Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 663

April 28, 201115 counties in Florida; 16 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2011, 12:19 PM EDT for 15 counties in Florida; 16 counties in Georgia. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Apr 28, 2011, 12:19 PM EDT (16:19 UTC)
Expired
Apr 28, 2011, 1:15 PM EDT
In force
56 min
Issued by
the Storm Prediction Center
All 31 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, Madison County, FL, Nassau County, FL, Suwannee County, FL, Taylor County, FL, Union County, FL, Appling County, GA, Bacon County, GA, Brantley County, GA, Camden County, GA, Charlton County, GA, Clinch County, GA, Echols County, GA, Glynn County, GA, Lanier County, GA, Liberty County, GA, Long County, GA, Lowndes County, GA, McIntosh County, GA, Pierce County, GA, Ware County, GA, Wayne County, GA

The nearest sounding before it

Jacksonville, FL (KJAX), launched 12:00Z, 4.3 hours before the alert went out and 94 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-pSkew-T log-p diagram, Jacksonville, FL at 12:00Z on 2011-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1394 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Jacksonville, FL at 12:00Z on 2011-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 161 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1394 J/kg
Mixed-layer CIN
-52 J/kg
Mixed-layer LCL
817 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
161 m²/s²
0-3 km storm-relative helicity
154 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.5

Open this sounding in Storm Lab

The text

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

324 
ACUS11 KWNS 281619
SWOMCD
SPC MCD 281619 
GAZ000-FLZ000-281715-

MESOSCALE DISCUSSION 0663
NWS STORM PREDICTION CENTER NORMAN OK
1119 AM CDT THU APR 28 2011

AREAS AFFECTED...NRN FL...SERN GA

CONCERNING...SEVERE THUNDERSTORM WATCH 254...

VALID 281619Z - 281715Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 254
CONTINUES.

WEAK WARM ADVECTION IN THE WAKE OF LEADING LINE OF TSTMS WILL
CONTRIBUTE TO ADDITIONAL ELEVATED CONVECTION ACROSS MUCH OF SERN GA
INTO THE MID AFTERNOON HOURS.  GRADUALLY VEERING/DEEPENING FLOW
ACROSS NRN FL WILL PROVIDE THE MOMENTUM NECESSARY FOR ONGOING
FRONTAL BAND OF STORMS TO PROGRESS ACROSS THE REMAINDER OF THE
WW...THOUGH ISOLATED TSTMS MAY YET EVOLVE AHEAD OF THIS ACTIVITY
WITHIN EXPANDING CU FIELD OVER THE WARM SECTOR.

..DARROW.. 04/28/2011

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

ATTN...WFO...CHS...TBW...JAX...TAE...

LAT...LON   29418457 31868237 31887980 29428207 29418457

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 28, 2:22 AM EDTMesoscale DiscussionSPCHolmes83 min
Apr 28, 9:47 AM EDTSevere Thunderstorm WatchSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 13 more9 hr
Apr 28, 3:34 PM EDTMesoscale DiscussionSPCBrevard, Broward, Charlotte, Collier, DeSoto, Glades and 25 more56 min
Apr 27, 8:55 PM EDTMesoscale DiscussionSPCChattooga, Walker65 min
Apr 28, 12:09 AM EDTMesoscale DiscussionSPCBanks, Barrow, Bartow, Bibb, Butts, Carroll and 65 more36 min
Apr 28, 12:56 AM EDTTornado WatchSPCBaldwin, Banks, Barrow, Bibb, Bleckley, Burke and 80 more4 hr
Apr 28, 3:30 AM EDTMesoscale DiscussionSPCBaldwin, Bibb, Bleckley, Burke, Chattahoochee, Columbia and 30 more90 min
Apr 28, 4:30 AM EDTTornado WatchSPCBaldwin, Bibb, Bleckley, Bulloch, Burke, Candler and 37 more10 hr
Apr 28, 8:05 AM EDTMesoscale DiscussionSPCBurke, Candler, Dodge, Emanuel, Jefferson, Jenkins and 5 more85 min
Apr 28, 8:48 AM EDTTornado WatchSPCBryan, Bulloch, Candler, Chatham, Effingham, Evans and 6 more7 hr
Apr 28, 11:22 AM EDTMesoscale DiscussionSPCBulloch, Burke, Candler, Chatham, Effingham, Emanuel and 2 more53 min

Nearby

Mesoscale Discussions in Georgia, 2011Mesoscale Discussions in Florida, 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.