Northeast US winter storm

February 9th, 2017

GOES-13 Water Vapor (6.5 µm) images, with surface fronts and MSLP pressure [click to play animation]

GOES-13 Water Vapor (6.5 µm) images, with surface fronts and MSLP pressure [click to play animation]

A strong winter storm impacted much of the Northeast US on 09 February 2017, dropping up to 24 inches of snow in Maine and producing wind gusts of 70 mph in Massachusetts (WPC storm summary). GOES-13 (GOES-East) Water Vapor (6.5 µm) images with surface fronts and Mean Sea Level Pressure (above) showed the rapid intensification of the mid-latitude cyclone.

GOES-13 Visible (0.63 µm) images, with hourly surface weather symbols [click to play animation]

GOES-13 Visible (0.63 µm) images, with hourly surface weather symbols [click to play animation]

GOES-13 Visible images (above) and Water Vapor images (below) with hourly surface weather symbols revealed the extent of thunderstorms in the south and heavy snow in the north. A number of sites in New England also reported thundersnow.

GOES-13 Water Vapor (6.5 Âm) images, with hourly surface weather symbols [click to play animation]

GOES-13 Water Vapor (6.5 Âm) images, with hourly surface weather symbols [click to play animation]

Suomi NPP VIIRS Visible (0.64 µm) and infrared Window (11.45 µm) images (below) provided a high-resolution snapshot of the storm at 1708 UTC. Note the areas of banded convective elements both south of the storm center over the Atlantic, and also inland over parts of New England.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with surface fronts and MSLP [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with surface fronts and MSLP [click to enlarge]

===== 10 February Update =====

Terra and Aqua MODIS false-color RGB images [click to enlarge]

Terra and Aqua MODIS false-color RGB images [click to enlarge]

As the storm moved northward over Newfoundland and Labrador in eastern Canada on 10 February, a toggle between Terra (1601 UTC) and Aqua (1743 UTC) MODIS false-color “snow/cloud discrimination” Red/Green/Blue (RGB) images (above) showed the extent of the snow cover (darker shades of red), although supercooled water droplet clouds (shades of white) persisted over many areas at the times of the 2 images. Glaciated ice crystal clouds also appeared as shades of red.

Snowfall totals in the Canadian Maritimes were as high as 38 cm (15 inches).


GOES-16 Views of Tornadic Thunderstorms over Louisiana

February 7th, 2017

Severe Weather hit Louisiana on Tuesday 7 February 2017, and the ABI on GOES-16 viewed the convective development. This website includes an animation (also available on YouTube) of the visible imagery (Band 2, 0.64 µm with 0.5-km resolution at the subsatellite point) from ABI during the time period of the strongest tornadoes in and near New Orleans. Click here for an animation that includes views of all 16 ABI Bands.

A comparison of GOES-13 (GOES-East) Visible (0.63 µm) and Infrared Window (10.7 µm) images is shown below, with hourly surface reports and locations of the tornado reports.

GOES-13 0.63 µm Visible (top) and 10.7 µm Infrared Window images (bottom), with hourly surface reports and locations of the tornado reports.

GOES-13 0.63 µm Visible (top) and 10.7 µm Infrared Window images (bottom), with hourly surface reports in yellow and locations of the tornado reports in cyan.

Suomi NPP overflew the convection shortly after the tornadoes were on the ground in Louisiana, and images from the three spectral bands shown below, 11.45 µm, 0.64 µm and 1.61 µm show a mature convective system with overshooting tops over the Gulf Coast states and the Gulf of Mexico. The 1.61 µm Snow Ice band helps in the discrimination between cloud tops comprised of water droplets (bright white) vs. cloud tops comprised of ice crystals (grey); the ABI on GOES-16 has a similar band.

Suomi NPP VIIRS Imagery from 1924 UTC on 07 February 2017. Infrared Window (11.45 µm), Visible (0.64 µm) and Snow/Ice (1.61 µm) bands are shown. (Click to enlarge)

Oil well fire in Utah

January 6th, 2017

GOES-15 Visible (0.63 µm) images, with hourly surface reports [click to play animation]

GOES-15 Visible (0.63 µm) images, with hourly surface reports [click to play animation]

GOES-15 (GOES-West) Visible (0.63 µm) images (above) showed a small, short-lived black cloud that formed south/southwest of Vernal (station identifier KVEL) in northeastern Utah on 06 January 2017. This feature was the result of a fire at an oil well site (media report | well location) that apparently started around 11:30 am local time (1830 UTC); the black cloud from the burning oil tanks — which was first apparent on the 1930 UTC visible image — stood out well against the snow-covered ground. The initial northwestward transport of the smoke plume was consistent with lower-tropospheric winds in Grand Junction, Colorado rawinsonde data at 07 January/00 UTC, which showed southeasterly winds as high as 784 hPa (2185 meters or 7169 feet above ground level). The sounding profile also showed that this height was the top of a well-defined temperature inversion, which acted as a cap to prevent the smoke from reaching higher altitudes (photo).

