Early Spring Nor’easter over the eastern United States

March 21st, 2018 |

NOAA-20 VIIRS Day Night Band Visible (0.70 µm) and I05 Infrared (11.45 µm) Imagery, 0645 UTC 21 March 2018 (Click to enlarge)

NOAA-20 Imagery shown in this post is Non-Operational and preliminary and undergoing testing.

The imagery above shows a toggle between the Day Night Band Visible (0.70 µm) Imagery and the I05 Infrared (11.45 µm) Imagery on NOAA-20. The strong nor’easter affecting the East Coast of the United States is apparent in the imagery. Strong convection over the warm water south of the Gulf Stream to the east of the Carolinas is apparent in cold cloud tops in the infrared, and in lightning streaks in the Day Night Band imagery. The waxing crescent moon at the time was below the horizon; Earthglow is thus the primary illumination source for the clouds over the ocean. Over land, city lights are apparent, even through the thick precipitating clouds associated with the storm.

Additionally, the fine spatial resolution in the Infrared imagery allows for the identification of cloud-top gravity wave features in the warm conveyor belt over eastern Pennsylvania and New York, and also elsewhere.

Microwave imagery from Suomi NPP can be used to estimate rain rate (Here’s the OSPO site that shows this product from NOAA-18 and -19, and also Metop A and B; the Operational Blended Rain Rate product is here). The Real Earth image below shows Rain Rate from Suomi NPP ATMS data as calculated from the Direct Broadcast signal in Madison, WI; the entire system is not quite captured from the antenna in Madison, WI. Data that are used to compute the Rain Rate include 90 Ghz, shown here (also from Real Earth).  The heavy precipitation with the convection over the Atlantic is readily apparent.  Precipitation with this system extends back into Indiana!

Rain Rate computed from ATMS on Suomi NPP early morning passes, 21 March 2018 (Click to enlarge)

GOES-16 captured the temporal evolution of this storm. The animation of low-level water vapor (7.34) infrared imagery, below, shows a well-developed warm conveyor belt well to the east of an upper level feature that is wobbling westward over northern Kentucky. A second upper-level circulation develops northern Virginia and is obvious over West Virginia at the end of the animation. Strong subsidence can be inferred behind the storm as well, where the yellows/oranges appear in this water vapor enhancement, suggesting brightness temperatures around -10ºC. Very dry air is apparent north of the storm: The St Lawrence River is visible in the water vapor animation!

GOES-16 Low-Level Water Vapor Infrared (7.34 µm) animation, 0107 – 1622 UTC (Click to play 110 Mb animation)

Ice Break-up on (and silt increase in) Lake Erie

March 20th, 2018 |

Suomi NPP True Color Imagery, daily from 17-20 March 2018 (Click to enlarge)

Suomi-NPP True-Color imagery (above, from Real Earth) from 17-20 March 2018 show the break-up of pack ice in eastern Lake Erie. (Clouds with the big Nor-easter prevented views on 21-22 March). Winds at both Erie and Buffalo switched to an easterly component during this time, which may have helped the ice fracture. Silt appears to be on the increase in western Lake Erie during this time as well.

Arabian Sea Ship Fire in the VIIRS Day Night Band

March 7th, 2018 |

VIIRS Day Night Band Visible (0.70 µm) Imagery from Suomi NPP (2056 UTC) and NOAA-20 (2146 UTC) on 6 March 2018 (Click to enlarge)

A large Maersk container vessel caught fire in the Indian Ocean on 6 March 2018 (news report 1, news report 2), killing 4 sailors and necessitating the evacuation of the ship (the MAERSK HONAM).

Suomi NPP and NOAA-20 (which trails Suomi NPP by half an orbit) both passed over the ship fire on 6 March. As a singular light source in the middle of the Indian Ocean, the ship fire was evident in the Day Night Band imagery, as shown above, at 10.5º N and 65.8º E). The ship drifted southward in the 50 minutes between VIIRS scans from the two satellites. (Similar signatures were apparent in the 1.61 µm, 2.25 µm and 4.05 µm imagery from VIIRS on the two satellites).

VIIRS Day Night Band Visible (0.70 µm) Imagery from Suomi NPP (2038 UTC) and NOAA-20 (2128 UTC) on 7 March 2018 (Click to enlarge)

One day later, on 7 March, above, Suomi NPP and then NOAA-20 (50 minutes later) again passed over the still-burning ship, then at 10.1º N and 65.6º E. A faint smoke plume is visible in the imagery from NOAA-20.

The zoomed-out image, below, might give you a better idea of how far away from the India and Africa this ship sits.

VIIRS Day Night Band Visible (0.70 µm) Imagery from NOAA-20 (2128 UTC) on 7 March 2018 (Click to enlarge)

(Hat tip to William Straka, CIMSS, for the imagery and also to Steve Miller, CIRA, for alerting us to this event)

Flooding in the Midwest and lower Ohio River Valley

February 26th, 2018 |

GOES-16 0.86 µm “Veggie” Band Imagery at 1902 UTC on 12 and 26 February 2018 (Click to enlarge)

Solar radiation at 0.86 µm is strongly absorbed by water on the surface, but reflected by land. There is therefore a big contrast in GOES-16 “Veggie” Band imagery between rivers and adjacent land, and that contrast difference can easily identify regions of inundation. The toggle above compares imagery from 26 February 2018 and from 12 February 2018 over the lower Ohio River Valley. Significant widening of many waterways is apparent in the 0.86 µm imagery on 26 February, especially over southern Indiana, a result of both snow melt and abundant precipitation in the past 7 days, shown below (from this link). This has caused many stream gauges to show Moderate (Red gauges) to Major (Purple Gauges) flooding (image from this link), also shown below.  A zoomed-in image over northern Indiana, at bottom, shows the major flooding along the Kankakee River.

Observed precipitation for the 7 days ending at 1200 UTC on 26 February 2018 (Click to enlarge)

Stream Gauge Observations at 1200 UTC on 26 February 2018 (Click to enlarge)

GOES-16 0.86 µm “Veggie” Band Imagery at 1902 UTC on 26 February 2018 (Click to enlarge). Green Arrows highlight the Kankakee River, in flood.

=============== Added, 27 February 2018 ===================
Suomi NPP’s Flood Product, produced via CSPP using data from a Direct Broadcast site (at UW-Madison) is shown below. Flooded regions in the lower Ohio River/Mississippi River Valley and surroundings are indicated by shading in yellow to red.

Suomi NPP Flood Product, 1923 UTC on 26 February 2018 (Click to enlarge)

Some of these areas of river flooding could also be seen in a comparison of Suomi NPP VIIRS True-color and False-color Red-Green-Blue RGB images (below) — the False-color image uses the Near-Infrared 2.2 µm and 0.86 µm bands for the Red and Green contributions, and highlights water as shades of blue.

Suomi NPP VIIRS True-color and False-color images [click to enlarge]

Suomi NPP VIIRS True-color and False-color RGB images [click to enlarge]