Alert archive / Florida / Mesoscale Discussions in 2009

Mesoscale Discussion 813

May 13, 200915 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at May 13, 2009, 3:07 PM EDT for 15 counties in Florida. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: May 13, 2009, 3:07 PM EDT (19:07 UTC)
Expired: May 13, 2009, 4:00 PM EDT
In force: 53 min
Issued by: the Storm Prediction Center

Counties Charlotte County, FL, Citrus County, FL, DeSoto County, FL, Glades County, FL, Hardee County, FL, Hernando County, FL, Highlands County, FL, Hillsborough County, FL, Lee County, FL, Manatee County, FL, Marion County, FL, Pasco 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 19:11 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, 7.1 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 601 J/kg
Mixed-layer CIN: -71 J/kg
Mixed-layer LCL: 949 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 84 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
ACUS11 KWNS 131907
SWOMCD
SPC MCD 131907 
FLZ000-132000-

MESOSCALE DISCUSSION 0813
NWS STORM PREDICTION CENTER NORMAN OK
0207 PM CDT WED MAY 13 2009

AREAS AFFECTED...W CENTRAL FL PENINSULA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 131907Z - 132000Z

THE THREAT FOR DAMAGING WIND GUSTS MAY DEVELOP OVER WRN PORTIONS OF
THE CENTRAL FL PENINSULA DURING THE AFTERNOON. THE POTENTIAL FOR
ORGANIZED SEVERE STORMS IS LOW...WHICH WILL PRECLUDE A WW.

GENERALLY WEAK SYNOPTIC SCALE REGIME RESIDES ACROSS THE SERN CONUS
INTO THE FL PENINSULA...RESULTING IN NEGLIGIBLE DEEP AND LOW LEVEL
VERTICAL WIND SHEAR...FAVORING UNORGANIZED MULTICELL THUNDERSTORM
DEVELOPMENT DURING THE AFTERNOON. HOWEVER...STRONG DAYTIME HEATING
IS OCCURRING OVER WRN PORTIONS OF THE CENTRAL FL
PENINSULA...ALLOWING TEMPERATURES TO CLIMB THROUGH THE 80S AND LOW
90S. THIS HEATING...COMBINED WITH A FAVORABLY MOIST BOUNDARY LAYER
/SURFACE DEWPOINTS GENERALLY IN THE MID 60S/...YIELDS MLCAPE VALUES
AOA 2000 J/KG. IN ADDITION...WARM SURFACE TEMPERATURES ARE AIDING IN
THE DEVELOPMENT OF STEEP LOW LEVEL LAPSE RATES /AROUND 9.5 C PER KM
BASED ON MODIFIED RUC SOUNDINGS/. THE COMBINATION OF LARGE
INSTABILITY /AND THUS POTENTIAL FOR SUBSTANTIAL PRECIPITATION
LOADING ALOFT/ AND THE WELL MIXED BOUNDARY LAYER MAY RESULT IN AN
ISOLATED DAMAGING WIND GUST THREAT DURING THE AFTERNOON WITH THE
STRONGER UPDRAFT CORES.

..GARNER.. 05/13/2009

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MFL...MLB...TBW...JAX...

LAT...LON   29188282 29548258 29328203 27158104 26278128 26148182
            27498267 29188282

Nearby

Mesoscale Discussions in Florida, 2009 Every mesoscale discussion in 2009

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.