Alert archive / Florida / Mesoscale Discussions in 2012

Mesoscale Discussion 468

April 6, 20126 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Apr 6, 2012, 8:44 AM EDT for 6 counties in Florida. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Apr 6, 2012, 8:44 AM EDT (12:44 UTC)
Expired: Apr 6, 2012, 10:15 AM EDT
In force: 91 min
Issued by: the Storm Prediction Center

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

The radar

The Miami radar (KAMX), 53 km from the middle of the area, began a volume at 12:46 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, 0.7 hours before the alert went out and 55 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: 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.

451 
ACUS11 KWNS 061244
SWOMCD
SPC MCD 061244 
FLZ000-061415-

MESOSCALE DISCUSSION 0468
NWS STORM PREDICTION CENTER NORMAN OK
0744 AM CDT FRI APR 06 2012

AREAS AFFECTED...SRN FL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 061244Z - 061415Z

SCATTERED SHOWERS/TSTMS FORMING ACROSS SRN FL SHOULD MOVE EWD WHILE
DEVELOPING SWD THROUGH MIDDAY. A FEW TSTMS MAY STRENGTHEN  AND POSE
A RISK OF ISOLATED SEVERE HAIL AND DAMAGING WINDS. THE REGION WILL
BE UPGRADED TO SLIGHT RISK WITH THE 13Z SWODY1 AND THE PROBABILITY
OF A WW ISSUANCE IS 40 PERCENT.

CONVECTION HAS INCREASED DURING THE PAST HOUR ALONG A PRE-FRONTAL
W/E-ORIENTED CONFLUENCE BAND THAT FORMED IN THE WAKE OF AN MCS WHICH
MOVED ACROSS THE FL KEYS LAST EVENING. 12Z MFL/EYW RAOBS ARE RATHER
FAVORABLE IN CAPE/SHEAR PARAMETER SPACE FOR ORGANIZED SEVERE
STORMS...ALTHOUGH THE LOW-LEVEL MOISTURE PROFILE IN MFL AND
RESULTANT PW VALUE NEAR 1.6 INCH IS LIKELY OVERDONE COMPARED TO GPS
PW VALUES OF AROUND 1.4 INCH. LATEST GUIDANCE REMAINS HIGHLY
CONSISTENT IN DEPICTING INCREASINGLY VEERED LOW-LEVEL FLOW TODAY AS
THE SHORT WAVE IMPULSE CENTERED ALONG THE CAROLINA COAST PROGRESSES
EWD. THIS WILL RESULT IN DECREASING SHEAR AND ORIENTATION OF THE
CONVECTION LARGELY PARALLEL TO THE CONFLUENCE BAND. THUS...POTENTIAL
FOR ISOLATED SEVERE STORMS SHOULD EXIST PRIMARILY THIS MORNING AND
ALONG THE SERN FL COAST AS STORMS MATURE OVER LAND...A SCENARIO
GENERALLY SUPPORTED BY RECENT HRRR/WRF-NSSL GUIDANCE.

..GRAMS.. 04/06/2012

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

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

LAT...LON   26398184 26988012 26677985 25967987 24988036 24868064
            25048112 25868184 26398184

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 5, 8:54 PM EDT	Mesoscale Discussion	SPC	Holmes	96 min

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.