WMOD00285 ‎(2)‎

• Title: Feasibility Study of Wintertime Cloud Seeding to Augment Arizona Water Supplies
• Date: 1/1/1987
• State: AZ
• Weather Modification - Doc Type: Report

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Figure 7. - Height contour pattern at the 500 millibar pressure level 24
hours after that in figure 6.

over 2-5 weeks, with each storm event requlrlng 3-6 days for development and
passage. The outstanding features of this type of system are the plunging
very cold air mass along the coastline, the slow-moving closed circulation and
tIe availability of ample moisture from the Pacific Ocean.

Similar to the type A-I system, and indicated here as A-2, are patterns where
the southward plunge of the cold air mass occurs farther east and the cir-
culation does not close in time to substantially impact Arizona (the cir-
culation may not close) as indicated in figures 8 and 9. Occasionally, the
cold-air plunge and closed circulation occur well off the coast, and the Cir-
culation opens as the system moves eastward over land. The A-2 system does
not draw moisture as well as the A-I type. It also moves eastward faster.
Consequently, the A-2 system generally lealds to less precipitation than the
A-I type.

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