Blowing snow in southern Manitoba and the Red River Valley

January 15th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Near-Infrared “Snow/Ice (1.61 µm, right) images, with hourly plots of surface wind and weather type [click to play animation | MP4]

A comparison of GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above) revealed plumes of blowing snow originating over northern Lake Winnipeg and southern Lake Manitoba, lofted by strong northerly winds in the wake of a cold frontal passage. The blowing snow originating over the southern portion of Lake Manitoba was then then channeled southward into the Red River Valley (topography), with horizontal convective roll clouds eventually developing.

In a sequence of MODIS Visible (0.65 µm) and Snow/Ice (1.61 µm) images from Terra and Aqua in addition to VIIRS Visible (0.64 µm) and Snow/Ice (1.61 µm) from NOAA-20 and Suomi NPP (below), the plumes of blowing snow were also easier to detect in the Snow/Ice images (due to better contrast against the existing snow cover).

MODIS Visible (0.65 µm) and Snow/Ice (1.61 µm) images from Terra and Aqua plus VIIRS Visible (0.64 µm) and Snow/Ice (1.61 µm) from NOAA-20 and Suomi NPP [click to enlarge]

MODIS Visible (0.65 µm) and Snow/Ice (1.61 µm) images from Terra and Aqua plus VIIRS Visible (0.64 µm) and Snow/Ice (1.61 µm) from NOAA-20 and Suomi NPP [click to enlarge]

A closer view of the Lake Manitoba plume is shown below; surface observations indicated that visibility was reduced to 1/4 statute mile at locations such as Calilier ND (plot | text) and Hallock MN (plot | text).

NOAA-20 and Suomi NPP VIIRS Snow/Ice (1.61 µm) images, with plots of surface observations [click to enlarge]

NOAA-20 and Suomi NPP VIIRS Snow/Ice (1.61 µm) images, with plots of surface observations [click to enlarge]

An Aqua MODIS True Color Red-Green-Blue (RGB) image centered on Winnipeg, Manitoba (source)  is shown below.

Aqua MODIS True Color image [click to enlarge]

Aqua MODIS True Color image [click to enlarge]

Toggles between 250-meter resolution Terra/Aqua MODIS True Color and False Color RGB images (centered between Lake Manitoba and the North Dakota border) from the MODIS Today site (below) provided a more detailed view of the blowing snow streaming southeastward from Lake Manitoba into far northeastern North Dakota and far northwestern Minnesota.

Terra MODIS True Color and False Color RGB images [click to enlarge]

Terra MODIS True Color and False Color RGB images [click to enlarge]

Aqua MODIS True Color and False Color RGB images [click to enlarge]

Aqua MODIS True Color and False Color RGB images [click to enlarge]

Lake effect clouds downwind of Fort Peck Lake, Montana

January 11th, 2019 |
GOES-17 (left) and GOES-16 (right)

GOES-17 (left) and GOES-16 (right) “Red” Visible (0.64 µm, top) and Shortwave Infrared (3.9 µm, bottom) images [click to play animation | MP4]

* GOES-17 images shown here are preliminary and non-operational *

A comparison of GOES-17 (soon to become GOES-West) and GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) revealed a plume of lake effect clouds streaming south of Fort Peck Lake in northeastern Montana on 11 January 2019. As a cold front moved south-southwestward across the region (surface analyses), surface winds shifted to northerly at Glasgow KGGW which brought a flow of colder air across the still-unfrozen lake. Note that before sunrise the initial formation of the lake effect clouds could be seen on Shortwave Infrared imagery — and after sunrise, the feature appeared progressively warmer (shades of orange) on 3.9 µm images as the supercooled water droplets at the cloud top reflected increasing amounts of incoming solar radiation.

An Aqua MODIS Sea Surface Temperature product at 1942 UTC (below) showed that mid-lake water temperatures south of Glasgow were as warm as 36ºF (lighter shades of blue) — significantly warmer than Glasgow’s early morning surface air temperatures that were as cold as 17ºF at 14 UTC.

Aqua MODIS Sea Surface Temperature product [click to enlarge]

Aqua MODIS Sea Surface Temperature product [click to enlarge]

A comparison of the Sea Surface Temperature product with the corresponding Aqua MODIS Visible (0.65 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.9 µm) and Infrared Window (11.0 µm) images at 1942 UTC (below) showed the lake effect cloud plume as well as a patch of snow cover northeast of the lake — snow absorbs radiation at the 1.61 µm wavelength, making it appear dark on the “Snow/Ice” image.

Aqua MODIS Visible (0.65 µm), Near-Infrared

Aqua MODIS Sea Surface Temperature, Visible (0.65 µm), Near-Infrared “Snow/Ice” (1.61 µm), Shortwave Infrared (3.9 µm) and Infrared Window (11.0 µm) images [click to enlarge]

Terra and Aqua MODIS True Color and False Color Red-Green-Blue (RGB) images viewed using RealEarth (below) showed that parts of the Missouri River upstream (to the west of) of Fort Peck Lake — in the area of the UL Bend National Wildlife Refuge — were beginning to freeze (ice and snow appear as shades of cyan on the False Color RGB images).

