Consolidation of ice within Green Bay

March 4th, 2021 |

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the wind-driven consolidation of ice within Green Bay during the 03 March04 March 2021 period. Northerly winds in the wake of a cold frontal passage on 03 March led to the fracturing of land-fast ice in the far northern portion of Green Bay — this ice then began drifting south-southwestward.

By sunrise on 04 March, GOES-16 Visible images indicated that the fractured ice had continued to drift farther southward overnight, eventually merging with the land-fast ice that had been covering the southern half of Green Bay; overnight low temperatures in the upper teens to low 20s F likely aided this merger process. Note that some filaments of ice had also migrated through gaps between islands, drifting southward across far western Lake Michigan (just off the coast of Wisconsin).

A toggle between 250-meter resolution Aqua MODIS True Color RGB images (source) on the 2 days is shown below.

Aqua MODIS True Color RGB images [click to enlarge]

Aqua MODIS True Color RGB images [click to enlarge]

As an aside, farther inland the tornado damage path from an EF3 tornado in northeastern Wisconsin was still evident, 13.5 years later (below).

Aqua MODIS True Color RGB images [click to enlarge]

Aqua MODIS True Color RGB images [click to enlarge]

Snow squalls in Montana

February 27th, 2021 |

GOES-16 “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Day Cloud Phase Distinction RGB images (above) showed a cluster of convective features propagating south-southeastward over and to the east of Billings, Montana on 27 February 2021. The shades of green in the RGB images indicated that some of these cloud tops were glaciating, suggesting enough vertical development to produce significant precipitation — and the resulting snow squalls could have contributed to a multi-vehicle accident which closed down Interstate 90 (between Billings and the I-90/I-94 junction) shortly after 1900 UTC. A brief accumulation of 1.3 inches was reported just north of Billings around the time of the accident, and the 1900 UTC surface visibility dropped to 3/4 mile at Billings airport (but was likely lower where the more intense snow squalls were occurring farther east).

The corresponding GOES-17 (GOES-West) Visible/RGB animations are available here: GIF | MP4. A toggle between the 1901 UTC Day Cloud Phase Distinction RGB images from GOES-16 and GOES-17 is shown below. The satellite viewing angles are nearly equivalent from both satellites (around 60 degrees) — but the apparent location of the snow squall features is shifted, due to parallax.

1901 UTC Day Cloud Phase Distinction RGB images from GOES-16 and GOES-17 [click to enlarge]

1901 UTC Day Cloud Phase Distinction RGB images from GOES-16 and GOES-17 [click to enlarge]

VIIRS Imagery shows ice cover on Great Lakes

February 20th, 2021 |

Suomi-NPP VIIRS true-color imagery (1843 UTC) and GOES-16 Band 5 (1.61 µm) imagery (1841 UTC) on 20 February 2021 (Click to enlarge)

An uncommon somewhat clear day on 20 February 2021 allowed VIIRS on Suomi-NPP to provide a true-color image of all 5 Great Lakes. The true-color image above is shown in a toggle with GOES-16 “Snow-Ice” Band 5 near-infrared data (1.61 µm) that allows for discrimination between clouds made up of water droplets (bright white) and underlying snow/ice (darker grey).  Much of western Lake Superior shows ice:  highly reflective in the true color imagery and much darker in the snow/ice channel (but not quite as dark as open water).  Lake Superior has about 50% ice coverage (this figure, originally from this website).  Western Lake Michigan shows little ice coverage (except over Green Bay);  ice coverage on Michigan is less than 30%.   Lake Erie is the most ice-covered of the Lakes:  around 80% ice-covered.  Recent northwesterly winds have moved the pack ice away from the northern shore (except for the far western basin).

Ice motion on the Great Lakes

February 19th, 2021 |

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) revealed the fracturing of land-fast ice in the far southern portion of Lake Michigan on 19 February 2021. Although the westerly wind speeds were not particularly strong — generally 15-20 knots over water, including Metop ASCAT winds early in the day — these winds in tandem with lake currents were enough to move some of this ice eastward.

Farther to the north over western Lake Superior, 5-minute CONUS sector GOES-16 Visible images (below) also showed a significant amount of ice motion during the day.

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

A 30-meter resolution Landsat-8 False Color RGB image viewed using RealEarth (below) provided a more detailed look at the ice structure over western Lake Superior at 1653 UTC. Ice and areas of vegetation-sparse snow cover (rivers, lakes and wildfire burn scars) appear as shades of cyan in the RGB image.

Landsat-8 False Color RGB image [click to enlarge]

Landsat-8 False Color RGB image [click to enlarge]

===== 20 February Update =====

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

On 20 February, another look at 1-minute GOES-16 Visible images over southern Lake Michigan (above) indicated that new ice leads were opening up within individual ice floes that had broken free a day earlier.

===== 21 February Update =====

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

On 21 February, GOES-16 Visible images (above) showed how southerly winds were shifting much the ice in Lake Erie to the north. However, the effects of lake currents on the ice motion were also evident. As mentioned in this blog post, ice coverage on Lake Erie was around 80%.