Severe thunderstorms and heavy rainfall/flooding in the Upper Midwest

July 12th, 2016

GOES-13 Infrared Window (10.7 µm) images, with SPC storm reports [click to play animation]

GOES-13 Infrared Window (10.7 µm) images, with SPC storm reports [click to play animation]

GOES-13 Infrared Window (10.7 µm) images (above; also available as an MP4 movie file) showed a series of mesoscale convective systems that moved across northeastern Minnesota, northwestern Wisconsin and the Upper Peninsula of Michigan during the 11 July12 July 2016 period. Some of these storms produced tornadoes, large hail, and damaging winds (SPC storm reports) in addition to heavy rainfall, with as much as 9.00 inches in Minnesota and 9.80 inches in Wisconsin (NWS Duluth storm summary). Several highways were closed due to flooding and/or washout, including a portion of Interstate 35 in Minnesota (interstates and highways are plotted in violet on the images).

A sequence of Infrared images from Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) (below) showed greater detail in the storm-top temperature structure at various times during the event.

Infrared images from Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) [click to play animation]

Infrared images from Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) [click to play animation]

===== 19 July Update =====

Comparison of before (09 July) and after (12 July through 19 July) Suomi NPP VIIRS true-color images [click to enlarge]

Comparison of before (09 July) and after (12 July through 19 July) Suomi NPP VIIRS true-color images [click to enlarge]

A comparison of Suomi NPP VIIRS true-color Red/Green/Blue (RGB) images from before the event (09 July) and after the event (12 through 19 July) (above) revealed the large amounts of sediment flowing offshore into the southwestern portion of Lake Superior.

Another comparison of before (09 July) and after (13 through 19 July) true-color RGB images from Terra and Aqua MODIS is shown below.

Comparison of before (09 July) and after (13 through 19 July) Terra/Aqua MODIS true-color images [click to enlarge]

Comparison of before (09 July) and after (13 July through 19 July) Terra/Aqua MODIS true-color images [click to enlarge]

A toggle between a Terra MODIS Visible (0.65 µm) image and the corresponding MODIS Sea Surface Temperature (SST) product on 16 July (below) showed that the SST values in the sediment-rich nearshore waters were significantly warmer (middle 60s F, red enhancement) than those found closer to the center of Lake Superior (middle 40s F, cyan enhancement).

Terra MODIS Visible (0.65 µm) image and Sea Surface Temperature product [click to enlarge]

Terra MODIS Visible (0.65 µm) image and Sea Surface Temperature product [click to enlarge]

Mesoscale Convective System in the Upper Midwest

July 6th, 2016

GOES-13 Infrared Window (10.7 um) images, with SPC storm reports [click to play animation]

GOES-13 Infrared Window (10.7 µm) images, with SPC storm reports [click to play animation]

GOES-13 (GOES-East) 4-km resolution Infrared Window (10.7 µm) images (above) showed the development of a large Mesoscale Convective System (MCS) which produced tornadoes, large hail, and damaging winds (SPC storm reports | NWS La Crosse summary) as it propagated southeastward across the Upper Midwest during the evening and overnight hours of 05 July06 July 2016.

A sequence of 1-km resolution Terra/Aqua MODIS (11.0 µm), 1-km resolution POES AVHRR (12.0 µm) and 375-meter resolution Suomi NPP VIIRS (11.45 µm) Infrared images (below) showed better details of such features as overshooting tops, some of which exhibited IR brightness temperature values as cold as -78º C on MODIS, -81º C on AVHRR and -86º C on VIIRS.

Infrared MODIS (11.0 um), AVHRR (12.0 um) and VIIRS (11.45 um) images, with SPC storm reports [click to play animation]

Infrared MODIS (11.0 µm), AVHRR (12.0 µm) and VIIRS (11.45 µm) images, with SPC storm reports [click to play animation]

A comparison of Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0852 UTC or 3:52 am local time (below) showed the MCS as its core was centered over northern Illinois. Note how the tall, dense cloud mass blocked the view of nearly all city lights over a large area — including the normally very large and very bright lights of the Chicago metroplex. With almost no illumination from the Moon (which was in its Waxing Crescent phase, at 1% of Full), only the faint light of airglow helped to illuminate some cloud features over the northern portion of the satellite scene. In addition, numerous bright white streaks were seen in the Day/Night Band image along the leading (southern) edge of the MCS, due to cloud illumination from intense lightning activity; one lone lightning streak was evident in Wisconsin, whose intensity was bright enough to saturate the Day/Night Band detectors (hence the long “post-saturation recovery” streak as the sensor continued scanning toward the southeast).

Suomi NPP VIIRS Infrared Window (11.45 um) and Day/Night Band (0.7 um) images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

A few hours earlier at 0339 UTC, the CLAVR-x POES AVHRR Cloud Top Height product (below) showed areas with height values of 16-17 km (lighter cyan color enhancement) — the large amount of water and ice particles contained within such tall clouds was therefore able to effectively block the view of city lights on the VIIRS Day/Night Band image. Note that a Cloud Top Height product will be available from the ABI instrument on GOES-R.

