Alert archive / Florida / Mesoscale Discussions in 2011

Mesoscale Discussion 666

April 28, 201131 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2011, 3:34 PM EDT for 31 counties in Florida. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Apr 28, 2011, 3:34 PM EDT (19:34 UTC)
Expired
Apr 28, 2011, 4:30 PM EDT
In force
56 min
Issued by
the Storm Prediction Center
All 31 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, Hernando County, FL, Highlands County, FL, Hillsborough County, FL, Indian River County, FL, Lake County, FL, Lee County, FL, Manatee County, FL, Marion County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Okeechobee County, FL, Orange County, FL, Osceola County, FL, Palm Beach County, FL, Pasco County, FL, Polk County, FL, Putnam County, FL, Saint Lucie County, FL, Sarasota County, FL, Seminole County, FL, Sumter County, FL, Volusia County, FL

The radar

The Tampa radar (KTBW), 88 km from the middle of the area, began a volume at 19:35 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 nearest sounding before it

Cape Canaveral, FL (KXMR), launched 12:00Z, 7.6 hours before the alert went out and 148 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, Cape Canaveral, FL at 12:00Z on 2011-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 671 joules per kilogram.LCLLFCEL10008507005003002001001 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, Cape Canaveral, FL at 12:00Z on 2011-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 34 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
671 J/kg
Mixed-layer CIN
-81 J/kg
Mixed-layer LCL
1082 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
34 m²/s²
0-3 km storm-relative helicity
46 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 28, 2:22 AM EDTMesoscale DiscussionSPCHolmes83 min
Apr 28, 9:47 AM EDTSevere Thunderstorm WatchSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 13 more9 hr
Apr 28, 12:19 PM EDTMesoscale DiscussionSPCAlachua, Baker, Bradford, Clay, Columbia, Dixie and 9 more56 min

Nearby

Mesoscale Discussions in Florida, 2011Every mesoscale discussion in 2011

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.