Alert archive / Florida / Tornado Watches in 2011
Tornado Watch 5
The Storm Prediction Center issued this tornado watch at Jan 17, 2011, 11:33 AM EST for 4 counties in Florida. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jan 17, 2011, 11:33 AM EST (16:33 UTC)
- Expired
- Jan 17, 2011, 7:00 PM EST
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
Counties Broward County, FL, Miami-Dade County, FL, Monroe County, FL, Palm Beach County, FL
The radar
The Miami radar (KAMX), 75 km from the middle of the area, began a volume at 16:36 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
- 30%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 5%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 40%
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 12:00Z, 4.6 hours before the alert went out and 97 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
- 44 J/kg
- Mixed-layer CIN
- -136 J/kg
- Mixed-layer LCL
- 894 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- 148 m²/s²
- 0-3 km storm-relative helicity
- 213 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
493
WWUS20 KWNS 171627
SEL5
SPC WW 171627
FLZ000-CWZ000-180000-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 5
NWS STORM PREDICTION CENTER NORMAN OK
1125 AM EST MON JAN 17 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
SOUTHERN FLORIDA
COASTAL WATERS
EFFECTIVE THIS MONDAY MORNING AND EVENING FROM 1125 AM UNTIL 700
PM EST.
TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE
MILES EITHER SIDE OF A LINE FROM 10 MILES WEST OF KEY WEST
FLORIDA TO 40 MILES SOUTHEAST OF WEST PALM BEACH FLORIDA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU5).
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...SHOWERS AND A FEW TSTMS EXPECTED TO PERSIST INVOF
SHALLOW WARM FRONT EDGING NE ACROSS S FL THROUGH THIS AFTN. LOW LVL
SHEAR EXPECTED TO REMAIN STRONGEST ALONG AND JUST NE OF FRONT...WITH
SFC-BASED INSTABILITY MAXIMIZED TO ITS WEST. LARGE SCALE FORCING
FOR ASCENT WILL REMAIN WEAK. BUT COMBINATION OF SIZABLE LOW LVL
DIRECTIONAL SHEAR/LOW LCLS NEAR FRONT...PRESENCE OF A FEW LONG-LIVED
UPDRAFTS...AND POTENTIAL FOR ADDITIONAL DEVELOPMENT AS AREA OF
STORMS NOW OFF THE SE FL CST CONTINUES ENE SUGGESTS RISK FOR A
COUPLE TORNADOES AND/OR LOCALLY DMGG WIND THROUGH EARLY EVE.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
400. MEAN STORM MOTION VECTOR 24030.
...CORFIDISPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jan 17, 10:17 AM EST | Mesoscale Discussion | SPC | Brevard, Broward, Charlotte, Collier, DeSoto, Glades and 15 more | 118 min |
| Jan 17, 11:54 AM EST | Tornado Watch | SPC | Brevard, Charlotte, DeSoto, Hardee, Highlands, Indian River and 9 more | 5 hr |
| Jan 17, 3:23 PM EST | Mesoscale Discussion | SPC | Broward, Miami-Dade, Monroe | 97 min |
| Jan 17, 6:27 PM EST | Mesoscale Discussion | SPC | Miami-Dade | 63 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.