Alert archive / Florida / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 252, NWS Jacksonville, FL

September 21, 2007Putnam County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Sep 21, 2007, 1:51 AM EDT for Putnam County, Florida. It was in force for 39 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Sep 21, 2007, 1:51 AM EDT (05:51 UTC)
Expired: Sep 21, 2007, 2:30 AM EDT
In force: 39 min
Issued by: NWS Jacksonville, FL
Area: Counties, with a storm outline in the text

County Putnam County, FL

The radar

The Jacksonville radar (KJAX), 97 km from the middle of the area, began a volume at 05:53 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.

What was reported inside it

Time	Report	Where	Remark
Sep 21, 2:15 AM EDT	TSTM WND DMG	1 N Florahome, FL	CLAY ELECTRIC REPORTS A FEW LINES DOWN AND TREES DOWN ON POWERLINES IN THE FLORAHOME VICINITY.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Sep 20, 11:19 PM EDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Jacksonville, FL (KJAX), launched 00:00Z, 5.9 hours before the alert went out and 99 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: 2537 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 634 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.5

Open this sounding in Storm Lab

The text

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

000 
WUUS52 KJAX 210550
SVRJAX
FLC107-210630-
/O.NEW.KJAX.SV.W.0252.070921T0551Z-070921T0630Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE JACKSONVILLE FL
151 AM EDT FRI SEP 21 2007

THE NATIONAL WEATHER SERVICE IN JACKSONVILLE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTERN PUTNAM COUNTY IN NORTHEAST FLORIDA

* UNTIL 230 AM EDT

* AT 143 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 9 MILES
  SOUTH OF HOLLISTER...OR 10 MILES NORTH OF SALT SPRINGS...AND MOVING
  NORTH AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
   HOLLISTER BY 205 AM EDT...
   INTERLACHEN BY 210 AM EDT...
   FLORAHOME BY 225 AM EDT...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. IF A TORNADO
IS SPOTTED... ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

REPORT SEVERE WEATHER OR DAMAGE TO THE NEAREST LAW ENFORCEMENT AGENCY
OR YOUR COUNTY EMERGENCY MANAGEMENT.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 700 AM EDT FRIDAY MORNING FOR
NORTHEASTERN FLORIDA.

LAT...LON 2945 8169 2950 8184 2953 8185 2950 8204
      2972 8204 2974 8201 2976 8193 2977 8193
      2984 8170
TIME...MOT...LOC 0551Z 170DEG 20KT 2953 8181

$$

PETERSON

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 20, 8:12 PM EDT	Severe Thunderstorm Warning	JAX	Marion	48 min
Sep 20, 10:02 PM EDT	Tornado Warning	JAX	Marion	43 min
Sep 20, 10:45 PM EDT	Tornado Warning	JAX	Marion	45 min
Sep 20, 11:28 PM EDT	Severe Thunderstorm Warning	JAX	Marion	47 min
Sep 20, 11:51 PM EDT	Tornado Warning	JAX	Alachua	39 min
Sep 21, 12:14 AM EDT	Severe Thunderstorm Warning	JAX	Marion	46 min
Sep 21, 12:30 AM EDT	Severe Thunderstorm Warning	JAX	Alachua	45 min
Sep 21, 1:00 AM EDT	Severe Thunderstorm Warning	JAX	Marion, Putnam	45 min
Sep 21, 1:24 AM EDT	Severe Thunderstorm Warning	JAX	Alachua, Bradford	51 min

Nearby

Severe Thunderstorm Warnings in Florida, 2007 Every severe thunderstorm warning in 2007

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.