Alert archive / Florida / Mesoscale Discussions in 2012
Mesoscale Discussion 819
The Storm Prediction Center issued this mesoscale discussion at May 15, 2012, 5:38 PM EDT for 32 counties in Florida; Brantley County, Camden County, Charlton County, Georgia. It was in force for 97 min.
The area
The outline as issued.
The facts
- Issued
- May 15, 2012, 5:38 PM EDT (21:38 UTC)
- Expired
- May 15, 2012, 7:15 PM EDT
- In force
- 97 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 35 counties
Alachua County, FL, Baker County, FL, Bradford County, FL, Brevard County, FL, Broward County, FL, Charlotte County, FL, Clay County, FL, Collier County, FL, DeSoto County, FL, Duval County, FL, Flagler County, FL, Glades County, FL, Hardee County, FL, Hendry County, FL, Highlands County, FL, Indian River County, FL, Lake County, FL, Marion County, FL, Martin County, FL, Nassau County, FL, Okeechobee County, FL, Orange County, FL, Osceola County, FL, Palm Beach County, FL, Polk County, FL, Putnam County, FL, Saint Johns County, FL, Saint Lucie County, FL, Seminole County, FL, Sumter County, FL, Union County, FL, Volusia County, FL, Brantley County, GA, Camden County, GA, Charlton County, GA
The radar
The Melbourne radar (KMLB), 101 km from the middle of the area, began a volume at 21:41 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 nearest sounding before it
Cape Canaveral, FL (KXMR), launched 12:00Z, 9.6 hours before the alert went out and 85 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1390 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- -5 m²/s²
- 0-3 km storm-relative helicity
- -2 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
448
ACUS11 KWNS 152139
SWOMCD
SPC MCD 152138
FLZ000-GAZ000-152315-
MESOSCALE DISCUSSION 0819
NWS STORM PREDICTION CENTER NORMAN OK
0438 PM CDT TUE MAY 15 2012
AREAS AFFECTED...MUCH OF THE FL PENINSULA AND PARTS OF SERN GA
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 152138Z - 152315Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...A THREAT FOR STRONG STORMS WILL CONTINUE INTO EARLY
EVENING. A MARGINAL/ISOLATED SVR THREAT CANNOT BE RULED OUT WITH THE
STRONGEST STORMS. THE ISSUANCE OF A WW IS UNLIKELY.
DISCUSSION...NUMEROUS BOUNDARIES ACROSS THE REGION...INCLUDING
INLAND-MOVING SEA BREEZE BOUNDARIES AND CONVECTIVE OUTFLOW
BOUNDARIES...CONTINUE TO FOSTER SCATTERED DEEP CONVECTION AMIDST A
MODERATELY UNSTABLE AIR MASS. THROUGH EARLY EVENING...THE ACTIVITY
WILL LIKELY REMAIN MOST CONCENTRATED ACROSS THE SRN HALF OF THE FL
PENINSULA...SOUTH OF A LINE FROM NEAR MELBOURNE TO NEAR SARASOTA. IN
THIS REGION...WATER VAPOR IMAGERY INDICATES THE PRESENCE OF WEAK
MID-LEVEL ASCENT IN ASSOCIATION WITH A SUBTLE/LOW-LATITUDE IMPULSE.
WHERE CONVECTIVE OVERTURNING HAS NOT ALREADY OCCURRED...THE
COMBINATION OF STEEP LOW-LEVEL LAPSE RATES AND FAIRLY RICH LOW-LEVEL
MOISTURE -- SFC DEWPOINTS IN THE MIDDLE 60S -- IS SUPPORTING MLCAPE
VALUES OF 1000-1500 J/KG. THIS WILL YIELD A THREAT FOR STRONG
STORMS...AND PERHAPS A MARGINALLY SVR STORM OR TWO. VERTICAL WIND
PROFILES PER VWP DATA SUGGEST ONLY MODEST DEEP SHEAR IN PLACE...WITH
0-6-KM BULK SHEAR MAGNITUDES GENERALLY 30 KT OR LESS...WHICH WILL
YIELD A PRIMARILY MULTICELLULAR CONVECTIVE MODE. STRONG WIND GUSTS
AND SMALL HAIL WILL BE THE MAIN CONCERNS WITH THESE STORMS.
HOWEVER...GIVEN PW VALUES OF 1.55-1.75 INCH PER GPS
DATA...WATER-LOADING PROCESSES MAY SUPPORT A FEW INSTANCES OF WET
MICROBURSTS CONTAINING MARGINALLY SVR WIND GUSTS. WEAK MID-LEVEL
LAPSE RATES AND WEAK MID/HIGH-LEVEL FLOW WILL PRECLUDE A MORE
SUBSTANTIAL SVR THREAT.
STORMS SHOULD DECREASE IN COVERAGE/INTENSITY AFTER 00Z IN
ASSOCIATION WITH THE DEVELOPMENT OF THE STABLE NOCTURNAL BOUNDARY
LAYER.
..COHEN/CORFIDI.. 05/15/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MFL...MLB...TBW...JAX...
LAT...LON 31038120 29998103 28598041 27057983 25768012 25668116
26838209 29408239 30758241 31338192 31038120SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 15, 1:07 PM EDT | Mesoscale Discussion | SPC | Burke, Columbia, Elbert, Glascock, Hart, Lincoln and 4 more | 113 min |
| May 15, 2:27 PM EDT | Severe Thunderstorm Watch | SPC | Bryan, Bulloch, Burke, Candler, Chatham, Columbia and 11 more | 7 hr |
| May 15, 3:13 PM EDT | Severe Thunderstorm Watch | SPC | Elbert, Franklin, Habersham, Hart, Rabun, Stephens | 7 hr |
| May 15, 6:30 PM EDT | Mesoscale Discussion | SPC | Bryan, Bulloch, Burke, Candler, Chatham, Columbia and 16 more | 90 min |
Nearby
Mesoscale Discussions in Florida, 2012Mesoscale Discussions in Georgia, 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.