GOES-14 SRSO-R: severe thunderstorms in parts of the Midwest and the Southern Plains

May 11th, 2016

GOES-14 Infrared Window (10.7 µm) images, with parallax-corrected SPC storm reports [click to play animation]

GOES-14 Infrared Window (10.7 µm) images, with parallax-corrected SPC storm reports [click to play animation]

The GOES-14 satellite remained in Super Rapid Scan Operations for GOES-R (SRSO-R) mode for part of the day on 11 May 2016; Infrared Window (10.7 µm) images (above) showed the nocturnal development of a severe thunderstorm ahead of an approaching occluded front (surface analyses) that dropped large amounts of hail in the northwestern section of Omaha, Nebraska (station identifier KOMA), stripping trees of foliage and clogging some city streets (even requiring the use of snow plows and shovels: photo 1 | photo 2). The storm began to exhibit an “enhanced-V” signature just prior to the time that it started producing large hail in Omaha. Note: the plotted location of the SPC storm reports on this animation (and all animations on this blog post) have been parallax-corrected, moving them slightly north-northeastward to match the location of cloud top features having a mean altitude of 10 km. The letters UNK after a W wind report denotes “unknown intensity”.

During the late afternoon and early evening, GOES-14 Visible (0.63 µm) images (below; also available as a large 59 Mbyte animated GIF) revealed additional thunderstorms which produced hail and damaging winds across eastern Missouri and southern Illinois (SPC storm reports). These storms fired along an outflow boundary left in the wake of another mesoscale convective system (MCS)  that moved through the region earlier in the day.

GOES-14 Visible (0.63 µm) images, with parallax-corrected SPC storm reports [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images, with parallax-corrected SPC storm reports [click to play MP4 animation]

Side note: there was a planned outage of GOES-14 SRSO-R imagery from 1059-2119 UTC. During this time, the GOES-13 (GOES-East) satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-7 minutes. Visible (0.63 µm) images (below) showed the mesoscale convective system that produced hail as large as 4.0 inches in diameter in the St. Louis, Missouri area.

GOES-13 visible (0.63 µm) images, with parallax-corrected SPC storm reports [click to play animation]

GOES-13 visible (0.63 µm) images, with parallax-corrected SPC storm reports [click to play animation]

Finally, late in the day another MCS developed in North Texas, just west of the Dallas/Fort Worth area. GOES-14 Visible (0.63 µm) images with parallax-corrected SPC storm reports (below; also available as a large 54 Mbyte animated GIF) showed the large hail and damaging winds produced by this storm. One feature of interest was the “storm-top plume” that emanated from the largest cluster of overshooting tops, and was blown northeastward.

GOES-14 Visible (0.63 µm) images, with parallax-corrected SPC storm reports [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images, with parallax-corrected SPC storm reports [click to play MP4 animation]

Sea ice off the coast of Labrador and Newfoundland, Canada

May 3rd, 2016

Suomi NPP VIIRS true-color and false-color RGB images [click to enlarge]

Suomi NPP VIIRS true-color and false-color RGB images [click to enlarge]

A comparison of Suomi NPP VIIRS true-color and false-color Red/Green/Blue (RGB) images from the SSEC RealEarth site (above) revealed the intricate structure of sea ice off the coast of Labrador, Canada on 03 May 2016. Snow cover and ice appear as shades of cyan in the false-color image (in contrast to supercooled water droplet clouds, which appear as shades of white).

A larger-scale view using GOES-13 (GOES-East) Visible (0.63 µm) images (below) showed the motion of this sea ice, which extended farther south off the coast of Newfoundland. The general southeastward ice motion was driven by the flow of the Labrador Current.

GOES-13 Visible (0.63 µm) images [click to play animation]

GOES-13 Visible (0.63 µm) images [click to play animation]

According to data from the Canadian Ice Service, the concentration of this medium to thick “first year ice” (Labrador | Labrador/Newfoundland) was as high as 9/10 to 10/10 (below). The departure of normal of portions of this ice was as high as 9/10 to 10/10 above normal.

