Alert archive / Florida / Mesoscale Discussions in 2011
Mesoscale Discussion 2339
The Storm Prediction Center issued this mesoscale discussion at Nov 17, 2011, 12:47 AM EST for 7 counties in Florida; 7 counties in Georgia. It was in force for 58 min.
The area
The outline as issued.
The facts
- Issued
- Nov 17, 2011, 12:47 AM EST (05:47 UTC)
- Expired
- Nov 17, 2011, 1:45 AM EST
- In force
- 58 min
- Issued by
- the Storm Prediction Center
Counties Alachua County, FL, Baker County, FL, Bradford County, FL, Columbia County, FL, Duval County, FL, Nassau County, FL, Union County, FL, Brantley County, GA, Camden County, GA, Charlton County, GA, Clinch County, GA, Echols County, GA, Glynn County, GA, Ware County, GA
The radar
The Jacksonville radar (KJAX), 54 km from the middle of the area, began a volume at 05:51 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 00:00Z, 5.8 hours before the alert went out and 53 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
- 769 J/kg
- Mixed-layer CIN
- -18 J/kg
- Mixed-layer LCL
- 991 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 123 m²/s²
- 0-3 km storm-relative helicity
- 139 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 2.4
The text
As transmitted, in the capitals the NWS used until 2016.
821 ACUS11 KWNS 170547 SWOMCD SPC MCD 170547 GAZ000-FLZ000-170645- MESOSCALE DISCUSSION 2339 NWS STORM PREDICTION CENTER NORMAN OK 1147 PM CST WED NOV 16 2011 AREAS AFFECTED...FAR SOUTHEAST GA/NORTH FL CONCERNING...TORNADO WATCH 892... VALID 170547Z - 170645Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 892 CONTINUES. TORNADO WATCH 892 CONTINUES UNTIL 07Z...ALTHOUGH THE SEVERE WEATHER THREAT WITHIN WW 892 IS EXPECTED TO CONTINUE TO STEADILY WANE/SHIFT OFFSHORE. ISOLATED SEVERE WIND/PERHAPS TORNADO THREAT OTHERWISE PERSISTS ACROSS EXTREME/COASTAL SOUTHEAST GA IN THE SHORT TERM AS WELL AS FAR NORTH FL. A NORTHEAST-SOUTHWEST ORIENTED BAND OF CONVECTION CONTINUES TO SHIFT EAST-NORTHEAST EARLY IN THE OVERNIGHT ACROSS FAR SOUTHEAST GA AND THE NORTHERN FL PENINSULA. MUCH OF THE CONVECTION ACROSS SOUTHEAST GA CONTINUES TO BE UNDERCUT BY COMPOSITE OUTFLOW...SUCH THAT THE SEVERE THREAT WILL CONTINUE TO WANE IN SPITE OF A VERY STRONG DEEP LAYER FLOW FIELD. A SEVERE THREAT WILL OTHERWISE REMAIN ACROSS FAR NORTH FL AT LEAST ON AN ISOLATED/MARGINAL BASIS...NAMELY IN ASSOCIATION WITH ANY PERSIST QLCS STRUCTURES/SMALL BOWING SEGMENTS...PERHAPS ESPECIALLY AS THIS CONVECTION INTERCEPTS THE AFOREMENTIONED OUTFLOW BOUNDARY. ..GUYER.. 11/17/2011 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CHS...JAX... LAT...LON 30728302 31408196 31478144 30748115 29608234 30728302
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 16, 8:14 PM EST | Tornado Watch | SPC | Appling, Atkinson, Bacon, Brantley, Camden, Charlton and 8 more | 4 hr |
Nearby
Mesoscale Discussions in Florida, 2011Mesoscale Discussions in Georgia, 2011Every mesoscale discussion in 2011
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.