The CSPP Geosphere site uses cloud-compatible technology with an on-site cluster and CSPP-Geo software (including geo2grid) to provide high-quality imagery from GOES-East and GOES-West. The site has recently been upgraded, with two level 2 products added (Cloud-top Height and Cloud-top Temperature). In addition, the landing (front) page of the site has been improved, as shown in the toggle above. The displayed image remains True Color (day time) and Night Microphysics (night time), but icons have been added on the left (as indicated) to change the Satellite (GOES-East and GOES-West are available); to change the Sector (Mode 6: Full Disk, CONUS/PACUS, 2 Mesoscale Sectors; Mode 4: Full Disk); to select the number of Frames (Default: 12 timesteps, no times skipped); to select a location on which to center; to select a latitude/longitude point on which to center; to toggle on/off auto-reloading, and to toggle on/off a mouse probe. On the right hand side, lower right, are icons to bring up the share menu, and also to enlarge the image to fit the screen. In the bottom left is link to a menu to select the products to be displayed, as shown below.

The Layers highlighted in Blue are what is currently displayed; these can be toggled off and on. Other layers that can be shown are in gray. Click a (grey) box to toggle on the band or product (or map/lat-lon grid); note that only three Bands/Level 2 fields can be displayed at once. When more than one field is displayed, they are overlain on top of each other, and can be toggled on and off for quick qualitative comparisons between fields. The Level 2 products — Cloud Top Height and Cloud Top Temperature — have information only where clouds are present, and are transparent otherwise.

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The screen capture below shows the result of two samplings at 1850 UTC on 22 January 2024 (Full Disk GOES-16 Data): for single band data, the probe is detecting the grey-scale in the 8-bit image, and uses knowledge of the enhancement to determine a brightness temperature or reflectance. For Level 2 products (Cloud Top Height and Cloud Top Temperature), the probe again detects the color shown, and displays the value range appropriate for the sensed color. In other words, the probe is not accessing the raw data used to create the image.

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NOAA-20 overflew the Samoan islands shortly after 1200 UTC on 22 January 2024, as shown above. The animation displays a series of 13 profiles and derived parameters to the east of American Samoa and Samoa. with locations as indicated by the circle. Most Unstable CAPE values derived from the profiles all are derived from the near-surface 986 mb — except for the profile location denoted in yellow, which has a MUCAPE level at 959 mb. That point also has the smallest value of MUCAPE: <200; Other values range from 2200 to as high as 4400. NUCAPS profiles are a useful source of thermodynamic information (independent of models) in regions where data are lacking.

GOES-18 also viewed this region, and the toggle below compares derived Total Precipitable Water and Lifted Index at 1200 UTC, the approximate time of the NOAA-20 overpass. The TPW shown below shows structures and values similar to the MIMIC TPW shown above. A careful observer will also see the convection below associated with the red NUCAPS sounding availability point above (many red points associated with the large convective complex near 17^o S, 166.5^o W are hidden in the figure above, but are viewable here). GOES Level 2 products are able to highlight relatively small-scale variability in moisture/stability (for example, the region of relatively stable air stretching southeast to northwest — tannish brown in the LI color enhancement — to east and north of the Samoan Islands. Use them in concert with NUCAPS fields (available in all sky conditions) to get a good feel of the moisture distribution in data-poor regions.

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Important NUCAPS note: NOAA-21 NUCAPS profiles are scheduled to flow via SBN to NWS forecast offices in February. At present, they will augment (not replace) NOAA-20 profiles, allowing forecasters to see short-term trends in NUCAPS fields.

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Target Sector (2.5-minute interval) JMA Himawari-9 AHI Clean Infrared Window (10.4 µm) images (above) showed Tropical Invest 90P as it moved westward across the Coral Sea on 20 January 2024. Intermittent convective bursts within the growing cold cloud canopy contained multiple overshooting tops that exhibited infrared brightness temperatures of -100ºC or colder (internal clusters of red pixels embedded within yellow-to-black regions). In fact, the minimum infrared brightness temperature of -103.83ºC on the 17:09:44 UTC image was colder than the -103.55ºC measured by Himawari-8 with Typhoon Kammuri in 2019 (which at that time was thought to be the coldest cloud-top infrared brightness temperature on record as sensed by a geostationary satellite).

Himawari-9 Infrared Window (11.2 µm) images from the CIMSS Tropical Cyclones site (below) showed that Invest 90P was moving through an environment of high deep-layer wind shear — which was inhibiting its further intensification.

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With the total solar eclipse occurring over parts of the contiguous U.S. on April 8, 2024, there are many wondering what the cloud cover might be on that day. As anticipation builds, we decided to look at the past 28 years of GOES cloud products on April 8. This is not a forecast, but a look back at the cloud climatology. Every spot on the eclipse path has had April 8ths where it was cloudy and every spot has had April 8ths where it was clear. So while you may choose to travel to southwest Texas to see the eclipse because that gives you the best chance historically at clear skies, there is going to be some uncertainty involved for eclipse viewers all along the path as to whether or not they’ll get a clear-sky view of the event. The potentially clearest areas still have at least 30% chance of being cloudy on April 8 based on the historical record. Of course the climatology does not have days with a total solar eclipse, and we have seen in earlier events how some fair-weather cumulus cloud coverage is briefly reduced as a result of the reduced incoming solar radiation. Still, an eclipse can be a fun event if you’re on the path even when it’s partly cloudy. This is an opportunity to discuss the science related to cloud cover on the upcoming eclipse day.

For comparison, see similar images derived from MODIS data and the ERA-5 (re-analysis). In general, climatologically it is more clear in Texas and less clear in New England in early April. Of course that is not a forecast for what will actually happen in 2024.

More information

There is much more information about this event, including this CIMSS Satellite Blog post, and the NWS and NOAA Satellites.

H/T

This image was made by M. Gunshor, UW/CIMSS (who also helped write this blog post) with NOAA geostationary cloud files processed by S. Wanzong, UW/CIMSS, with input files from UW-Madison, SSEC; SSEC Data Services. Thanks also for the Eclipse Predictions by Fred Espenak, NASA’s GSFC. T. Schmit works for NOAA/NESDIS/STAR and is stationed in Madison, WI.

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