Alert archive / Florida / Tornado Watches in 2008

Tornado Watch 840

August 18, 200819 counties in Florida

The Storm Prediction Center issued this tornado watch at Aug 18, 2008, 10:44 PM EDT for 19 counties in Florida. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued
Aug 18, 2008, 10:44 PM EDT (02:44 UTC)
Expired
Aug 19, 2008, 8:00 AM EDT
In force
9 hr
Issued by
the Storm Prediction Center
Strongest gust expected
60 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), 140 km from the middle of the area, began a volume at 02:47 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
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
40%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 19, 12:41 AM EDTTornado WarningMFLPalm Beach19 min
Aug 19, 1:02 AM EDTTornado WarningMFLPalm Beach28 min
Aug 19, 1:28 AM EDTTornado WarningMFLPalm Beach32 min
Aug 19, 1:32 AM EDTTornado WarningMLBMartin43 min
Aug 19, 1:57 AM EDTTornado WarningMFLCollier, Hendry63 min
Aug 19, 2:04 AM EDTTornado WarningMFLPalm Beach41 min
Aug 19, 2:15 AM EDTTornado WarningMLBMartin33 min
Aug 19, 2:55 AM EDTTornado WarningMFLPalm Beach50 min
Aug 19, 3:06 AM EDTTornado WarningMLBOkeechobee39 min
Aug 19, 3:07 AM EDTTornado WarningMFLCollier, Hendry53 min
Aug 19, 3:35 AM EDTTornado WarningMFLCollier40 min
Aug 19, 3:43 AM EDTTornado WarningMFLPalm Beach47 min
Aug 19, 4:25 AM EDTTornado WarningMFLPalm Beach20 min
Aug 19, 4:36 AM EDTTornado WarningMFLPalm Beach24 min
Aug 19, 5:00 AM EDTTornado WarningMFLHendry, Palm Beach30 min
Aug 19, 5:02 AM EDTTornado WarningMFLPalm Beach28 min
Aug 19, 5:07 AM EDTTornado WarningMFLPalm Beach23 min
Aug 19, 5:30 AM EDTTornado WarningMFLGlades, Hendry, Palm Beach30 min
Aug 19, 5:36 AM EDTTornado WarningMFLMiami-Dade24 min
Aug 19, 5:49 AM EDTTornado WarningMFLPalm Beach26 min
Aug 19, 5:50 AM EDTTornado WarningMLBSaint Lucie40 min
Aug 19, 5:59 AM EDTTornado WarningMFLPalm Beach31 min
Aug 19, 6:28 AM EDTTornado WarningMLBSaint Lucie20 min
Aug 19, 6:28 AM EDTTornado WarningMLBMartin47 min
Aug 19, 6:45 AM EDTTornado WarningMLBMartin, Saint Lucie30 min
Aug 19, 6:48 AM EDTTornado WarningMFLPalm Beach27 min
Aug 19, 7:10 AM EDTTornado WarningMFLPalm Beach20 min
Aug 19, 7:15 AM EDTTornado WarningMFLPalm Beach30 min
Aug 19, 7:32 AM EDTTornado WarningMFLPalm Beach28 min
Aug 19, 7:38 AM EDTTornado WarningMFLMonroe22 min
Aug 19, 7:40 AM EDTTornado WarningMFLBroward, Miami-Dade35 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, 2.7 hours before the alert went out and 143 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, Miami, FL at 00:00Z on 2008-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1454 joules per kilogram.LCLEL10008507005003002001001 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, Miami, FL at 00:00Z on 2008-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 161 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
1454 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
807 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
161 m²/s²
0-3 km storm-relative helicity
222 m²/s²
Significant tornado parameter
0.9
Supercell composite
7.7

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 19, 3:37 AM EDTMesoscale DiscussionSPCBrevard, Broward, Charlotte, Collier, DeSoto, Glades and 13 more53 min
Aug 19, 6:29 AM EDTMesoscale DiscussionSPCBrevard, Broward, Glades, Hardee, Hendry, Highlands and 11 more31 min
Aug 19, 7:05 AM EDTTornado WatchSPCBrevard, Broward, Charlotte, Collier, DeSoto, Glades and 16 more9 hr
Aug 19, 11:32 AM EDTMesoscale DiscussionSPCBrevard, Broward, Charlotte, Collier, DeSoto, Flagler and 20 more88 min
Aug 19, 3:04 PM EDTMesoscale DiscussionSPCBrevard, Flagler, Indian River, Lake, Orange, Osceola and 3 more86 min
Aug 19, 3:46 PM EDTTornado WatchSPCBrevard, Flagler, Indian River, Orange, Osceola, Putnam and 3 more9 hr
Aug 19, 7:10 PM EDTMesoscale DiscussionSPCBrevard95 min

Nearby

Tornado Watches in Florida, 2008Every tornado watch in 2008

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.