Alert archive / Mississippi / Mesoscale Discussions in 2012
Mesoscale Discussion 127
The Storm Prediction Center issued this mesoscale discussion at Feb 18, 2012, 1:03 PM CST for Baldwin County, Escambia County, Mobile County, Alabama; Orleans Parish, Saint Bernard Parish, Saint Charles Parish, Louisiana; 6 counties in Mississippi. It was in force for 57 min.
The area
The outline as issued.
The facts
- Issued
- Feb 18, 2012, 1:03 PM CST (19:03 UTC)
- Expired
- Feb 18, 2012, 2:00 PM CST
- In force
- 57 min
- Issued by
- the Storm Prediction Center
Counties Baldwin County, AL, Escambia County, AL, Mobile County, AL, Orleans Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Stone County, MS
The radar
The Mobile radar (KMOB), 29 km from the middle of the area, began a volume at 19:04 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, 7.1 hours before the alert went out and 119 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
- 449 m above ground
- 0-6 km bulk shear
- 57 kt
- 0-1 km storm-relative helicity
- 160 m²/s²
- 0-3 km storm-relative helicity
- 177 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
913
ACUS11 KWNS 181903
SWOMCD
SPC MCD 181903
ALZ000-FLZ000-MSZ000-LAZ000-182000-
MESOSCALE DISCUSSION 0127
NWS STORM PREDICTION CENTER NORMAN OK
0103 PM CST SAT FEB 18 2012
AREAS AFFECTED...SERN LA...SRN MS...SWRN AL...WRN FL PANHANDLE
CONCERNING...TORNADO WATCH 28...29...
VALID 181903Z - 182000Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 28...29...CONTINUES.
SEVERE THREAT REMAINS CONFINED TO A CONTRACTING LINE-SEGMENT ACROSS
PEARL RIVER COUNTY MS AND ST TAMMANY PARISH LA. THE RISK FOR
ISOLATED DAMAGING WINDS AND A BRIEF TORNADO PERSISTS...BUT APPEARS
TO BE INCREASINGLY LOCALIZED.
RECENT RADAR AND SATELLITE TRENDS INDICATE THE QLCS HAS SPATIALLY
CONTRACTED AS IT HAS PROGRESSED INTO SRN MS. THIS FEATURE REMAINS
CO-LOCATED WITH A SUB-SYNOPTIC CYCLONE ALONG AND JUST N OF A WARM
FRONT EXTENDING ALONG THE CNTRL GULF COAST. THIS ACTIVITY SHOULD
REMAIN ON THE FRINGE OF THE RICHER MARITIME AIR MASS /CHARACTERIZED
BY MIDDLE 60S SURFACE DEW POINTS/ ACROSS SERN LA AND THE IMMEDIATE
MS/AL/FL COAST. THUS...THE OVERALL SEVERE RISK APPEARS MARGINAL
GIVEN THE LIKELY PRESENCE OF WEAK MUCAPE /AOB 500 J/KG/.
NEVERTHELESS...0-1 KM SHEAR AROUND 40 KT /PER MOB VWP/ WILL REMAIN
SUFFICIENT FOR TRANSIENT MESOVORTICES CAPABLE OF ISOLATED DAMAGING
WINDS AND A BRIEF TORNADO.
FARTHER SW OF THE LINE...WIDESPREAD STRATIFORM AND CONVECTIVE
OUTFLOW HAS EFFECTIVELY SHUNTED THE WARM SECTOR OFFSHORE FROM SWRN
LA AHEAD OF PRIMARY SYNOPTIC LOW OFF THE SERN TX COAST. IT REMAINS
POSSIBLE THAT TSTMS OVER THE WRN GULF MAY EVENTUALLY OVERRIDE THE
REMNANT WARM SECTOR IN SERN LA LATER TODAY.
..GRAMS.. 02/18/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MOB...JAN...LIX...
LAT...LON 30568977 30828942 31218880 31328821 31428758 31348709
31128693 30898697 30638711 30528741 30348793 30068850
29918925 29749012 29989047 30438987 30568977SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 18, 11:21 AM CST | Mesoscale Discussion | SPC | Baldwin, Escambia, Mobile | 54 min |
| Feb 18, 11:49 AM CST | Tornado Watch | SPC | Baldwin, Covington, Escambia, Mobile | 5 hr |
| Feb 18, 2:02 PM CST | Mesoscale Discussion | SPC | Baldwin, Coffee, Conecuh, Covington, Dale, Escambia and 3 more | 58 min |
| Feb 18, 2:58 PM CST | Tornado Watch | SPC | Coffee, Dale, Geneva, Henry, Houston | 5 hr |
| Feb 18, 3:41 PM CST | Mesoscale Discussion | SPC | Baldwin, Coffee, Conecuh, Covington, Crenshaw, Dale and 4 more | 64 min |
| Feb 18, 4:29 PM CST | Mesoscale Discussion | SPC | Baldwin, Covington, Escambia, Mobile | 31 min |
| Feb 18, 4:48 PM CST | Tornado Watch | SPC | Baldwin, Covington, Escambia, Mobile | 4 hr |
| Feb 18, 4:35 AM CST | Mesoscale Discussion | SPC | Calcasieu, Cameron, Jefferson Davis, Vermilion | 55 min |
| Feb 18, 4:46 AM CST | Severe Thunderstorm Watch | SPC | Acadia, Calcasieu, Cameron, Jefferson Davis, Vermilion | 5 hr |
| Feb 18, 8:29 AM CST | Mesoscale Discussion | SPC | Acadia, Assumption, Cameron, Iberia, Iberville, Jefferson Davis and 4 more | 31 min |
| Feb 18, 9:31 AM CST | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, Iberia, Iberville, Jefferson and 16 more | 59 min |
| Feb 18, 9:55 AM CST | Tornado Watch | SPC | Ascension, Assumption, East Baton Rouge, Iberia, Iberville, Jefferson and 15 more | 7 hr |
| Feb 18, 2:21 PM CST | Mesoscale Discussion | SPC | Jefferson, Lafourche, Plaquemines, Saint Bernard, St. Mary, Terrebonne | 24 min |
Nearby
Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Alabama, 2012Mesoscale Discussions in Louisiana, 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.