Alert archive

Mesoscale Discussion 469

April 6, 2012

The Storm Prediction Center issued this mesoscale discussion at Apr 6, 2012, 10:46 AM CDT. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued
Apr 6, 2012, 10:46 AM CDT (15:46 UTC)
Expired
Apr 6, 2012, 12:15 PM CDT
In force
89 min
Issued by
the Storm Prediction Center

The radar

The Miami radar (KAMX), 52 km from the middle of the area, began a volume at 15:48 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, 3.8 hours before the alert went out and 26 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 2012-04-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2930 joules per kilogram.LCLEL10008507005003002001001 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 2012-04-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 167 square meters per square second.19395878Sfc1 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
2930 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
478 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
167 m²/s²
0-3 km storm-relative helicity
257 m²/s²
Significant tornado parameter
3.7
Supercell composite
16.2

Open this sounding in Storm Lab

The text

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

351 
ACUS11 KWNS 061547
SWOMCD
SPC MCD 061546
FLZ000-061715-

MESOSCALE DISCUSSION 0469
NWS STORM PREDICTION CENTER NORMAN OK
1046 AM CDT FRI APR 06 2012

AREAS AFFECTED...SE FLORIDA COASTAL AREAS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 061546Z - 061715Z

GENERALLY WEAK LOW-LEVEL CONVERGENCE OVER THE INTERIOR SOUTHERN
FLORIDA PENINSULA PROBABLY WILL CONTINUE TO LIMIT THE CONVECTIVE
POTENTIAL TODAY.  BUT A WEAK PRE-FRONTAL CONFLUENCE ZONE APPEARS TO
BE FORMING ALONG A EAST-WEST AXIS ACROSS PARTS OF COLLIER AND
BROWARD COUNTIES...WHICH COULD BECOME A FOCUS FOR CONVECTIVE
DEVELOPMENT/INTENSIFICATION DURING THE NEXT COUPLE OF HOURS.  IN THE
PRESENCE OF SIZABLE CAPE OF 2000+ J/KG...DEEP LAYER VERTICAL SHEAR
IS STRONG BENEATH 40-50 KT WEST NORTHWESTERLY 500 MB FLOW.  ISOLATED
SUPERCELL DEVELOPMENT APPEARS A POSSIBILITY BY 17-18Z...
PARTICULARLY NEAR EASTERN BROWARD COUNTY COASTAL AREAS.  WITH THE
SEA-BREEZE LIKELY TO REMAIN OFFSHORE...TORNADIC POTENTIAL OVER
INLAND AREAS SEEMS LOW...BUT LARGE HAIL IS POSSIBLE...ALONG WITH
SOME RISK FOR A LOCALLY STRONG WIND GUST OR TWO.

..KERR.. 04/06/2012

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

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

LAT...LON   26218046 26268018 26247998 26057987 25917995 25848010
            25848036 25938055 26058058 26218046

Nearby

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.