Alert archive / Florida / Mesoscale Discussions in 2013
Mesoscale Discussion 577
The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2013, 12:38 PM EDT for 18 counties in Florida. It was in force for 97 min.
The area
The outline as issued.
The facts
- Issued
- Apr 29, 2013, 12:38 PM EDT (16:38 UTC)
- Expired
- Apr 29, 2013, 2:15 PM EDT
- In force
- 97 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
Counties Broward County, FL, DeSoto County, FL, Glades County, FL, Hardee County, FL, Hendry County, FL, Highlands County, FL, Indian River County, FL, Lake County, FL, Martin County, FL, Miami-Dade County, FL, Monroe County, FL, Okeechobee County, FL, Orange County, FL, Osceola County, FL, Palm Beach County, FL, Polk County, FL, Saint Lucie County, FL, Seminole County, FL
The radar
The Melbourne radar (KMLB), 127 km from the middle of the area, began a volume at 16:40 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, 4.6 hours before the alert went out and 133 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
- 9 J/kg
- Mixed-layer CIN
- -166 J/kg
- Mixed-layer LCL
- 1018 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 64 m²/s²
- 0-3 km storm-relative helicity
- 58 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
968
ACUS11 KWNS 291639
SWOMCD
SPC MCD 291638
FLZ000-291815-
MESOSCALE DISCUSSION 0577
NWS STORM PREDICTION CENTER NORMAN OK
1138 AM CDT MON APR 29 2013
AREAS AFFECTED...CNTRL/SRN FL PENINSULA
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 291638Z - 291815Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...SCATTERED THUNDERSTORMS ARE FORECAST TO DEVELOP THIS
AFTERNOON OVER THE CNTRL/SRN FL PENINSULA. ISOLATED DAMAGING WIND
GUSTS AND LARGE HAIL WILL BE POSSIBLE...BUT THREAT DOES NOT APPEAR
TO JUSTIFY A WW.
DISCUSSION...MIDDAY SURFACE OBSERVATIONS SHOW TEMPERATURES WARMING
INTO THE 80S OVER THE CNTRL/SRN PENINSULA...WITH DEWPOINTS HOLDING
IN THE LOW 60S OVER INLAND LOCATIONS...TO THE MID/UPPER 60S ALONG
THE COAST. THE WARM/MOIST SURFACE AIRMASS COMBINED WITH FAVORABLY
COLD MIDLEVEL TEMPERATURES IS YIELDING MLCAPE VALUES NEAR 1000 J/KG.
IN ADDITION...THE WARMING SURFACE AIRMASS IS AIDING IN BOUNDARY
LAYER DESTABILIZATION AND DEEPENING CUMULUS PER VISIBLE SATELLITE
IMAGERY...WHICH IS EXPECTED TO LEAD TO SCATTERED THUNDERSTORM
DEVELOPMENT AS THE AFTERNOON PROGRESSES. AREA VAD WIND PROFILES
INDICATE VERTICAL WIND PROFILES ARE WEAK...WITH EFFECTIVE BULK SHEAR
VALUES BELOW 30 KT. THUS...DISORGANIZED MULTICELL CLUSTERS WILL BE
THE PREDOMINANT CONVECTIVE MODE...A FEW OF WHICH MAY PRODUCE
ISOLATED INSTANCES OF DAMAGING WINDS/LARGE HAIL.
..GARNER/HART.. 04/29/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MFL...MLB...TBW...JAX...
LAT...LON 27838212 29748156 26717999 25458034 25588102 26528155
27838212Nearby
Mesoscale Discussions in Florida, 2013Every mesoscale discussion in 2013
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.