Early-season winter storm in the Northern Plains

October 12th, 2019 |

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly surface weather type plotted in red [click to play animation | MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly surface weather type plotted in red [click to play animation | MP4]

With the approach of an anomalously-deep 500 hPa low, an early-season winter storm produced very heavy snowfall and blizzard conditions across the Northern Plains — particularly in central/eastern North Dakota and southern Manitoba — during the 10 October12 October 2019 period. GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) showed the long duration of precipitation across that region. Text listings of snowfall totals and wind gusts are available from WPC, NWS Bismarck and NWS Grand Forks (more complete storm summaries: NWS Bismarck | NWS Grand Forks). The highest storm total snowfall amount in far southern Manitoba was 32 inches south of Morten (which reported a snow depth of 30 inches on the morning of 12 October), with 30 inches in central North Dakota at Harvey.

GOES-16 “Red” Visible (0.64 µm) images (below) displayed the storm during the daylight hours on 10/11/12 October.

GOES-16 "Red" Visible (0.64 µm) images on 10/11/12 October, with hourly precipitation type plotted in red [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images on 10/11/12 October, with hourly precipitation type plotted in red [click to play animation | MP4]

On 11 October, GOES-16 Visible images with an overlay of GLM Flash Extent Density (below) revealed intermittent clusters of lightning activity over northwestern Minnesota, northeastern North Dakota and southern Manitoba — while no surface stations explicitly reported a thunderstorm, NWS Grand Forks received calls from the public about thundersnow. The texture of cloud tops in the Visible imagery also supported the presence of embedded convective elements, which likely enhanced snowfall rates as they pivoted across that area. An animation of GOES-16 Visible imagery with plots of GLM Groups and surface weather type is available here.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with an overlay of GLM Flash Extent Density [click to play animation | MP4]

Note that this lightning-producing convection was occurring near the leading edge of the cyclone’s mid-tropospheric dry slot, as seen in GOES-16 Water Vapor imagery (below).

GOES-16 "Red" Visible (0.64 µm, left) and Mid-level Water Vapor (6.9 µm, right) images, with GLM Groups plotted in red [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, left) and Mid-level Water Vapor (6.9 µm, right) images, with GLM Groups plotted in red [click to play animation | MP4]

One important aspect of this storm was the formation of a trough of warm air aloft or trowal (SHyMet | Martin, 1998) as the surface low began to enter its occluded phase on 11 October — contours of Equivalent Potential Temperature along the 295 K isentropic surface (below) helped to diagnose the axis of the trowal as it curved cyclonically from southwestern Ontario to southern Manitoba and then southward over North Dakota.

GOES-16 Mid-level Water Vapor (6.9 µm) images, with 295 K equivalent potential temperature contours plotted in yellow and surface fronts plotted in red [click to play animation | MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with 295 K Equivalent Potential Temperature contours plotted in yellow and surface fronts plotted in red [click to play animation | MP4]

A similar animation with contours of 295 K specific humidity (below) also displayed the orientation of a west-to-east cross section B-B’ (green) across northern Northern Minnesota and northern Minnesota.

GOES-16 Mid-level Water Vapor (6.9 µm) images, with 295 K Specific Humidity contours plotted in yellow and surface fronts plotted in red [click to play animation | MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with 295 K Specific Humidity contours plotted in yellow and surface fronts plotted in red [click to play animation | MP4]

The Line B-B’ cross section at 16 UTC (with and without contours of Equivalent Potential Temperature) is shown below. Note the deep column of upward vertical velocity (highlighted by color shading of Omega) centered over Langdon, North Dakota — the moist trowal airstream can be seen sloping isentropically upward and westward behind the 3 g/kg Specific Humidity contour, as it approached the region of upward vertical motion. Langdon received 27 inches of snowfall; the prolonged southward passage of the trowal over North Dakota likely contributed to this accumulation.

Cross section of RAP40 model fields along Line B-B' at 16 UTC [click to enlarge]

Cross section of RAP40 model fields along Line B-B’ at 16 UTC [click to enlarge]

As the storm was gradually winding down on 12 October, its circulation exhibited a very broad middle-tropospheric signature on GOES-16 Water Vapor imagery (below).

