5-minute CONUS Sector GOES-18 (GOES-West) Nighttime Microphysics RGB + daytime True Color RGB images from the CSPP GeoSphere site (above) revealed a curious cloud arc located southeast of the Big Island of Hawai`i (near 150 W longitude) on 30 May 2026. The fact that the typical westward transport of marine boundary layer stratocumulus clouds seemed to abruptly halt to the west of that cloud arc caused this blog post author to immediately wonder “What the heck is this?” — and assign it to the aptly-named “What the heck is this?” blog category of seemingly unexplainable meteorological phenomena.

GOES-18 Infrared Window images (above) and Visible images (below) included plots of surface analyses every 6 hours — which depicted a broad inverted trough over the area, although the position and orientation/shape of the analyzed trough axis did not match that of the actual cloud arc feature (those tropical surface analyses were produced by multiple collaborating agencies; surface analyses from NWS Honolulu also showed a trough axis near 150 W longitude).

In a toggle between GOES-18 Visible, Infrared Window and Cloud Top Height images at 1801 UTC (above), the infrared brightness temperatures of the leading edge of the cloud arc were around +10C, with Cloud Top Height values generally in the 9500-10000 ft range. According to a plot of 1200 UTC rawinsonde data from Hilo (below), those temperature and height values were near the top of the trade wind inversion.

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A CONUS Sector GOES-19 (GOES-East) Visible image with overlays of 1-minute GLM Flash Extent Density and GLM Flash Points (above) showed the signature of a high-altitude bolide that was entering the Earth’s mesosphere over far eastern Massachusetts at 1807 UTC on 30 May 2026. This bolide created a sonic boom that was heard in several communities.

Cursor samples (below) indicated that the maximum GLM Flash Extent Density values were 7 flashes/min (darker red pixels within the northern portion of the bolide signature), in addition to a flash duration of 0.024 sec with a flash area of 67 km².

 

A map of fireball reports from the American Meteor Society site (below) displayed the large area from which this daytime event was seen. A closer view indicated that the bolide likely traveled along a northwest-to-southeast trajectory.

#MeteorSighting: Eyewitnesses in New England and @NOAA’s GOES-19 satellite reported a bright fireball on Saturday, May 30, at 2:06 p.m EDT accompanied by a loud noise. The meteor appears to have fragmented at an altitude of 40 miles over northeast MA and southeast NH. The energy…

— NASA Space Alerts (@NASASpaceAlerts) May 30, 2026

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It may be tempting to look out on a pleasant, synoptically quiescent day, and think that there’s not much going on. However, one of the great things about being a meteorologist is that we always seem to be able to find things worth looking at even in the most mundane of environments. For example, let’s look at this broad field of fair-weather cumulus across the southeastern continental United States, as captured by GOES-19’s (GOES West) true color imagery. At first glance, it’s just a typical warm weather afternoon, with scattered cumulus over a broad area.

But a closer look reveals that there’s a lot going on. Let’s start by zooming in over Houston, the fourth most populated city and fifth most populated metro area in the United States. Houston lies in a somewhat unusual position: it’s kind of, but not really, coastal. This is the legacy of the great 1900 Galveston hurricane that destroyed its namesake city and caused those residents and businesses to relocate further inland to avoid the wrath of future storms. Today, downtown Houston is over forty miles from the shores of the Gulf but is located much closer to a series of bays. By zooming in, we see a number of interesting processes taking place. Due to the potential of severe weather in western Texas, the GOES-19 mesoscale scan was out and just happened to collect Houston in the far southeastern corner. Here is the highest spatial resolution band (Band 2 at 0.5 km) at the highest temporal resolution (1 min).

There are quite a few things worth watching in this image. First, notice the presence of the sea breeze. The southeastern edge of the clouds parallels the Gulf shore and is pushing inland. This, of course, is due to the temperature difference between the relatively cool water and the relatively warm land. Sea breezes bring stabilizing air ashore and kill convective plumes, and thus they cause clearing as they move inland. Second, notice how both the city of Houston and the bays to its east are both inhibiting the development of cumulus clouds as the locations downstream of those places tend to have clearer skies. In the case of the bay-influenced air, this is likely due to the cool waters killing convective plumes; we recently discussed this in the context of cold Minnesota lakes. However, why is Houston also inhibitiing the development of convective clouds. After all, cities are known to be warmer than the surrounding countryside. In fact, we can load up the Band 13 (10.3 micron infrared window) to see just how the temperatures vary across the region.

Note how mow much warmer Houston is over the surrounding rural areas, and how those areas themselves are warmer than the Gulf and the bays. That latter temperature imbalance is what is inducing the sea breeze. However, why are there fewer clouds forming over Houston even though it’s warmer? After all, a warmer surface should lead to more convection. However, it also takes moisture to produce clouds, and while there’s plenty of evaporation and transpiration surrounding Houston, there’s comparatively few moisture sources within the developed area. Existing moist plumes may get enhanced by the warm temperatures as they move over the city, but new ones struggle to form.

Let’s now turn our attention to an area further to the north along the Texas/Louisiana border. Once again, here’s the true color loop.

Again, it looks like a typical cumulus field, and we can once again see the influence of a cool lake on reducing cumulus development. However, look at the wind shear present here: the shallowest clouds appear to be moving from the south to the north. However, the tops of the deeper convection are moving from the north to the south. And if you go even higher up in the atmosphere, the cirrus clouds are clearly streaking from the west to the east. In the end, there are three clearly different wind directions that are easily resolvable as a function of different heights. We don’t need radiosondes or specialized multidimensional retrievals to tell us something useful about the wind; we can just look at a simple satellite loop.

Finally, let’s look at Louisiana’s bayous and Gulf coast, again with the true color view.

Look at all the brown that is in the water. This is silt that has been carried into the Gulf by the Atchafalaya River and other waterways. That water provides a marked contrast to the blue of the ocean. If you look carefully, you can even see how the currents in that silty discharge evolve over the 80 minutes covered by this animation.

Let’s take a look at how that brown area has evolved over just a few days. Here is a slider that compares this day to one just a few days earlier. It’s easy to see that in the interim three days, the silt has penetrated much further into the Gulf.

Why did this happen? Simple: there was a lot of rain on May 27th, as can be seen in this radar loop. With significant rainfall over the land, that water collected dirt and silt, flowed downstream, and out into the Gulf.

It’s clear that just because there are no active hazardous weather situations, it doesn’t mean the satellites aren’t worth looking at. There’s always something interesting to see.

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During “static fire” pre-launch testing of Blue Origin’s New Glenn rocket on its launch pad at Cape Canaveral, Florida just after sunset on 28 May 2026, a malfunction caused a significant explosion (which occurred around 0100 UTC on 29 May).  The cloud that resulted from this explosion exhibited a distinct cold signature in GOES-19 (GOES-East) ABI spectral bands 07-16, as it drifted east-northeast away from the Florida coast.

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