A rare, mostly clear day over the Great Lakes (and favorable orbital geometry) allowed NOAA-20, above, and Suomi-NPP, below, to image all 5 Great Lakes in one scene.  These images were produced from data that were downloaded at the Direct Broadcast site at CIMSS and processed with CSPP and Polar2Grid;  imagery is available at this link:  ftp://ftp.ssec.wisc.edu/pub/eosdb.  Although many bays appear ice covered (Green Bay in Lake Michigan, Saginaw Bay in Lake Huron, Chequamegon Bay in Lake Superior, there is otherwise a notable lack of ice in the lakes (the feature in central Lake Michigan is cloud).  Current forecasts of sub-zero weather over the western Great Lakes by this coming weekend suggest an increase in ice cover is likely.

The biggest difference between Lake Erie and the other lakes is color.  Why is Lake Erie not a dark blue?  Part of this is depth:  Lake Erie is the shallowest of the Great Lakes.  The browns and lighter blues are the result of sediment from both rivers and from white clay minerals along the northern shore of Lake Erie.  Phytoplankton is also affecting the water color;  not in the sense of an algal bloom, but a persistent algal presence  (Click here for an estimate of Chlorophyll from 21 January, from this website).  (Thanks to scientists at the Great Lakes node of NOAA’s Coast Watch — part of GLERL — for this explanation).

The (mostly) clear skies over the Lakes allowed for an estimate of Lake Surface Temperatures using VIIRS data and the ACSPO (Advanced Clear Sky Processor for Oceans) algorithm, shown below with colors representing temperatures from 32 to 41ºF (0 to 5º C).  Portions of Lakes Michigan, Huron and Ontario (red and white in the color enhancement) show surface temperatures near 41ºF.  Lakes Superior and Erie are relatively cooler.  Much of central Lake Erie is near 35ºF (cyan in the enhancement);  values in eastern Lake Erie are closer to 38ºF (yellow in the enhancement).  Eastern Lake Superior also shows values in the upper 30s.

GOES ABI

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GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images with plots of hourly surface weather type (above) showed the formation of a well-defined cold conveyor belt that moved westward across parts of the Northeast US during the 01 February – 02 February 2021 period. This moist airstream helped to enhance snowfall rates, with 2-4 inches per hour occurring at some locations. Storm total snowfall accumulations were as high as 36.1″ in Pennsylvania, 35.5″ in New Jersey, 25.6″ in New York, 24.0″ in Massachusetts, and 19.0″ in Connecticut.

Another feature that played an important role in enhancing/prolonging heavy snowfall rates was a TROWAL — appearing as a tongue of higher Equivalent Potential Temperature within the 850-700 hPa layer, just north of the surface occluded front — moving inland and feeding moisture into the southern edge of the cold conveyor belt seen on GOES-16 Water Vapor imagery (below).

 

Updated January 30-February 2 snowfall reports based on reports received as of 6 pm Tuesday. Here are the latest highest totals in each state (1 of 2).
PA – Nazareth 36.1″
NJ – Mount Arlington 35.5″
NY – Fishkill/Saugerties 25.6″
MA – Lowell 24″
WV – Terra Alta 22.1″ pic.twitter.com/unxodO5ccS

— NWS Eastern Region (@NWSEastern) February 2, 2021

1-minute Mesoscale Domain Sector GOES-16  “Red” Visible (0.64 µm) images with 5-minute plots of Derived Motion Winds (below) revealed a mesoscale circulation just south-southwest of the analyzed location of the surface low — the majority of these wind vectors had height assignments within the 900-990 hPa range, indicating that the circulation was located above the surface. The highest DMW speed was 36 knots.

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GOES-16 (GOES-East) True Color RGB images created using Geo2Grid (above) revealed multiple plumes of blowing dust — which had their sources in drought-stricken portions of New Mexico and the Texas/Oklahoma Panhandles — moving across Texas in the wake of a cold frontal passage on 30 January 2021. Other features of interest included an undular bore that developed ahead of the advancing cold front in Texas, and smaller plumes of blowing dust that originated from a cluster of dry lake beds in central New Mexico late in the day. Surface wind gusts in the 50-60 knot range were seen, and visibility was restricted to less than 1 mile at some locations.

1-minute Mesoscale Domain Sector GOES-16 Dust RGB and Split Window Difference (10.3 µm – 12.3 µm) images (below) showed that the dust signatures (brighter shades of magenta in the Dust RGB images, and brighter shades of yellow in the SWD images) diminished as the winds began to subside during the late afternoon hours.

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Geo2Grid is a scripting tool that accesses various Python packages to display Geostationary Satellite data, described on this blog before here, here and here (Polar2Grid is a similar package for Low Earth Orbit satellite data).  The animation above shows GOES-16 Band-13 (Clean Window, 10.3 µm) infrared data for an hour over Oklahoma/Kansas/Missouri/Arkansas during a time when tornadoes occurred (imagery was produced using Geo2Grid and GOES-16 level-1b radiance files).  (SPC Storm Reports).

Gridded GLM data are available at this website;  both CONUS and Full Disk domains are available, CONUS data are a simple subset of the Full Disk imagery.  These netCDF files (with ‘GLMC’ in the filename) are available each minute, and contain a variety of gridded GLM products, some of which as distributed to National Weather Service forecast offices. By using the ‘glm_l2’ reader in Geo2Grid, data can be plotted, and subsequently overlain on top of the ABI imagery, as shown below.

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