Ice concentration off the Labrador coast [click to enlarge]

Ice concentration off the Labrador coast [click to enlarge]

Ice concentration off the coast of Labrador and Newfoundland [click to enlarge]

Ice concentration off the coast of Labrador and Newfoundland [click to enlarge]

 

Blowing dust in northeastern Arkansas

April 12th, 2016

GOES-13 Visible (0.63 um) images [click to play animation]

GOES-13 Visible (0.63 um) images [click to play animation]

Strong southwesterly winds (gusting as high as 39 knots or 45 mph) created areas of blowing dust that reduced visibility to near zero and caused 2 incidents of multiple-vehicle accidents (NWS Local Storm Reports) near Portia in northeastern Arkansas on 10 April 2016. GOES-13 (GOES-East) Visible (0.63 um) images (above) showed the faint hazy signature of a few narrow plumes of blowing dust moving northeastward, one of which moved across Lawrence County and between Portia (denoted by the red * symbol) and Walnut Ridge (station identifier KARG). The blowing dust plumes are perhaps a bit easier to see on these images without county outlines and highways, though they are still somewhat difficult to identify with the patches of thin cirrus and contrails drifting from west to east overhead. Video of the conditions on the ground can be seen here.

Time series plots of surface data for Walnut Ridge (KARG) located just to the northeast and Newport (KM19) located farther to the south-southwest are shown below. Surface reports indicated that the visibility was reduced to less than 1 mile at 1756 UTC at Newport, and less than 3 miles at 1735 UTC at Walnut Ridge.

Time series plot of surface data for Walnut Ridge, Arkansas [click to enlarge]

Time series plot of surface data for Walnut Ridge, Arkansas [click to enlarge]

Time series plot of surface data for Newport, Arkansas [click to enlarge]

Time series plot of surface data for Newport, Arkansas [click to enlarge]

On the previous day, a comparison of the 1849 UTC Aqua MODIS Visible (0.65 µm) image and the corresponding Normalized Difference Vegetation Index (NDVI) product (below) showed that there were many areas upwind (to the southwest of) Portia and Walnut Ridge — in both southern Lawrence and northern Jackson counties — that exhibited low NDVI values (tan color enhancement), indicative of recently-plowed and/or unplanted agricultural fields within that part of the Mississippi Alluvial Plain. It is possible that field plowing activities on that windy day may have been the catalyst for the some of the  blowing dust plumes.

Aqua MODIS Visible (0.65 um) and Normalized Difference Vegetation Index (NDVI) product [click to enlarge]

Aqua MODIS Visible (0.65 um) and Normalized Difference Vegetation Index (NDVI) product [click to enlarge]

Similarly, a comparison of the 1849 UTC Aqua MODIS NDVI and Land Surface Temperature (LST) products (below) showed that the land surface in areas with less vegetation were warming up more quickly, with some LST values in excess of 90º F (darker red enhancement).

Aqua MODIS Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature products [click to enlarge]

Aqua MODIS Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature products [click to enlarge]

Middle and upper-atmospheric wave structures in the vicinity of a subtropical jet stream

April 4th, 2016

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with ECMWF model maximum wind isotachs [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images, with ECMWF model maximum wind isotachs [click to enlarge]

A strong (120-knot) subtropical jet stream was moving eastward across the Gulf of Mexico during the 03 April – 04 April 2016 period. During the overnight hours between these 2 days, a Suomi NPP VIIRS Day/Night Band (0.7 µm) image at 0753 UTC (above) revealed a large packet of arc-shaped mesospheric airglow waves south of the axis of the jet stream (as indicated by isotachs of the maximum tropospheric wind speed from the ECMWF model). Note how there were no cloud features which corresponded to these waves in the 0753 UTC VIIRS Infrared Window (11.45 µm) image; since the Moon was in the waning Gibbous phase (at 13% of Full), there was very little lunar illumination of cloud features, so airglow — essentially the “night glow” emitted from a variety of high-altitude (80-105 km) gases (primarily the sodium layer) near the mesopause — was allowing these high-altitude waves to be detected using the sensitive Day/Night Band (reference: “Suomi satellite brings to light a unique frontier of nighttime environmental sensing capabilities”).

During the subsequent daytime hours on 04 April, more interesting (tropospheric) waves were seen in the vicinity of this subtropical jet stream — small packets of waves that were propagating westward, against the ambient flow –one over Florida/Georgia/South Carolina, and another over South Texas. Unfortunately, these features fall into the “What the heck is this?” blog category, so no coherent explanation of them can be offered at this time.

GOES-13 Water Vapor (6.5 µm) images, with ECMWF model maximum wind isotachs [click to play animation]

GOES-13 Water Vapor (6.5 µm) images, with ECMWF model maximum wind isotachs [click to play animation]

An interesting question from Shea Gibson: