Cyclone Habana in the South Indian Ocean

March 10th, 2021 |

US Space Force EWS-G1 Infrared Window (10.7 µm) images [click to play animation | MP4]

US Space Force EWS-G1 Infrared Window (10.7 µm) images [click to play animation | MP4]

US Space Force EWS-G1 Infrared Window (10.7 µm) images (above) displayed the well-defined eye and eyewall structure of Cyclone Habana in the South Indian Ocean on 10 March 2021. This was the second period of Category 4 intensity (ADT | SATCON) during the life cycle of Habana.

Meteosat-8 Infrared images with contours of deep-layer wind shear from the CIMSS Tropical Cyclones site (below) showed that Habana was moving through an environment of relatively low shear.

Meteosat-8 Infrared images, with contours of deep-layer wind shear [click to enlarge]

Meteosat-8 Infrared images, with contours of deep-layer wind shear [click to enlarge]

Meteosat-8 Infrared images with an overlay of 1505 UTC Metop ASCAT winds (below) depicted a fairly uniform distribution of winds within the eyewall region, as Habana developed an annular structure.

Meteosat-8 Infrared images, with a plot of Metop ASCAT winds [click to enlarge]

Meteosat-8 Infrared images, with a plot of Metop ASCAT winds [click to enlarge]

SSMIS Microwave (85 GHz) images from DMSP-16 at 1139 UTC and DMSP-18 at 2327 UTC are shown below.

DMSP-16 SSMIS Microwave (85 GHz) image at 1139 UTC [click to enlarge]

DMSP-16 SSMIS Microwave (85 GHz) image at 1139 UTC [click to enlarge]

DMSP-18 SSMIS Microwave (85 GHz) image at 2327 UTC [click to enlarge]

DMSP-18 SSMIS Microwave (85 GHz) image at 2327 UTC [click to enlarge]

 

Re-suspended ash from the Katmai volcano in Alaska

February 28th, 2021 |

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

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

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) showed the hazy signature of a plume of re-suspended ash from the 1912 Katmai volcanic eruption. Strong surface winds gusting to 50-55 knots — caused by a strong pressure gradient along the western periphery of a Storm Force low in the Gulf of Alaska (surface analyses) — lofted some of the thick layer of ash that has remained on the ground in the vicinity of the volcano. The most dense portion of the aerosol plume was  moving across the Barren Islands (between Kodiak Island to the south and the Kenai Peninsula to the north); near the northern edge of the aerosol plume, surface visibility was reduced to 5 miles at Homer and 7 miles at Seldovia.

A sequence of Suomi NPP VIIRS Day/Night Band (0.7 µm) images (below) showed that the plume had formed before sunrise — ample illumination from a Full Moon provided vivid “visible mages at night” (at 1131 UTC and 1311 UTC).

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

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

ASCAT winds from Metop-C at 0743 UTC and 2124 UTC (source) are shown below — they indicated a dramatic increase in surface wind speeds  of 50 knots or greater emerging from the Barren Islands into the Gulf of Alaska later in the day.

ASCAT winds from Metop-C, at 0743 UTC and 2124 UTC [click to enlarge]

ASCAT winds from Metop-C, at 0743 UTC and 2124 UTC [click to enlarge]

GOES-17 True Color RGB images created using Geo2Grid (below) provided a clearer view of the re-suspended ash plume. North of the plume, note the tidal ebb and flow of ice within Cook Inlet and Turnagain Arm leading into the Anchorage area.

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

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

Ice motion on the Great Lakes

February 19th, 2021 |

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

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

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) revealed the fracturing of land-fast ice in the far southern portion of Lake Michigan on 19 February 2021. Although the westerly wind speeds were not particularly strong — generally 15-20 knots over water, including Metop ASCAT winds early in the day — these winds in tandem with lake currents were enough to move some of this ice eastward.

Farther to the north over western Lake Superior, 5-minute CONUS sector GOES-16 Visible images (below) also showed a significant amount of ice motion during the day.

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

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

A 30-meter resolution Landsat-8 False Color RGB image viewed using RealEarth (below) provided a more detailed look at the ice structure over western Lake Superior at 1653 UTC. Ice and areas of vegetation-sparse snow cover (rivers, lakes and wildfire burn scars) appear as shades of cyan in the RGB image.

Landsat-8 False Color RGB image [click to enlarge]

Landsat-8 False Color RGB image [click to enlarge]

===== 20 February Update =====

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

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

On 20 February, another look at 1-minute GOES-16 Visible images over southern Lake Michigan (above) indicated that new ice leads were opening up within individual ice floes that had broken free a day earlier.

===== 21 February Update =====

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

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

On 21 February, GOES-16 Visible images (above) showed how southerly winds were shifting much the ice in Lake Erie to the north. However, the effects of lake currents on the ice motion were also evident. As mentioned in this blog post, ice coverage on Lake Erie was around 80%.

Arctic outbreak with snow cover extending to South Texas

February 15th, 2021 |

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]

In the wake of a southward surge of arctic air across the central US — which produced surface temperatures as cold as -50ºF in Minnesota on 13 February — GOES-16 (GOES-East) Day Cloud Phase Distinction RGB images (above) showed the large areal extent of snow cover (brighter shades of green) across Oklahoma, New Mexico and Texas on 15 February 2021. In the RGB images, low-level supercooled water droplet clouds appear as pale shades of white.


A closer view of GOES-16 Day Cloud Phase Distinction RGB images (below) showed the far southern extent of snow cover across northern Mexico and southern Texas. Precipitation briefly transitioned from rain to snow as far south as Brownsville, but there was no accumulation at that site.

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]

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images (below) revealed a number of lake effect cloud plumes across northern and eastern Texas, as cold air moved across the warmer waters of small lakes.

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images, with and without plots of surface reports [click to play animation | MP4]

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images, with and without plots of surface reports [click to play animation | MP4]

Farther north over the Texas Panhandle, GOES-16 “Snow/Ice” images (below) showed a small cloud plume originating at the Xcel Energy Harrington Station power plant just north-northwest of Amarillo (KAMA). Note the drop in surface visibility to 5 miles at 17 UTC — this was likely due to snow flurries as the cloud plume drifted over the airport.

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

A timely overpass of Landsat-8 provided a 30-meter resolution False Color RGB image at 1721 UTC, as viewed using RealEarth (below) — as the cloud plume drifted over the KAMA airport, the 17 UTC METAR surface report indicated that the cloud base was at 1000 feet.

Landsat-8 False Color RGB image [click to enlarge]

Landsat-8 False Color RGB image [click to enlarge]

===== 16 February Update =====

GOES-16 CIMSS Natural Color RGB images, with plots of Metop-A ASCAT winds and surface/ship reports [click to play animation | MP4]

GOES-16 CIMSS Natural Color RGB images, with plots of Metop-A ASCAT winds and surface/ship reports [click to play animation | MP4]

On the following day, GOES-16 CIMSS Natural Color RGB images with plots of Metop-A ASCAT winds (above) showed how Tehuano gap winds had moved through Chivela Pass in southern Mexico (topography) and were spreading out across the Gulf of Tehuantepec (south of Ixtepec, station identifier MMIT). The highest surface scatterometer wind speeds were 24 knots near the coast.

With a low sun angle maximizing forward scattering, a plume of blowing dust could be seen right after sunrise in GOES-17 (GOES-West) True Color RGB images created using Geo2Grid (below), moving southward across the Gulf of Tehuantepec.

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

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