Alert archive / Florida / Mesoscale Discussions in 2012

Mesoscale Discussion 836

May 19, 20128 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at May 19, 2012, 12:44 PM EDT for 8 counties in Florida. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
May 19, 2012, 12:44 PM EDT (16:44 UTC)
Expired
May 19, 2012, 2:15 PM EDT
In force
91 min
Issued by
the Storm Prediction Center
Chance of a watch
40%

Counties Broward County, FL, Collier County, FL, Glades County, FL, Hendry County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Palm Beach County, FL

The radar

The Miami radar (KAMX), 93 km from the middle of the area, began a volume at 16:47 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.

The nearest sounding before it

Miami, FL (KMFL), launched 12:00Z, 4.7 hours before the alert went out and 80 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 2012-05-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1791 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 2012-05-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 square meters per square second.1939587897Sfc1 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
1791 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
625 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
51 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

663 
ACUS11 KWNS 191645
SWOMCD
SPC MCD 191644
FLZ000-191815-

MESOSCALE DISCUSSION 0836
NWS STORM PREDICTION CENTER NORMAN OK
1144 AM CDT SAT MAY 19 2012

AREAS AFFECTED...SOUTH FL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 191644Z - 191815Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS SOUTH FL
DURING THE AFTERNOON. ISOLATED DAMAGING WIND GUSTS AND LARGE HAIL
WILL BE POSSIBLE. TRENDS WILL BE MONITORED FOR A WW.

DISCUSSION...SURFACE OBSERVATIONS AT 16Z SHOW TEMPERATURES ACROSS S
FL ARE WARMING INTO THE MID 80S...WHICH IS AIDING IN BOUNDARY LAYER
DESTABILIZATION AND DEEPENING CUMULUS. THIS HEATING COMBINED WITH A
MOIST LOW-LEVEL AIRMASS /SURFACE DEWPOINTS IN THE UPR 60S TO LOW
70S/ WILL YIELD MLCAPE VALUES FROM 1000-2000 J/KG...WHICH WILL FAVOR
SCATTERED THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON. ORGANIZED
MULTICELL THUNDERSTORMS WILL BE POSSIBLE WITH THIS ACTIVITY...GIVEN
LOW-LEVEL ELYS OCCURRING BENEATH 100 KT WLY SUB-TROPICAL JET. PRECIP
LOADING WITH STRONGER CELLS WILL FAVOR WET MICROBURSTS...WHILE LARGE
BUOYANCY AND FAVORABLE DEEP-LAYER SHEAR WILL SUPPORT AN ISOLATED
THREAT FOR LARGE HAIL.

IN ADDITION TO THE SVR WEATHER THREAT...LOCALLY HEAVY RAINFALL WILL
ALSO BE POSSIBLE GIVEN HIGH PWAT VALUES AND SLOW STORM MOTIONS.

..GARNER/WEISS.. 05/19/2012

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

ATTN...WFO...MFL...MLB...KEY...TBW...

LAT...LON   27008005 25498020 25208048 25138110 25948178 26858206
            27318119 27388043 27008005

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.