Alert archive / Florida / Tornado Warnings in 2017

Tornado Warning 3, NWS Key West, FL

September 9, 2017Monroe County, Florida

NWS Key West, FL issued this tornado warning at Sep 9, 2017, 7:07 PM EDT for Monroe County, Florida. It was in force for 23 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 9, 2017, 7:07 PM EDT (23:07 UTC)
Expired: Sep 9, 2017, 7:30 PM EDT
In force: 23 min
Issued by: NWS Key West, FL
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.0 in

County Monroe County, FL

The radar

The Key West radar (KBYX), 20 km from the middle of the area, began a volume at 23:09 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.

Issued	Product	Office	Lasted
Sep 9, 12:09 PM EDT	Tornado Watch	SPC	12 hr

The nearest sounding before it

Key West, FL (KEYW), launched 12:00Z, 11.1 hours before the alert went out and 24 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: 429 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 1024 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 41 m²/s²
0-3 km storm-relative helicity: 54 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

541 
WFUS52 KKEY 092307
TORKEY
FLC087-092330-
/O.NEW.KKEY.TO.W.0003.170909T2307Z-170909T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Key West FL
707 PM EDT SAT SEP 9 2017

The National Weather Service in Key West has issued a

* Tornado Warning for...
  Lower Keys in Monroe County in Florida...

* Until 730 PM EDT
    
* At 706 PM EDT, a severe thunderstorm capable of producing a tornado
  was located 8 miles northwest of Pidgeon Key, or 8 miles north of
  Seven Mile Bridge, moving west at 70 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. 

* Locations impacted include...
  Key West, Boca Chica, Big Coppitt Key, Boca Chica Channel Bridge,
  Niles Channel Bridge, Saddlebunch Keys, Geiger Key, Shark Key,
  Little Torch Key and Upper Sugarloaf Key.

This includes US 1 between mile markers 1 and 31. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or 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 2452 8179 2462 8182 2466 8180 2473 8168
      2470 8162 2478 8159 2478 8154 2481 8152
      2483 8149 2479 8135 2481 8128 2477 8125
      2470 8127 2471 8122 2455 8163
TIME...MOT...LOC 2306Z 071DEG 59KT 2482 8122 

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

$$

Heavener

1 follow-up statement

219 
WWUS52 KKEY 092323
SVSKEY

Severe Weather Statement
National Weather Service Key West FL
723 PM EDT SAT SEP 9 2017

FLC087-092332-
/O.EXP.KKEY.TO.W.0003.000000T0000Z-170909T2330Z/
Lower Keys in Monroe FL-
723 PM EDT SAT SEP 9 2017

...THE TORNADO WARNING FOR LOWER KEYS IN MONROE COUNTY WILL EXPIRE AT
730 PM EDT...
    
The tornadic thunderstorm which prompted the warning has weakened. 
Therefore, the warning will be allowed to expire.

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

LAT...LON 2452 8179 2462 8182 2466 8180 2473 8168
      2470 8162 2478 8159 2478 8154 2481 8152
      2483 8149 2479 8135 2481 8128 2477 8125
      2470 8127 2471 8122 2455 8163
TIME...MOT...LOC 2322Z 071DEG 59KT 2474 8148 

$$

Heavener

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 9, 12:02 AM EDT	Special Weather Statement	KEY		58 min
Sep 9, 1:06 AM EDT	Special Weather Statement	KEY		54 min
Sep 9, 7:50 AM EDT	Special Weather Statement	KEY		85 min
Sep 9, 2:46 PM EDT	Special Weather Statement	KEY		59 min
Sep 9, 5:34 PM EDT	Tornado Warning	KEY	Monroe	26 min
Sep 9, 5:56 PM EDT	Tornado Warning	KEY	Monroe	49 min

Nearby

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