Radar imagery from the upper midwest at 1858 UTC, below, showed convection moving into lower Michigan. NUCAPS thermodynamics, above, suggest that the convection would not dissipate in Michigan. An elevated mixed layer with lapse rates of 7 C/km between 500 and 700 mb is indicated.

NUCAPS Points for the afternoon pass over Michigan are shown below. Lower clouds are apparent over much of lower Michigan, but the NUCAPS Soundings did converge to values. The sounding point over southwest Michigan, here, and for just southwest of Saginaw Bay, here, show the steep mid-level lapse rates. NUCAPS Lapse Rates can also be viewed at this website from SPoRT; Lapse rates of 850-700 and 700-500 are available.

GOES-16 Visible imagery (0.64 µm), below, along with GLM Observations of Flash Extent Density, show how the convection continued across lower Michigan.

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GOES-16 (GOES-East) Upper-level Water Vapor (6.2 µm) (above) and Mid-level Water Vapor (6.9 µm) images (below) displayed a well defined leeside cold frontal gravity wave (reference) as it began to propagate southward from Colorado/Kansas late in the day on 11 October 2020. A bore structure eventually developed near the leading edge of the cold frontal gravity wave as it continued moving south over New Mexico/Texas/Oklahoma during the subsequent overnight hours.

As the surface cold front moved southward across the drought-impacted plains of eastern Colorado, 1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) and CIMSS Natural Color Red-Green-Blue (RGB) images (below) revealed the hazy signature of blowing dust lofted by post-frontal northerly winds with peak gusts in the 60-80 knot range. Blowing dust reduced the surface visibility to 1-2 miles at several reporting stations, falling to near zero at some locations (causing a multi-vehicle accident along Interstate 70 in Kansas).

GOES-16 True Color images created using Geo2Grid (below) provided a clearer view of the blowing dust along and immediately behind the cold front across the Colorado/Kansas border region.

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Multi-spectral views from Himawari-8’s “Target Sector” that provides 2-minute imagery, above, show weakening Typhoon Chan-hom south of Japan. The Typhoon shows a sheared structure, with the surface circulation southwest of the main convection, a shift that is especially evident in the Band 5 1.61 µm channel that differentiates between low clouds containing water droplets and upper clouds containing ice crystals. (Himawari data courtesy of the Japan Meteorological Agency.)  A 24-hour animation (ending at 0500 UTC on 9 October) of Mimic Total Precipitable water (from this site) shows that the storm is surrounded by dry air to the north and west.

An analysis of Advanced Microwave Sounder Unit (AMSU) Channel 7 (54.94 GHz), below, (from this site) shows a warm anomaly over the storm.  Atmospheric shear (200-850 mb) is also shown in this figure, and the storm is approaching a region of high shear.

 

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images — with and without an overlay of GLM Flash Extent Density — and “Red” Visible (0.64 µm) images (above) showed showed Hurricane Delta as it intensified from a Category 2 to a Category 3 storm over the Gulf of Mexico during the daytime hours on 08 October 2020. Cloud-top infrared brightness temperatures of -90ºC and colder  (yellow pixels embedded within the darker shades of purple) were occasionally seen within the eyewall region of Delta, along with intermittent bursts of lightning activity.

A toggle between Suomi NPP VIIRS Infrared Window (11.45 µm) and Visible (0.64 µm) images of Hurricane Delta shortly before it intensified to a Category 3 storm are shown below; the coldest cloud-top infrared brightness temperature at that time was -93.0ºC.

In a time-matched comparison of Infrared images from Suomi NPP and GOES-16 (below), the coldest cloud-top infrared brightness temperature sensed by GOES-16 was 5.6ºC warmer (-87.4ºC); note the small northwestward parallax displacement that is inherent with GOES-16 imagery over the Gulf of Mexico. The same color enhancement is applied to both images.

===== 09 October Update =====

In a toggle between Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0734 UTC or 2:34 am CDT on 09 October (above), the coldest cloud-top infrared brightness temperature was -93.8ºC (just northwest of the storm center).

1-minute GOES-16 Infrared and Visible images (below) showed Category 2 Hurricane Delta making landfall in southwestern Louisiana at 2300 UTC, producing wind gusts as high as 100 mph at Texas Point, Texas.

The MIMIC Total Precipitable Water product (below) indicated that Hurricane Delta was transporting a large amount of moisture northward across the Gulf of Mexico — rainfall totals included 15.64 inches at Evangeline Gardner, Louisiana.

The MIMIC-TC product (below) showed the deterioration of the eye and eyewall structure as Delta approached the Gulf Coast.

===== 10 October Update =====

A before (04 October) / after (10 October) comparison of Suomi NPP VIIRS True Color RGB images from the VIIRS Today site (above) revealed a marked increase of turbidity within the more shallow shelf waters of Texas and Louisiana, due to extensive mixing from the wind field associated with Delta. A comparison of VIIRS False Color images from those 2 days (below) highlighted inland areas with significant flooding that resulted from heavy rainfall and/or storm surge (darker shades of blue).

A GOES-16 River Flood Detection product viewed using RealEarth (below) helped to quantify the severity of flooding resulting from the landfall of Delta.

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