Springtime showers and thunderstorms dumped heavy rains over parts ofnorthwestern Arkansas and south central Missouri over the weekend.Hardest hit was northwestern Arkansas where two children were sweptaway by flood waters west of Huntsville, Arkansas. A stationary frontdraped across central Arkansas from northern Texas to the Mid-Atlanticregion provided the focus for strong storms as southerly winds pumpedlow-level moisture up from the Gulf of Mexico.
This image shows an instantaneous snapshot of the storms that led to the flooding taken by the Tropical Rainfall Measuring Mission (TRMM) satellite. The image was taken at 06:30 UTC on 24 April 2004. It shows the horizontal distribution of rain intensity as seen from above by the TRMM satellite. Rain rates in the center swath are from the TRMM Precipitation Radar (PR), the first and only precipitation radar in space, and rain rates in the outer swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner VIRS).
TRMM shows three different mesoscale convective systems known as MCSs:one over south central Texas, one over north central Texas and one alongthe Oklahoma-Arkansas border. MCSs typically contain showers and/orthundershowers along their leading edge that contain strong updrafts andproduce heavy rain (as seen by the red areas) followed by or adjacent toareas of stratiform rain with weaker rainrates (green areas). Thesouthernmost MCS has a horseshoe type shape indicative of a mature MCSwhereby strong winds entering the rear of the system deform the stormsalong the leading edge into a bow shape. Convection in the middle MCSis more linear and very intense as shown by the dark red areas indicativeof a squall line. The third MCS that is farthest north has a broad areaof stratiform rain (green area) of moderate intensity centered on theconvection.
An additional image shows a vertical slice taken by the TRMM PR through thecentral MCS looking east. It shows intense rainrates associated with theleading edge convection. The leading edge is made up of many convectiveelements as evidenced by the cellular nature of the intense echoes (darkred areas) associated with the numerous protruding towers (green andyellow areas extending vertically).
TRMM is a joint mission between NASA and the Japanese space agency JAXA.
References & Resources
Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).
