Alert archive / Alabama / Mesoscale Discussions in 2012

Mesoscale Discussion 326

March 22, 20124 counties in Alabama; Jackson County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 22, 2012, 9:53 AM CDT for 4 counties in Alabama; Jackson County, Mississippi. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Mar 22, 2012, 9:53 AM CDT (14:53 UTC)
Expired
Mar 22, 2012, 11:00 AM CDT
In force
67 min
Issued by
the Storm Prediction Center

Counties Baldwin County, AL, Clarke County, AL, Mobile County, AL, Washington County, AL, Jackson County, MS

The radar

The Mobile radar (KMOB), 30 km from the middle of the area, began a volume at 14:53 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 12:00Z, 2.9 hours before the alert went out and 155 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 12:00Z on 2012-03-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLEL10008507005003002001001 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 12:00Z on 2012-03-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 148 square meters per square second.19395878Sfc1 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
2 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
438 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
148 m²/s²
0-3 km storm-relative helicity
377 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

524 
ACUS11 KWNS 221454
SWOMCD
SPC MCD 221453
ALZ000-FLZ000-MSZ000-LAZ000-221600-

MESOSCALE DISCUSSION 0326
NWS STORM PREDICTION CENTER NORMAN OK
0953 AM CDT THU MAR 22 2012

AREAS AFFECTED...FAR SERN MS...SWRN AL

CONCERNING...TORNADO WATCH 99...

VALID 221453Z - 221600Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 99 CONTINUES.

A RISK FOR LOCALLY DAMAGING WINDS AND A BRIEF TORNADO...ALONG WITH
HEAVY RAIN SHOULD CONTINUE FOR THE NEXT FEW HOURS WITHIN A
PERSISTENT N/S-ORIENTED CONVECTIVE BAND. THIS THREAT /ALBEIT
MARGINAL/ WILL LIKELY EXTEND E INTO PORTIONS OF AL...WHERE A NEW WW
ISSUANCE IS BEING CONSIDERED.

N/S-ORIENTED CONVECTIVE BAND FROM GREENE COUNTY MS TO MARINE ZONE
557 HAS PERSISTED FOR SEVERAL HOURS WHILE MAINTAINING A VERY SLOW
EWD MOVEMENT. LOW-LEVEL SLYS REMAIN STRONG AHEAD OF THE LINE WITH
THE MOB VAD WIND PROFILE INDICATING 0-1 KM SRH AROUND 300 M2/S2.
ALTHOUGH LOW-LEVEL FLOW IS FORECAST TO WEAKEN AS PRIMARY SHORT WAVE
IMPULSE ROTATES ACROSS THE OZARK PLATEAU...SHEAR SHOULD REMAIN
SUFFICIENT FOR RISKS OF DAMAGING WINDS/TORNADOES GIVEN THE PRESENCE
OF UPPER 60S TO AROUND 70 SURFACE DEW POINTS. DOWNSTREAM HEATING
SHOULD BE RETARDED BY ABUNDANT CLOUD COVERAGE...AND MAY LIMIT A MORE
ROBUST SEVERE THREAT.

..GRAMS.. 03/22/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BMX...MOB...LIX...

LAT...LON   29878885 30938858 31338854 31758839 31958821 32038803
            32018785 31758771 31618763 30308754 29388871 29538893
            29878885

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 22, 2:28 AM CDTMesoscale DiscussionSPCMobile, Washington2 hr
Mar 22, 6:49 AM CDTMesoscale DiscussionSPCMobile116 min
Mar 22, 10:55 AM CDTTornado WatchSPCBaldwin, Clarke, Mobile, Monroe, Washington, Wilcox6 hr
Mar 22, 1:00 PM CDTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Butler, Chilton, Conecuh and 10 more60 min
Mar 22, 3:30 PM CDTMesoscale DiscussionSPCBaldwin, Conecuh, Escambia, Mobile, Monroe, Wilcox60 min
Mar 21, 9:27 PM CDTMesoscale DiscussionSPCClarke, Forrest, George, Greene, Hancock, Harrison and 8 more93 min
Mar 21, 11:49 PM CDTMesoscale DiscussionSPCClarke, George, Greene, Harrison, Jackson, Lauderdale and 2 more56 min
Mar 22, 7:15 AM CDTTornado WatchSPCGeorge, Harrison, Jackson, Stone5 hr

Nearby

Mesoscale Discussions in Alabama, 2012Mesoscale Discussions in Mississippi, 2012Every mesoscale discussion in 2012

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.