Alert archive / Florida / Mesoscale Discussions in 2012

Mesoscale Discussion 580

April 22, 201228 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2012, 2:21 AM EDT for 28 counties in Florida. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: Apr 22, 2012, 2:21 AM EDT (06:21 UTC)
Expired: Apr 22, 2012, 3:15 AM EDT
In force: 54 min
Issued by: the Storm Prediction Center

All 28 counties

Brevard County, FL, Broward County, FL, Charlotte County, FL, Citrus 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, Lee County, FL, Levy County, FL, Manatee County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Okeechobee County, FL, Osceola County, FL, Palm Beach County, FL, Pasco County, FL, Pinellas County, FL, Polk County, FL, Saint Lucie County, FL, Sarasota County, FL, Sumter County, FL

The radar

The Tampa radar (KTBW), 72 km from the middle of the area, began a volume at 06:24 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

Tampa Bay, FL (KTBW), launched 00:00Z, 6.4 hours before the alert went out and 72 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: 12 J/kg
Mixed-layer CIN: -208 J/kg
Mixed-layer LCL: 622 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 228 m²/s²
0-3 km storm-relative helicity: 217 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

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

591 
ACUS11 KWNS 220622
SWOMCD
SPC MCD 220621
FLZ000-220715-

MESOSCALE DISCUSSION 0580
NWS STORM PREDICTION CENTER NORMAN OK
0121 AM CDT SUN APR 22 2012

AREAS AFFECTED...CNTRL/SRN FL PENINSULA

CONCERNING...TORNADO WATCH 186...

VALID 220621Z - 220715Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 186 CONTINUES.

THE THREAT FOR DAMAGING WINDS AND PERHAPS A COUPLE OF TORNADOES
CONTINUES...MAINLY ALONG AND E OF A LINE FROM POLK TO LEE AND
COLLIER COUNTIES.

AS OF 0605Z...REGIONAL RADAR IMAGERY SHOWED TWO MORE PROMINENT LINE
SEGMENTS...ONE FROM LAKE COUNTY SWWD TO MANATEE AND SARASOTA
COUNTIES...AND ANOTHER FROM WRN GLADES AND HENDRY COUNTIES TO WRN
COLLIER COUNTY.  MOVEMENT OF THESE LINES WAS GENERALLY E AT 20-25
KT.  LATEST MESOANALYSIS SHOWS A CORRIDOR OF ENHANCED PRESSURE FALLS
ALONG THE E-CNTRL/SERN PENINSULA WHICH APPEARS TO COINCIDE WITH A
ZONE OF ENHANCED LOW-LEVEL WAA ATTENDANT TO A 50 KT LLJ /PER MLB
VWP/.  WHILE THE AIR MASS IS EXPECTED TO REMAIN ONLY MARGINALLY
UNSTABLE /I.E. MLCAPE VALUES OF 500-1000 J PER KG/...THE PRESENCE OF
STRONG VERTICAL SHEAR /REF. MLB VWP/ AND INCREASING FORCING FOR
ASCENT ATTENDANT TO MIDLEVEL TROUGH OVER THE ERN GOM WILL REMAIN
SUPPORTIVE OF EMBEDDED SUPERCELL AND BOWING STRUCTURES CAPABLE OF
DAMAGING WINDS AND PERHAPS A COUPLE OF TORNADOES.

..MEAD.. 04/22/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MFL...MLB...KEY...TBW...JAX...TAE...

LAT...LON   25498196 26188250 26938293 27588326 28098336 28528323
            28858347 29238363 29488306 29168261 29038205 29008186
            28448189 28468106 28898103 28938014 27417971 26507950
            25377976 24947995 24998057 24858130 25138177 25498196

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 21, 10:10 PM EDT	Mesoscale Discussion	SPC	Charlotte, Collier, DeSoto, Glades, Hardee, Hendry and 10 more	65 min
Apr 21, 11:08 PM EDT	Tornado Watch	SPC	Brevard, Broward, Charlotte, Citrus, Collier, DeSoto and 21 more	7 hr

Nearby

Mesoscale Discussions in Florida, 2012 Every mesoscale discussion in 2012

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.