Alert archive / Florida / Mesoscale Discussions in 2014

Mesoscale Discussion 1920

November 17, 201417 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Nov 17, 2014, 12:14 PM EST for 17 counties in Florida. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Nov 17, 2014, 12:14 PM EST (17:14 UTC)
Expired: Nov 17, 2014, 2:15 PM EST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 80%

Counties Brevard County, FL, Citrus County, FL, Dixie County, FL, Flagler County, FL, Hernando County, FL, Hillsborough County, FL, Lake County, FL, Levy County, FL, Marion County, FL, Orange County, FL, Osceola County, FL, Pasco County, FL, Pinellas County, FL, Polk County, FL, Seminole County, FL, Sumter County, FL, Volusia County, FL

The radar

The Tampa radar (KTBW), 81 km from the middle of the area, began a volume at 17:16 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 556Nov 17, 12:30 PM EST

The nearest sounding before it

Tampa Bay, FL (KTBW), launched 12:00Z, 5.2 hours before the alert went out and 81 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: 152 J/kg
Mixed-layer CIN: -104 J/kg
Mixed-layer LCL: 702 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 251 m²/s²
0-3 km storm-relative helicity: 278 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

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

340 
ACUS11 KWNS 171714
SWOMCD
SPC MCD 171714 
FLZ000-171915-

MESOSCALE DISCUSSION 1920
NWS STORM PREDICTION CENTER NORMAN OK
1114 AM CST MON NOV 17 2014

AREAS AFFECTED...CNTRL INTO NRN FL

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 171714Z - 171915Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...STORMS WILL CONTINUE EWD OFF THE GULF OF MEXICO AND ACROSS
FL WITH LOCALLY DAMAGING WINDS POSSIBLE. A WATCH MAY BE NEEDED.

DISCUSSION...A ROBUST LINE OF STORMS CURRENTLY EXTENDS FROM NRN FL
SWWD ACROSS THE ERN GULF OF MEXICO JUST AHEAD OF AN ADVANCING COLD
FRONT. NRN SECTIONS OF THE LINE ARE ACCELERATING DUE IN PART TO
AMASSING OUTFLOW...WITH DAMAGING WINDS POSSIBLE AS THEY MOVE ASHORE.
STRONG DEEP-LAYER SHEAR EXISTS ALONG WITH SOME LOW-LEVEL VEERING PER
TBW VWP...SUGGESTING EMBEDDED AREAS OF ROTATION WITHIN THE QLCS.

..JEWELL/CORFIDI.. 11/17/2014

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

ATTN...WFO...MLB...TBW...JAX...TAE...

LAT...LON   27618218 27478328 27508441 27838437 28518388 29058380
            29608324 29638224 29468098 28968073 28378040 27878120
            27618218

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Nov 17, 12:50 AM EST	Mesoscale Discussion	SPC	Escambia, Santa Rosa	55 min
Nov 17, 2:13 AM EST	Mesoscale Discussion	SPC	Bay, Calhoun, Escambia, Franklin, Gadsden, Gulf and 12 more	32 min
Nov 17, 2:32 AM EST	Tornado Watch	SPC	Bay, Calhoun, Escambia, Franklin, Gadsden, Gulf and 9 more	7 hr
Nov 17, 5:39 AM EST	Mesoscale Discussion	SPC	Bay, Calhoun, Dixie, Escambia, Franklin, Gadsden and 14 more	66 min
Nov 17, 6:11 AM EST	Tornado Watch	SPC	Columbia, Dixie, Franklin, Gadsden, Hamilton, Jefferson and 7 more	8 hr
Nov 17, 8:43 AM EST	Mesoscale Discussion	SPC	Bay, Calhoun, Columbia, Dixie, Franklin, Gadsden and 15 more	92 min
Nov 17, 10:57 AM EST	Tornado Watch	SPC	Alachua, Baker, Bradford, Clay, Duval, Flagler and 5 more	4 hr
Nov 17, 12:30 PM EST	Tornado Watch	SPC	Brevard, Charlotte, Citrus, DeSoto, Hardee, Hernando and 16 more	6 hr
Nov 17, 3:10 PM EST	Mesoscale Discussion	SPC	DeSoto, Hardee, Highlands, Hillsborough, Lake, Manatee and 5 more	65 min

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.