Transport of Canadian wildfire smoke across the Northeast US

May 22nd, 2019 |

GOES-16 CIMSS Natural Color images, with an overlay of the Smoke Detection Product ;click to play animation | MP4]

GOES-16 CIMSS Natural Color RGB images, with an overlay of the Smoke Detection Product [click to play animation | MP4]

GOES-16 (GOES-East) CIMSS Natural Color Red-Green-Blue (RGB) images with an overlay of the Smoke Detection Product (above) revealed curved filaments of wildfire smoke moving southeastward across the Northeast US and the adjacent offshore waters of the Atlantic Ocean on 22 May 2019. The smoke filaments were classified as Medium/High confidence by the algorithm — additional information on GOES-R Aerosol Detection Products in AWIPS is available here and here.

During the preceding overnight hours, with ample illumination from the Moon (in the Waning Gibbous phase, at 92% of Full) smoke filaments were evident over the Atlantic Ocean on Suomi NPP VIIRS Day/Night Band (0.7 µm) imagery at 0722 UTC or 3:22 AM Eastern Time (below). Note that the smoke did not exhibit a signature in the corresponding VIIRS Infrared Window (11.45 µm) image, since thin smoke layers are effectively transparent to infrared radiation.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0722 UTC [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 0722 UTC [click to enlarge]

Daily composites of Suomi NPP VIIRS True Color RGB images with VIIRS Fire Detections viewed using RealEarth (below) showed that thick smoke from wildfires in northern Alberta initially was lofted above the meteorological clouds over the Northwest Territories and Nunavut on 19 May and 20 May, before eventually moving southeastward across central/eastern Canada.

Daily composites of Suomi NPP VIIRS True Color RGB images with Fire Detections, 18-22 May [click to play animation]

Daily composites of Suomi NPP VIIRS True Color RGB images with Fire Detections, 18-22 May [click to play animation]

HYSPLIT model 72-hour back trajectories from 3 points corresponding to the smoke filaments seen in the GOES-16 imagery off the Northeast US coast (below) confirmed an initial anticyclonic transport from the region of the Alberta wildfires, with a subsequent southeastward transport across Canada and eventually the Northeast US.

HYSPLIT model 72-hour back trajectories from 3 points off the Northeast US coast [click to enlarge]

HYSPLIT model 72-hour back trajectories from 3 points off the Northeast US coast

6-hourly GFS 500 hPa analyses (source) shown below help to explain the smoke transport as seen in both the VIIRS imagery and the HYSPLIT trajectories — a ridge of high pressure was present over western Canada early in the period, with a transition to a deepening longwave trough over eastern Canada with a shortwave trough digging across Quebec and the Maritimes on 21-22 May. Strong descent of the trajectories occurred during the final 12 hours of transport, on the back side of the digging shortwave trough.

6-hourly GFS 500 hPa analyses [click to enlarge]

6-hourly GFS 500 hPa analyses, from 12 UTC on 18 May to 12 UTC on 22 May [click to enlarge]

Asian dust entrained into a midlatitude cyclone

May 12th, 2019 |

True Color RGB images from MODIS (Terra) and VIIRS (NOAA-20 and Suomi NPP) [click to enlarge]

True Color RGB images from MODIS (Terra) and VIIRS (NOAA-20 and Suomi NPP) [click to enlarge]

True Color Red-Green-Blue (RGB) images from the MODIS instrument (on the Terra satellite) and the VIIRS instrument (on the NOAA-20 and Suomii NPP satellites) as viewed using RealEarth (above) revealed a tan-colored swirl of dust that had been lofted from the surface and entrained into the circulation of a midlatitude cyclone along the Mongolia/China border on 12 May 2019.

A sequence of MODIS/VIIRS True Color RGB images from Terra and Suomi NPP on 10, 11 and 12 May (below) showed the initial signature of surface-based blowing dust appearing in the Kumul and Jiuquan areas of northwestern China on 11 May, before it became wrapped into the circulation of the aforementioned midlatitude cyclone on 12 May.

True Color RGB images from MODIS (Terra) and VIIRS (Suomi NPP) [click to enlarge]

True Color RGB images from MODIS (Terra) and VIIRS (Suomi NPP) [click to enlarge]

Surface analyses at 3-hour intervals (source), from 12 UTC on 11 May to 00 UTC on 13 May (below) illustrated the strong pressure gradient between a large dome of high pressure over Mongolia and a developing midlatitude cyclone along the Mongolia/China border on 11 May — strong surface winds generated by this pressure gradient initially caused the blowing dust to begin in northwestern China.

Surface analyses at 3-hour intervals from 12 UTC on 11 May to 00 UTC on 13 May [click to enlarge]

Surface analyses at 3-hour intervals from 12 UTC on 11 May to 00 UTC on 13 May [click to enlarge]

JMA Himawari-8 Split Window Difference (10.4-12.3 µm) images (below) showed the signature of dust (yellow to cyan enhancement) moving eastward from the desert source region in northwestern China and becoming wrapped into the circulation of the midlatitude cyclone along the Mongolia/China border.

