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ROBERT M. CUNNINGHAM 
UPPER WINDS 
DENVER SCOTTSBLUFF 
—l0Ombs  j2097 
ABOVE ts VT {Ith lakh 
DENVER —__- 
'200Z I|SEPT 58 
Fie. 4—Skew T log P plot 
lack of distinet individual turrets at the top sug- 
gests that the storm is characterized by a large 
region of fairly continuous upward velocity with 
a narrow velocity spectrum, in contrast to many 
Cumulus systems where the velocity spectrum is 
wide and individual turret production is a major 
feature. Much of the cloud material that reaches 
these heights gains momentum from the ambient 
air and spreads downstream in the anvil. This 
feature is best seen in the young cloud in the 
upper middle of Figure 2. The Cirrostratus layer 
at flight level (Figs. 5 and 6), may be caused 
by the upwind spreading of that portion of 
the upper cloud material that has lost its up- 
ward momentum, is relatively cold, and descends 
against the ambient wind down to the isothermal 
layer. More hkely, however, this upstream Cir- 
rostratus is formed by an uplift of the ambient 
air flowing around the storm. The horizontal, 
thin protrusions on the north side of the storm, 
pictured best in Figure 3 at about 27,000 ft and 
22,00 ft, may be caused by this blocking action 
forcing the ambient air to ascend. That portion 
of the protrusion at 22,000 ft, visible on Figures 
5 and 6, appears rather to be caused by motions 
within the storm. Mammatus formations mark 
the lower portion of this protrusion, suggesting 
that small precipitation particles and clouds are 
flowing down and out of the main cloud and 
evaporating into the ambient air. 
The most interesting feature shown on Figure 
5 and sketched on Figure 6 is the great fall of 
hydrometeors into the sunshine below the marked 
protrusion. The bright portion of this fallout 
is presumably a region of snow, snow pellets, and 
hail (S + A). The dimmer portion, rain and hail 
(R + A). The brightest portion in these two 
regions may be shafts and bunches of falling 
heavy hail. The level at which most of the small 
frozen particles have melted is 8000 to 12,000 ft 
or at +20 to +8°C ambient air temperature; the 
more relevant local air and wet bulb tempera- 
ture in the precipitation is unknown. 
To the right of the precipitation is a large 
