Alert archive / Florida / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 270, NWS Jacksonville, FL
NWS Jacksonville, FL issued this severe thunderstorm warning at Jul 15, 1998, 5:51 PM EDT for Nassau County, Florida. It was in force for 64 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 15, 1998, 5:51 PM EDT (21:51 UTC)
- Expired
- Jul 15, 1998, 6:55 PM EDT
- In force
- 64 min
- Issued by
- NWS Jacksonville, FL
- Area
- Whole counties
County Nassau County, FL
The radar
The Jacksonville radar (KJAX), 16 km from the middle of the area, began a volume at 21:53 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, 9.9 hours before the alert went out and 14 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.
- Mixed-layer CAPE
- 283 J/kg
- Mixed-layer CIN
- -45 J/kg
- Mixed-layer LCL
- 665 m above ground
- 0-6 km bulk shear
- 7 kt
- 0-1 km storm-relative helicity
- -20 m²/s²
- 0-3 km storm-relative helicity
- 4 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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 15, 3:50 PM EDT, 2 hours 1 minute earlier.
Area forecast discussion, Jul 15, 3:50 PM EDT, 2 hours 1 minute before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 230 PM EDT WED JUL 15 1998 SFC LOW OVER S GA SLOWLY LIFTING NORTH FROM NEAR AYS...A BIT FASTER THAN PROGGED. NORTHWEST FLOW PUNCHING INTO NORTH SUWANNEE VALLEY SETTING UP A CONVERGENCE LINE FROM BIG BEND TO JAX ALONG THE STATE LINE WITH STRONG SOUTHWEST FLOW TO SOUTH AS EXPECTED. THIS WILL SET UP STRONG MOIST FLOW ACROSS THE NECK OF FL PENINSULA AND CONTINUE DESTABILIZING NE FL AND SE GA WHERE STRONG DIURNAL HEATING IN PLACE UNDER CLEAR SKY. WITH TEMPS NOW NEAR 90 OVER AREA CAPE IS IN VICINITY OF 2500 J/KG...WITH HIGH PRECIP WATER. ANTICIPATE MAJOR RAIN EVENT BREAKING OUT WITH WIDESPREAD 2 INCH AND SOME 4 PLUS TOTALS LIKELY. EVENT WILL CONTINUE INTO NIGHT. EXPECT INCREASED WINDS TO REMAIN AT OR ABOVE 15 KTS OVERNIGHT INTO FRIDAY. DO NOT EXPECT GRADIENT TO WEAKEN AS LOW IS ESSENTIALLY TROPICAL OVER LAND AND GAINING LATENT HEAT FROM PM RAINS. COASTAL GA FLOODING POSSIBLE. JAX TR 75/95 75/96 73 13795 GNV TR 72/92 74/95 74 13674 SSI TT 76/88 76/92 75 13995 WELSH
The office that day
Everything else NWS Jacksonville, FL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 15, 7:18 PM EDT | Flash Flood Warning | JAX | Suwannee | 2 hr |
Nearby
Severe Thunderstorm Warnings in Florida, 1998Every severe thunderstorm warning in 1998
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.