Alert archive / Florida / Mesoscale Discussions in 2004

Mesoscale Discussion 2159

September 4, 20047 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Sep 4, 2004, 7:16 AM EDT for 7 counties in Florida. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Sep 4, 2004, 7:16 AM EDT (11:16 UTC)
Expired: Sep 4, 2004, 8:45 AM EDT
In force: 89 min
Issued by: the Storm Prediction Center

Counties Brevard County, FL, Broward County, FL, Indian River County, FL, Martin County, FL, Okeechobee County, FL, Palm Beach County, FL, Saint Lucie County, FL

The radar

The Melbourne radar (KMLB), 89 km from the middle of the area, began a volume at 11:17 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

Miami, FL (KMFL), launched 00:00Z, 11.3 hours before the alert went out and 170 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: 219 J/kg
Mixed-layer CIN: -101 J/kg
Mixed-layer LCL: 836 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 64 m²/s²
0-3 km storm-relative helicity: 74 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

485 
ACUS11 KWNS 041119
SWOMCD
SPC MCD 041116 
FLZ000-041245-

MESOSCALE DISCUSSION 2159
NWS STORM PREDICTION CENTER NORMAN OK
0616 AM CDT SAT SEP 04 2004

AREAS AFFECTED...CNTRL/LOWER ERN FL PENINSULA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 041116Z - 041245Z

IN ADDITION TO EXCESSIVE RAINFALL...POTENTIAL FOR AN ISOLATED
TORNADO WILL EXIST WITH LANDFALLING CONVECTIVE BANDS.

LATEST MELBOURNE/MIAMI RADAR IMAGERY SHOWS A WELL-DEFINED RAINBAND
WITH EMBEDDED STRONGER CONVECTIVE ELEMENTS FROM BREVARD/OSCEOLA
COUNTIES SSWWD ACROSS ERN GLADES COUNTY. LOCAL VWPS INDICATE NNELY
WINDS INCREASINGLY SIGNIFICANTLY ATOP SHALLOW BOUNDARY-LAYER WITH
1KM SRH VALUES OF 150-250 M2/S2. THOUGH AN ISOLATED TORNADO REMAINS
POSSIBLE OVER THE NEXT 2-3 HOURS...PRIMARY FACTOR LIMITING SUPERCELL
POTENTIAL APPEARS TO BE THE WEAK INSTABILITY /I.E. MLCAPES AOB 200
J/KG/. POTENTIAL FOR A BRIEF TORNADO OR TWO IS EXPECTED TO INCREASE
THROUGH THE LATE MORNING AND AFTERNOON HOURS AS AIRMASS SLOWLY
DESTABILIZES...ESPECIALLY INVOF OF THE ATLANTIC COAST WITH ANY CELLS
MOVING ONSHORE.

ADDITIONALLY...INFLUX OF VERY MOIST AIRMASS CHARACTERIZED BY PW
VALUES OF 2.30-2.40 INCHES AND WARM CLOUD DEPTHS OF 5-5.5 KFT SHOULD
ENHANCE RAINFALL EFFICIENCY WITH LANDFALLING CONVECTIVE ELEMENTS
WITH HOURLY RATES APPROACHING 2-2.5 INCHES.

..MEAD.. 09/04/2004

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

ATTN...WFO...MFL...MLB...TBW...

27557985 26397986 26058042 26288096 27508126 28798080
28688011

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 4, 7:30 PM EDT	Mesoscale Discussion	SPC	Alachua, Brevard, Charlotte, Citrus, DeSoto, Flagler and 23 more	90 min
Sep 4, 7:55 PM EDT	Tornado Watch	SPC	Alachua, Brevard, Citrus, DeSoto, Dixie, Flagler and 25 more	12 hr

Nearby

Mesoscale Discussions in Florida, 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.