Mesoscale Data
Analyzed surface temperatures (red/purple), dew points (brown/green), and wind barbs from SPC at 18 UTC on Saturday, April 12, 2008
Southwesterly surface winds transported moist air with dew points in the lower to mid
60s across the Coastal Plain. Sunshine earlier in the day allowed surface temperatures to climb into the lower 80s.
850 MB heights, temperatures (red/blue), dew points (green), and wind barbs (black) from SPC at 18 UTC on Saturday, April 12, 2008
A southwesterly jet with wind speeds of 50 to 55 knots and an enhanced area of moisture
was present across the Coastal Plain. A short wave trough is located just east of the Appalachians.
Analyzed low level lapse rates in the 0-3 km layer (blue, green, and orange) from SPC at 18 UTC on Saturday, April 12, 2008
A lapse rate is the rate of temperature change with height and the image below
is for the layer from the surface to around 10,000 feet. Note the surface based, low level
lapse rates shown below range in the 6.5 to 7.0 deg C/km across include much of central North
Carolina. Values less than 6 degrees C/km represent "stable" conditions, while values near 9 degrees
C/km are considered "absolutely unstable." The greatest lapse rates and greatest instability
is located across the Coastal Plain and Coast.
Analyzed surface based convective available potential energy (SBCAPE) (red) and surface based
convective inhibition (blue lines - shaded) from SPC at 18 UTC on Saturday, April 12, 2008
SBCAPE values ranged between 500 and around 1000 J/kg across the Coastal Plain.
Analyzed mixed layer convective available potential energy (MLCAPE) (red) and mixed layer
convective inhibition (blue lines - shaded) from SPC at 18 UTC on Saturday, April 12, 2008
MLCAPE values ranged between 250 and around 500 J/kg across the Coastal Plain.
0-3 Km Storm Relative Helicity (blue) and storm motion (brown) from SPC at 18 UTC on Saturday, April 12, 2008
Note the 0-3 Km SRH values ranged around 150 units in the Coastal Plain.
Analyzed Lifting Condensation Level (red, blue, and green) from SPC at 18 UTC on Saturday, April 12, 2008
The LCL height is the height at which a parcel becomes saturated when lifted dry adiabatically.
The importance of LCL height is thought to relate to sub-cloud evaporation and the potential
for outflow dominance. Low LCL heights imply less evaporational cooling from precipitation
and less potential for a strong outflow that would likely inhibit low-level mesocyclone development.
Thunderstorms that produce tornadoes generally have a lower LCL height with LCL heights
less than 1,000 meters typically favorable for the development of significant tornadoes. The LCL values during this
event were between 1,000 and 1,250 meters in the Coastal Plain.
NWS Composite Reflectivity Imagery from 1830 UTC on Saturday, April 12, 2008
The composite reflectivity imagery is from the approximate time in which the analysis imagery above is valid.
|
|