Alert archive / Florida / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 108, NWS Jacksonville, FL

July 20, 2002Marion County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Jul 20, 2002, 6:38 PM EDT for Marion County, Florida. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 20, 2002, 6:38 PM EDT (22:38 UTC)
Expired: Jul 20, 2002, 7:15 PM EDT
In force: 37 min
Issued by: NWS Jacksonville, FL
Area: Whole counties

County Marion County, FL

The radar

The Jacksonville radar (KJAX), 146 km from the middle of the area, began a volume at 22:39 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

Jacksonville, FL (KJAX), launched 12:00Z, 10.6 hours before the alert went out and 148 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: 2866 J/kg
Mixed-layer CIN: -87 J/kg
Mixed-layer LCL: 980 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 30 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Jacksonville, FL wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 20, 2:18 PM EDT, 4 hours 20 minutes earlier.

Area forecast discussion, Jul 20, 2:18 PM EDT, 4 hours 20 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
218 PM EDT SAT JUL 20 2002

CURRENTLY...SURFACE TROUGH FROM THE CAROLINAS TO ACROSS SOUTHEAST
GEORGIA AND NORTHEAST FLORIDA. SHORT WAVE TROUGH DROPPING SOUTHEAST
ACROSS CENTRAL GA. THUNDERSTORMS RAPIDLY ERUPTING ALONG I-10 IN NORTH
FLORIDA.

MODELS/ZFP...UNMODIFIED MORNING SOUNDINGS ALREADY SHOWED CAPE OF
4100+J AND LIFTED INDEX -8 WITH CAP OF 3 DEGREES. AFTER CAP IS BROKEN
SHOULD SEE A ROUND OF NUMEROUS THUNDERSTORMS THE REMAINDER OF THE
AFTERNOON. MAIN CONCERNS WILL BE THE FREQUENT CLOUD TO GROUND
LIGHTNING (FROM HIGH CAPE AND PW) AND POSSIBLE PULSE SEVERE STORMS.
SURFACE TROUGH CONTINUES OVER THE REGION WITH SHORT WAVE DROPPING
SOUTHEAST THRU SUNDAY...AND CLOSING OFF ACROSS GEORGIA AND ALABAMA.
MODELS IN GOOD AGREEMENT THAT THERE WILL BE MORE THAN SUFFICIENT
MOISTURE AND LIFT TO SEE NUMEROUS MAINLY AFTERNOON THUNDERSTORMS AT
LEAST FOR THE NEXT SEVERAL DAYS. WITH MEAN 1000-500 MB WIND FLOW
GENERALLY WEST OR SOUTHWEST...WILL SEE ACTIVITY FIRST FORM NEAR GULF
COAST AND SPREAD EAST...WITH MOST OF THE ACTIVITY NEAR EAST COAST IN
THE LATE AFTERNOON AND INTO THE EVE. HEAT INDICES ARE RUNNING 105 TO
110 DEGREES TODAY AND WILL SEE AT LEAST 105 SUNDAY. WILL HEADLINE
THIS.

PRELIM
AMG TT 075/093 072/094 074 08464
SSI TT 078/090 077/092 076 08464
JAX TT 076/093 073/093 075 08464
SGJ TT 077/090 075/093 077 08464
GNV TT 074/093 073/093 074 08363
OCF TT 074/092 074/093 074 08353=

.JAX...
.GA...NONE.
.FL...NONE.

PP

In the hours before

Local storm report, Jul 20, 5:45 PM EDT, 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JACKSONVILLE, FL
545 PM EDT SAT JUL 20 2002

TIME(EDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0325 PM    JACKSONVILLE              FL   WIND DAMAGE
07/20/02   DUVAL                          TREES AND POWERLINES DOWN
                                          NEAR ATLANTIC AND SOUTHSIDE

0255 PM    LAKE CITY                 FL   WIND DAMAGE
07/20/02   COLUMBIA                       TREES AND POWERLINES DOWN

0400 PM    1NE   KEYSTONE HEIGHTS    FL   WIND DAMAGE
07/20/02   CLAY                           BARN DESTROYED. ROOF BLOWN
                                          OFF 2 SHEDS

PP

The office that day

Everything else NWS Jacksonville, FL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 20, 2:13 PM EDT	Severe Thunderstorm Warning	JAX	Columbia	47 min
Jul 20, 2:30 PM EDT	Severe Thunderstorm Warning	JAX	Baker	45 min
Jul 20, 3:14 PM EDT	Severe Thunderstorm Warning	JAX	Clay	46 min
Jul 20, 3:26 PM EDT	Severe Thunderstorm Warning	JAX	Duval	49 min
Jul 20, 3:43 PM EDT	Special Marine Warning	JAX		2 hr
Jul 20, 3:50 PM EDT	Severe Thunderstorm Warning	JAX	Bradford	40 min
Jul 20, 4:19 PM EDT	Severe Thunderstorm Warning	JAX	Saint Johns	41 min
Jul 20, 4:26 PM EDT	Severe Thunderstorm Warning	JAX	Alachua	49 min
Jul 20, 4:46 PM EDT	Special Marine Warning	JAX		89 min
Jul 20, 4:46 PM EDT	Special Marine Warning	JAX		89 min
Jul 20, 5:14 PM EDT	Severe Thunderstorm Warning	JAX	Alachua	46 min
Jul 20, 5:54 PM EDT	Severe Thunderstorm Warning	JAX	Marion	36 min
Jul 20, 6:18 PM EDT	Special Marine Warning	JAX		102 min
Jul 20, 6:31 PM EDT	Severe Thunderstorm Warning	JAX	Flagler	29 min
Jul 20, 3:07 PM EDT	Severe Thunderstorm Warning	JAX	Charlton	38 min
Jul 20, 3:58 PM EDT	Severe Thunderstorm Warning	JAX	Camden	47 min
Jul 20, 5:20 PM EDT	Severe Thunderstorm Warning	JAX	Brantley	40 min
Jul 20, 5:49 PM EDT	Severe Thunderstorm Warning	JAX	Glynn	41 min

Nearby

Severe Thunderstorm Warnings in Florida, 2002 Every severe thunderstorm warning in 2002

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.