Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 653

April 28, 20114 counties in Alabama; Holmes County, Florida; 8 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2011, 1:22 AM CDT for 4 counties in Alabama; Holmes County, Florida; 8 counties in Georgia. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
Apr 28, 2011, 1:22 AM CDT (06:22 UTC)
Expired
Apr 28, 2011, 2:45 AM CDT
In force
83 min
Issued by
the Storm Prediction Center

Counties Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Holmes County, FL, Baker County, GA, Calhoun County, GA, Clay County, GA, Early County, GA, Miller County, GA, Quitman County, GA, Randolph County, GA, Seminole County, GA

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 00:00Z, 6.4 hours before the alert went out and 142 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, Tallahassee Rgnl, FL at 00:00Z on 2011-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3101 joules per kilogram.LCLEL10008507005003002001001 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, Tallahassee Rgnl, FL at 00:00Z on 2011-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 80 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
3101 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
607 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
80 m²/s²
0-3 km storm-relative helicity
161 m²/s²
Significant tornado parameter
1.9
Supercell composite
13.8

Open this sounding in Storm Lab

The text

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

824 
ACUS11 KWNS 280623
SWOMCD
SPC MCD 280622
GAZ000-FLZ000-ALZ000-280745-

MESOSCALE DISCUSSION 0653
NWS STORM PREDICTION CENTER NORMAN OK
0122 AM CDT THU APR 28 2011

AREAS AFFECTED...EXTREME SERN AL...WRN FL PANHANDLE AND SWRN GA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 280622Z - 280745Z

TRENDS ARE BEING MONITORED FOR A POSSIBLE WW FROM EXTREME SERN
AL...SWRN GA INTO THE WRN FL PANHANDLE.

STORMS ARE DEVELOPING ALONG A PRE-FRONTAL CONFLUENCE BAND FROM THE
WRN FL PANHANDLE INTO SERN AL. ACTIVITY MAY EVENTUALLY SPREAD INTO
SWRN GA. ATMOSPHERE REMAINS MODERATELY UNSTABLE EAST OF DEVELOPING
STORMS WITH 40 KT EFFECTIVE SHEAR. HOWEVER...0-2 KM HODOGRAPHS ARE
RELATIVELY STRAIGHT WITH MODEST STORM RELATIVE HELICITY. TENDENCY
WILL BE FOR LOW LEVEL FLOW TO VEER AND WEAKEN WITH TIME AS PRIMARY
LLJ LIFTS NWD THROUGH THE MID ATLANTIC REGION IN RESPONSE TO VORT
MAX EJECTING THROUGH THE OH VALLEY. THIS COULD SERVE AS A LIMITING
FACTOR FOR A SUSTAINED TORNADO THREAT. NEVERTHELESS...AT LEAST A
MODEST THREAT WILL EXIST FOR STRONG WIND GUSTS AND AN ISOLATED
TORNADO OR TWO WITHIN THE NEXT COUPLE HOURS.

..DIAL.. 04/28/2011

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

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

LAT...LON   30768630 31438596 31888498 31638434 30958459 30568610
            30768630

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 27, 7:55 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Butler, Calhoun, Cherokee and 27 more65 min
Apr 27, 9:20 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Butler, Calhoun, Cherokee and 29 more25 min
Apr 27, 9:42 PM CDTTornado WatchSPCAutauga, Bibb, Butler, Calhoun, Cherokee, Chilton and 19 more4 hr
Apr 27, 11:09 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Chambers, Clay, Cleburne, Elmore and 7 more36 min
Apr 28, 8:47 AM CDTSevere Thunderstorm WatchSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 13 more9 hr
Apr 28, 11:19 AM CDTMesoscale DiscussionSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 9 more56 min
Apr 28, 2:34 PM CDTMesoscale DiscussionSPCBrevard, Broward, Charlotte, Collier, DeSoto, Glades and 25 more56 min
Apr 27, 11:56 PM CDTTornado WatchSPCBaldwin, Banks, Barrow, Bibb, Bleckley, Burke and 80 more4 hr
Apr 28, 2:30 AM CDTMesoscale DiscussionSPCBaldwin, Bibb, Bleckley, Burke, Chattahoochee, Columbia and 30 more90 min
Apr 28, 3:30 AM CDTTornado WatchSPCBaldwin, Bibb, Bleckley, Bulloch, Burke, Candler and 37 more10 hr
Apr 28, 7:05 AM CDTMesoscale DiscussionSPCBurke, Candler, Dodge, Emanuel, Jefferson, Jenkins and 5 more85 min
Apr 28, 7:48 AM CDTTornado WatchSPCBryan, Bulloch, Candler, Chatham, Effingham, Evans and 6 more7 hr
Apr 28, 10:22 AM CDTMesoscale DiscussionSPCBulloch, Burke, Candler, Chatham, Effingham, Emanuel and 2 more53 min

Nearby

Mesoscale Discussions in Georgia, 2011Mesoscale Discussions in Alabama, 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.