Contributors: Scott Bachmeier, Mat Gunshor, Rick Kohrs, Margaret Mooney, Jim Nelson, Tim Schmit, and Eric Verbeten.

Another CIMSS Satellite Blog on the Eclipse, when time compositing imagery from 2024 (and 2017).

A similar loop as above, but with a special enhancement (contrast stretch) is in this CIMSS Satellite Blog post (which also includes a comparison of the 2017 and 2024 eclipse events).

---

The eclipse starts in the GOES-West footprint, as shown above (Here’s a link to a Full-Disk GOES-West animation). By 1700 UTC, however, GOES-East starts to view it, as shown below (Here’s a link to a Full-Disk GOES-East animation).

---

Here are CIMSS Natural Color animations from GOES-West and GOES-East Full Disk showing the eclipse shadow.

---

To examine the effects of the eclipse shadow on surface weather, let’s turn to GOES-16 Near-Infrared “Vegetation” images (below), centered over North Texas. Many sites recorded drops in surface air temperature of 4-5 degrees F as the shadow traversed the area — for example, see these plots of surface report data across North Texas at Brownwood, Fort Worth, DFW Airport and Paris.

The corresponding hourly GOES-16 Land Surface Temperature (LST) derived product (below) displayed cooling LSTs as the shadow’s arrival halted the trend of midday heating.

The eclipse shadow and its effect on surface cooling was also evident in imagery from polar-orbiting satellites. 3 consecutive overpasses of NOAA-20 and Suomi-NPP provided VIIRS False Color RGB and Shortwave Infrared images centered over northwest Arkansas (below) — which showed a notable cooling of surface infrared brightness temperatures across the Mississippi Alluvial Plain as the shadow moved across the region. In addition, a number of METAR sites reported surface air temperature drops of 5-6 degrees F as incoming solar radiation decreased.

---

More imagery of the 2024 Eclipse is available at the Satellite Liaison Blog.

---

Early on 8 April (CSPP Geosphere link also shown below), there are some obvious winners and losers as far as Eclipse-viewing goes, as shown with GOES imagery. If you’re in western New York State, for example, things look unfortunate. Texas? Hit or miss: plenty of clouds, but not completely overcast. Maine? That looks pretty good to this blogger! We’ll see how things evolve during the day however. Here in Madison WI, skies look like a view of a 90%-eclipsed sun is likely. Check out the CSPP Geosphere site for the latest imagery.

Real-time animations of the Eclipse will be available at the website shown above, https://www.ssec.wisc.edu/datacenter/eclipse2024/ . Animations will include ABI and SUVI data.

Just seven years after a total eclipse swept northwest to southeast across the Contiguous United States (as discussed in blog posts here and here), a total solar eclipse will move southwest to northeast from Mexico to the eastern Great Lakes to New England on 8 April 2024. During and after the event, we will post an animation (above) with combined views from GOES-18 and GOES-16 showing the satellite view of the Moon’s shadow. There will also possibly be mesoscale sectors covering the path of the eclipse (link).

The paths of the 2017 eclipse and the 2024 eclipse are shown below. (Shout out to those Americans who had the foresight to live in the intersecting paths of totality near Carbondale IL as shown in the figure below the two globes, from this handy website). See composite eclipse shadow images from the 2017 and 2024 events at this blog post.

The animation below (from Rick Kohrs, SSEC/CIMSS), shows the region of the shadow as it moves across North American and adjacent waters, from sunrise over the Equatorial Pacific to sunset over the north Atlantic. (The same animation with a stationary map is here).

