WMOD00125

• Contract/Permit #: #90-3
• Applicant: Western Kansas Groundwater
• Project Name: Kansas Weather Modification
• Date: 6/1/1990
• Weather Modification - Doc Type: Public Hearing

~)

-,
I

AE~

JUll 1 '90

NEWSLETTER 90 - 10

COLOMDO WATER
CONSERVATION
BOAP"

FOR THE PERIOD JULY 1 - JULY 6, 1990

GENERAL INTEREST: With slightly more than two
operations completed, we have had 20 operational
increase rainfall, reducing hail or a combination
74% of our 15-year average for the same date.

full months
days seeding
of both. This

of
to
is

Ending June 30th, we have seeded for 124.7 hours at cloud base
and have dispensed 23,855 grams of silver iodide. The cloud top
plane has dispensed 683 kilograms (1505 lbs.) of dry ice in 5.0
hours seeding. Seeding time should not be confused with flight
time; in the case of the cloud top aircraft the seeding time
represents the actual time dispensing dry ice while flying through
clouds or near cloud top.

OPERATIONS: Hot, relatively dry weather returned after a cold front
penetrated western and southwestern Kansas on July 4th---the only
day during the period for which there were seeding operations.

JULY 4th---OPERATIONAL DAY #20: Between 2:27 and 3:00 p.m., MDT,
three planes were scrambled for seeding as convective clouds began
forming along a cold frontal boundary in an arcing E-W line from
Greeley County to Ness County that dipped into Kearny and Finney
counties as well. The day was forecast to be ripe for rainfall
stimulation in the early part operations with hail suppression
possibilities later. At the time the first plane was initially
launched; radar showed storms west of Stanton County (in Colorado)
near the county line in SE Prowers County-NE Baca County which
became the first of area storms that appeared to contain hail. No
seeding was performed in Colorado.

Initially, rain stimulation was performed along the line of
developing storms just north of Lakin at 3:04 p.m. Eventually all
aircraft got into the act working along the line in various parts.
We transitioned into hail suppression when radar observed one area
intensifying more strongly in southern Scott County around 4: 12
p.m. Other areas along the line soon intensified over southern
Lane, southwest Wichita and central Greeley counties.

As the front moved more southerly, more new storms formed on
its boundary, growing and merging with the others and thereby
increasing overall levels of storm intensification. The area where
the strongest intensification occurred was along the county lines
between Greeley and Hamilton and eastward along Wichita-Kearny.
Fortunately, storm. movement was to the NE and the severe storms
moved into the colder, drier air behind the cold frontal boundary
and dissipate in a relatively short time for lack of sustained
warm, moist air.