Alert archive / Florida / Mesoscale Discussions in 2012
Mesoscale Discussion 2198
The Storm Prediction Center issued this mesoscale discussion at Dec 20, 2012, 6:22 PM EST for 13 counties in Florida; 5 counties in Georgia. It was in force for 53 min.
The area
The outline as issued.
The facts
- Issued
- Dec 20, 2012, 6:22 PM EST (23:22 UTC)
- Expired
- Dec 20, 2012, 7:15 PM EST
- In force
- 53 min
- Issued by
- the Storm Prediction Center
Counties Alachua County, FL, Baker County, FL, Bradford County, FL, Clay County, FL, Columbia County, FL, Dixie County, FL, Duval County, FL, Gilchrist County, FL, Hamilton County, FL, Lafayette County, FL, Nassau County, FL, Suwannee County, FL, Union County, FL, Camden County, GA, Charlton County, GA, Clinch County, GA, Echols County, GA, Ware County, GA
The radar
The Jacksonville radar (KJAX), 78 km from the middle of the area, began a volume at 23:23 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
Jacksonville, FL (KJAX), launched 12:00Z, 11.4 hours before the alert went out and 79 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
- 888 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 155 m²/s²
- 0-3 km storm-relative helicity
- 217 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
306 ACUS11 KWNS 202322 SWOMCD SPC MCD 202322 FLZ000-GAZ000-210015- MESOSCALE DISCUSSION 2198 NWS STORM PREDICTION CENTER NORMAN OK 0522 PM CST THU DEC 20 2012 AREAS AFFECTED...NORTH FL/SOUTHEAST GA CONCERNING...TORNADO WATCH 690... VALID 202322Z - 210015Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 690 CONTINUES. SUMMARY...TORNADO WATCH 690 WILL BE ALLOWED TO EXPIRE AT/BY 00Z...BUT A NEW WATCH MAY BE NEEDED TO THE EAST OF WW 690 ACROSS NORTHEAST FL/SOUTHEAST GA. DAMAGING WINDS WOULD BE THE PRIMARY THREAT...BUT AN ISOLATED TORNADO MAY BE POSSIBLE AS WELL. DISCUSSION...A QUASI-LINEAR CONVECTIVE COMPLEX WITH LEADING STRATIFORM AND TRAILING/EMBEDDED SUPERCELLULAR STRUCTURE CONTINUES TO STEADILY SHIFT EASTWARD ACROSS NORTH FL/FAR SOUTHERN GA EARLY THIS EVENING. THE AIRMASS CONTINUES TO COOL IN VICINITY OF THE STORMS...AND A WARMING OF CLOUD TOPS PER IR SATELLITE IMAGERY HAS BEEN NOTED ALONG WITH AN ABSENCE OF CLOUD-GROUND LIGHTNING. EVEN SO...A HIGHLY SHEARED ENVIRONMENT /300 0-1 KM SRH PER JAX WSR-88D VWP/ WILL HELP TO MAINTAIN EMBEDDED ROTATIONAL STRUCTURES WITH EPISODIC POTENTIAL FOR DAMAGING WINDS/PERHAPS A TORNADO. ..GUYER/CARBIN.. 12/20/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...TBW...JAX...TAE... LAT...LON 29628342 31178268 31158138 30418123 29098246 29628342
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 20, 5:23 AM EST | Tornado Watch | SPC | Escambia, Okaloosa, Santa Rosa | 9 hr |
| Dec 20, 8:09 AM EST | Mesoscale Discussion | SPC | Escambia, Okaloosa, Santa Rosa | 96 min |
| Dec 20, 9:49 AM EST | Mesoscale Discussion | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 9 more | 56 min |
| Dec 20, 10:19 AM EST | Tornado Watch | SPC | Bay, Calhoun, Dixie, Franklin, Gadsden, Gulf and 11 more | 9 hr |
| Dec 20, 10:56 AM EST | Mesoscale Discussion | SPC | Escambia, Santa Rosa | 64 min |
| Dec 20, 2:31 PM EST | Mesoscale Discussion | SPC | Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 7 more | 59 min |
| Dec 20, 12:24 PM EST | Mesoscale Discussion | SPC | Baldwin, Bibb, Bleckley, Butts, Chattahoochee, Coweta and 36 more | 66 min |
Nearby
Mesoscale Discussions in Florida, 2012Mesoscale Discussions in Georgia, 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.