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Dorian moves across the Maritime Provinces of Canada

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... Read More

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]


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Typhoon Faxai makes landfall in Japan

#Typhoon #Faxai made landfall in Chiba Pref. Monday morning (9/9) with its central pressure 960hPa and sustained winds 144kph. Faxai is the windiest typhoon to hit the Greater Tokyo area in recorded history. pic.twitter.com/j5TQQ2FF0q — Sayaka Mori (@sayakasofiamori) September 8, 2019 2.5-minute rapid scan JMA Himawari-8 “Clean” Infrared Window (10.4 µm)... Read More


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]

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Hurricane Dorian off the coasts of South Carolina and North Carolina

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... Read More

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″.

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Mesospheric airglow waves over the Northern Plains

Kudos to Carl Jones (NWS Grand Forks) for spotting this vivid example of mesospheric airglow waves (reference) produced by severe thunderstorms that were responsible for a swath of hail across South Dakota from 0515-1010 UTC on 02 September 2019. In the toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images... Read More

VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 (0740 UTC) and Suomi NPP (0831 UTC) [click to enlarge]

VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 (0740 UTC), Suomi NPP (0831 UTC) and NOAA-20 (0921 UTC) [click to enlarge]

Kudos to Carl Jones (NWS Grand Forks) for spotting this vivid example of mesospheric airglow waves (reference) produced by severe thunderstorms that were responsible for a swath of hail across South Dakota from 0515-1010 UTC on 02 September 2019. In the toggles between VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 (at 0740 UTC), Suomi NPP (at 0831 UTC) and NOAA-20 (at 0921 UTC), note that the epicenter of the circular gravity wave patterns appeared to be located west of the convection on the earliest NOAA-20 image and east of the convection in the later NOAA-20 image — this is due to parallax (since the vertically-propagating waves were likely at an altitude near 90 km). This parallax shift was more pronounced in the NOAA-20 images since the high-altitude waves were near the limb of those two satellite swaths. The Moon was in the Waxing Crescent phase (at only 6% of Full), so features seen on the Day/Night Band images were primarily illuminated by airglow.

Closer views centered on the convection are shown below. Cloud-top infrared brightness temperatures in both South Dakota and Nebraska were -70ºC and colder in the NOAA-20 images (which are mislabeled as Suomi NPP), and -80ºC and colder in the Suomi NPP image. Bright white “lightning streak” signatures associated with the thunderstorms were more apparent in these closer views.

 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 (0740 UTC), Suomi NPP (0831 UTC) and NOAA-20 (0921 UTC) [click to enlarge]

VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images from NOAA-20 (0740 UTC), Suomi NPP (0831 UTC) and NOAA-20 (0921 UTC) [click to enlarge]

GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images (below) revealed the rapid development of an isolated hail-producing thunderstorm that generated the mesospheric airglow waves.

GOES-16

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

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