Nocturnal heat in the Desert Southwest
Unusually hot conditions developed across parts of the Desert Southwest during the first week of July 2007 — daily maximum temperatures on 05 July included 127º F (53º C) at Death Valley, California, 122º F (50º C) at several locations within the Lake Mead/Lake Mohave basin region of Nevada/Arizona, 120º F (49º C) at Needles, California, and 116º F (47º C) at Las Vegas, Nevada (1º F shy of their all-time record high temperature). Following such hot daytime temperatures, a nighttime AWIPS image of the MODIS 11.0µm InfraRed (IR) channel (above) showed that nocturnal temperatures remained rather warm — IR brightness temperatures at 09:22 UTC (2:22 AM local time) were still 30º C / 86º F or warmer (orange to red enhancement) over a good deal of the Death Valley and Lake Mead/Lake Mohave basin regions. In fact, the official cooperative weather observation site at Death Valley (DEVC1) reported an overnight minimum temperature of 95º F (35º C), while a nearby mesonet site at Death Valley National Park (CQ162) only dropped to 105º F (41º C) at 7:00 AM local time (14:00 UTC).
An AWIPS comparison of MODIS IR, GOES imager IR, and GOES Sounder Skin Temperature (above) revealed brightness temperatures in the lowest elevations of Death Valley were still as warm as 86-96º F (30-36º C) at 09 UTC. In addition, an AWIPS image of the MODIS sea surface temperature product (below) indicated that water temperatures were as warm as 87-89º F (31-32º C) (dark red enhancement) in portions of Lake Mead and Lake Mohave.
