Severe thunderstorms in Wyoming, Nebraska and South Dakota

September 10th, 2019 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 “Red” Visible (0.64 µm) images (above) showed  the development of thunderstorms that produced large hail, tornadoes and damaging winds (SPC Storm Reports) across eastern Wyoming, northern Nebraska and southern South Dakota on 10 September 2019. Note that many of the storms exhibited Above-Anvil Cirrus Plumes. Pulsing overshooting tops reached -80ºC and colder (violet pixels) just east of Valentine, Nebraska (KVTN) from 0001-0004 UTC (0002 UTC image) — and a few minutes following their collapse, a wind gust of 60 mph was reported in that general vicinity.

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images are shown below.

GOES-16 "Clean" Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

During the subsequent nighttime hours, GOES-16 Infrared images (below) showed a convective cluster which produced 3 EF-2 tornadoes and damaging winds in and around Sioux Falls, South Dakota (NWS summary). Note that pulsing overshooting tops west of Sioux Falls (KFSD) exhibited infrared brightness temperatures of -80ºC and colder (violet pixels) from 0402-0406 UTC (0404 UTC image), which was about 20 minutes prior to the first tornado reports.

GOES-16 "Clean" Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with SPC Storm Reports plotted in cyan [click to play animation | MP4]

Dorian moves across the Maritime Provinces of Canada

September 8th, 2019 |

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed Hurricane Dorian as it briefly intensified from a Category 1 to a Category 2 storm during the morning of 07 September 2019. Later in the day, Dorian transitioned to a post-tropical storm before making landfall over Nova Scotia around 2215 UTC. Due to high amounts of  deep-layer wind shear, the low-level circulation center of Dorian remained exposed while deep convection remained to its north and northeast. The eye of Dorian moved over Buoy 44011, which recorded a wind gust to 82 knots; in western Nova Scotia, winds gusted to 70 knots at Yarmouth.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 as visualized using RealEarth (above) revealed a brighter region exhibiting a somewhat hazy appearance within the cloud-free slot southwest of the eye during the 16-17 UTC period. This could have been a signature of diffuse solar reflection off highly-agitated ocean waves — a NHC discussion noted strong Metop-B ASCAT winds of 80 knots or higher in that area around 15 UTC (below).

Metop-B ASCAT winds [click to enlarge]

Metop-B ASCAT winds [click to enlarge]

On the following day, Suomi NPP VIIRS True Color and Infrared  images (below) showed Post-Tropical Cyclone Dorian when its center was over the Gulf of St. Lawrence. Wind gusts included 68 knots at Heath Point, Quebec (CWHP) and 57 knots at Deer Lake, Newfoundland (CYDF).

Suomi NPP VIIRS True Color RGB and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS True Color RGB and Infrared Window (11.45 µm) images [click to enlarge]


Typhoon Faxai makes landfall in Japan

September 8th, 2019 |


2.5-minute rapid scan JMA Himawari-8 “Clean” Infrared Window (10.4 µm) images centered on Tokyo (with plots of hourly wind gusts) are shown below — wind gusts included 90 knots (167 km/h) at New Tokyo International Airport (RJAA) and 85 knots (157 km/h) at Tokyo International Airport (RJTT).

Himawari-8

Himawari-8 “Clean” Infrared Window (10.4 µm), with hourly wind gusts (in knots) plotted in yellow [click to play animation | MP4]

Hurricane Dorian off the coasts of South Carolina and North Carolina

September 5th, 2019 |

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed Hurricane Dorian off the coast of South Carolina from 1116-1900 UTC on 05 September 2019. During this period, Dorian weakened from a Category 3 to a Category 2 hurricane — a plot of deep-layer wind shear from the CIMSS Tropical Cyclones site (below) showed that the storm was moving into an environment of increasingly unfavorable shear.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with contours of deep-layer wind shear at 19 UTC [click to enlarge]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with an overlay of deep-layer wind shear at 19 UTC [click to enlarge]

Dorian’s eye passed directly over EDISTO Buoy 41004; a combined plot of wind speed, wind gust, and air pressure is shown below.  Across the region, peak wind gusts were 98 mph and rainfall was as high as 10.19 inches.

Plot of wind speed (blue), wind gust (red) and air pressure (green) for Buoy 41004

Plot of wind speed (blue), wind gust (red) and air pressure (green) for Buoy 41004

A sequence of VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 as viewed using RealEarth are shown below.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi NPP and NOAA-20 [click to enlarge]

===== 06 September Update =====

GOES-16 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

Dorian made landfall on Cape Hatteras, North Carolina around 1235 UTC on 06 September — 1-minute GOES-16 Infrared images (above) showed the eye moving northeastward across the Outer Banks. Peak wind gusts were as high as 110 mph, with rainfall amounts up to 13.74″.