Alert archive / Florida / Mesoscale Discussions in 2012
Mesoscale Discussion 1822
The Storm Prediction Center issued this mesoscale discussion at Aug 27, 2012, 2:28 PM EDT for 12 counties in Florida. It was in force for 92 min.
The area
The outline as issued.
The facts
- Issued
- Aug 27, 2012, 2:28 PM EDT (18:28 UTC)
- Expired
- Aug 27, 2012, 4:00 PM EDT
- In force
- 92 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
Counties Citrus County, FL, DeSoto County, FL, Hardee County, FL, Hernando County, FL, Highlands County, FL, Hillsborough County, FL, Manatee County, FL, Pasco County, FL, Pinellas County, FL, Polk County, FL, Sarasota County, FL, Sumter County, FL
The radar
The Tampa radar (KTBW), 45 km from the middle of the area, began a volume at 18:31 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, 6.5 hours before the alert went out and 45 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
- 566 J/kg
- Mixed-layer CIN
- -21 J/kg
- Mixed-layer LCL
- 548 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 391 m²/s²
- 0-3 km storm-relative helicity
- 419 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.6
The text
As transmitted, in the capitals the NWS used until 2016.
095
ACUS11 KWNS 271828
SWOMCD
SPC MCD 271828
FLZ000-272000-
MESOSCALE DISCUSSION 1822
NWS STORM PREDICTION CENTER NORMAN OK
0128 PM CDT MON AUG 27 2012
AREAS AFFECTED...PARTS OF WEST CENTRAL AND NWRN FL PENINSULA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 271828Z - 272000Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...KINEMATIC ENVIRONMENT IS CONDUCIVE FOR ISOLATED/BRIEF LOW
LEVEL ROTATION/TORNADO THREAT...BUT THERMODYNAMICS ARE NOT
SUPPORTIVE AT THIS TIME FOR DEEP UPDRAFTS FAVORING LONGER-LIVED
STORMS. CONVECTIVE TRENDS WILL BE MONITORED BOTH AT SPC AND LOCAL
WFO/S FOR ANY INCREASED TORNADO THREAT...AND THE SUBSEQUENT
POTENTIAL NEED FOR A TORNADO WATCH.
DISCUSSION...TRENDS IN SURFACE STREAMLINE ANALYSES AND TEMPERATURES
SUGGEST A BAROCLINIC ZONE EXTENDED FROM JUST N OF LAKE OKEECHOBEE
WWD TO INVOF SRQ. ELY SURFACE TRAJECTORIES LOCATED N OF THIS
BOUNDARY VEERING TO SLY AT 2-3 KM AGL PER TBW WSR-88D VAD ARE
RESULTING IN LOW LEVEL HODOGRAPH CURVATURE AND SFC-1 KM SHEAR OF 30
KT. RADAR DATA INDICATED CLOUD TOPS ARE RANGING FROM 20-30
KFT...WHILE LIGHTNING DATA HAS NOT DETECTED ANY CG STRIKES WITH THE
SHALLOW CONVECTIVE CELLS MOVING NNWWD THROUGH WEST CENTRAL FL.
ALTHOUGH THE UPDRAFTS HAVE NOT BECOME DEEP ENOUGH FOR LIGHTNING
PRODUCTION...THE KINEMATIC ENVIRONMENT IS FAVORABLE FOR AT LEAST
ISOLATED/BRIEF LOW LEVEL ROTATION. SURFACE DEW POINTS IN THE UPPER
70S TO NEAR 80 F AND SOME SURFACE HEATING HAVE BOOSTED MLCAPE TO
AROUND 1000 J/KG. IF CONVECTIVE TRENDS INDICATE THE DEVELOPMENT OF
DEEPER AND MORE PERSISTENT UPDRAFTS...A TORNADO WATCH WOULD NEED TO
BE CONSIDERED FOR PARTS OF WEST CENTRAL INTO NWRN FL PENINSULA.
..PETERS/WEISS.. 08/27/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MFL...MLB...TBW...JAX...
LAT...LON 28598324 29248303 29108223 28348151 27458111 27158117
27078205 27308270 28598324SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 10:44 PM EDT | Mesoscale Discussion | SPC | Broward, Charlotte, Collier, DeSoto, Glades, Hendry and 4 more | 2 hr |
| Aug 26, 11:24 PM EDT | Tornado Watch | SPC | Brevard, Broward, Charlotte, Collier, DeSoto, Glades and 17 more | 12 hr |
| Aug 27, 3:44 AM EDT | Mesoscale Discussion | SPC | Broward, Charlotte, Collier, DeSoto, Glades, Hardee and 16 more | 2 hr |
| Aug 27, 7:26 AM EDT | Mesoscale Discussion | SPC | Brevard, Citrus, Dixie, Gilchrist, Hernando, Indian River and 13 more | 3 hr |
| Aug 27, 7:55 AM EDT | Mesoscale Discussion | SPC | Broward, Charlotte, Collier, DeSoto, Glades, Hardee and 16 more | 95 min |
| Aug 27, 11:54 AM EDT | Mesoscale Discussion | SPC | Indian River, Lake, Marion, Orange, Osceola, Saint Lucie and 3 more | 2 hr |
Nearby
Mesoscale Discussions in Florida, 2012Every 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.