Alert archive / Georgia / Mesoscale Discussions in 2017

Mesoscale Discussion 151

February 7, 201729 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Feb 7, 2017, 5:25 PM EST for 29 counties in Georgia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Feb 7, 2017, 5:25 PM EST (22:25 UTC)
Expired
Feb 7, 2017, 7:30 PM EST
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 29 counties

Baldwin County, GA, Bibb County, GA, Bleckley County, GA, Butts County, GA, Crawford County, GA, Dodge County, GA, Dooly County, GA, Emanuel County, GA, Glascock County, GA, Hancock County, GA, Houston County, GA, Jasper County, GA, Jefferson County, GA, Johnson County, GA, Jones County, GA, Lamar County, GA, Laurens County, GA, Macon County, GA, Monroe County, GA, Peach County, GA, Pulaski County, GA, Putnam County, GA, Taliaferro County, GA, Treutlen County, GA, Twiggs County, GA, Warren County, GA, Washington County, GA, Wheeler County, GA, Wilkinson County, GA

The radar

The Robins AFB radar (KJGX), 11 km from the middle of the area, began a volume at 22:29 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

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 10.4 hours before the alert went out and 130 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, Peachtre/Fal Fld, GA at 12:00Z on 2017-02-07Temperature 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, Peachtre/Fal Fld, GA at 12:00Z on 2017-02-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 142 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1498 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
142 m²/s²
0-3 km storm-relative helicity
172 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

766 
ACUS11 KWNS 072226
SWOMCD
SPC MCD 072225 
GAZ000-080030-

Mesoscale Discussion 0151
NWS Storm Prediction Center Norman OK
0425 PM CST Tue Feb 07 2017

Areas affected...Portions of GA

Concerning...Severe potential...Watch unlikely 

Valid 072225Z - 080030Z

Probability of Watch Issuance...20 percent

SUMMARY...Convection spreading across portions of GA into the early
evening hours could produce locally damaging wind gusts. Watch
issuance is not anticipated.

DISCUSSION...Loosely organized clusters of convection will continue
spreading east-northeastward across portions of GA during the next
few hours. While convective inflow should remain marginally
unstable, with ample cloud coverage stunting surface heating and
dewpoints only holding in the middle 50s, buoyancy/vertical shear
will be sufficient for a risk for locally intense convection to
continue spreading downstream. This activity would be enhanced by
local storm-scale circulations/MCVs noted in recent radar data. With
around 35 kt of flow in the 1-2-km above-ground layer per JGX VAD
wind profile, convective momentum transport could support locally
damaging wind gusts -- aided by sub-cloud evaporative
cooling/downdraft enhancements in the only modestly moist
environment. Weak instability, and veered flow ahead of the
convection, will limit the overall severe risk.

..Cohen/Hart.. 02/07/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...CHS...CAE...FFC...

LAT...LON   32128402 32828427 33308413 33648294 33338230 32778209
            32068268 32128402

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 7, 3:44 PM ESTMesoscale DiscussionSPCBaker, Calhoun, Clay, Colquitt, Decatur, Dougherty and 7 more91 min
Feb 7, 5:33 PM ESTSevere Thunderstorm WatchSPCBaker, Ben Hill, Berrien, Brooks, Calhoun, Colquitt and 17 more4 hr
Feb 7, 6:24 PM ESTMesoscale DiscussionSPCBaker, Brooks, Colquitt, Cook, Decatur, Grady and 6 more96 min
Feb 7, 6:58 PM ESTMesoscale DiscussionSPCBrantley, Camden, Charlton, Glynn, Pierce, Ware and 1 more3 hr

Nearby

Mesoscale Discussions in Georgia, 2017Every mesoscale discussion in 2017

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.