Alert archive / Georgia / Mesoscale Discussions in 2012
Mesoscale Discussion 1622
The Storm Prediction Center issued this mesoscale discussion at Jul 27, 2012, 12:54 PM CDT for 5 states. It was in force for 66 min.
The area
The outline as issued.
The facts
- Issued
- Jul 27, 2012, 12:54 PM CDT (17:54 UTC)
- Expired
- Jul 27, 2012, 2:00 PM CDT
- In force
- 66 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 50 counties
Cherokee County, AL, DeKalb County, AL, Etowah County, AL, Marshall County, AL, Banks County, GA, Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Dade County, GA, Dawson County, GA, Fannin County, GA, Floyd County, GA, Forsyth County, GA, Gilmer County, GA, Gordon County, GA, Habersham County, GA, Hall County, GA, Lumpkin County, GA, Murray County, GA, Pickens County, GA, Polk County, GA, Rabun County, GA, Stephens County, GA, Towns County, GA, Union County, GA, Walker County, GA, White County, GA, Whitfield County, GA, Avery County, NC, Buncombe County, NC, Burke County, NC, Caldwell County, NC, Cherokee County, NC, Clay County, NC, Graham County, NC, Haywood County, NC, Henderson County, NC, Jackson County, NC, Macon County, NC, McDowell County, NC, Mitchell County, NC, Polk County, NC, Rutherford County, NC, Transylvania County, NC, Yancey County, NC, Greenville County, SC, Oconee County, SC, Pickens County, SC, Polk County, TN
The radar
The Greer radar (KGSP), 129 km from the middle of the area, began a volume at 17:54 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, 5.9 hours before the alert went out and 192 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
- 2176 J/kg
- Mixed-layer CIN
- -16 J/kg
- Mixed-layer LCL
- 726 m above ground
- 0-6 km bulk shear
- 3 kt
- 0-1 km storm-relative helicity
- -58 m²/s²
- 0-3 km storm-relative helicity
- -22 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
543
ACUS11 KWNS 271755
SWOMCD
SPC MCD 271754
NCZ000-SCZ000-GAZ000-TNZ000-ALZ000-271900-
MESOSCALE DISCUSSION 1622
NWS STORM PREDICTION CENTER NORMAN OK
1254 PM CDT FRI JUL 27 2012
AREAS AFFECTED...WRN NC...NWRN SC...FAR SERN TN...NRN GA...NERN AL
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 271754Z - 271900Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...AN ISOLATED DMGG WIND THREAT IS EXPECTED TO DEVELOP THIS
AFTERNOON. THE NEED FOR A WW IS UNCERTAIN...BUT CONVECTIVE TRENDS
WILL BE MONITORED.
DISCUSSION...VISIBLE SATELLITE LOOP SHOWS A GROWING TOWERING CU/CB
FIELD PRIMARILY ANCHORED OVER THE HIGHER TERRAIN...ALONG SWRN
EXTENSION OF A MID-ATLANTIC SFC TROUGH...FROM WRN NC WSWD INTO NRN
AL. ADDITIONAL TSTMS WERE FORMING FARTHER S ACROSS PORTIONS OF
N-CNTRL GA/AL ALONG WEAKLY CONFLUENT WIND SHIFTS. THIS ACTIVITY IS
OCCURRING WITHIN A HOT AND VERY MOIST BOUNDARY LAYER...WITH
TEMPERATURES CURRENTLY IN THE LOWER 90S AND PW NEAR 2 INCHES /PER
REGIONAL 12Z SOUNDINGS/. WITH FURTHER HEATING...TSTMS SHOULD
CONTINUE TO EXPAND IN AREAL COVERAGE...EVENTUALLY CONSOLIDATING INTO
LOOSELY ORGANIZED CLUSTERS...BUT ORGANIZATION WILL BE LIMITED BY
WEAK/UNIDIRECTIONAL DEEP-LAYER FLOW. WEAK MIDLEVEL LAPSE RATES WILL
LIMIT POTENTIAL INSTABILITY SOMEWHAT...BUT GIVEN THE DEGREE OF
TROPOSPHERIC MOISTURE AND WARM THERMAL PROFILES...A THREAT FOR
ISOLATED WET DOWNBURSTS WILL EXIST.
..ROGERS/CORFIDI.. 07/27/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...RNK...GSP...MRX...FFC...BMX...HUN...
LAT...LON 35778110 35048210 34438320 34128436 33908522 33778562
33818623 34208647 34678611 35478356 35898265 36168182
36168131 35778110SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 27, 12:08 PM CDT | Mesoscale Discussion | SPC | Rockingham, Stokes, Surry | 67 min |
| Jul 27, 12:54 PM CDT | Severe Thunderstorm Watch | SPC | Alamance, Alleghany, Anson, Ashe, Bertie, Camden and 41 more | 8 hr |
| Jul 27, 3:52 PM CDT | Mesoscale Discussion | SPC | Alamance, Alleghany, Caswell, Forsyth, Granville, Guilford and 7 more | 53 min |
| Jul 27, 6:50 PM CDT | Mesoscale Discussion | SPC | Bertie, Camden, Chatham, Chowan, Cumberland, Currituck and 27 more | 85 min |
Nearby
Mesoscale Discussions in Georgia, 2012Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in Alabama, 2012Every mesoscale discussion in 2012
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.