POWESHIEK

107145 · 41.580, -92.530

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The record

Everything the slot carries, as measured. Series arrays are drawn above and listed here in full.

Event typeevent_type	Lightning
NOAA NCEI event IDncei_event_id	107,145
Episode IDepisode_id	18,024
Begin UTCbegin_utc	2008-07-21T09:19:00+00:00
End UTCend_utc	2008-07-21T09:19:00+00:00
Statestate	IOWA
County/zone typecz_type	C
County/zone namecz_name	POWESHIEK
Latitudelat	41.580
Longitudelon	-92.530
End latitudeend_lat	41.580
End longitudeend_lon	-92.530
Deaths directdeaths_direct	0
Deaths indirectdeaths_indirect	0
Injuries directinjuries_direct	0
Injuries indirectinjuries_indirect	0
Damage propertydamage_property	10.00K
Damage cropsdamage_crops	0.00K
Weather forecast office sourcewfo_source	Emergency Manager
Episode narrativeepisode_narrative	A very unstable situation set up during the afternoon and evening of the 20th as a frontal boundary and remnants of the outflow boundary was established across southern Iowa. Temperatures warmed into the low to mid 90s across southern Iowa along and just south of the boundary. Dewpoint readings soared into the mid 70s to low 80s by evening. This resulted in very unstable CAPE values in the 5000 to 5500 J/kg range, and lifted indices of -10 to -13 C. during the evening. A low level jet of 40 kts set up while the atmosphere showed fairly strong shear, in the 40 to 55 kt range. There wasn't as much deep moisture as had been present in previous days with 1.3 to 1.6 inches of precipitable water. The freezing level remained quite high at around 14,600 feet and CAPE in the -10 to -30 C. layer of the atmosphere was only 300 to 500 J/kg. Downdraft CAPE was considerable however with 1000 to 1500 J/kg available. The LCL was also higher than it had been the previous day and was between 1500 and 2000 meters. During the evening, thunderstorms formed rapidly over northern Nebraska and far southern South Dakota to the north of the boundary. By late evening, additional development took place across Iowa. For the most part, these storms remained just below severe levels. One of them produced one and one quarter inch diameter hail over central Iowa however. The main event was the MCC from Nebraska. The MCC moved into Iowa after midnight and produced high winds and hail as it moved through. A portion of the system became a Derecho over west central Iowa and advanced across the state during the early morning hours. Winds of 60 to 75 MPH were common, with a few gusts estimated as high as 100 MPH in central Iowa. A radio tower was blown over by the winds in the Dawson area of Dallas County. Tree damage was very extensive from the winds with local utilities reporting as many as 200,000 homes were without power following the passage of the system. In Jamaica, in Guthrie County, 50 percent of the trees in town were damaged with 30 trees completely down. The roof was damaged at the race track there. The Guthrie County mobile EOC was tossed 150 feet into a field and roads were impassible. In Polk County, in Ankeny, 20 tO 30 Black Locust trees of 1 to 2 feet in diameter were snapped or uprooted near the intersection of 35th street and Highway 415. Winds estimated at 100 MPH in Dawson, in Dallas County, caused considerable damage. Roads were blocked by trees, with heavy equipment required to clear them. LP tanks were leaking in town as they were thrown about and damaged by trees. The grain elevator in town was also damaged. Bulldozers were also required to clear streets of tree damage in Boone County at Madrid. In Polk County, at Mitchellville, the roof was taken off of a modular building at the Mitchellville Correctional Facility. Lightning struck a house west of Nevada in Story County, setting it on fire. A second house was struck by lightning in Poweshiek County in Montezuma. Minor damage was reported to the building.
Yearyear	2,008

Provenance

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