Alert archive / Georgia / Mesoscale Discussions in 2012

Mesoscale Discussion 874

May 22, 2012Nassau County, Florida; 19 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at May 22, 2012, 8:01 PM EDT for Nassau County, Florida; 19 counties in Georgia. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: May 22, 2012, 8:01 PM EDT (00:01 UTC)
Expired: May 22, 2012, 9:00 PM EDT
In force: 59 min
Issued by: the Storm Prediction Center

Counties Nassau County, FL, Atkinson County, GA, Baker County, GA, Berrien County, GA, Brantley County, GA, Brooks County, GA, Camden County, GA, Charlton County, GA, Clinch County, GA, Colquitt County, GA, Cook County, GA, Echols County, GA, Glynn County, GA, Lanier County, GA, Lowndes County, GA, Mitchell County, GA, Pierce County, GA, Thomas County, GA, Tift County, GA, Ware County, GA

The nearest sounding before it

Jacksonville, FL (KJAX), launched 00:00Z, 0.0 hours before the alert went out and 127 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 407 J/kg
Mixed-layer CIN: -87 J/kg
Mixed-layer LCL: 1926 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 77 m²/s²
0-3 km storm-relative helicity: 103 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

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

009 
ACUS11 KWNS 230001
SWOMCD
SPC MCD 230001 
GAZ000-FLZ000-230100-

MESOSCALE DISCUSSION 0874
NWS STORM PREDICTION CENTER NORMAN OK
0701 PM CDT TUE MAY 22 2012

AREAS AFFECTED...SRN GA...NRN FL

CONCERNING...SEVERE THUNDERSTORM WATCH 289...

VALID 230001Z - 230100Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 289
CONTINUES.

SUMMARY...SVR THREAT WITHIN WW 289 IS NOW PRIMARILY CONFINED TO
PORTIONS OF SRN GA...WHILE ADDITIONAL AREAS E OF WW 289 MAY SEE AN
ISOLATED SVR THREAT WITHIN THE NEXT 1-2 HRS. ISSUANCE OF A NEW WW IS
NOT EXPECTED BEYOND SCHEDULED EXPIRATION TIME OF 01Z.

DISCUSSION...ISOLATED TSTMS CONTINUE ALONG/NEAR A SLOW-MOVING COLD
FRONT...WHICH WAS POSITIONED 15 NE MAI TO 15 W VDI AS OF 23Z.
STRONGEST TSTMS NOW APPEAR TO BE ALONG ERN PORTIONS OF WW 289 MOVING
INTO PORTIONS OF SERN GA AND NRN FL. THREAT HERE IS EXPECTED TO
PERSIST FOR AT LEAST THE NEXT 1-2 HRS WITHIN FOCUSED ZONE OF ASCENT
ATTENDANT TO UPPER LOW OVER W-CNTRL GA. DIURNAL BOUNDARY LAYER
COOLING SHOULD REDUCE POTENTIAL INSTABILITY SOMEWHAT...BUT MODEL
FORECAST SOUNDINGS INDICATE MUCAPE VALUES BETWEEN 1000-1500 J/KG
WILL STILL EXIST THROUGH THE LATE EVENING. CONVECTION-ALLOWING MODEL
OUTPUT ALSO SUPPORTS PERSISTENCE OF TSTMS THROUGH 03Z BEFORE MOVING
OFFSHORE. REDUCTION IN INSTABILITY SHOULD LEAD TO A GENERAL
DOWNTREND IN TSTM INTENSITY...BUT ISOLATED DMGG WIND GUSTS/HAIL WILL
STILL BE POSSIBLE. GIVEN EXPECTED ISOLATED AND SHORT-LIVED NATURE OF
ANY SVR THREAT...A NEW WW IS NOT EXPECTED.

..ROGERS.. 05/23/2012

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

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

LAT...LON   30498130 30628338 30988453 31418464 31528399 31558274
            31558203 31388151 30498130

Nearby

Mesoscale Discussions in Georgia, 2012 Mesoscale Discussions in Florida, 2012 Every 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.