1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Visible images with an overlay of the Fire Mask derived product (above) showed the thermal signature of the Hawk Fire as it rapidly expanded to the northeast on 22 August 2026. Due to the close proximity of the fire, the Reno/Stead Airport (METAR identifier KRTS) was closed to civilian aircraft (remaining open for firefighting operations only). Evacuation Orders were issued for areas west and northwest of Reno, as the wind-driven brush fire eventually jumped US 395 (plotted in magenta), causing part of that highway to be closed. By the end of the day on 22 August, the Hawk Fire had burned approximately 10500 acres, at 0% containment. One fatality was attributed to the fire.

1-minute GOES-18 GeoColor RGB images with an overlay of Next Generation Fire System (NGFS) Fire Detection polygons (below) provided a closer view of the thermal signature, smoke plume and occasional bursts of pyrocumulus clouds produced by the Hawk Fire (the initial NGFS detection occurred at 1819 UTC). Wind gusts in the vicinity of the fire were as high as 49 mph (red numbers in the lower right corner of the Surface Observation plots).

A longer animation of 1-minute GOES-18 Fire Temperature RGB images (below) indicated that the fire’s thermal signature had significantly diminished by 0400 UTC on 23 August.

The Hawk Fire burned very hot, first exhibiting the 137.88ºC saturation temperature of GOES-18 ABI Shortwave Infrared (3.9 µm, Band 07) detectors at 2041 UTC (below). The fire frequently exhibited this saturation temperature for nearly 6 hours, until 0230 UTC on 23 August.

===== 27 August Update =====

5 days after the Hawk Fire started, its burn scar (darker shades of brown) was evident in a Landsat-9 Natural Color RGB image (above). The fire was 95% contained at that point in time.

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1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Infrared Window images (above) included Flash Flood Warning polygons and 1-hour precipitation accumulations during a period when thunderstorms produced heavy rainfall and flash flooding across parts of the Northeast US on 20 August 2026. Notable rainfall occurred in the New York City area, with over 5 inches recorded in Suffolk County on Long Island; the highest 1-hour precipitation accumulation at nearby La Guardia International Airport was 1.82 inches.

Some of these thunderstorms also produced tornadoes and damaging winds — 1-minute GOES-19 Visible images (above) and Infrared Window images (below) included time-matched plots of SPC Storm Reports.

The thunderstorm that produced a tornado in Dover, Delaware exhibited a well-defined Enhanced-V storm top signature (below).

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Earlier this week we introduced you to Lala, a Pacific tropical cyclone. In our first post, Lala was a tropical storm that was setting its sights on Hawaii. Some interesting things have happened since then. First, Lala strengthened to hurricane intensity as it approached the big island of Hawaii. Here’s an animation of the true color view from GOES-18 (GOES West) as the eye passed just to the south of the Big Island. Note that this storm has the visual hallmarks of a weaker tropical cyclone, including an obscured eye.

Of course, just because it’s a weaker storm doesn’t mean it’s not a dangerous storm. Given the westerly trajectory of Lala, the strongest winds are going to be be on the north side of the system where the cyclonic flow is pushing with the storm’s motion instead of on the south side where the flow is acting opposite to the storm’s motion. The impact of this flow was notable, and the NCEP storm summary is astonishing: 140 mph wind gusts at Mauna Kea, hurricane-force winds throughout Hawaii, over a dozen stations with more than two feet of rain. Hundreds of thousands of Hawaiians were without power, and flash floods tore through the islands’ rugged terrain. But perhaps no impact captured the imagination of mainlanders quite like the the snowfall experienced on Hawaii’s highest peaks. Hawaiian snow isn’t altogether rare, as we discussed in this post back in February. August is a little different, however, and this was extremely atypical behavior. However, for most deep storms including hurricanes, the clouds are so deep that precipitation starts out as snow before melting into rain as it falls. With tropical cyclones, most of the time there isn’t a 13,800 foot tall mountain in the way to be hit by one of the rain bands and so we never see this snow before it has the chance to melt.

Consider this sounding from Hilo on the Big Island at 0600 UTC on the 16th (8:00 pm local time on the 15th), taken as the hurricane was passing by to the southwest and archived by the invaluable University of Wyoming Atmospheric Science Radiosonde Archive. This is a typical tropical cyclone profile, with saturated air all the way through the troposphere and strong winds all the way to the surface, and wind that shifts from blowing toward the low at the ground (convergence) to blowing away from it aloft (divergence). But look at that freezing level: it’s around 550 mb or 5140 m. While that’s still almost 1 kilometer above the height of Mauna Kea, the slow lapse rate in this saturated and well-mixed environment means that the temperature at the mountain’s peak is only a couple of degrees warmer than freezing. Snowflakes could easily have formed at the higher levels and not completely melted before reaching the surface at this significant altitude.

While Lala dished out a blow to the people of Hawaii, it didn’t emerge unscathed. The interactions with the terrain scoured the storm of some of its momentum, and it dropped back down to tropical storm status. It’s mid-August, however, and so the waters to the southwest of Hawaii are typically warm. This year, those waters are also 0.5 to 1.0 degrees C above normal thanks to being on the outermost periphery of El Niño as can be seen on the below map. This puts the sea surface temperatures in the area around 80-82 F, which is plenty warm for tropical development.

Maneuvering into a warm sea and low-shear environment was beneficial for Lala’s development, and it rapidly intensified. From 0000 UTC on the 18th to 24 hours later, it strengthened from a strong tropical storm all the way to a weak Category 4 hurricane. The time series of automated intensity estimates from the CIMSS D-MINT product tells the story well.

As of 1400 UTC on the 19th, Lala is straddling the line between Category 3 and Category 4. One of the mesoscale sector scans from GOES-18 has been trained on it, so it’s possible to see it evolve on a minute-by-minute scale. Here is an animation from around 1430 UTC of the Band 13 infrared window channel. It’s night at this time, so no shortwave products are available. Still, this is an excellent way to assess just how intense this storm is. There’s a clear, well-defined eye that even has a hint of some mesovortices in the inside. The cold thick clouds have the classic cyclonic rotation to them while the outer cirrus bands are exhibiting the anticyclonic spin of the divergent flow aloft.

Lala’s westward progression is projected to end as it’s forecasted to make a northward turn. Fortunately, while it is still a major hurricane its current path is taking it over the open ocean and its impact on lives and property is expected to be minimal.

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10-minute Full Disk scan GOES-18 (GOES-West) GeoColor RGB images with an overlay of Next Generation Fire System (NGFS) Fire Detection polygons (above) showed the thermal signature associated with the Mukluk Fire near Tok, Alaska — which began around 1940 UTC on 17 August 2026. With winds at Tok gusting to 20-30 mph, the fire spread quickly and forced some evacuations in the Tok area (18 August update).

10-minute GOES-18 Visible images with an overlay of the Fire Mask derived product (below) provided another view of the fire’s thermal signature.

The areal coverage of NGFS Fire Detection polygons was somewhat distorted in GOES-18 imagery, due to the large effective pixel size of the spectral bands used to create the NGFS product (as shown in a plot of pixel size vs. satellite viewing angle; the GOES-18 viewing angle or zenith angle for Tok is around 72 degrees). Polar-orbiting satellites such as NOAA-20 and NOAA-21 flew directly over Alaska as the Mukluk Fire was burning, and offered a more accurate mapping of the fire’s thermal signature (below).

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