Alert archive / Florida / Tornado Warnings in 2017

Tornado Warning 77, NWS Jacksonville, FL

September 10, 2017Saint Johns County, Florida

NWS Jacksonville, FL issued this tornado warning at Sep 10, 2017, 4:39 PM EDT for Saint Johns County, Florida. It was in force for 24 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 10, 2017, 4:39 PM EDT (20:39 UTC)
Expired
Sep 10, 2017, 5:03 PM EDT
In force
24 min
Issued by
NWS Jacksonville, FL
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.0 in

County Saint Johns County, FL

The radar

The Jacksonville radar (KJAX), 80 km from the middle of the area, began a volume at 20:40 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 watch it was issued in

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

IssuedProductOfficeLasted
Sep 10, 12:02 PM EDTTornado WatchSPC13 hr

The nearest sounding before it

Jacksonville, FL (KJAX), launched 12:00Z, 8.7 hours before the alert went out and 82 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-pSkew-T log-p diagram, Jacksonville, FL at 12:00Z on 2017-09-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 396 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Jacksonville, FL at 12:00Z on 2017-09-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 226 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
396 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
476 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
226 m²/s²
0-3 km storm-relative helicity
297 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.9

Open this sounding in Storm Lab

The text

As transmitted.

197 
WFUS52 KJAX 102039
TORJAX
FLC109-102115-
/O.NEW.KJAX.TO.W.0077.170910T2039Z-170910T2115Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Jacksonville FL
439 PM EDT SUN SEP 10 2017

The National Weather Service in Jacksonville has issued a

* Tornado Warning for...
  Southeastern St. Johns County in northeastern Florida...

* Until 515 PM EDT
    
* At 439 PM EDT, a severe thunderstorm capable of producing a tornado
  was located near Saint Augustine Beach, or 8 miles east of Saint
  Augustine, moving west at 35 mph.

  HAZARD...Tornado. 

  SOURCE...Radar indicated rotation. 

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely. 

* This dangerous storm will be near...
  Saint Augustine Beach, Butler Beach and Crescent Beach around 450 
  PM EDT. 
  Saint Augustine, Saint Augustine South and Saint Augustine Shores 
  around 455 PM EDT. 

Other locations impacted by this tornadic thunderstorm include Spuds,
Anastasia, Dupont Center, Elkton and Bakersville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to an interior room on the lowest floor of a
sturdy building. Avoid windows. If you are outdoors, in a mobile
home, or in a vehicle, move to the closest substantial shelter and
protect yourself from flying debris.

&&

LAT...LON 2972 8153 2976 8153 2977 8154 2991 8156
      2994 8124 2976 8118
TIME...MOT...LOC 2039Z 083DEG 32KT 2986 8117 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

TW
1 follow-up statement
926 
WWUS52 KJAX 102103
SVSJAX

Severe Weather Statement
National Weather Service Jacksonville FL
503 PM EDT SUN SEP 10 2017

FLC109-102113-
/O.CAN.KJAX.TO.W.0077.000000T0000Z-170910T2115Z/
St. Johns FL-
503 PM EDT SUN SEP 10 2017

...THE TORNADO WARNING FOR SOUTHEASTERN ST. JOHNS COUNTY IS
CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore the warning has been cancelled.

A tornado watch remains in effect until midnight EDT for northeastern
Florida.

LAT...LON 2972 8153 2976 8153 2977 8154 2991 8156
      2994 8124 2976 8118
TIME...MOT...LOC 2101Z 083DEG 32KT 2983 8142 

$$

TW

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 9, 9:25 PM EDTRiver Flood WarningJAXClay5 days
Sep 9, 9:27 PM EDTRiver Flood WarningJAXBaker, Nassau16 days
Sep 9, 9:39 PM EDTRiver Flood WarningJAXAlachua, Columbia, Gilchrist32 days
Sep 9, 9:42 PM EDTRiver Flood WarningJAXClay5 days
Sep 10, 5:10 AM EDTSpecial Marine WarningJAX65 min
Sep 10, 6:18 AM EDTAreal Flood WarningJAXBaker, Bradford, Clay, Duval, Saint Johns6 hr
Sep 10, 8:14 AM EDTAreal Flood WarningJAXClay, Putnam3 hr
Sep 10, 9:11 AM EDTAreal Flood WarningJAXAlachua, Bradford, Clay, Columbia, Gilchrist, Union3 hr
Sep 10, 9:59 AM EDTRiver Flood WarningJAXColumbia, Hamilton, Suwannee3 days
Sep 10, 9:59 AM EDTRiver Flood WarningJAXHamilton, Suwannee5 days
Sep 10, 10:12 AM EDTAreal Flood WarningJAXAlachua, Flagler, Marion, Putnam3 hr
Sep 10, 11:57 AM EDTAreal Flood WarningJAXAlachua, Bradford, Clay, Flagler, Putnam, Saint Johns3 hr
Sep 10, 12:05 PM EDTSpecial Marine WarningJAX25 min
Sep 10, 12:09 PM EDTAreal Flood WarningJAXClay, Duval, Nassau, Saint Johns3 hr
Sep 10, 12:19 PM EDTTornado WarningJAXFlagler, Saint Johns22 min
Sep 10, 1:11 PM EDTAreal Flood WarningJAXNassau3 hr
Sep 10, 1:28 PM EDTTornado WarningJAXFlagler32 min
Sep 10, 3:09 PM EDTAreal Flood WarningJAXFlagler, Putnam3 hr
Sep 10, 4:11 PM EDTAreal Flood WarningJAXNassau3 hr
Sep 10, 4:39 PM EDTAreal Flood WarningJAXClay, Duval, Saint Johns3 hr
Sep 10, 4:58 PM EDTAreal Flood WarningJAXDuval, Nassau, Saint Johns3 hr
Sep 10, 5:21 PM EDTAreal Flood WarningJAXClay, Flagler, Putnam, Saint Johns3 hr
Sep 10, 5:43 PM EDTAreal Flood WarningJAXDuval, Nassau3 hr
Sep 10, 5:48 PM EDTAreal Flood WarningJAXFlagler, Putnam3 hr
Sep 10, 7:36 PM EDTTornado WarningJAXFlagler24 min
Sep 10, 7:42 PM EDTTornado WarningJAXSaint Johns33 min
Sep 10, 7:59 PM EDTAreal Flood WarningJAXNassau3 hr

Nearby

Tornado Warnings in Florida, 2017Every tornado warning in 2017Tornadoes in 2017

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.