POES AVHRR Cloud Top Height product and Infrared (12.0 um) image [click to enlarge]

POES AVHRR Cloud Top Height product and Infrared (12.0 µm) image [click to enlarge]

Deadly tornado in Yancheng, China

June 23rd, 2016

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play animation]

Himawari-8 0.64 µm Visible (top) and 10.4 µm Infrared Window (bottom) images [click to play animation]

Himawari-8 AHI Visible (0.64 µm) and Infrared Window (10.4 µm) images (above) showed the east-southeastward propagation of a mesoscale convective system which produced a deadly tornado in Yancheng, China around 2:30 pm local time on 23 June 2016 (Weather Underground blog). The location of Yancheng (33°23?N, 120°7?E) is denoted by the cyan * symbol, and the animation briefly pauses on the 0630 UTC images which match the reported time of the tornado. Overshooting tops are evident on the visible imagery, and cloud-top infrared brightness temperatures of -80º C or colder (violet color enhancement) also appear, even after the storm crossed the coast and moved over the adjacent offshore waters of the Yellow Sea (note: due to parallax, the apparent location of the storm top features is displaced several miles to the north-northwest of their actual position above the surface). The spatial resolutions (0.5 km visible, 2 km infrared) of the AHI images are identical to those of the corresponding spectral bands that will be available from the ABI instrument on GOES-R.

An experimental version of the MIMIC Total Precipitable Water product which uses the MIRS retrieval TPW from POES, Metop, and Suomi NPP VIIRS satellites (below) revealed the band of high moisture pooled along the Mei-yu front, which appeared to surge northward across eastern China early in the day on 23 June.

MIMIC Total Precipitable Water product [click to play animation]

MIMIC Total Precipitable Water product [click to play animation]

The 23 June/00 UTC rawinsonde report from Nanjing (located about 260 km southwest of Yancheng) indicated a total precipitable water value of 66.2 mm or 2.6 inches (below).

Nanjing, China rawinsonde report [click to enlarge]

Nanjing, China rawinsonde report [click to enlarge]

Mesoscale Convective Vortex (MCV) in Texas

June 12th, 2016

GOES-13 Infrared Window (10.7 µm) images [click to play animation]

GOES-13 Infrared Window (10.7 µm) images [click to play animation]

GOES-13 Infrared Window (10.7 µm) images (above) showed a large Mesoscale Convective System (MCS) that developed in far eastern New Mexico after 2000 UTC on 11 June 2016, then moved eastward and eventually southward over West Texas during the nighttime hours on 12 June. The MCS produced wind gusts to 75 mph and hail of 1.00 inch in diameter in Texas (SPC storm reports).

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]


Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0801 UTC or 3:01 am local time (above) showed cloud-top infrared brightness temperatures were as cold as -83º C (violet color enhancement), along with a number of bright streaks on the Day/Night Band image due to cloud illumination by intense lightning activity (there were around 5000 cloud-to-ground lightning strikes associated with this MCS). On the infrared image, note the presence of cloud-top gravity waves propagating outward away from the core of overshooting tops.

This MCS produced heavy rainfall, with as much as 3.44 inches reported near Lomax (NWS Midland TX rainfall map | PNS). An animation of radar reflectivity (below, courtesy of Brian Curran, NWS Midland) showed the strong convective cells moving southward (before the Midland radar was struck by lightning and temporarily rendered out of service).

Midland, Texas radar reflectivity [click to play MP4 animation]

Midland, Texas radar reflectivity [click to play MP4 animation]

During the subsequent daytime hours, GOES-13 Visible (0.63 µm) images (below) revealed the presence of a large and well-defined Mesoscale Convective Vortex (MCV) as the cirrus canopy from the decaying MCS eroded. A fantastic explanation of this MCV was included in the afternoon forecast discussion from NWS Dallas/Fort Worth. New thunderstorms were seen to develop over North Texas during the late afternoon and early evening hours as the MCV approached — there were isolated reports of hail and damaging winds with this new convection (SPC storm reports). Initiation of this new convection may have also been aided by convergence of the MCV with a convective outflow boundary moving southward from Oklahoma.

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

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

A sequence of Visible images from POES AVHRR (0.86 µm), Terra MODIS (0.65 µm), and Suomi NPP VIIRS (0.64 µm) (below) showed snapshots of the MCV at various times during the day.

Visible images from POES AVHRR (0.86 µm), Terra MODIS (0.65 µm), and Suomi NPP VIIRS (0.64 µm) [click to enlarge]

Visible images from POES AVHRR (0.86 µm), Terra MODIS (0.65 µm), and Suomi NPP VIIRS (0.64 µm) [click to enlarge]