WMOD00379

• Title: Potential Opportunities for Precipitation Augmentation in the Eastern Tennessee Valley
• Date: 2/1/1988
• Weather Modification - Doc Type: Report

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Figure 4.16 (a) Mesoscale convective complex approaching the
eastern TVA region on 5 April 1983 as seen on a
combined visible/infrared image. Infrared super-
imposed for visible at CTT1s colder than -32 oC.
,(b) Total 4-day preci~itation total over southeast
United States from a series of MCC1s (from Fritsch

et al., 1986). ................... 27

Figure 4.17 Same as Fig. 4.14, only showing results for month of
March for each year. Percentages shown beneath each year
are percentages of normal precipitation above Chattanooga
for March of that year. . . . . . . . . . . . . 28

Figure 4.18

Figure 4.19
Figure 4.20
Figure 4.21
Figure 4.22

Same as Fig. 4.17, only for synoptic/mesoscale
classifications. . . . . . . . . . . 28
Same as Fig. 4.17, only for April. . 30
Same as Fig. 4.18, only for April.. . 30
Same as Fig. 4.17, only for May. . . . . 31
Same as Fig. 4.18, only for May. . 31

Figure 4.23 Bristol radar areal coverage with inner dark range ring
at 120 nmi and outer ring at 240 nmi. Location of four
primary target areas and rawinsonde sites also

. annotated. ....................... 34

Figure 4.24 Number of hours having radar echoes by month for each
year as observed by Bristol radar. Percentages atop each
bar are the percent of the total hours available each
month. The percentages shown to right of each month are
the averages for the 6-year study. ......... 34

Figure 4.25 Same as Fig. 4.24, only showing the number of days per
month having radar echoes. ............. 36

Figure 4.26 Average number of echo hours per day with echoes. . . 36

Figure 4.27 Percent frequency of radar echoes classified as either
convective or stratiform. See text for details. .. 37

Figure 4.28 Pro9ability of occurrence of cloud base temperature
colder than the indicated temperature for upper air
stations in the vicinity of the TVA region. The
analysis represents all soundings taken during May
from 1981 through 1987. Soundings were generally
taken twice daily, at 0000 and 1200 GMT (0700 and

1900 e.s.t) . . .. ............... 40

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