Alert archive / Florida / Tornado Watches in 2017
Tornado Watch 482
The Storm Prediction Center issued this tornado watch at Sep 9, 2017, 11:45 PM EDT for 19 counties in Florida. It was in force for 12 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 9, 2017, 11:45 PM EDT (03:45 UTC)
- Expired
- Sep 10, 2017, 12:00 PM EDT
- In force
- 12 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 50 kt
Counties Brevard County, FL, Broward County, FL, Charlotte County, FL, Collier County, FL, DeSoto County, FL, Glades County, FL, Hardee County, FL, Hendry County, FL, Highlands County, FL, Indian River County, FL, Lee County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Okeechobee County, FL, Osceola County, FL, Palm Beach County, FL, Polk County, FL, Saint Lucie County, FL
The radar
The Melbourne radar (KMLB), 134 km from the middle of the area, began a volume at 03:49 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 SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 60%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 10%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 10, 3:24 AM EDT | Flash Flood Warning | MLB | Saint Lucie | 111 min |
| Sep 10, 3:46 AM EDT | Tornado Warning | MFL | Broward, Palm Beach | 29 min |
| Sep 10, 3:49 AM EDT | Tornado Warning | MLB | Indian River, Saint Lucie | 16 min |
| Sep 10, 5:14 AM EDT | Tornado Warning | MLB | Brevard | 31 min |
| Sep 10, 5:53 AM EDT | Tornado Warning | MLB | Brevard | 22 min |
| Sep 10, 6:21 AM EDT | Tornado Warning | MFL | Palm Beach | 28 min |
| Sep 10, 7:35 AM EDT | Tornado Warning | MFL | Palm Beach | 14 min |
| Sep 10, 7:36 AM EDT | Tornado Warning | MFL | Broward, Miami-Dade | 24 min |
| Sep 10, 7:57 AM EDT | Tornado Warning | TBW | Polk | 13 min |
| Sep 10, 8:56 AM EDT | Tornado Warning | TBW | Hardee | 19 min |
| Sep 10, 9:19 AM EDT | Tornado Warning | MLB | Brevard | 26 min |
| Sep 10, 9:42 AM EDT | Tornado Warning | MFL | Palm Beach | 18 min |
| Sep 10, 10:28 AM EDT | Tornado Warning | MLB | Osceola | 32 min |
| Sep 10, 10:45 AM EDT | Tornado Warning | TBW | Polk | 30 min |
| Sep 10, 11:01 AM EDT | Tornado Warning | MLB | Brevard | 29 min |
| Sep 10, 11:08 AM EDT | Tornado Warning | TBW | Hillsborough, Pasco, Polk, Sumter | 22 min |
| Sep 10, 11:12 AM EDT | Tornado Warning | MLB | Brevard | 48 min |
| Sep 10, 11:21 AM EDT | Tornado Warning | MLB | Saint Lucie | 24 min |
| Sep 10, 11:40 AM EDT | Tornado Warning | MLB | Okeechobee | 35 min |
| Sep 10, 11:48 AM EDT | Tornado Warning | MLB | Saint Lucie | 27 min |
| Sep 10, 11:58 AM EDT | Tornado Warning | MLB | Brevard, Indian River | 30 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Miami, FL (KMFL), launched 00:00Z, 3.8 hours before the alert went out and 124 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1179 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- -25 m²/s²
- 0-3 km storm-relative helicity
- 32 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
962 WWUS20 KWNS 100340 SEL2 SPC WW 100340 FLZ000-CWZ000-101600- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 482 NWS Storm Prediction Center Norman OK 1140 PM EDT Sat Sep 9 2017 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of East-central and southern Florida Peninsula Coastal Waters * Effective this from 1140 PM until NOON EDT. * Primary threats include... A few tornadoes likely SUMMARY...The risk for tornadoes should persist throughout this morning within the intermediate and outer bands of Hurricane Irma. The tornado watch area is approximately along and 50 statute miles east and west of a line from 30 miles north of Melbourne FL to 35 miles east southeast of Marathon FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...This tornado watch replaces tornado watch number 481. Watch number 481 will not be in effect after 1140 PM EDT. AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 0.5 inches. Extreme turbulence and surface wind gusts to 50 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 09050. ...Grams
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 9, 10:26 PM EDT | Mesoscale Discussion | SPC | Broward, Collier, Glades, Hendry, Highlands, Indian River and 7 more | 94 min |
| Sep 10, 2:23 AM EDT | Mesoscale Discussion | SPC | Broward, Collier, Glades, Hendry, Highlands, Indian River and 7 more | 2 hr |
| Sep 10, 6:05 AM EDT | Mesoscale Discussion | SPC | Brevard, Broward, Charlotte, Collier, DeSoto, Glades and 13 more | 115 min |
| Sep 10, 8:32 AM EDT | Mesoscale Discussion | SPC | Broward, Charlotte, Collier, DeSoto, Glades, Hendry and 9 more | 118 min |
| Sep 10, 12:02 PM EDT | Tornado Watch | SPC | Alachua, Baker, Bradford, Brevard, Charlotte, Citrus and 36 more | 13 hr |
| Sep 10, 3:01 PM EDT | Mesoscale Discussion | SPC | Alachua, Baker, Bradford, Brevard, Charlotte, Citrus and 34 more | 119 min |
Nearby
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.