Alert archive / Florida / Mesoscale Discussions in 2011

Mesoscale Discussion 324

March 31, 201116 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Mar 31, 2011, 6:22 PM EDT for 16 counties in Florida. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Mar 31, 2011, 6:22 PM EDT (22:22 UTC)
Expired: Mar 31, 2011, 7:45 PM EDT
In force: 83 min
Issued by: the Storm Prediction Center

Counties Brevard County, FL, Charlotte County, FL, DeSoto County, FL, Glades County, FL, Hardee County, FL, Highlands County, FL, Hillsborough County, FL, Indian River County, FL, Lee County, FL, Manatee County, FL, Martin County, FL, Okeechobee County, FL, Osceola County, FL, Palm Beach County, FL, Polk County, FL, Saint Lucie County, FL

The radar

The Tampa radar (KTBW), 76 km from the middle of the area, began a volume at 22:22 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

Tampa Bay, FL (KTBW), launched 12:00Z, 10.4 hours before the alert went out and 76 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: 728 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 787 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: 543 m²/s²
0-3 km storm-relative helicity: 606 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 8.9

Open this sounding in Storm Lab

The text

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

887 
ACUS11 KWNS 312222
SWOMCD
SPC MCD 312222 
FLZ000-312345-

MESOSCALE DISCUSSION 0324
NWS STORM PREDICTION CENTER NORMAN OK
0522 PM CDT THU MAR 31 2011

AREAS AFFECTED...CNTRL FL

CONCERNING...TORNADO WATCH 81...

VALID 312222Z - 312345Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 81 CONTINUES.

AN ISOLATED TORNADO AND WIND DAMAGE THREAT WILL LIKELY CONTINUE
EARLY THIS EVENING ACROSS THE CNTRL FL PENINSULA. WW ISSUANCE TO
REPLACE WW 81 WILL BE CONSIDERED AS THE EXPIRATION OF THE CURRENT
TORNADO WATCH APPROACHES.

A SLOW MOVING LINE OF THUNDERSTORMS EMBEDDED WITH SOME STRONGER
CONVECTIVE ELEMENTS IS LOCATED IN CNTRL FL ORIENTED PARALLEL TO A 40
TO 50 KT LOW-LEVEL JET. THE AIRMASS JUST TO THE SOUTH OF THE LINE IS
CHARACTERIZED BY MODERATE INSTABILITY /MLCAPE VALUES OF 1200 TO 1800
J/KG/ AND STRONG DEEP LAYER SHEAR /0-6 KM SHEAR OF 60 TO 70 KT. THIS
COMBINED 30 TO 40 KT OF FLOW JUST BELOW 1 KM AGL EVIDENT ON THE
WSR-88D VWP FROM MELBOURNE FL SHOULD BE ENOUGH FOR A WIND DAMAGE
THREAT WITH THE MORE INTENSE CELLS EMBEDDED IN THE LINE. ALTHOUGH
THE LOW-LEVEL FLOW IS VEERED WLY...ENOUGH SPEED SHEAR EXISTS IN THE
BOUNDARY LAYER FOR AN ISOLATED TORNADO THREAT. THE THREAT MAY
PERSIST BEYOND WATCH EXPIRATION AND WW ISSUANCE MAY BE NEEDED
ESPECIALLY IF THE LINE CAN INTENSIFY AND REORGANIZE EARLY THIS
EVENING.

..BROYLES.. 03/31/2011

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

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

LAT...LON   28308278 28318048 26577994 26568219 28308278

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 31, 4:40 AM EDT	Mesoscale Discussion	SPC	Alachua, Bradford, Citrus, Columbia, Dixie, Franklin and 19 more	2 hr
Mar 31, 6:00 AM EDT	Tornado Watch	SPC	Brevard, Charlotte, Citrus, DeSoto, Flagler, Glades and 25 more	7 hr
Mar 31, 9:39 AM EDT	Mesoscale Discussion	SPC	Brevard, Charlotte, Citrus, DeSoto, Glades, Hardee and 21 more	66 min
Mar 31, 12:12 PM EDT	Mesoscale Discussion	SPC	Brevard, Charlotte, Citrus, DeSoto, Glades, Hardee and 22 more	63 min
Mar 31, 12:46 PM EDT	Tornado Watch	SPC	Brevard, Charlotte, DeSoto, Glades, Hardee, Hendry and 15 more	7 hr
Mar 31, 2:56 PM EDT	Mesoscale Discussion	SPC	Brevard, Charlotte, DeSoto, Glades, Hardee, Highlands and 10 more	64 min

Nearby

Mesoscale Discussions in Florida, 2011 Every mesoscale discussion in 2011

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.