Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 449

April 16, 20115 counties in Alabama; 10 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 16, 2011, 1:43 AM CDT for 5 counties in Alabama; 10 counties in Georgia. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued
Apr 16, 2011, 1:43 AM CDT (06:43 UTC)
Expired
Apr 16, 2011, 3:15 AM CDT
In force
92 min
Issued by
the Storm Prediction Center

Counties Coffee County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Baker County, GA, Calhoun County, GA, Clay County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Miller County, GA, Mitchell County, GA, Randolph County, GA, Seminole County, GA

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 00:00Z, 6.7 hours before the alert went out and 128 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 2011-04-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2011-04-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 75 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1577 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
78 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.

655 
ACUS11 KWNS 160643
SWOMCD
SPC MCD 160643 
GAZ000-FLZ000-ALZ000-160815-

MESOSCALE DISCUSSION 0449
NWS STORM PREDICTION CENTER NORMAN OK
0143 AM CDT SAT APR 16 2011

AREAS AFFECTED...SERN AL INTO SRN GA...AND ADJACENT PORTIONS OF THE
FL PANHANDLE/NRN FL

CONCERNING...TORNADO WATCH 146...

VALID 160643Z - 160815Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 146 CONTINUES.

A NEW WW WILL LIKELY BE NEEDED PRIOR TO 08Z EXPIRATION OF WW 146.

WITH ANOTHER SIGNIFICANT SHORT WAVE IMPULSE STILL IN THE PROCESS OF
PIVOTING AROUND THE SOUTHERN PERIPHERY OF THE LARGE CLOSED LOW OVER
THE MIDDLE MISSISSIPPI VALLEY...A SURFACE COLD FRONT...AND A
CONFLUENCE ZONE JUST AHEAD OF IT...WILL ONLY SLOWLY ADVANCE EASTWARD
THROUGH NORTHWEST GEORGIA/EASTERN ALABAMA AND THE WESTERN FLORIDA
PANHANDLE TONIGHT.  IN ADVANCE OF THE PRE-FRONTAL CONFLUENCE
ZONE...A NARROW TONGUE OF BETTER MOISTURE RETURN OFF THE GULF OF
MEXICO /CHARACTERIZED BY MID 60S SURFACE DEW POINTS/ CONTINUES TO
SUPPORT WEAK TO MODERATE BOUNDARY LAYER INSTABILITY...WITH CAPE ON
THE ORDER OF 500-1000 J/KG AS FAR NORTH AS SOUTHEASTERN ALABAMA AND
SOUTHWESTERN GEORGIA.  COUPLED WITH FAVORABLE LARGE-SCALE
ASCENT...THIS SEEMS LIKELY TO MAINTAIN DISCRETE ONGOING CONVECTIVE
DEVELOPMENT NOW APPROACHING THE DOTHAN AL AREA...WHICH PROBABLY WILL
SPREAD INTO SOUTHWEST GEORGIA ...NEAR AND SOUTHWEST OF
ALBANY...THROUGH 08-10Z.  ALTHOUGH STRONGER LOW-LEVEL FLOW FIELDS
MAY CONTINUE TO SHIFT NORTHEAST OF THE REGION...TO THE LEE OF THE
SOUTHERN APPALACHIANS THROUGH THE REMAINDER OF THE
NIGHT...HODOGRAPHS CLOSER TO COASTAL AREAS STILL SHOULD REMAIN
FAVORABLE FOR SUPERCELLS CAPABLE OF PRODUCING TORNADOES.

..KERR.. 04/16/2011

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

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

LAT...LON   31548591 31758527 31788471 31708418 31368396 30938423
            30828482 30868537 30908584 31218613 31548591

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 15, 7:16 PM CDTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Blount, Bullock, Butler and 46 more59 min
Apr 15, 7:48 PM CDTTornado WatchSPCAutauga, Baldwin, Barbour, Bibb, Bullock, Butler and 34 more6 hr
Apr 15, 10:41 PM CDTMesoscale DiscussionSPCAutauga, Baldwin, Barbour, Bullock, Butler, Chambers and 28 more94 min
Apr 16, 2:05 AM CDTTornado WatchSPCBarbour, Bullock, Coffee, Covington, Dale, Geneva and 5 more7 hr
Apr 15, 7:52 PM CDTMesoscale DiscussionSPCBaldwin, Barrow, Bibb, Bleckley, Butts, Clarke and 40 more53 min
Apr 15, 8:12 PM CDTTornado WatchSPCBaldwin, Banks, Barrow, Bibb, Bleckley, Butts and 69 more9 hr
Apr 16, 4:09 AM CDTMesoscale DiscussionSPCClarke, Columbia, Elbert, Franklin, Glascock, Greene and 12 more96 min
Apr 16, 4:57 AM CDTTornado WatchSPCBaldwin, Bibb, Bleckley, Bulloch, Burke, Butts and 56 more8 hr
Apr 16, 6:57 AM CDTMesoscale DiscussionSPCAtkinson, Bacon, Brantley, Camden, Charlton, Clinch and 10 more63 min
Apr 16, 9:39 AM CDTMesoscale DiscussionSPCBryan, Bulloch, Burke, Candler, Chatham, Effingham and 12 more2 hr

Nearby

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