Himawari-8 Split Window Difference (10.4-12.3 µm) iimages [click to play animation |MP4]

Himawari-8 Split Window Difference (10.4-12.3 µm) images [click to play animation | MP4]

Ash fall streak from the Sheveluch volcano in Kamchatka

May 12th, 2019 |

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images, with topography [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images, with topography [click to enlarge]

In a comparison of Suomi NPP VIIRS Visible (0.64 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images on 12 May 2019 (above), a dark volcanic ash fall streak was evident in the Visible image, which extended over 100 miles southward from the Sheveluch volcano on the Kamchatka Peninsula of Russia. This feature was a layer of volcanic ash that had been deposited on top of existing snow cover — note that most of the dark ash fall streak exhibited much cooler infrared brightness temperatures compared to the bare ground of the interior valley to the west (since the ash streak existed on top of a higher-altitude area of snow cover).

This ash fall streak was a result of an explosive eruption of the volcano over a month earlier, on 10 April — the volcanic ash plume could be seen moving southward in Himawari-8 Visible (0.64 µm) images (below).

Himawari-8

Himawari-8 “Red” Visible (0.64 µm) images [click to play animation | MP4]

An interesting aspect of this long-lived ash fall streak was that a portion of it was apparently covered by a layer of fresh snowfall at some point after the eruption — and a 7-day sequence of Suomi NPP VIIRS True Color Red-Green-Blue (RGB) images viewed using RealEarth (below) suggested that this layer of new snow was melting with the aid of the high May sun angle, gradually revealing more of the original length of the ash fall streak.

Suomi NPP VIIRS True Color RGB images, 06-12 May 2019 [click to play animation | MP4]

Suomi NPP VIIRS True Color RGB images, 06-12 May 2019 [click to play animation | MP4]

Note that there was another small volcanic plume moving south-southwestward from Sheveluch in the 09 May VIIRS True Color image — retrieved quantities of ash probability, height, loading and effective radius for this volcanic plume (source) are shown below.

Suomi NPP False Color, Ash Probability, Height, Loading and Effective Radius [click to enlarge]

Suomi NPP False Color, Ash Probability, Height, Loading and Effective Radius [click to enlarge]

This type of volcanic ash fall streak frequently occurs on the snow-covered Kamchatka Peninsula — here is an example from March 2013.

Thanks go out to Santiago Gassó for bringing this interesting feature to our attention.

Cyclone Fani makes landfall in India

May 3rd, 2019 |

EUMETSAT-8 Meteosat-8 Infrared Window (10.8 µm) umages [click to play animation | MP4]

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images [click to play animation | MP4]

EUMETSAT Meteosat-8 Infrared Window (10.8 µm) images (above) showed the intensification of Cyclone Fani to a high-end Category 4 storm on 02 May 2019 (ADT | SATCON | PGTW advisory), before eventually making landfall in northeastern India at 0230 UTC on 03 May. During its life cycle, Fani moved over warm sea surface temperature values of 29-30ºC — and deep-layer wind shear of only 5-10 knots on 02 May provided an environment favorable for rapid intensification.

Once inland, Fani was in the process of rapidly weakening to a Category 1 storm as it passed over Bhabaneswar (VEBS), and surface wind gusts to 75 knots were reported at that site (below).

Time series plot of surface observations from Bhabaneswar, India [click to enlarge]

Time series plot of surface observations from Bhabaneswar, India [click to enlarge]

A sequence of VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth (below) showed snapshots of Fani from 19 UTC on 01 May (over the Bay of Bengal) to 07 UTC on 03 May (after landfall).

Sequence of NOAA-20 and Suomi NPP VIIRS Infrared Window (11.45 µm) images [click to enlarge]

Sequence of NOAA-20 and Suomi NPP VIIRS Infrared Window (11.45 µm) images [click to enlarge]

A comparison of VIIRS True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP on 02 May (below) showed Fani shortly after it had reached Category 4 intensity.

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

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

DMSP-17 SSMIS Microwave (85 GHz) image at 1230 UTC + Meteosat-8 Infrared Window (10.8 µm) image at 1300 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 1230 UTC + Meteosat-8 Infrared Window (10.8 µm) image at 1300 UTC [click to enlarge]

A toggle between a DMSP-17 SSMIS Microwave image at 1230 UTC and a Meteosat-8 Infrared Window image at 1300 UTC  from the CIMSS Tropical Cyclones site (above) showed the eye and totally closed eyewall of Fani when it was at its peak intensity on 02 May. However, the MIMIC TC product (below) indicated that the eastern portion of the eyewall started to erode as Fani approached the coast and began to undergo an eyewall replacement cycle.

MIMIC TC morphed microwave product, 01-02 May [click to enlarge]

MIMIC TC morphed microwave product, 01-02 May [click to enlarge]

On 30 April, VIIRS DayNight Band (0.7 µm) images (below, courtesy of William Straka, CIMSS) revealed widespread mesospheric airglow waves (reference) within the western semicircle of the storm, along with numerous bright lightning streaks associated with convection south of the storm center.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1939 UTC on 30 April [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 1939 UTC on 30 April [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 2029 UTC on 30 April [click to enlarge]

NOAA-20 VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images at 2029 UTC on 30 April [click to enlarge]