Alert archive / Florida / Mesoscale Discussions in 2012

Mesoscale Discussion 1173

June 15, 201213 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Jun 15, 2012, 3:11 PM EDT for 13 counties in Florida. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Jun 15, 2012, 3:11 PM EDT (19:11 UTC)
Expired
Jun 15, 2012, 4:15 PM EDT
In force
64 min
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Broward County, FL, Charlotte County, FL, Collier County, FL, DeSoto County, FL, Glades County, FL, Hardee County, FL, Hendry County, FL, Highlands County, FL, Lee County, FL, Manatee County, FL, Miami-Dade County, FL, Monroe County, FL, Palm Beach County, FL

The radar

The Miami radar (KAMX), 141 km from the middle of the area, began a volume at 19:13 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Miami, FL (KMFL), launched 12:00Z, 7.2 hours before the alert went out and 134 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 12:00Z on 2012-06-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1194 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, Miami, FL at 12:00Z on 2012-06-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 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
1194 J/kg
Mixed-layer CIN
-61 J/kg
Mixed-layer LCL
805 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

841 
ACUS11 KWNS 151911
SWOMCD
SPC MCD 151911 
FLZ000-152015-

MESOSCALE DISCUSSION 1173
NWS STORM PREDICTION CENTER NORMAN OK
0211 PM CDT FRI JUN 15 2012

AREAS AFFECTED...SRN FL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 151911Z - 152015Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED SEVERE WIND/HAIL WILL EXIST THROUGH THE AFTERNOON
AS THUNDERSTORMS DEVELOP ALONG THE SEA-BREEZE ACROSS SRN FL.
ISOLATED NATURE OF THE SEVERE THREAT IS EXPECTED TO PRECLUDE THE
NEED FOR A WW.

DISCUSSION...AMPLE INSTABILITY AND INCREASED CONVERGENCE ALONG
MULTIPLE MESOSCALE BOUNDARIES WILL LEAD TO AN ISOLATED SEVERE THREAT
THROUGH THE AFTERNOON ACROSS SRN FL. WWD/SWWD PROGRESSING CONFLUENCE
BAND /LOCATED ROUGHLY ALONG A LINE FROM VDF SEWD TO BCT/ WILL LIKELY
INTERSECT THE W COAST SEA-BREEZE THIS AFTERNOON...ENHANCING SURFACE
CONVERGENCE AND AIDING IN THUNDERSTORM DEVELOPMENT. 18Z MESOANALYSIS
DEPICTED MLCAPE AOA 1500 J/KG AND EFFECTIVE SHEAR VALUES NEAR 25 KTS
ACROSS MUCH OF SRN FL. THIS SUGGESTS BRIEFLY ORGANIZED MULTICELLS
WITH AN ISOLATED THREAT FOR SEVERE HAIL/WIND. ISOLATED NATURE OF THE
SEVERE THREAT IS EXPECTED TO PRECLUDE THE NEED FOR A WW.

..MOSIER/HART.. 06/15/2012

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

ATTN...WFO...MFL...TBW...

LAT...LON   25288077 25648128 26158171 26908226 27498248 27718225
            27748182 27608157 27028087 26458003 25488037 25288077

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 15, 3:56 PM EDTSevere Thunderstorm WatchSPCBroward, Charlotte, Collier, DeSoto, Glades, Hardee and 8 more5 hr
Jun 15, 7:13 PM EDTMesoscale DiscussionSPCBroward, Charlotte, Collier, DeSoto, Glades, Hardee and 7 more62 min

Nearby

Mesoscale Discussions in Florida, 2012Every 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.