Alert archive / Florida / Mesoscale Discussions in 2014

Mesoscale Discussion 366

April 18, 201412 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2014, 5:48 PM EDT for 12 counties in Florida. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Apr 18, 2014, 5:48 PM EDT (21:48 UTC)
Expired: Apr 18, 2014, 7:15 PM EDT
In force: 87 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Baker County, FL, Bradford County, FL, Clay County, FL, Columbia County, FL, Duval County, FL, Flagler County, FL, Nassau County, FL, Putnam County, FL, Saint Johns County, FL, Seminole County, FL, Union County, FL, Volusia County, FL

The radar

The Jacksonville radar (KJAX), 96 km from the middle of the area, began a volume at 21:47 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

Jacksonville, FL (KJAX), launched 12:00Z, 9.8 hours before the alert went out and 97 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 607 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 276 m²/s²
0-3 km storm-relative helicity: 337 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.

220 
ACUS11 KWNS 182148
SWOMCD
SPC MCD 182148 
FLZ000-GAZ000-182315-

MESOSCALE DISCUSSION 0366
NWS STORM PREDICTION CENTER NORMAN OK
0448 PM CDT FRI APR 18 2014

AREAS AFFECTED...PORTIONS OF NORTHEAST FLORIDA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 182148Z - 182315Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THERE WILL EXIST SOME POTENTIAL FOR ISOLATED SVR
THUNDERSTORMS TO OCCUR ACROSS NORTHEAST FLORIDA AS CONVECTION
SPREADS TOWARD THE ATLANTIC COAST DURING THE NEXT HOUR OR TWO. THE
ISSUANCE OF A WW IS UNLIKELY.

DISCUSSION...CONVECTION IS ARCING NWWD OVER NORTH FLORIDA...AND
RECENT RADAR TRENDS INDICATE THIS ACTIVITY IS EXHIBITING MORE OF A
SEMI-DISCRETE MODE NW OF A MORE CONTIGUOUS LINE REACHING DAYTONA
BEACH VICINITY. CLOUDS AND PRECIPITATION IN ADVANCE OF THIS ACTIVITY
HAVE TEMPERED DIURNAL BUOYANCY INCREASES. HOWEVER...A MOISTURE-RICH
BOUNDARY LAYER -- E.G. SFC DEWPOINTS IN THE LOWER 70S -- IS BOOSTING
LOW-LEVEL BUOYANCY AMIDST STRONG LOW-LEVEL SHEAR -- E.G. 0-1-KM BULK
SHEAR AROUND 25-30 KT PER JAX VWP DATA. AS SUCH...ISOLATED LOW-LEVEL
MESOVORTICES WITH A COUPLE INSTANCES OF DMGG WIND GUSTS COULD OCCUR.
A TORNADO CANNOT BE RULED OUT IN PROXIMITY TO AN ENE/WSW-ORIENTED
STATIONARY BOUNDARY...WHERE LOW-LEVEL SRH IS RELATIVELY ENHANCED.
HOWEVER...THE LIMITED SPATIOTEMPORAL WINDOW OF THE SVR POTENTIAL
PRECLUDES WW ISSUANCE.

..COHEN/MEAD.. 04/18/2014

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

ATTN...WFO...MLB...JAX...

LAT...LON   30108303 30388242 30818149 29968127 28938073 28408073
            28428118 29038148 29628185 29938234 29938275 30108303

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 18, 11:48 AM EDT	Mesoscale Discussion	SPC	Alachua, Charlotte, Citrus, DeSoto, Flagler, Hardee and 16 more	117 min
Apr 18, 1:51 PM EDT	Severe Thunderstorm Watch	SPC	Citrus, DeSoto, Hardee, Hernando, Highlands, Hillsborough and 7 more	4 hr
Apr 18, 3:57 PM EDT	Mesoscale Discussion	SPC	Highlands, Lake, Marion, Polk, Sumter	93 min
Apr 18, 7:11 PM EDT	Mesoscale Discussion	SPC	Martin, Palm Beach, Saint Lucie	2 hr

Nearby

Mesoscale Discussions in Florida, 2014 Every mesoscale discussion in 2014

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.