View only this post Read Less

For a solar eclipse to occur, the moon must be in between the Earth and the Sun. This occurs when the Moon is new — that is, when the side of the moon facing the Earth receives no solar illumination. The Day Night Band on Suomi-NPP, or NOAA-21, or NOAA-20 (NOAA-20 is shown above), is therefore only detecting light Cities/Towns, from Gas Flares (as in the arc of light over parts of south Texas, or over the Gulf of Mexico), from Aurora (not in this picture), from fires (none burning in this imagery) or from reflected Earth Air Glow. What information in the Day Night Band tells you where clouds are in such as case? Clouds are faintly visible over the western Gulf of Mexico because of reflected Air Glow. Note also how the city lights over western Louisiana and over northern Mississippi (for example), are slightly blurred. This occurs when visible light energy from city lights is scattered as it moves upward through clouds.

The VIIRS instrument also includes infrared detectors that can better articulate (compared to the Day Night Band image above) where clouds occur. A line of convection (with cold cloud tops) over eastern Arkansas/northern Mississippi is responsible for the attenuation of the visible light there. Cirrus and mid-level clouds are present over western Louisiana. Note in the toggle below the lack of apparent surface features in both the 11.45 µm and 3.74 µm infrared imagery over southeast Texas — compared to the presence of warmer features (likely lakes) over northern Texas. (Click here for an annotated 11.45 µm image).

The 3.74 µm brightness temperature in that uniform region is cooler than the 11.45 µm brightness temperature. This is consistent with the presence of low stratus in that location, and IFR Probability fields at that time agree with the likelihood of low stratus.

View only this post Read Less

For a period of about 45 days on either side of the Spring (Vernal) and Fall (Autumnal) Equinox (NOAA OSPO Bulletin), each GOES briefly passes through the Moon’s shadow (requiring it to operate on battery power). Near the times of the satellite “local midnight” — around 0900 UTC for GOES-18 and 0500 UTC for GOES-16 — stray light can enter the ABI instrument, potentially causing damage. Portions of the Earth likely affected by this stray light are not scanned, leading to areas of missing data (referred to as Stray Light Zones or Keep-Out Zones).

Daily GOES-18 (GOES-West) Water Vapor images during  the 19 February to 07 April 2024 period are shown near the beginning (above) and end (below) of the Eclipse period — displaying the maximum coverage of missing data on each of those days.

Daily GOES-16 (GOES-East) Water Vapor images for that same 19 February to 07 April period are shown below, near the end of that satellite’s Eclipse period.

It should be noted that the size of the Stray Light Zone varies for each of the Infrared spectral bands, as shown below.

View only this post Read Less

5-minute CONUS Sector GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) and Upper-level Water Vapor (6.2 µm) images (above) revealed that the outline of a portion of Florida’s east coast (specifically along the Gold Coast and the Emerald Coast) could briefly be seen during the day on 05 April 2024. 1901 UTC Water Vapor images with/without a map overlay are shown below. The outline of Florida has been evident in Water Vapor imagery in the past, but usually during the much colder and drier winter months (for example, February 2019).

Along the west coast of Florida that morning at Tampa Bay, 1200 UTC rawinsonde data (above) depicted a Total Precipitable Water value of 0.44 in; while that TPW value was unusually low for Tampa Bay, their sounding climatology (below) indicated it was greater than the record low 12 UTC / 05 April value of 0.20 in. It is that dry air that then moved eastward across Florida during the day.

Plots of Weighting Functions for GOES-16 Mid-level Water Vapor and Upper-level Water Vapor (below) showed the dry middle/upper-tropospheric air’s effect on the height of the peak contribution for those two spectral bands that morning at Tempa Bay — lowering their peaks to 661 hPa and 535 hPa, respectively — with some radiation being sensed from as low as the 750-850 hPa layer (low enough to detect some of the upwelling radiation emitted by the land/water thermal gradient along Florida’s east coast).

For reference, the GOES-16 Upper-level Water Vapor (Band 08) and Mid-Level Water Vapor (Band 09) Weighting Functions (calculated using a US Standard Atmosphere temperature/moisture profile, at a satellite Zenith Angle of 35º) typically peak at 344 hPa and 442 hPa, respectively (below).

View only this post Read Less