Alert archive / South Carolina / Mesoscale Discussions in 2004

Mesoscale Discussion 337

April 12, 2004Chatham County, Effingham County, Screven County, Georgia; 14 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2004, 2:18 AM EDT for Chatham County, Effingham County, Screven County, Georgia; 14 counties in South Carolina. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Apr 12, 2004, 2:18 AM EDT (06:18 UTC)
Expired: Apr 12, 2004, 3:45 AM EDT
In force: 87 min
Issued by: the Storm Prediction Center

Counties Chatham County, GA, Effingham County, GA, Screven County, GA, Allendale County, SC, Bamberg County, SC, Beaufort County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Dorchester County, SC, Georgetown County, SC, Hampton County, SC, Jasper County, SC, Orangeburg County, SC, Williamsburg County, SC

The radar

The Charleston,SC radar (KCLX), 63 km from the middle of the area, began a volume at 06:19 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

Charleston AFB, SC (KCHS), launched 00:00Z, 6.3 hours before the alert went out and 43 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: 19 J/kg
Mixed-layer CIN: -177 J/kg
Mixed-layer LCL: 1655 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 36 m²/s²
0-3 km storm-relative helicity: 42 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.

026 
ACUS11 KWNS 120618
SWOMCD
SPC MCD 120618 
SCZ000-GAZ000-120745-

MESOSCALE DISCUSSION 0337
NWS STORM PREDICTION CENTER NORMAN OK
0118 AM CDT MON APR 12 2004

AREAS AFFECTED...MOUTH OF SAVANNAH RIVER NWD ACROSS ERN SC

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 120618Z - 120745Z

POTENTIAL FOR AN ISOLATED TORNADO APPEARS TO BE INCREASING ACROSS
REGION. ALTHOUGH A WW IS NOT ANTICIPATED...CONVECTIVE TRENDS WILL BE
MONITORED.

TSTMS HAVE INCREASED IN COVERAGE AND INTENSITY OVER THE PAST HOUR OR
SO ALONG A LINE FROM 15S OF SAV NWD TO AROUND CAE. LATEST
MESOANALYSIS SUGGESTS THAT ENHANCED LOW-LEVEL CONVERGENCE INVOF OF
MESOLOW NEAR SAV NWD ALONG ATTENDANT WARM/STATIONARY FRONT IS
FOCUSING THIS ACTIVITY. MOIST LOW-LEVEL AIRMASS CURRENTLY PRESENT
ALONG AND E OF THIS BOUNDARY IS CONTRIBUTING TO A MODERATELY
UNSTABLE AIRMASS EARLY THIS MORNING WITH MLCAPES OF 1000-1500 J/KG.
WHILE CURRENT WIND PROFILE OBSERVED ON CHS VWP IS NOT PARTICULARLY
CONDUCIVE TO MID-LEVEL UPDRAFT ROTATION...LOW-LEVEL SHEAR IS
EXPECTED TO INCREASE OVER THE NEXT FEW HOURS OWING TO BACKING OF
NEAR SURFACE WINDS AHEAD OF SURFACE LOW AND STRENGTHENING OF SSELY
LLJ. CONVECTIVE MODE HAS QUICKLY TRANSITIONED INTO LINEAR ALONG
FRONT...HOWEVER AN ISOLATED TORNADO WILL BE POSSIBLE WITH ANY
DISCRETE STORMS THAT CAN BECOME ESTABLISHED.

..MEAD.. 04/12/2004

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

ATTN...WFO...ILM...CHS...CAE...

31948136 32728175 33378137 33808074 33997976 33887917
33257882 32667946 31848083

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 12, 1:52 PM EDT	Mesoscale Discussion	SPC	Bryan, Bulloch, Burke, Candler, Chatham, Effingham and 7 more	113 min
Apr 12, 2:25 PM EDT	Tornado Watch	SPC	Baldwin, Bleckley, Burke, Columbia, Emanuel, Glascock and 19 more	6 hr
Apr 12, 2:33 PM EDT	Mesoscale Discussion	SPC	Calhoun, Chattahoochee, Clay, Decatur, Early, Miller and 5 more	117 min
Apr 12, 3:10 PM EDT	Severe Thunderstorm Watch	SPC	Baker, Banks, Barrow, Bartow, Bibb, Butts and 58 more	5 hr
Apr 12, 4:44 PM EDT	Mesoscale Discussion	SPC	Baldwin, Bleckley, Burke, Columbia, Dodge, Emanuel and 19 more	91 min
Apr 12, 7:31 PM EDT	Mesoscale Discussion	SPC	Baker, Butts, Calhoun, Chattahoochee, Clay, Coweta and 21 more	59 min
Apr 12, 7:50 PM EDT	Severe Thunderstorm Watch	SPC	Baker, Baldwin, Ben Hill, Berrien, Bibb, Bleckley and 67 more	5 hr

Nearby

Mesoscale Discussions in South Carolina, 2004 Mesoscale Discussions in Georgia, 2004 Every mesoscale discussion in 2004

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.