Alert archive / Florida / Mesoscale Discussions in 2011
Mesoscale Discussion 321
The Storm Prediction Center issued this mesoscale discussion at Mar 31, 2011, 9:39 AM EDT for 27 counties in Florida. It was in force for 66 min.
The area
The outline as issued.
The facts
- Issued
- Mar 31, 2011, 9:39 AM EDT (13:39 UTC)
- Expired
- Mar 31, 2011, 10:45 AM EDT
- In force
- 66 min
- Issued by
- the Storm Prediction Center
All 27 counties
Brevard County, FL, Charlotte County, FL, Citrus County, FL, DeSoto County, FL, Glades County, FL, Hardee County, FL, Hendry County, FL, Hernando County, FL, Highlands County, FL, Hillsborough County, FL, Indian River County, FL, Lake County, FL, Lee County, FL, Levy County, FL, Manatee County, FL, Marion County, FL, Martin County, FL, Okeechobee County, FL, Orange County, FL, Osceola County, FL, Palm Beach County, FL, Pasco County, FL, Polk County, FL, Saint Lucie County, FL, Seminole County, FL, Sumter County, FL, Volusia County, FL
The radar
The Tampa radar (KTBW), 86 km from the middle of the area, began a volume at 13:41 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.
The nearest sounding before it
Tampa Bay, FL (KTBW), launched 12:00Z, 1.7 hours before the alert went out and 86 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.
- 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
The text
As transmitted, in the capitals the NWS used until 2016.
686
ACUS11 KWNS 311339
SWOMCD
SPC MCD 311339
FLZ000-311445-
MESOSCALE DISCUSSION 0321
NWS STORM PREDICTION CENTER NORMAN OK
0839 AM CDT THU MAR 31 2011
AREAS AFFECTED...FL PENINSULA
CONCERNING...TORNADO WATCH 80...
VALID 311339Z - 311445Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 80 CONTINUES.
ALTHOUGH A SURFACE LOW WAS LOCATED IN THE FAR NERN GULF OF MEXICO
AND A STATIONARY FRONT STRETCHED ACROSS THE NRN FL PENINSULA...THE
EFFECTIVE BOUNDARY FOR THE MOST INTENSE SEVERE CONVECTION STRETCHED
E-W FROM APPROXIMATELY 30 N PIE TO 30 MLB. ALONG AND NORTH OF THE
BOUNDARY...EXTENSIVE CLOUDS...RAIN AND SEVERE STORMS WERE
OCCURRING...WHILE MOSTLY SUNNY SKIES WERE LOCATED SOUTH. STORMS ARE
EXPECTED TO KEEP TRACKING EWD FROM THE GULF THROUGH THE CENTRAL
PENINSULA...WITH THE BOUNDARY GRADUALLY BEING PUSHED SWD DUE TO
OUTFLOW FROM THE PCPN. GIVEN DEEP LAYER SHEAR NEAR 60 KT...
SUPERCELLS AND MODERATE INSTABILITY SOUTH OF THE BOUNDARY...
SUPERCELLS ARE LIKELY. WIND PROFILES FAVOR BOTH SUPERCELLS WITH
TORNADOES...ESPECIALLY ALONG THE EFFECTIVE BOUNDARY WHERE 35-40 KT
LOW LEVEL SHEAR EXISTS...AND BOW ECHOES WITH WIND DAMAGE. GREATEST
TORNADO THREAT THE NEXT HOUR OR SO WILL BE ASSOCIATED WITH INTENSE
SUPERCELL MOVING EWD AT 50 KT THROUGH POLK COUNTY TOWARD OSCEOLA AND
EVENTUALLY BREVARD COUNTIES.
..IMY.. 03/31/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MFL...MLB...TBW...JAX...TAE...
LAT...LON 29308321 27888268 26458204 26398080 26457971 28158033
29308073 29368195 29308321SPC 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, 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 |
| Mar 31, 6:22 PM EDT | Mesoscale Discussion | SPC | Brevard, Charlotte, DeSoto, Glades, Hardee, Highlands and 10 more | 83 min |
Nearby
Mesoscale Discussions in Florida, 2011Every 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.