SPC MESOSCALE DISCUSSION 1525 FOR NRN/NERN NEB...ERN SD
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

VALID 161955Z - 162130Z

VISIBLE IMAGERY INDICATES CONVECTION COULD BE CLOSE TO BREAKING THE
CAP FROM NRN/NERN NEB INTO SRN SD WHERE 50MB MIXED LAYER CAPES ARE
APPROACHING 3000 J/KG. IF CONVECTION CONTINUES ON THE INCREASE...A
WW WILL BE NEEDED.

VISIBLE/RADAR IMAGERY REVEALS A DISCERNABLE INCREASING TREND IN
ACTIVITY IN NRN/NERN NEB ABOUT 25 MILES EAST OF ANW. GIVEN THE
DEGREE OF INSTABILITY IN THIS REGION...WITH TEMPERATURES FROM 85-90
DEGREES AND DEWPOINTS IN THE MIDDLE 60S TO LOWER 70S...AN INCREASE
IN CONVECTION APPEARS IMMINENT ACROSS THESE AREAS. FORECAST
SOUNDINGS ACROSS THIS AREA FOR LATE AFTERNOON INDICATE STEEP MID-
LEVEL LAPSE RATES...OVER 4000 J/KG OF CAPE...WITH AROUND 40 KT OF
0-6KM SHEAR. IF CAP CONTINUES TO DECREASE...SEVERE CONVECTION WITH
A MEAN MOVEMENT OF 260-270 DEGREES WILL BE LIKELY WITH A PRIMARY
THREAT OF DAMAGING WIND GUSTS AND LARGE HAIL. 

..NADEN.. 07/16/01