Alert archive / Florida / Mesoscale Discussions in 2003

Mesoscale Discussion 1

December 31, 20028 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Dec 31, 2002, 10:39 PM EST for 8 counties in Florida. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Dec 31, 2002, 10:39 PM EST (03:39 UTC)
Expired: Jan 1, 2003, 12:45 AM EST
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Charlotte County, FL, Collier County, FL, DeSoto County, FL, Glades County, FL, Hendry County, FL, Highlands County, FL, Lee County, FL, Okeechobee County, FL

The radar

The Tampa radar (KTBW), 136 km from the middle of the area, began a volume at 03:40 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

Tampa Bay, FL (KTBW), launched 00:00Z, 3.7 hours before the alert went out and 136 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: 371 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 991 m above ground
0-6 km bulk shear: 75 kt
0-1 km storm-relative helicity: 320 m²/s²
0-3 km storm-relative helicity: 442 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 3.8

Open this sounding in Storm Lab

The text

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

889 
ACUS11 KWNS 010340
SWOMCD
SPC MCD 010339 
FLZ000-010545-

MESOSCALE DISCUSSION 0001
NWS STORM PREDICTION CENTER NORMAN OK
0939 PM CST TUE DEC 31 2002

AREAS AFFECTED...S FL

CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 010339Z - 010545Z

LINE OF STRONG/POSSIBLY SEVERE STORMS OVER THE SERN GULF ARE
MOVING RAPIDLY EWD AND MAY POSE A THREAT TO PORTIONS OF S F.
HOWEVER...ENVIRONMENT SHOULD BECOME LESS FAVORABLE FOR AN
ORGANIZED SEVERE THREAT INLAND LATER TONIGHT. THUS WW IS NOT
ANTICIPATED AT THIS TIME.


LINE OF STORMS WITH EMBEDDED BOWS AND SUPERCELLS IS MOVING
RAPIDLY ENEWD AT 40 TO 45 KT. LINE APPEARS WELL ORGANIZED AND IS
OVER RELATIVELY WARM GULF WATERS WHICH IS LIKELY ENHANCING
INSTABILITY. ALSO...STORMS APPEAR TO BE EMBEDDED WITHIN A ZONE OF
FAVORABLE UPPER DIVERGENCE/LOW LEVEL CONFLUENCE ALONG WARM
CONVEYOR BELT WELL ESE OF THE UPPER LOW CENTER. MAIN UNCERTAINTY
IS WHETHER OR NOT STORMS WILL MAINTAIN THEIR INTENSITY LATER THIS
EVENING AS THEY BEGIN TO MOVE INLAND WHERE INSTABILITY IS MORE
MARGINAL. THOUGH ENVIRONMENT REMAINS FAVORABLE FOR A SEVERE
THREAT JUST OFFSHORE...LARGE SCALE FORCING FOR ASCENT AND
VERTICAL SHEAR SHOULD TEND TO WEAKEN LATER THIS EVENING WHICH MAY
FURTHER LIMIT ABILITY FOR THE LINE TO MAINTAIN ITS INTENSITY AS
IT MOVES INLAND.


..DIAL.. 01/01/2003

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

26798229 27388175 27648054 26208066 25858149

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 1, 2:27 AM EST	Mesoscale Discussion	SPC	Glades, Hendry, Martin, Saint Lucie	2 hr

Nearby

Mesoscale Discussions in Florida, 2003 Every mesoscale discussion in 2003

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.