Alert archive / Florida / Mesoscale Discussions in 2012

Mesoscale Discussion 2153

December 10, 2012Collier County, Florida

The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2012, 11:34 PM EST for Collier County, Florida. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued: Dec 10, 2012, 11:34 PM EST (04:34 UTC)
Expired: Dec 11, 2012, 1:00 AM EST
In force: 86 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

County Collier County, FL

The radar

The Miami radar (KAMX), 80 km from the middle of the area, began a volume at 04:37 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 00:00Z, 4.6 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-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: 2247 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 560 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 111 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 4.0

Open this sounding in Storm Lab

The text

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

703 
ACUS11 KWNS 110435
SWOMCD
SPC MCD 110434
FLZ000-110600-

MESOSCALE DISCUSSION 2153
NWS STORM PREDICTION CENTER NORMAN OK
1034 PM CST MON DEC 10 2012

AREAS AFFECTED...SRN FL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 110434Z - 110600Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...STORMS MAY POSE AT LEAST A MARGINAL THREAT FOR ISOLATED
STRONG WIND GUSTS OVER SRN PORTION OF THE FL PENINSULA THROUGH 06Z.
THREAT DOES NOT APPEAR SUFFICIENT TO WARRANT A WW ISSUANCE.

DISCUSSION...STORMS HAVE INCREASED IN COVERAGE AND INTENSITY ALONG
THE SWRN FL COAST WITH A CORRESPONDING INCREASE IN LIGHTNING
FREQUENCY AND COOLING CLOUD TOPS NOTED. THE BOUNDARY LAYER ACROSS
SRN FL IS VERY MOIST AND HAS LITTLE CONVECTIVE INHIBITION WITH MID
70S DEWPOINTS SUPPORTING 2000-2300 J/KG MLCAPE PER 00Z RAOBS FROM
MIAMI AND KEY WEST. INFLOW OF HIGH THETA-E AIR AND A WEAK CAP SHOULD
CONTINUE TO PROMOTE FORWARD PROPAGATION INTO THE FL PENINSULA NEXT
FEW HOURS.  WINDS THROUGH LOWEST 5 KM ARE MODEST /20-25 KT/ BUT
INCREASE SUFFICIENTLY ABOVE THIS LEVEL TO SUPPORT EFFECTIVE BULK
SHEAR AROUND 40 KT. BROAD MID LEVEL UPDRAFT ROTATION HAS BEEN
OBSERVED WITH STORMS EMBEDDED WITHIN THE LINE WHICH COULD PROMOTE
BOWING SEGMENTS AND AT LEAST A MARGINAL THREAT FOR ISOLATED STRONG
WIND GUSTS. LIMITING FACTORS FOR A MORE ROBUST SEVERE EVENT ARE THE
MODEST WINDS AND MOIST THERMODYNAMIC PROFILES THROUGH 5 KM.

..DIAL/EDWARDS.. 12/11/2012

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

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

LAT...LON   25958161 26308129 26458070 26268046 25858058 25678102
            25958161

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 10, 7:51 PM EST	Mesoscale Discussion	SPC	Osceola, Polk	84 min
Dec 11, 4:55 PM EST	Mesoscale Discussion	SPC	Broward, DeSoto, Glades, Hendry, Highlands, Indian River and 5 more	95 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.