Alert archive / Florida / Mesoscale Discussions in 2004

Mesoscale Discussion 1981

August 12, 200415 counties in Florida; 5 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Aug 12, 2004, 7:02 PM EDT for 15 counties in Florida; 5 counties in Georgia. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Aug 12, 2004, 7:02 PM EDT (23:02 UTC)
Expired: Aug 12, 2004, 8:30 PM EDT
In force: 88 min
Issued by: the Storm Prediction Center

Counties Brevard County, FL, Clay County, FL, Duval County, FL, Flagler County, FL, Hardee County, FL, Indian River County, FL, Lake County, FL, Nassau County, FL, Orange County, FL, Osceola County, FL, Polk County, FL, Putnam County, FL, Saint Johns County, FL, Seminole County, FL, Volusia County, FL, Brantley County, GA, Camden County, GA, Glynn County, GA, McIntosh County, GA, Wayne County, GA

The radar

The Melbourne radar (KMLB), 126 km from the middle of the area, began a volume at 23:05 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

Cape Canaveral, FL (KXMR), launched 12:00Z, 11.0 hours before the alert went out and 97 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: 1605 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 743 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 24 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.

420 
ACUS11 KWNS 122303
SWOMCD
SPC MCD 122302 
FLZ000-GAZ000-130030-

MESOSCALE DISCUSSION 1981
NWS STORM PREDICTION CENTER NORMAN OK
0602 PM CDT THU AUG 12 2004

AREAS AFFECTED...ERN FL AND EXTREME SERN GA

CONCERNING...TORNADO WATCH 744...

VALID 122302Z - 130030Z

TORNADO WATCH 744 EXPIRES AT 0100 UTC AND WILL PROBABLY NOT BE
REISSUED.  

CENTER OF REMNANT BONNIE WAS MOVING ACROSS EXTREME SERN GA SOUTH OF
THE KSAV AREA WITH A SURFACE TROUGH EXTENDING SWD INTO CNTRL FL. 
WINDS TO THE WEST OF THE TROUGH HAVE VEERED AND THE TORNADO THREAT
HAS DIMINISHED.  TO THE EAST OF THE TROUGH...LOW LEVEL FLOW REMAINS
SLY...WITH THE STRONGEST 0-1KM STORM RELATIVE HELICITY FROM KJAX
NEWD TO KSAV.  POSSIBLE TORNADIC TSTM MOVING NEAR/SOUTH OF KSAV AREA
WILL LIKELY MOVE OFFSHORE SERN GA BY 0000 UTC...ENDING THE TORNADO
THREAT.  FARTHER S...IT IS POSSIBLE THAT INCREASING SUBSIDENCE AHEAD
OF HRCN CHARLEY IS SPREADING NWD OVER SRN PARTS OF THE TORNADO WATCH
AND LIMITING DEEP MOIST CONVECTION.  THE TORNADO THREAT WILL
INCREASE AGAIN ACROSS CNTRL/SRN FL LATER THIS EVENING/OVERNIGHT AS
HRCN CHARLEY APPROACHES FROM THE SOUTH.

..RACY.. 08/12/2004

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

ATTN...WFO...CHS...MLB...TBW...JAX...

27498183 31768205 31627947 27538026

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 12, 8:00 AM EDT	Mesoscale Discussion	SPC	Alachua, Baker, Bay, Bradford, Calhoun, Columbia and 18 more	3 hr
Aug 12, 8:50 AM EDT	Tornado Watch	SPC	Alachua, Baker, Bay, Bradford, Calhoun, Clay and 23 more	5 hr
Aug 12, 12:50 PM EDT	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Clay, Columbia, Dixie and 19 more	55 min
Aug 12, 1:50 PM EDT	Tornado Watch	SPC	Alachua, Baker, Bradford, Brevard, Citrus, Clay and 30 more	7 hr
Aug 12, 4:09 AM EDT	Mesoscale Discussion	SPC	Barrow, Bartow, Carroll, Cherokee, Clayton, Cobb and 14 more	3 hr
Aug 12, 10:02 AM EDT	Mesoscale Discussion	SPC	Bleckley, Bulloch, Burke, Candler, Columbia, Effingham and 13 more	88 min
Aug 12, 11:45 AM EDT	Tornado Watch	SPC	Bleckley, Bryan, Bulloch, Burke, Candler, Chatham and 25 more	6 hr
Aug 12, 4:06 PM EDT	Mesoscale Discussion	SPC	Bryan, Bulloch, Candler, Chatham, Effingham, Evans and 6 more	84 min

Nearby

Mesoscale Discussions in Florida, 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.