“Sting Jet” signature associated with a high wind event in Scotland

January 3rd, 2012
EUMETSAT Meteosat-9 7.35 µm water vapor channel images (click image to play animation)

EUMETSAT Meteosat-9 7.35 µm water vapor channel images (click image to play animation)

 

A rapidly intensifying mid-latitude cyclone (named “Cyclone Ulli” by the Europeans | surface analysis) was responsible for a high wind event as it moved over Scotland on 03 January 2012. A sequence of EUMETSAT Meteosat-9 7.35 µm water vapor channel images (above; click image to play animation) revealed two notable signatures: (1) the formation of a pronounced area of warm/dry water vapor brightness temperatures (bright yellow to orange color enhancement) over the open water north of Ireland, which indicated a strongly forced region of rapidly descending middle-tropospheric air, and (2) a classic “Sting Jet” signature (Monthly Weather Review | Wikipedia) which then moved eastward across Scotland. Just to the south of the sting jet signature, a wind gust of 78 knots (90 mph) was recorded at Glasgow at 08:20 UTC, followed by a wind gust of 70 knots (81 mph) at Edinburgh at 08:50 UTC.  There were additional reports of wind gusts in excess of 87 knots (100 mph) at non-METAR sites in Scotland.

The Sting Jet signature can also be seen in EUMETSAT Meteosat-9 10.8 µm IR images (Animated GIF | QuickTime movie) and EUMETSAT Meteosat-9 0.635 µm visible channel images (Animated GIF | QuickTime movie).

A comparison of 1-km resolution NOAA-19 0.63 µm visible channel and 10.8 µm IR channel images at 12:54 UTC (below) showed the structure of the cyclone as it was centered over the North Sea between the British Isles and Norway.

 

NOAA-19 0.63 µm visible channel image + NOAA-19 10.8 µm IR channel image

NOAA-19 0.63 µm visible channel image + NOAA-19 10.8 µm IR channel image

Additional images of this Sting Jet event are available on the EUMETSAT and NASA Wide World of SPoRT sites.

Snow streaks across Illinois, Indiana, and Kentucky

January 3rd, 2012
MODIS true color RGB image (viewed using Google Earth)

MODIS true color RGB image (viewed using Google Earth)

 

An interesting pattern of “snow streaks” across parts of Illinois, Indiana, and Kentucky was seen on a MODIS true color Red/Green/Blue (RGB) image from the SSEC MODIS Today site on 03 January 2012 — this pattern was caused by narrow cells of convective snowfall which propagated southeastward across the region on the previous day. The amount of snow on the ground was only a Trace to 1 inch, which allowed the snow streaks to quickly melt during the day.