Terra and Aqua MODIS True Color and False Color RGB images [click to enlarge]

Terra and Aqua MODIS True Color and False Color RGB images [click to enlarge]

Standing wave cloud over Minnesota and Lake Superior

January 8th, 2019 |

GOES-16 Mid-level Water Vapor (6.9 µm) images [click to play animation |MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) revealed the formation of a standing wave cloud along the Minnesota shoreline of Lake Superior on 08 January 2019. This cloud feature was formed by a vertically-propagating internal gravity wave that resulted from the interaction of strong post-frontal northwesterly flow with the topography of the shoreline — the terrain quickly drops from an elevation of about 2000 feet above sea level (over northeastern Minnesota) to about 600 feet above sea level (over Lake Superior) in a very short distance.

A northwest-to-southeast oriented cross section of RAP40 model fields along line segment B-B’ (below) showed a deep pocket of positive Omega (upward vertical motion, yellow to red colors) that corresponded to the cloud band along the Minnesota Lake Superior shoreline. Note that this Omega feature was vertically tilted in an “upshear” direction (toward the northwest), and extended upward to the 350-400 hPa pressure level. There was also an increasing upward component of the ageostrophic vertical circulation, which was likely the initial forcing mechanism leading to formation of the standing wave cloud seen on satellite imagery.

RAP40 model cross section along line B-B' [click to play animation | MP4]

RAP40 model cross section along line B-B’ [click to play animation | MP4]

A comparison of Aqua MODIS Visible (0.65 µm), Near-Infrared “Cirrus” (1.37 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images at 1912 UTC (below) showed characteristics indicative of a cirrus cloud band composed of small ice crystals: a highly reflective signature at 1.37 µm, warm brightness temperatures (around -5ºC) at 3.7 µm and cold brightness temperatures (-40 to -43ºC) at 11.0 µm.

Aqua MODIS Visible (0.65 µm), Near-Infrared

Aqua MODIS Visible (0.65 µm), Near-Infrared “Cirrus” (1.37 µm), Shortwave Infrared (3.7 µm) and Infrared Window (11.0 µm) images [click to enlarge]

A sequence of NOAA-20 (at 1808 and 1949 UTC) Suomi NPP (at 1859 UTC) VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images (below) exhibited a similar warm 3.74 µm / cold 11.45 µm signature of the standing wave cloud.

Suomi NPP and NOAA-20 VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP and NOAA-20 VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images [click to enlarge]

The coldest wave cloud infrared brightness temperature values of -40 to -47ºC seen on MODIS and VIIRS imagery roughly corresponded altitudes of 6.6 to 7.3 km (21,600 to 23,900 feet) according to 12 UTC rawinsonde data from International Falls, Minnesota (below).

Plots of rawinsonde data from International Falls, Minnesota [click to enlarge]

Plots of rawinsonde data from International Falls, Minnesota [click to enlarge]

Snowfall in Texas and Oklahoma

January 4th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of surface reports [click to play animation | MP4]

A winter storm produced 6-8 inches of snowfall from the eastern Texas Panhandle to central Oklahoma on 03 January 2019 (NWS AmarilloNWS Norman). On the following day, GOES-16 “Red” Visible (0.64 µm) images (above) revealed the areal extent of the snow cover, with significant melting occurring by the late afternoon hours. The snow cover seen in the far northwestern portion of the images is from a winter storm that occurred 8 days earlier on 27 December 2018.

In a comparison between Terra and Aqua MODIS Visible (0.65 µm) images and the corresponding Land Surface Temperature product at 1757 and 1936 UTC (below), LST values in the 30s F (darker shades of blue) were 20ºF colder over the snow cover than over adjacent bare ground in Oklahoma, and 35-40ºF colder than the more sparsely-vegetated bare ground in Texas. By increasing the surface albedo, the snow cover acted to suppress daily maximum temperatures by several degrees.

Terra and Aqua MODIS Visible (0.65 µm) image and Land Surface Temperature product at 1757 an 1936 UTC [click to enlarge]

Terra and Aqua MODIS Visible (0.65 µm) image and Land Surface Temperature product at 1757 an 1936 UTC [click to enlarge]

===== 05 January Update =====

GOES-16 "Red" Visible (0.64 µm) images, 04 and 05 January [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images with hourly plots of surface reports, 04 and 05 January [click to play animation | MP4]

A sequence of GOES-16 “Red” Visible (0.64 µm) images on 04 and 05 January (above) showed the continued melting of residual snow cover.

A toggle between NOAA-20 VIIRS True Color Red-Green-Blue (RGB) images on 04 and 05 January as viewed using RealEarth (below) provided a higher-resolution view of the snow cover just after 1 PM local time on those two days.

NOAA-20 VIIRS True Color RGB images on 04 and 05 January [click to enlarge]

NOAA-20 VIIRS True Color RGB images on 04 and 05 January [click to enlarge]