McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) showed the development of widespread plumes of blowing dust over parts of New Mexico and Texas on 09 February 2013. Surface wind gusts across the region were as high as 79 mph in New Mexico and 71 MPH in Texas. Most of the blowing dust appeared to have originated from dry lake beds in northern Mexico, but early in the animation a narrow dust plume can be seen whose source region was White Sands, New Mexico. Due to an increasingly favorable forward scattering angle, the dust became more apparent on the visible imagery during the afternoon hours.

A comparison of AWIPS images of 1-km resolution MODIS 0.65 µm visible channel and 1.61 µm near-IR “cirrus detection channel” data (below) demonstrated how the MODIS cirrus channel can be used to more accurately identify the leading edge of the airborne dust over eastern New Mexico — the 1.61 µm channel can detect the presence of partcles that are efficient scatterers of light (such as cirrus cloud ice crystals, volcanic ash, smoke, dust).

A closer view using 250-meter resolution Terra (18:28 UTC) and Aqua (20:04 UTC) MODIS true-color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (below) helped to identify a few of the blowing dust source regions in far northern Mexico.

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A large winter storm began to intensify just off the East Coast of the US on 08 February 2013 — and a sequence of 1-km resolution POES AVHRR 0.86 µm, MODIS 0.65 µm, and Suomi NPP VIIRS 0.64 µm Visible images (above) revealed the formation of gravity waves in the lower-tropospheric cloud field within the southwest quadrant of the area of low pressure (corresponding Infrared images).

4-km resolution GOES-13 6.5 µm Water Vapor images (below) showed a very well-defined dry slot and the development of a distinct comma head. Strong northwesterly winds were also causing mountain waves to the lee of the Appalachians.

The MIMIC Total Precipitable Water (TPW) product (below) showed TPW values as high as 48 mm or 1.9 inches being drawn northward into the intensifying low.

Similarly, the Blended Total Precipitable Water product (below) also showed high values of TPW (up to 36 mm or 1.4 inches) off the Virginia/North Carolina coast as the low was intensifying.

These TPW values were in excess of 200% of normal for this region and this time of year (below).

A MODIS 11.0 µm Infrared Window image at 03:04 UTC on 09 February (10:04 PM local time on 08 February) revealed a distinct hook-shaped pattern to the cloud features near the storm center as it continued to intensify (below). Peak wind gusts at this time were 58 knots at Nantucket and 54 knots at Boston.

===== 09 February Update =====

As the storm was nearing peak intensity on the morning of 09 February 2013, the formation of a tight circulation around its center was becoming evident in 1-km resolution Visible images with overlays of surface data from MODIS at 15:06 UTC (above) and VIIRS at 17:01 UTC (below).

A 250-meter resolution MODIS true-color Red-Green-Blue (RGB) image from the SSEC MODIS Today site (below; displayed using Google Earth) showed the locations of maximum snowfall totals for select states (which included 40.0 inches at Hamden, Connecticut), as well as some of the maximum wind gusts (which included 83 mph at Cuttyhunk, Massachusetts).

GOES-13 Water Vapor imagery, displayed in a 2-day loop below, captures many interesting aspects of this potent storm.

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The Day/Night band on Suomi/NPP once again detected an extensive display of Aurora Borealis over northern Canada, as shown in the image toggle above. The Day/Night Band shows bright illumination over the northern halves of Quebec, Ontario and Manitoba. At the same time, near-infrared imagery at 3.74 µm shows very cold air, strongly suggestive of clear skies. The High Pressure responsible for the clear skies will influence the large snowstorm predicted to hit the Northeast United States on February 8th and 9th.

A magnified version of the imagery above, shown below, focuses on the area of Ontario between Lake Superior and James Bay. Highway 11, part of the TransCanada Highway, shows up as an thin strand of light. Airports near this Highway confirm the numbing cold depicted in the 3.74 µm imagery. There are a few relatively warm pixels near Kapuskasing (CYYU), however. Brightness temperatures are at -33 and -34 C rather than -38 to -40 C in the regions that are dark in the Day/Night band. Even a town of 9000 can have a thermal signature detectable from satellite.

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McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) showed that the effect of strong winds in the wake of an unusually intense storm off the coast of Labrador could be seen in the motion of sea ice in the waters of the Canadian Maritimes on 05 February 2013.

A comparison of AWIPS images of MODIS 0.65 µm visible channel data and the corresponding false-color Red/Green/Blue (RGB) composite at 15:28 UTC (below) demonstrated the value of using RB images for cloud vs snow discrimination (snow and ice appear as darker shades of red in the RGB image). Surface reports plotted on the images showed that 2 sites were reporting wind gusts of 50 knots or higher at that time.

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