WMOD00058

• Contract/Permit #: #98-1
• Applicant: Western Kansas Groundwater Management
• Project Name: Western Kansas Weather Modification Program
• Date: 4/28/2001
• Weather Modification - Doc Type: Report

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During this season we observed both storm intensities and their numbers on May 27th and
May 29th and knew these were going to be significant hail-days in Kansas, especially for the
WKWMP on May 27th, Our weekly newsletter for May 19th-26th, was written well before the
hail claims damage reports came in. In it was predicted that May 27th would be a significant hail-
day this season, It was, It was the single worst day for hail damage in Kansas in 2001 with 43
counties submitting hail damage claims, numbering 1,453 of them for the State in all, Below is
that newsletter's General Interest section, written despite the fact that the event had occurred on a
weekend after the cut-off time for commenting on the prior week's seeding activities:

--start of newsletter--

"On the day before Memorial Day, Sunday, May 27th, numerous severe thunderstorms
raked Southwestern and Western Kansas producing extensive wind and hail damage to crops and
property. Typically, this region experiences about 5-6 days, or around 10 % of its hail-days each
season accounting for about two-thirds of its seasonal hail damage, May 27th will undoubtedly go
into the record books as one of 2001's worst hail-days, if not the worst. If not, we're going to be
in for some really big trouble the remainder of the season, Winds of78 mph were recorded at the
Lakin field headquarters at the Kearny County Airport, probably the strongest winds experienced
at Lakin in this writer's 17 seasons here.

The severe storm scenario on the 27th fit the weather pattern predicted from data analyzed
the night prior and confirmed again in the next morning's early weather data, A high probability
of very severe storms were expected,

The only county to escape unscathed from hail damage was Hamilton County; however,
Hamilton did have some wind damage although most likely minor compared to counties east of
it. Damage from wind was caused mainly by gusts from collapsing extremely severe storms
which might have been either "channeled" by terrain-to help produce higher-velocity winds, or
simply just from having been positioned more directly in the path of the highest speed winds
much as what happens during micro-burst damages.

When severe weather occurs, such as on the 27th, the severity of damage from wind and
hail at a given location can only be estimated a relatively short time prior to its occurrence---
"now-casting" at it's termed. One problem with forecasting for specific extreme weather events
at a given time very far in advance is that one doesn't really know just how extreme an event it
can be; this is where "chaos" enters picture, Damage severity at anyone location cannot be
estimated with any high degree of accuracy because it is unknown just how a gust front will
interact with its surroundings until after it has dropped out of a cloud and can be tracked. When a
storm collapses and thrusts out gusts in a fan-shaped boundary, or gust front, it's speed and
direction greatly regulates the interactive process as it undercuts moist air in an inherently
unstable air mass. This is especially true if it passes under other precipitating storms as opposed
to simply moving through clear air. Upper air wind speed and direction and convergence at the
surface and aloft also can be important in affecting subsequent storm development and severity,

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