GOES-16 Mid-level Water Vapor (6.9 µm) images, with surface frontal positions [click to play animation]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with surface frontal positions [click to play animation | MP4]

===== 17 October Update =====

Aqua MODIS True Color and False Color RGB images [click to enlarge]

Aqua MODIS True Color and False Color RGB images [click to enlarge]

After the area had already experienced its wettest Fall season on record, additional rainfall and snowmelt from this winter storm exacerbated ongoing flooding problems. A comparison of 250-meter resolution Aqua MODIS True Color and False Color Red-Green-Blue (RGB) images (source) centered over northeastern North Dakota (above) revealed flooding along the Red River (which flows northward along the North Dakota / Minnesota border) — water appears as darker shades of blue in the False Color image.

A Suomi NPP VIIRS Flood Product depicting floodwater fractions in the Red River Valley north of Grand Forks ND (as visualized using RealEarth) is shown below.

Suomi NPP VIIRS Flood Product, depicting floodwater fractions in the Red River Valley north of Grand Forks, ND [click to enlarge]

Suomi NPP VIIRS Flood Product, depicting floodwater fractions in the Red River Valley north of Grand Forks, ND [click to enlarge]

===== 18 October Update =====

GOES-16 Day Cloud Phase Distinction RGB images [click to play animation | MP4]

GOES-16 Day Cloud Phase Distinction RGB images [click to play animation | MP4]

On 18 October — 1 week after the height of the historic blizzard — GOES-16 Day Cloud Phase Distinction RGB images showed snow cover (brighter shades of green) remaining in areas that received the highest snowfall accumulations (such as Morden MB 32″; Vang ND 29″; Olga ND 28″; Langdon ND 27″).

Elevated NO2 signatures over the Northeast US

July 19th, 2019 |

TROPOMI NO2 concentration [click to enlarge]

TROPOMI NO2 concentration, courtesy of Bob Carp, SSEC [click to enlarge]

High temperatures (along with high dewpoints) prompted the issuance of Excessive Heat Warnings across much of the Northeast US on 19 July 2019. Under such conditions, surface NO2 concentrations in densely-populated urban areas often become elevated (primarily driven by emissions from motor vehicle exhaust, along with secondary sources such as coal-fired power plants and manufacturing / food processing industrial sources) — the high temperatures accelerate chemical reactions that form pollutants. The TROPOMI instrument detected plumes of elevated NO2 extending downwind (to the northeast) of major cities such as Philadelphia, New York City and Boston (above). The data are displayed using McIDAS-V.

A closer view centered on New York City is shown below.

TROPOMI NO2 concentration [click to enlarge]

TROPOMI NO2 concentration, courtesy of Bob Carp, SSEC [click to enlarge]

The Aqua MODIS Land Surface Temperature product around that time (below) revealed LST values in the 100-110ºF range across the New York City and Boston areas, where the daily maximum surface air temperatures were 95ºF and 93ªF, respectively.

Aqua MODIS Land Surface Temperature, with plots of daily maximum surface air temperatures [click to enlarge]

Aqua MODIS Land Surface Temperature, with plots of daily maximum surface air temperatures [click to enlarge]

Tropical Storm Barry

July 11th, 2019 |

GOES-16 "Red" Visible (0.64 µm) and "Clean" Infrared Window (10.35 µm) images, with plots of buoy and ship reports [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images, with plots of buoy and ship reports [click to play MP4 animation]

Tropical Storm Barry formed in the far northern Gulf of Mexico on 11 July 2019 — 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) displayed increasing convection associated with the tropical cyclone. The coldest cloud-top infrared brightness temperatures were -86ºC.

As was seen in an animation of GOES-16 Infrared imagery from the CIMSS Tropical Cyclones site (below), Barry was in an environment of low deep-layer wind shear — a factor that was favorable for further intensification.

