Alert archive / Florida / Tornado Watches in 2014

Tornado Watch 84

April 19, 201413 counties in Florida

The Storm Prediction Center issued this tornado watch at Apr 19, 2014, 3:07 AM EDT for 13 counties in Florida. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Apr 19, 2014, 3:07 AM EDT (07:07 UTC)
Expired: Apr 19, 2014, 8:05 AM EDT
In force: 5 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1 in
Strongest gust expected: 65 kt

Counties Brevard County, FL, Broward County, FL, Collier County, FL, Glades County, FL, Hendry County, FL, Indian River County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Okeechobee County, FL, Osceola County, FL, Palm Beach County, FL, Saint Lucie County, FL

The radar

The Miami radar (KAMX), 128 km from the middle of the area, began a volume at 07:09 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 40%
One or more EF2 to EF5 tornadoes: 10%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 20%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 50%

Warnings issued inside it

1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Apr 19, 6:26 AM EDT	Severe Thunderstorm Warning	MFL	Miami-Dade	49 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, 7.1 hours before the alert went out and 118 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: 1093 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 910 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 94 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 4.0

Open this sounding in Storm Lab

The text

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

936 
WWUS20 KWNS 190708
SEL4  
SPC WW 190708
FLZ000-CWZ000-191400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 84
NWS STORM PREDICTION CENTER NORMAN OK
310 AM EDT SAT APR 19 2014

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  SOUTHERN AND EASTERN FLORIDA
  COASTAL WATERS

* EFFECTIVE THIS SATURDAY MORNING FROM 310 AM UNTIL 1000 AM EDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  ISOLATED SIGNIFICANT DAMAGING WIND GUSTS TO 75 MPH POSSIBLE
  ISOLATED LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 75 MILES NORTHWEST OF WEST
PALM BEACH FLORIDA TO 60 MILES SOUTHWEST OF MIAMI FLORIDA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU4).

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.

&&

DISCUSSION...A MODERATELY UNSTABLE AIRMASS IS IN PLACE ACROSS THE
SOUTHERN AND EASTERN FLORIDA PENINSULA WITH SURFACE DEWPOINTS IN THE
LOWER 70S F. THIS ALONG WITH MODERATE DEEP LAYER SHEAR AND
SUFFICIENT LOW-LEVEL SHEAR WILL CREATE CONDITIONS FAVORABLE FOR
SEVERE THUNDERSTORMS AND A RISK OF TORNADOES DURING THE OVERNIGHT
PERIOD.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 65 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450.
MEAN STORM MOTION VECTOR 24035.


...BROYLES

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 19, 12:46 AM EDT	Mesoscale Discussion	SPC	Broward, Collier, Miami-Dade, Monroe, Palm Beach	119 min
Apr 19, 5:56 AM EDT	Mesoscale Discussion	SPC	Broward, Martin, Miami-Dade, Monroe, Palm Beach, Saint Lucie	2 hr

Nearby

Tornado Watches in Florida, 2014 Every tornado watch in 2014

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.