1 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
174 J/kg
Mixed-layer CIN
-29 J/kg
Mixed-layer LCL
572 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
108 m²/s²
0-3 km storm-relative helicity
124 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

880 
ACUS11 KWNS 190608
SWOMCD
SPC MCD 190608 
FLZ000-ALZ000-MSZ000-LAZ000-190845-

Mesoscale Discussion 1006
NWS Storm Prediction Center Norman OK
0108 AM CDT Sat Jun 19 2021

Areas affected...Far Southeast Louisiana...Far Southern
Alabama...Florida Panhandle

Concerning...Severe potential...Watch possible 

Valid 190608Z - 190845Z

Probability of Watch Issuance...60 percent

SUMMARY...A tornado threat will be possible in the coastal areas
from far southeast Louisiana eastward to the western Florida
Panhandle. Weather watch issuance may be needed along this portion
of the coast later tonight.

DISCUSSION...A tropical weather system is currently located near the
coast of Louisiana about 40 statute miles to the south-southeast of
Morgan City. A north-to-south band of moderate to heavy rainfall is
located about 50 statute miles to northeast of the center extending
inland about 100 statute miles. This band of rainfall is located
along an axis of moderate instability, with the RAP estimating
MLCAPE in the 1000 to 2000 J/kg range. The Mobile WSR-88D VWP
currently has a looping hodograph with 0-1 km shear near 40 kt and
0-3 storm relative helicity near 475 m2/s2. The strong low-level
shear will likely support a tornado threat as the band of rainfall
moves eastward along the coast. Supercells with a potential for
tornadoes will also be possible just to the east of the band. The
tornado threat may continue for several more hours as the band moves
across far southern Alabama and into the far western Florida
Panhandle around daybreak.

..Broyles/Edwards.. 06/19/2021

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

ATTN...WFO...TAE...MOB...JAN...LIX...

LAT...LON   30738948 31138883 31248772 31228680 31128640 30778625
            30508629 30218672 29978815 29568903 29458916 29408934
            29478973 30048974 30738948

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 19, 1:40 AM CDTTornado WatchSPCBaldwin, Butler, Conecuh, Covington, Crenshaw, Escambia and 3 more9 hr
Jun 19, 8:33 AM CDTMesoscale DiscussionSPCButler, Coffee, Conecuh, Covington, Crenshaw, Dale and 3 more57 min
Jun 19, 9:33 AM CDTTornado WatchSPCBarbour, Bullock, Butler, Coffee, Covington, Crenshaw and 10 more9 hr
Jun 19, 6:22 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Dale, Geneva, Henry, Houston and 2 more83 min

Nearby

Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Alabama, 2021Mesoscale 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.