GOES-16 Infrared (11.2 µm) images, with contours of deep-layer wind shear [click to enlarge]

GOES-16 Infrared (11.2 µm) images, with contours of deep-layer wind shear [click to enlarge]

===== 12 July Update =====

GOES-16

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

1-minute GOES-16 Visible images (above) revealed a mesovortex that was rotating counter-clockwise around the low-level circulation center of Barry, which was approaching the coast of Louisiana on 12 July. Note that the METAR site located immediately east of the mesovortex around 17 UTC — KMDJ, Mississippi Canyon Oil Platform — had a wind gust of 73 knots or 84 mph around that time (and later had a wind gust to 90 mph at 2135 UTC or 4:35 PM CDT)

The corresponding GOES-16 Infrared images (below) showed that deep convection remained to the south of the center of Barry.

 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]

===== 17 July Update =====

Aqua MODIS Sea Surface Temperature product [click to enlarge]

Aqua MODIS Sea Surface Temperature product on 09 July [click to enlarge]

An Aqua MODIS Sea Surface Temperature image 2 days prior to the formation of Tropical Storm Barry (above) showed SST values in the upper 80s to low 90s F (darker shades of orange to red) in the northern Gulf of Mexico just south of Louisiana.

8 days later, a Terra MODIS SST image (below) revealed values predominantly in the lower to middle 80s F (green to yellow enhancement) — the slow movement of Barry as it eventually reached hurricane intensity just prior to landfall induced an upwelling of cooler sub-surface water over that area.

Terra MODIS Sea Surface Temperature product on 17 July [click to enlarge]

Terra MODIS Sea Surface Temperature product on 17 July [click to enlarge]

Eruption of the Raikoke volcano in the Kuril Islands

June 21st, 2019 |

Himawari-8 False Color RGB images [click to play animation | MP4]

Himawari-8 False Color RGB images [click to play animation | MP4]

For the first time since 1924, a major eruption of the Raikoke volcano occurred around 1800 UTC on 21 June 2019. Himawari-8 False Color Red-Green-Blue (RGB) images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed — via the brighter yellow areas — that a large portion of the volcanic plume was rich in both ash and sulfur dioxide (SO2). The Tokyo VAAC estimated the maximum ash height to be 43,000 feet (~13 km) above ground level — and CALIPSO CALIOP data indicated a maximum ash height around 12 km shortly after 02 UTC on 22 June (between 45-50º N latitude and 159-161º E longitude).

A comparison of an Aqua MODIS False Color RGB image with the corresponding Ash Height, Ash Loading and Ash Effective Radius retrieved products at 0310 UTC on 22 June (below) indicated maximum ash height values of 18-20 km (black pixels) immediately downwind of the eruption site. Maximum Himawari-8 Ash Height values were in the 16-18 km range.

Aqua MODIS False Color RGB, Ash Height, Ash Loading and Ash Effective Radius at 0310 UTC on 22 June [click to enlarge]

Aqua MODIS False Color RGB image with Ash Height, Ash Loading and Ash Effective Radius retrieved products [click to enlarge]

In a comparison of Himawari-8 Upper-level (6.2 µm), Mid-level (6.9 µm) and Low-level (7.3 µm) Water Vapor images (below), since the 7.3 µm spectral band is also sensitive to SO2 absorption, those images showed a good signature of the leading filament of volcanic SO2 as it was transported east-southeastward over the North Pacific Ocean.

Water Vapor images from Himawari-8: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

Water Vapor images from Himawari-8: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

Similarly, the GOES–17 (GOES-West) Low-level Water Vapor (7.3 µm) images also showed the filament of volcanic SO2 that was being drawn into the circulation of a Gale Force Low south of the Aleutian Islands. As a result, the Anchorage VAAC issued aviation Volcanic Ash Advisories that covered large areas of the North Pacific Ocean and southern Bering Sea; they continued to estimate the maximum ash height to be 43,000 feet. Around 16 UTC on 22 June, CALPSO CALIOP data sampled a small portion of the ash at an altitude near 17 km (between 45-50º N latitude, 155-157º W longitude).

Water Vapor images from GOES-17: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

Water Vapor images from GOES-17: Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) [click to play animation | MP4]

VIIRS True Color RGB and Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth are shown below at approximately 01 UTC, 02 UTC and 03 UTC on 22 June. The combination of True Color and Infrared imagery indicated that volcanic ash was present a multiple altitudes.

