Alert archive / Mississippi / Mesoscale Discussions in 2012

Mesoscale Discussion 324

March 22, 2012Mobile County, Washington County, Alabama; George County, Greene County, Jackson County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 22, 2012, 2:28 AM CDT for Mobile County, Washington County, Alabama; George County, Greene County, Jackson County, Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Mar 22, 2012, 2:28 AM CDT (07:28 UTC)
Expired
Mar 22, 2012, 4:30 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center

Counties Mobile County, AL, Washington County, AL, George County, MS, Greene County, MS, Jackson County, MS

The radar

The Mobile radar (KMOB), 28 km from the middle of the area, began a volume at 07:29 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 nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 7.5 hours before the alert went out and 121 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 2012-03-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 131 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 2012-03-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -10 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
131 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
505 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
-10 m²/s²
0-3 km storm-relative helicity
17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

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

131 
ACUS11 KWNS 220728
SWOMCD
SPC MCD 220728 
ALZ000-MSZ000-LAZ000-220930-

MESOSCALE DISCUSSION 0324
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CDT THU MAR 22 2012

AREAS AFFECTED...PARTS OF COASTAL SOUTHEAST LOUISIANA...SRN MS AND
SWRN AL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 220728Z - 220930Z

AN ADDITIONAL WW IS NOT ANTICIPATED.

THUNDERSTORM ACTIVITY CONTINUES NEAR A WEAK SURFACE LOW...OR ZONE OF
ENHANCED LOW-LEVEL CONVERGENCE...ALONG THE STALLED OR VERY SLOW
EASTWARD MOVING CONVECTIVE OUTFLOW BOUNDARY NEAR SOUTHEASTERN
LOUISIANA AND SOUTHERN MISSISSIPPI COASTAL AREAS.  AND THIS MAY
CONTINUE THROUGH MUCH OF THE REMAINDER OF THE NIGHT...IN THE
PRESENCE OF WEAK TO MODERATE CAPE ASSOCIATED WITH THE WEDGE OF MOIST
BOUNDARY LAYER AIR CHARACTERIZED BY 70F SURFACE DEW POINTS NOSING
ACROSS COASTAL AREAS NEAR/WEST OF MOBILE BAY.  FLOW ALOFT WILL
REMAIN STRONGLY DIFLUENT...DOWNSTREAM OF A SHORT WAVE IMPULSE
PIVOTING AROUND THE LARGE SLOW MOVING UPPER LOW NOW CENTERED OVER
THE RED RIVER VALLEY.  

VWP DATA FROM MOBILE DOES CONTINUE TO INDICATE THE PRESENCE OF AT
LEAST MODESTLY LARGE LOW-LEVEL SHEAR...BUT LATEST RUC GUIDANCE
CONTINUES TO SUGGEST THAT THIS WILL WEAKEN BY 09-10Z...AS 850 MB
FLOW ALONG COASTAL AREAS BEGINS TO DECREASE BELOW 30 KTS. 
SUFFICIENT DEEP LAYER SHEAR MAY PERSIST FOR THE CONTINUING EVOLUTION
OF OCCASIONAL MID-LEVEL UPDRAFT ROTATION...BUT LOW TORNADIC
POTENTIAL SEEMS LIKELY TO DIMINISH FURTHER THROUGH DAYBREAK.

..KERR.. 03/22/2012

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

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

LAT...LON   30968891 31788834 31168774 29838798 29438847 29568898
            30968891

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 22, 6:49 AM CDTMesoscale DiscussionSPCMobile116 min
Mar 22, 9:53 AM CDTMesoscale DiscussionSPCBaldwin, Clarke, Mobile, Washington67 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 Mississippi, 2012Mesoscale Discussions in Alabama, 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.