Above-freezing ground temperatures caused snow melt in lower Minnesota, as seen in this GOES-16 true color imagery from RealEarth. Temperatures in the area reached a balmy 40 degrees Fahrenheit, dissipating what snow had accumulated. At the beginning of the animation, you can see a dark ‘V’ shape that is in contrast with the lighter snow. This is the Minnesota River. The ‘V’ mark disappears as the snow melts.

GOES-16 provides five-minute imagery that can capture changes occurring rapidly, such as snow melt on a warm day. GOES-16 five-minute animations are available to anyone for free on the RealEarth data visualization platform. Visit this link to be taken directly to this GOES-16 true color imagery in RealEearth.

More snow is forecast for the area tomorrow (Friday December 10).

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If you were restricted to just one satellite-based observation and had to describe a week of weather, what would you choose? Submitted for your consideration: Morphed microwave estimates of moisture. The animation above shows MIMIC estimates of total precipitable water (created by using GFS winds to morph individual swaths of MIRS TPW estimates) centered on Hawai’i from 29 November through 7 December. What do these fields show you? There is a general increase in moisture over the Hawai’ian islands from the end of November to 2 December, at which point a polar front associated with a strong southward moving extratropical cyclone moves through the islands, generating snow over the Big Island’s highest peaks. Subsequently, a westward-moving subtropical low develops and draws moisture up from the ITCZ, resulting in heavy rain over the island chain. By the end of the animation, dry air starts to move over the islands from the east.

MIMIC Total Precipitable Water fields are available here. A archive of all fields and various domains is here. Filenames are such that it’s relatively easy to create cron jobs that create animations showing the latest fields, for example here for the eastern Pacific, here for the western Pacific, and here for the southern Pacific.

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MIMIC Total Precipitable Water product [click to play animation | MP4]

As an anomalously-deep Kona low moved northwest of and then west of Hawai`i during the 04-07 December 2021 period, it began to tap moisture from the Pacific ITCZ and channel it northward across the islands — setting the stage for a prolonged heavy rainfall event (which produced the wettest December day on record at Honolulu). Hourly MIMIC TPW images viewed using RealEarth (above) showed the convergence of 2 northward-moving streams of ITCZ moisture, that then flowed across various portions of Hawai’i (located at the center of the images) from 00 UTC on 04 December to 00 UTC on 08 December.

Air Mass RGB images created using Geo2Grid (below) highlighted the southwestward migration of the Kona low (darker shades of red) as well as the northward motion of deep convection within the stream of ITCZ moisture.

GOES-17 Air Mass RGB images [click to play animated GIF | MP4]

In addition to the heavy rainfall across many of the islands, the high-elevation summits of Mauna Kea and Mauna Loa on the Big Island of Hawai`i also received accumulating snowfall — a signature of this snow cover (darker shades of magenta) was evident in GOES-17 Day Snow-Fog RGB images shown below.

GOES-17 Day Snow-Fog RGB images [click to play animated GIF | MP4]

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GOES-16 Night Fog BTD (10.3 – 3.9 µm) and Day Snow Fog RGB images [click to play animated GIF | MP4]

As cold arctic air moved across the still-unfrozen waters of Lake Sakakawea on 06 December 2021, a lake effect cloud plume was seen downwind (southeast) of the lake in GOES-16 (GOES-East) Night Fog BTD (10.3 – 3.9 µm) and Day Snow Fog RGB images (above).

In a comparison of NOAA-20 VIIRS True Color RGB, False Color RGB and Infrared Window (11.45 µm) images at 1925 UTC (below), the lake effect cloud plume was diminishing as winds across/along the lake became lighter — and the unfrozen portions of Lake Sakakawea appeared dark in RGB imagery, with surface infrared brightness temperatures in the 1 to 2ºC range (darker shades of orange).

NOAA-20 VIIRS True Color RGB, False Color RGB and Infrared Window (11.45 µm) images [click to enlarge]

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