Alert archive / Florida / Mesoscale Discussions in 2012
Mesoscale Discussion 1816
The Storm Prediction Center issued this mesoscale discussion at Aug 26, 2012, 4:28 PM EDT for 8 counties in Florida. It was in force for 62 min.
The area
The outline as issued.
The facts
- Issued
- Aug 26, 2012, 4:28 PM EDT (20:28 UTC)
- Expired
- Aug 26, 2012, 5:30 PM EDT
- In force
- 62 min
- Issued by
- the Storm Prediction Center
Counties Broward County, FL, Collier County, FL, Glades County, FL, Hendry County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Palm Beach County, FL
The radar
The Miami radar (KAMX), 75 km from the middle of the area, began a volume at 20:30 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
Miami, FL (KMFL), launched 12:00Z, 8.5 hours before the alert went out and 75 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
- 1782 J/kg
- Mixed-layer CIN
- -7 J/kg
- Mixed-layer LCL
- 619 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 204 m²/s²
- 0-3 km storm-relative helicity
- 224 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 6.1
The text
As transmitted, in the capitals the NWS used until 2016.
371
ACUS11 KWNS 262028
SWOMCD
SPC MCD 262028
FLZ000-262130-
MESOSCALE DISCUSSION 1816
NWS STORM PREDICTION CENTER NORMAN OK
0328 PM CDT SUN AUG 26 2012
AREAS AFFECTED...S FL AND KEYS
CONCERNING...TORNADO WATCH 589...
VALID 262028Z - 262130Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 589 CONTINUES.
SUMMARY...SOME THREAT FOR ISOLATED TORNADOES IS EXPECTED TO PERSIST
INTO THE EVENING OVER SRN FL...GENERALLY ALONG AND SOUTH OF LAKE
OKEECHOBEE. OVERALL TORNADO THREAT DOES NOT APPEAR PARTICULARLY
ROBUST AT THIS TIME...BUT CONDITIONS MAY REMAIN AT LEAST MARGINALLY
SUFFICIENT FOR ANOTHER TORNADO WATCH ISSUANCE PRIOR TO EXPIRATION OF
WW 589 AT 21Z. A MEET ME CALL WILL INITIATED SOON TO DISCUSS WHETHER
OR NOT WW 589 WILL NEED TO BE REPLACED.
DISCUSSION...THE CENTER OF TROPICAL STORM ISAAC REMAINS SOUTH OF KEY
WEST FL AND IS SLOWLY MOVING IN A GENERAL WNWLY DIRECTION. SEE
LATEST ADVISORIES FROM NHC FOR MORE INFORMATION.
WIDESPREAD CLOUDS AND RAIN RELATED TO THE OUTER BANDS CONTINUE TO
LIMIT DESTABILIZATION OVER THE SRN FL PENINSULA. HOWEVER...RECENT
TRENDS HAVE SHOWN AN INCREASE IN LIGHTNING ACTIVITY OVER THE SRN TIP
OF FL WHERE A ZONE OF PARTIAL CLEARING HAS SHIFTED NWD. NEW
RAINBANDS ARE ALSO IN THE PROCESS OF DEVELOPING OFF THE SERN FL
COAST WITHIN ZONE OF MORE FAVORABLE LOW LEVEL DESTABILIZATION. VWP
DATA FROM MIAMI SHOW ALMOST UNIDIRECTIONAL SELY FLOW ABOVE 1 KM WITH
0-1 KM HELICITY AOB 100 M2/S2 BASED ON OBSERVED STORM MOTION.
OBJECTIVE ANALYSIS SHOWS GREATER HELICITY VALUES OVER THE SRN
INTERIOR PART OF THE PENINSULA WHERE STRONGER LOW LEVEL WINDS EXIST.
WHILE OVERALL TORNADO RISK IS NOT ROBUST...CURRENT THINKING IS BEST
THREAT NEXT 2-3 HOURS MAY EXIST AS CONVECTION DEVELOPING OVER SERN
FL LIFTS NWD AND INTERACTS WITH PRE-EXISTING BOUNDARY SOUTH OF LAKE
OKEECHOBEE.
..DIAL/WEISS.. 08/26/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MFL...MLB...KEY...TBW...
LAT...LON 26418182 27038160 27408071 27128023 26248009 25638019
24998061 24738119 24848149 25508128 26418182SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 7:05 AM EDT | Mesoscale Discussion | SPC | Broward, Charlotte, Collier, Glades, Hendry, Lee and 4 more | 2 hr |
| Aug 26, 8:29 AM EDT | Tornado Watch | SPC | Broward, Charlotte, Collier, DeSoto, Glades, Hendry and 9 more | 9 hr |
| Aug 26, 12:58 PM EDT | Mesoscale Discussion | SPC | Broward, Collier, Glades, Hendry, Highlands, Lee and 6 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.