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 at 01, 02 and 03 UTC on 22 June [click to enlarge]

Due to the highly-oblique satellite viewing angle of GOES-17, multiple Raikoke eruption pulses of significant vertical extent were clearly evident in GOES-17 “Red” Visible (0.64 µm) images (below).

GOES-17

GOES-17 “Red” Visible (0.64 µm) images [click to play animation | MP4]

A somewhat less oblique view from the west was provided by the NSMC FY-2G satellite (below).

NSMC FY-2G Visible (0.73 µm) images [click to play animation | MP4]

NSMC FY-2G Visible (0.73 µm) images [click to play animation | MP4]

Himawari-8 “Red” Visible (0.64 µm) images (below) provided another interesting view of the multiple eruption pulses — and since the eruption began around 5 AM local time, long early morning shadows were cast by the initial bursts of tall volcanic clouds. A faster animation revealed shock waves propagating radially outward from the eruption site.

Himawari-8

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




Incidentally, an astronaut aboard the International Space Station took a photo of the volcanic cloud at 2246 UTC on 21 June — and the two Visible images that bracket that time (2240 and 2250 UTC) from GOES-17 and Himawari-8 are shown below.

Photo taken by an astronaut on the International Space Station [click to enlarge]

Photo taken by an astronaut on the International Space Station at 2246 UTC [click to enlarge]

GOES-17 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

GOES-17 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

Himawari-8 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

Himawari-8 Visible (0.64 µm) images at 2240 and 2250 UTC {click to enlarge]

===== 23 June Update =====

Himawari-8 False Color RGB images [click to play MP4 animation]

Himawari-8 False Color RGB images [click to play MP4 animation]

A 2-day animation of 10-minute Himawari-8 False Color images (above) showed the ash- and SO2-rich volcanic plume (brighter shades of yellow) eventually being transported northeastward across the western Aleutian Islands and circulating cyclonically over the Bering Sea. Similarly, this volcanic cloud transport was also seen in the corresponding GOES-17 False Color imagery.

===== 24 June Update =====

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB imagery (above) continued to show a signature of the volcanic cloud (brighter shades of yellow) from the Raikoke eruption over a large portion of the Bering Sea on 24 June. Volcanic ash advisories were issued for flight altitudes as high as 40,000 feet — and a pilot report of SO2 over the Bering Sea at 47,000 feet was received at 1822 UTC (below).

GOES-17 SO2 RGB, Split Clout Top Phase (11.2-8.4 µm) and Dust RGB images, with a pilot report of SO2 [click to enlarge]

GOES-17 SO2 RGB, Split Clout Top Phase (11.2-8.4 µm) and Dust RGB images, with a pilot report of SO2 [click to enlarge]

===== 25 June Update =====

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images [click to play animation | MP4]

GOES-17 SO2 RGB images (above) showed the persistent signature of the SO2-rich volcanic cloud as much of it remained within the circulation of a quasi-stationary low pressure system in the Bering Sea.

An interesting Pilot Report north of the Aleutians at 36,000 feet (below) noted thin grey-colored layers below the altitude of the aircraft. GOES-17 Air Mass RGB images showed a subtle brown/tan plume — could this have been a thin filament of ash from the Raikoke eruption that was drawn into the circulation of the Bering Sea low?

GOES-17 SO2 RGB, Air Mass RGB, Dust RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2008 UTC Pilot Report [click to enlarge]

GOES-17 SO2 RGB, Air Mass RGB, Dust RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2008 UTC Pilot Report [click to enlarge]

Another Pilot Report farther to the west at 2119 UTC (below) was close to the southern edge of the GOES-17 SO2 signatures, but no sulphur odor was reported; however, they did note the presence of an apparent ash layer south of Shemya in the western Aleutian Islands.

GOES-17 SO2 RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2119 UTC Pilot Report [click to enlarge]

GOES-17 SO2 RGB and Split Cloud Top Phase (11.2-8.4 µm) images, with a 2119 UTC Pilot Report [click to enlarge]