Lake/river effect clouds in North Dakota

November 7th, 2017 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top) and Near-Infrared “Snow/Ice” (1.61 µm, bottom) images, with plots of hourly surface reports [click to play MP4 animation]

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

As cold arctic air continued to move eastward across North Dakota on 07 November 2017, GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Snow/Ice” (1.61 µm) images (above) showed “lake effect” cloud plumes streaming east-northeastward from Lake Sakakawea (and also from Missouri River). The Snow/Ice images were the most useful for discriminating between supercooled water droplet cloud plumes (brighter shades of white) and the surrounding snow-covered land surfaces (darker shades of gray).

During the preceding nighttime hours, Suomi NPP VIIRS and Aqua MODIS Infrared Brightness Temperature Difference images (below) — the legacy “fog/stratus product” — revealed that the orientation of the Lake Sakakawea cloud plume changed as surface winds switched from northwesterly to westerly.

Infrared Brightness Temperature Difference images from Suomi NPP VIIRS (11.45 µm = 3.74 µm) and Aqua MODIS (11.0 µm - 3.7 µm) [click to enlarge]

Infrared Brightness Temperature Difference images from Suomi NPP VIIRS (11.45 µm = 3.74 µm) and Aqua MODIS (11.0 µm – 3.7 µm) [click to enlarge]

The Aqua MODIS Sea Surface Temperature product (below) indicated that the water in Lake Sakakawea was as warm as 47.9ºF (darker green enhancement) — significantly warmer than the surface air passing over it, which was generally in the 5 to 15ºF range.

Aqua MODIS Sea Surface Temperature product [click to enlarge]

Aqua MODIS Sea Surface Temperature product [click to enlarge]

The large cloud plume from Lake Sakakawea was also very evident on GOES-16 Day Snow-Fog Red-Green-Blue (RGB) images (below). Farther to the east, smaller and shorter-lived cloud plumes could also be seen originating from Devils Lake (along the Benson/Ramsey county line) and Stump Lake (in Nelson county).

GOES-16 Day Snow-Fog RGB images [click to animate]

GOES-16 Day Snow-Fog RGB images [click to animate]

Taking a closer look at the Lake Sakakawea area, the brighter signature of steam plumes rising from power plants located south and southeast of the lake (2 in Mercer county, and 1 in McLean county) could be spotted on the Day Snow-Fog RGB images (below).

GOES-16 Day Snow-Fog RGB images [click to animate]

GOES-16 Day Snow-Fog RGB images [click to animate]

Due to the low sun angle and the snow-covered land surface, morning shadows from these rising steam plumes could be seen on GOES-16 “Red” Visible (0.64 µm) images (below).

GOES-16

GOES-16 “Red” Visible images [click to animate]

Special thanks to Carl Jones (NWS Grand Forks) for bringing this case to our attention, and supplying the AWIPS RGB and Visible images at the bottom of the blog post.

 

Severe weather across Indiana and Ohio

November 5th, 2017 |

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with SPC storm reports plotted in red (on Visible images) and black (on Infrared images) [click to play MP4 animation]

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with SPC storm reports plotted in red (on Visible images) and black (on Infrared images) [click to play MP4 animation]

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

An outbreak of severe weather occurred across the Midwestern US on 05 November 2017, with a number of tornadoes (including a 39-mile long track EF-2 tornado) in Indiana and Ohio. A GOES-16 Mesoscale Sector provided imagery at 1-minute intervals during this event — “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) with plots of SPC storm reports (T=tornado; W=damaging winds; H=hail) showed the development and motion of the severe thunderstorms. The locations of the plotted SPC storm reports have been parallax-corrected upward from the surface, to match a mean storm-top height of 10 km.

A toggle between Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (below) showed a snapshot of the storm at 1803 UTC. SPC storm reports within about  +/- 30 minutes of the image time are also plotted. The coldest storm-top infrared brightness temperatures were -71ºC (black enhancement), over southern and eastern Indiana. The VIIRS instrument will also fly on the JPSS series of satellites.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with plots of SPC storm reports [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images, with plots of SPC storm reports [click to enlarge]

One interesting aspect seen on 1806 UTC Aqua MODIS Water Vapor (6.7 µm) imagery (below) was the signature of strong subsidence (darker blue enhancement) immediately upwind — along the western edge — of the 2 larger areas of severe convection. Once again, SPC storm reports within about +/- 30 minutes of the image time are plotted.

Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm) and Water Vapor (6.7 µm) images, with SPC storm reports [click to enlarge]

Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm) and Water Vapor (6.7 µm) images, with SPC storm reports [click to enlarge]

Additional information on this event can be found on the Satellite Liaison Blog, as well as the NWS forecast offices at Indianapolis IN, Northern IN, and Wilmington OH.

Power Outages in the wake of a strong Nor’easter

October 31st, 2017 |

Suomi NPP Day Night Band Visible Imagery (0.70 µm) on 4 October 2017 (2:43 AM EST) and on 30 October 2017 (2:38 AM EST) (Click to enlarge)

The toggle above includes nocturnal visible Suomi NPP VIIRS  Day Night Band (0.7 µm) imagery over New England after a strong storm (blogged here), compared with a reference image from 04 October 2017.  The primary nighttime light source for the Day Night Band over land on 31 October was cities (since the Moon was below the horizon), thus a comparison between the latest image with one earlier in the month having different lunar illumination (from October 4th) highlights regions that experienced significant power outages due to high winds.  Clouds will affect the interpretation of the Day Night Band imagery, and a reference Infrared Window (11.45 µm) image from 31 October at 2:38 AM EST is here.  The Day Night Band image with only cloud outlines is here.  (VIIRS imagery courtesy of Will Straka, CIMSS).

Dissipation of nocturnal valley fog across New England

October 28th, 2017 |

GOES-16 Visible (0.64 µm) images, with hourly surface reports of fog plotted in yellow [click to play animation]

GOES-16 Visible (0.64 µm) images, with hourly surface reports of fog plotted in yellow [click to play animation]

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

With high pressure dominating across the region during the pre-dawn nighttime hours (surface analyses), strong radiational cooling (minimum temperatures) aided in the formation of widespread valley fog across New England on 28 October 2017.  Post-sunrise GOES-16 “Red” Visible (0.64 µm) images revealed the areal extent of the valley fog; however, fog dissipation was fairly rapid during the morning hours as surface heating from abundant sunlight promoted sufficient boundary layer mixing.

During the preceding nighttime hours, development of widespread valley fog could be seen on Suomi NPP VIIRS Infrared Brightness Temperature Difference (11.45 µm – 3.74 µm) images (below) — although surface fog features were obscured at times by patchy cirrus clouds aloft (black enhancement). This example demonstrates that because of the wide (3000 km) scan swath of the VIIRS instrument, in many cases the same region might be sampled by 2 consecutive overpasses. VIIRS will also be part of the instrument payload on the upcoming JPSS series of polar-orbiting satellites.

Suomi NPP VIIRS Infrared Brightness Temperature Difference (11.45 µm - 3.74 µm) images [click to enlarge]

Suomi NPP VIIRS Infrared Brightness Temperature Difference (11.45 µm – 3.74 µm) images [click to enlarge]