February 2007: A month of Northern Hemisphere water vapor channel images

February 28th, 2007

AWIPS northern hemisphere water vapor image

An animation of 3-hourly water vapor channel image composites from AWIPS during the entire month of February 2007 (35 MB QuickTime animation; 1280×1024 screen resolution required) shows the diverse variety of storms that affected the Northern Hemisphere during that particular month. Significant weather events in the US included fatal tornadoes in central Florida (02 February) and New Orleans (13 February), heavy lake-effect snow in western New York (141 inches in 10 days at Redfield, 03-12 February), and winter storms affecting much of the eastern US (13-14 February) and the northcentral US and Great Lakes (24-26 February). February 2007 ended up being unusually cold and snowy across much of the Upper Midwest and Great Lakes regions — Grand Rapids, Michigan and Rochester, Minnesota had their snowiest February on record (33.6 inches and 19.6 inches, respectively), and La Crosse, Wisconsin experienced their greatest storm total snowfall on record (21.0 inches from 23-25 February).

Hail damage to Space Shuttle external fuel tanks

February 26th, 2007

GOES-12 10.7µm IR image

An isolated thunderstorm developed over east-central Florida and moved over the Kennedy Space Center during the late afternoon on 26 February 2007, producing golf ball size hail (2.0 inches in diameter) and wind gusts as high as 72 mph (SPC storm reports). This hail produced damage to the external fuel tanks of the Space Shuttle Atlantis, which was on the launch pad undergoing preparations for a 15 March 2007 launch. This particular convective cell was relatively compact and formed rather quickly, and exhibited cloud top temperatures between -50 to -60º C (orange to red enhancement) on GOES-12 10.7µm InfraRed (IR) imagery (above; Java animation).

A comparison of 4-km resolution GOES-12 IR imagery with the corresponding 1-km resolution NOAA-15 AVHRR IR image (below) shows that more accurate (and significantly colder) cloud top temperatures can be detected using satellite instruments with better spatial resolution. Note the distinct “overshooting top” region with a minimum brightness temperature of -65º C (dark red enhancement) on the 21:50 UTC NOAA-15 image, versus cloud top temperature values that were only as cold as -54º C (orange enhancement) on the 21:45 UTC GOES-12 image (these two IR images were about 20-25 minutes prior to the time of the reported hail damage). The Advanced Baseline Imager (ABI) instrument on GOES-R (scheduled for launch in 2014) will have IR channels with a spatial resolution of 2 km, which should improve cloud top temperature detection capabilities over the current GOES imager IR channels.
NOAA-15 / GOES-12 IR image comparison

Dust storm and wildfires in Texas

February 24th, 2007

GOES-12 visible image

Strong winds gusting to 60-70 mph in the wake of a cold frontal passage on 24 February 2007 caused widespread blowing dust and wildfire activity across much of the Texas panhandle region. GOES-12 visible channel imagery (above; Java animation) showed the development of a large cloud of blowing dust, as well as several smaller smoke plumes to the south of the blowing dust feature. The dust cloud exhibited a pronounced reddish-brown hue on MODIS true color imagery, due to the composition of the soil in the source region near the Texas / New Mexico border. This airborne dust reduced surface visibilities to less than one mile at several locations, causing traffic accidents and even producing brown-colored snow and rain   (NWS Lubbock TX summary).

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GOES-12 3.9µm InfraRed (IR) imagery (below; Java animation) revealed several “hot spots” (black enhancement) due to wildfire activity that also flared up due to the strong winds. Note that one fire (near Killeen TX, station identifier KGRK, bottom center of the image) became hot enough to saturate the GOES-12 3.9µm detectors at 19:32 UTC, causing the brightness temperature to “wrap around” and actually show up as a “cold” pixel (white enhancement).

GOES-12 3.9µm IR image

Changes to GOES-10 Sounder scanning strategy

February 19th, 2007

GOES-10 sounder coverage

On 18 February 2007 NOAA/NESDIS/OSO implemented a new schedule for GOES-10 sounder scans during house-keeping periods. The previous sounder schedule had spatial gaps between the hourly scan sectors (above), while the new sounder schedule allows for continuous north-to-south coverage of the entire South American continent (below), while making narrower scans. The GOES-10 satellite has been postioned at 60º W longitude to support the Earth Observation Partnership of the Americas (EOPA) project. The latest GOES-10 sounder and imager products are available on the CIMSS GOES Realtime Derived Products site.
GOES-10 sounder coverage