10 June 2009 High Plains Downbursts

During the afternoon of 10 June 2009, isolated convective storms developed over the High Plains of New Mexico, Oklahoma, and Texas in association with an upper-level disturbance. Downburst wind gusts between 38 and 53 knots were recorded over the Oklahoma and Texas Panhandles and eastern New Mexico during the two-hour period, 2155 and 2355 UTC. The Geostationary Operational Environmental Satellite (GOES) imager microburst product indicated elevated risk values (output brightness temperature difference (BTD) >40K) in proximity to the location of the downbursts one to three hours prior to each event. In general, the pre-convective environment over the southern High Plains was favorable for hybrid microbursts, characterized by a deep convective mixed layer with a steep temperature lapse rate, especially below the 600-mb level.

The images above are Geostationary Operational Environmental Satellite (GOES) imager microburst product at 2000 UTC 10 June 2009 (top), with mesonet observations of downburst wind gusts plotted on the image, and a corresponding Rapid Update Cycle (RUC) model analysis sounding at Hereford, Texas. The GOES imager microburst product displayed scattered cumulus cloud (black shading) development in the unstable air mass over western Texas near the New Mexico border. Moderate to high microburst risk, indicated by yellow to orange shading, was in place over western Texas, near Hereford, where strong downbursts would occur about two hours later. The corresponding Rapid Update Cycle (RUC) model sounding profile over Hereford exhibited a classic “inverted-V” and indicated that the environment over the Panhandle region was favorable for hybrid microbursts with a steep temperature lapse rate and well-developed mixed layer below 600 mb. Near 2200 UTC, downburst wind gusts of 38 and 50 knots were recorded at Dimmitt and Hereford (West Texas) mesonet stations, respectively. Note that the stronger downburst recorded at Hereford was associated with higher output BTD near 50K (orange shading).

The images above are Geostationary Operational Environmental Satellite (GOES) imager microburst product at 2200 UTC 10 June (top), with mesonet observations of downburst wind gusts plotted on the image, and a corresponding Rapid Update Cycle (RUC) model analysis sounding at Kenton, Oklahoma. The GOES imager microburst product displayed convective storm activity in progress over the Texas Panhandle and eastern New Mexico, including downburst-producing storms near Hereford and Dimmitt. The corresponding Rapid Update Cycle (RUC) model sounding profile over Kenton exhibited a more well-defined “inverted-V” profile. The product image and sounding profile signified that the environment over the Panhandle region was especially favorable for hybrid microbursts. Downburst wind gusts of 40 and 48 knots occurred between 2300 and 0000 UTC 11 June at Boise City and Kenton, Oklahoma mesonet stations, respectively, where a moderate to high risk of microbursts was indicated at 2200 UTC. In a similar manner to the 2000 UTC product image, this image indicated a local maximum in output BTD near the location of the downbursts that occurred over the western Oklahoma Panhandle.


The above images are GOES microburst products with overyling radar reflectivity imagery from Amarillo NEXRAD. These images, visualized by McIDAS-V software, display that downbursts were associated with multicell storms that occurred in regions of elevated microburst risk (orange shading). For this High Plains convective storm event, the GOES imager microburst product effectively indicated downburst potential with a correlation between output BTD and wind gust speed of .64 and a mean difference between output BTD and wind gust speed of 1.2.