GOES-13 (GOES-East) Visible (0.63 µm) images (below) also displayed the dark smoke plume. The viewing angles from the 2 satellites were similar (~53 degrees from GOES-15 vs ~57 degrees from GOES-13), but the time sampling was slightly better from GOES-15 (due to the extra “SUB-CONUS” scan images at :11 and :41 minutes nearly every hour). Image frequency will be even better with the GOES-R series of satellites (beginning with GOES-16), with routine scans every 5 minutes; the visible image spatial resolution will also be improved (to 0.5 km, vs 1.0 km with the current GOES).

GOES-13 Visible (0.63 µm) images, with hourly surface reports [click to play animation]

GOES-13 Visible (0.63 µm) images, with hourly surface reports [click to play animation]

MODIS Visible (0.645 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images from a 2036 UTC overpass of the Aqua satellite (below) showed the black smoke cloud in the Visible, but there was no evidence of a fire “hot spot” in the Shortwave Infrared (the media report indicated that the fire was extinguished about 2 hours after it started, which would have been around or just before the time of the MODIS images). On the Infrared Window image, the smoke plume actually did exhibit a slightly colder (darker blue color enhancement) signature, which is unusual since conventional fire and wildfire smoke is normally transparent to thermal radiation.

Aqua MODIS Visible (0.645 µm) and Shortwave Infrared (3.7 µm) images at 2036 UTC [click to enlarge]

Aqua MODIS Visible (0.645 µm) and Shortwave Infrared (3.7 µm) images at 2036 UTC [click to enlarge]

A view of the 250-meter resolution Aqua MODIS true-color Red/Green/Blue (RGB) image from the MODIS Today site is shown below.

Aqua MODIS true-color image at 2036 UTC [click to enlarge]

Aqua MODIS true-color image at 2036 UTC [click to enlarge]

Christmas Blizzard

December 26th, 2016

GOES-13 Water Vapor (6.5 µm) images, with hourly surface weather symbols [click to play animation]

GOES-13 Water Vapor (6.5 µm) images, with hourly surface weather symbols [click to play animation]

A mid-latitude cyclone intensified as it moved northeastward across Nebraska, the eastern Dakotas and northern Minnesota (3-hourly surface analyses) during 25 December26 December 2016. GOES-13 (GOES-East) Water Vapor (6.5 µm) images (above) showed distinct banding within the warm conveyor belt, a well-defined dry slot, and a large comma head that formed from the cold conveyor belt. The storm produced blizzard conditions across much of the Northern Plains and Upper Midwest, with heavy snowfall (as much as 22.0 inches in western North Dakota), freezing rain (ice accretion as thick as 0.5 inch in Minnesota and North Dakota) , sleet (up to 2.0 inches deep in Minnesota) and heavy rainfall; in Kansas there were also a few tornadoes (SPC storm reports).

A noteworthy characteristic of the storm was very strong winds — a closer view of GOES-13 Water Vapor imagery with hourly plots of surface wind gusts (in knots) is shown below.

GOES-13 Water Vapor (6.5 µm) images, with hourly surface wind barbs and wind gusts in knots [click to play animation]

GOES-13 Water Vapor (6.5 µm) images, with hourly surface wind barbs and wind gusts in knots [click to play animation]

Note the swath of wind gusts in the 50-60 knot range which progressed across central and northeastern Nebraska into northwestern Iowa and finally southwestern Minnesota during the 02 UTC to 12 UTC period on 26 December — this was pointed out in a tweet by Anthony Sagliani as a “sting jet” feature:


As observed in previous sting jet cases (03 Jan 2012 | 28 Oct 2013), the strongest winds occurred near the curved “scorpion tail” signature seen in the water vapor imagery (which marked the leading edge of the cold conveyor belt as it advanced into the rear edge of the dry slot of the cyclone circulation).

A comparison of Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm) and Water Vapor (6.7 µm) images at 2001 UTC on 25 December is shown below.

Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm) and Water Vapor (6.7 µm) images [click to enlarge]

Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm) and Water Vapor (6.7 µm) images [click to enlarge]

A closer view with Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1952 UTC on 25 December (below) showed a detailed view of the banded cloud structures from Kansas into South Dakota, as well as small overshooting tops associated with thunderstorms in southeastern South Dakota and southwestern Minnesota. This storm produced the first Christmas Day thunderstorms on record in both Sioux Falls and Rapid City, South Dakota; thundersnow was also observed in Bismarck, North Dakota.

Suom NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suom NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images [click to enlarge]