Alert archive / Alabama / Mesoscale Discussions in 2012

Mesoscale Discussion 2220

December 25, 201223 counties in Alabama; 6 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Dec 25, 2012, 5:17 PM CST for 23 counties in Alabama; 6 counties in Florida. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Dec 25, 2012, 5:17 PM CST (23:17 UTC)
Expired: Dec 25, 2012, 6:45 PM CST
In force: 88 min
Issued by: the Storm Prediction Center

All 29 counties

Baldwin County, AL, Barbour County, AL, Bullock County, AL, Butler County, AL, Clarke County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Dallas County, AL, Escambia County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Lowndes County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Pike County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL

The radar

The Eglin Afb radar (KEVX), 117 km from the middle of the area, began a volume at 23:18 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

Birmingham, AL (KBMX), launched 12:00Z, 11.3 hours before the alert went out and 206 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1008 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 65 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

229 
ACUS11 KWNS 252317
SWOMCD
SPC MCD 252317 
GAZ000-FLZ000-ALZ000-MSZ000-260045-

MESOSCALE DISCUSSION 2220
NWS STORM PREDICTION CENTER NORMAN OK
0517 PM CST TUE DEC 25 2012

AREAS AFFECTED...SRN AL...WRN FL PANHANDLE

CONCERNING...TORNADO WATCH 695...696...

VALID 252317Z - 260045Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 695...696...CONTINUES.

SUMMARY...GREATEST TORNADO RISK EVOLVING EWD...BECOMING CENTERED
ACROSS SRN AL AND THE WRN FL PANHANDLE.

DISCUSSION...SEVERAL DISCRETE SUPERCELLS...ALONG WITH SUPERCELLS
EMBEDDED WITH A PRE-FRONTAL CONFLUENCE BAND SHOULD CONTINUE TO TRACK
NEWD ACROSS SRN AL AND THE WRN FL PANHANDLE. GIVEN PRESENCE OF LOWER
TO MIDDLE 60S SURFACE DEW POINTS S OF THE WARM FRONT EXTENDING FROM
CHOCTAW COUNTY AL TO NEAR ABY AS OF 23Z. WITH 0-1 KM SHEAR FROM
30-40 KT PER AREA VWP DATA...ENVIRONMENT WILL REMAIN FAVORABLE FOR
TORNADOES /SOME OF WHICH COULD BE SIGNIFICANT/ ALONG WITH DAMAGING
WINDS.

..GRAMS.. 12/25/2012

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

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

LAT...LON   31608836 32268796 32368695 32108537 31808507 31528504
            31278510 30648550 30258599 30368750 30458823 31008861
            31608836

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 25, 12:58 PM CST	Tornado Watch PDS	SPC	Autauga, Baldwin, Barbour, Bullock, Chambers, Choctaw and 19 more	9 hr
Dec 25, 2:32 PM CST	Mesoscale Discussion	SPC	Butler, Coffee, Conecuh, Covington, Crenshaw, Dale and 5 more	28 min
Dec 25, 2:41 PM CST	Tornado Watch	SPC	Butler, Coffee, Conecuh, Covington, Crenshaw, Dale and 4 more	7 hr
Dec 25, 3:44 PM CST	Mesoscale Discussion	SPC	Autauga, Baldwin, Butler, Choctaw, Clarke, Crenshaw and 13 more	91 min
Dec 25, 4:34 PM CST	Mesoscale Discussion	SPC	Bibb, Calhoun, Chambers, Clay, Cleburne, Coosa and 9 more	26 min
Dec 25, 4:38 PM CST	Severe Thunderstorm Watch	SPC	Bibb, Blount, Calhoun, Chilton, Clay, Cleburne and 11 more	5 hr
Dec 25, 5:57 PM CST	Mesoscale Discussion	SPC	Gadsden, Jefferson, Leon, Liberty, Madison, Wakulla	2 hr

Nearby

Mesoscale Discussions in Alabama, 2012 Mesoscale Discussions in Florida, 2012 Every 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.