Alert archive / Alabama / Mesoscale Discussions in 2012
Mesoscale Discussion 130
The Storm Prediction Center issued this mesoscale discussion at Feb 18, 2012, 3:41 PM CST for 4 states. It was in force for 64 min.
The area
The outline as issued.
The facts
- Issued
- Feb 18, 2012, 3:41 PM CST (21:41 UTC)
- Expired
- Feb 18, 2012, 4:45 PM CST
- In force
- 64 min
- Issued by
- the Storm Prediction Center
Counties Baldwin County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Escambia County, AL, Geneva County, AL, Mobile County, AL, Pike County, AL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Jefferson Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Jackson County, MS
The radar
The Mobile radar (KMOB), 50 km from the middle of the area, began a volume at 21:42 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, 9.7 hours before the alert went out and 192 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.
802
ACUS11 KWNS 182142
SWOMCD
SPC MCD 182141
ALZ000-FLZ000-MSZ000-LAZ000-182245-
MESOSCALE DISCUSSION 0130
NWS STORM PREDICTION CENTER NORMAN OK
0341 PM CST SAT FEB 18 2012
AREAS AFFECTED...FAR SERN LA/MS...SRN AL...WRN FL PANHANDLE
CONCERNING...TORNADO WATCH 29...30...
VALID 182141Z - 182245Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 29...30...CONTINUES.
WW/S 28/29 ARE SCHEDULED TO EXPIRE AT 23Z. REPLACEMENT OR LOCAL
EXTENSION OF WW/S ARE POSSIBLE FOR PARTS OF THESE AREAS BY 23Z.
PRIMARY THREAT FOR ISOLATED DAMAGING WINDS AND A BRIEF TORNADO
REMAINS WITH NRN PORTION OF LONG-LIVED SQUALL LINE PROGRESSING EWD
ALONG THE AL/FL BORDER IN THE NRN PORTION OF WW 29. THIS FEATURE HAS
SLOWED DOWN IN THE PAST HOUR...WITH EWD PROGRESSION NOW AROUND 40-45
KT. THIS TRACK EXTRAPOLATES TO THE BORDER OF WW/S 29/30 NEAR 23Z.
EXTENDING SW TO THE MS DELTA...POTENTIAL STILL EXISTS FOR TSTMS TO
INTENSIFY ALONG THE REMNANT OUTFLOW/EFFECTIVE SURFACE FRONT. THUS
FAR...AS THIS BOUNDARY HAS SAGGED SEWD...INTENSIFICATION HAS LARGELY
HELD BELOW SEVERE LIMITS AND IS EFFECTIVELY SHUNTING THE WARM SECTOR
BACK OFFSHORE. AS SUCH...OVERALL DAMAGING WIND/TORNADO POTENTIAL MAY
BECOME SUFFICIENTLY MARGINAL TO NOT WARRANT FURTHER
EXTENSION/REPLACEMENT OF WW/S 28/29. AT THE VERY LEAST...SEVERAL
ROUNDS OF OVERRUNNING CONVECTION WILL POSE A CONTINUED THREAT FOR
HEAVY RAIN GIVEN GPS PW VALUES AROUND 1.75 IN.
..GRAMS.. 02/18/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...TAE...BMX...MOB...LIX...
LAT...LON 31528718 31718674 31848595 31758566 31478556 31148555
30308597 30228744 29618868 28838924 28859093 29069090
29559020 30608862 31168785 31528718SPC 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, 1:03 PM CST | Mesoscale Discussion | SPC | Baldwin, Escambia, Mobile | 57 min |
| 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, 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 Alabama, 2012Mesoscale Discussions in Florida, 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.