Wildfire smoke, a cold front and a “Pnuemonia Front”

By Scott Bachmeier • 16 May 2023

GOES-16 True Color RGB images [click to play MP4 animation]

Southern Wisconsin experienced the convergence of 3 cooling mechanisms during the afternoon hours of 16 May 2023: (1) the arrival of a dense band of smoke aloft — transported southward from wildfires in Alberta and Saskatchewan — which reduced incoming solar radiation, (2) a southward-moving cold front and (3) the inland surge of a lake breeze (or “Pneumonia Front“) from Lake Michigan. Signatures of all 3 features were evident in GOES-16 (GOES-East) True Color RGB images from the CSPP GeoSphere site (above), with the cold front and lake breeze marked by broken lines of cumulus clouds that could be seen through the thick veil of smoke.

GOES-16 Day Land Cloud RGB image at 1826 UTC, with readouts of Aerosol Optical Depth, MVFR Fog Probability, Land Surface Temperature and Fire Temperature derived products for a point beneath the thick smoke layer [click to enlarge]

In a comparison of GOES-16 Day Land Cloud RGB images at 1826 UTC that include readouts of Aerosol Optical Depth (AOD), MVFR Fog Probability, Land Surface Temperature and Fire Temperature derived products for a point beneath the thick smoke layer (above) and just south of the thick smoke layer (below), the degree to which the smoke was reducing the amount of incoming solar radiation was apparent in a reduction in Land Surface Temperature (78.26ºF beneath the thick smoke where the AOD was 2.08, vs. 83.98ºF just south of the thick smoke where the AOD was negligible). Both points — and the W-E oriented band of thickest smoke — were located south of the approaching cold front (1800 UTC surface analysis).

CIMSS Natural Color RGB images (below) include plots of surface and buoy reports along with frontal analyses — note the significant drop in air temperatures across southeast Wisconsin as the lake breeze moved inland (for example, from the low 80s F to the middle 50s F within a 30-45 minute period at Milwaukee and Racine; further inland, a notable temperature drop was also seen in Madison just after 19:30 or 7:30 PM local time). Water temperatures reported by Buoy 45007 in southern Lake Michigan were in the 44-46ºF range during the day, and just after 1800 UTC the NOAA-20 VIIRS Sea Surface Temperature value over that buoy location was 47ºF.

CIMSS Natural Color RGB images, with plots of surface and buoy reports along with frontal analyses [click to play animated GIF | MP4].

A plot of lidar backscatter (source) at Madison, Wisconsin (below) depicted increasing smoke within 2 layers: one at an altitude around 3 km, and another within the 5-6 km altitude range.

Plot of lidar backscatter at Madison, Wisconsin [click to enlarge]

Categories: General interpretation, GOES-16, Level 2 Product Readouts, NOAA-20, Red-Green-Blue (RGB) images, VIIRS

CIMSS Satellite Blog

CIMSS Satellite Blog

Wildfire smoke, a cold front and a “Pnuemonia Front”