5-minute CONUS Sector GOES-18 (GOES-West) Shortwave Infrared (3.9 µm) and Fire Mask derived product images (above) displayed a pronounced thermal signature associated with Episode 20 of the ongoing eruption in the Halema’uma’u crater (located within the Kilauea summit caldera) on the Big Island of Hawai’i, which began around 0328 UTC on 07 May 2025. Shortwave Infrared 3.9 µm brightness temperatures exhibited values of 137.88ºC — the saturation temperature of GOES-18 ABI Band 7 detectors — for several hours, beginning at 0336 UTC. This prolonged multi-episode Kilauea eruption began on 23 December 2024.

The sustained period of lava fountaining during this episode ended around 0758 UTC — but a GOES-18 thermal signature of prolonged surface lava flow was still apparent several hours later at 1156 UTC, and the bright nighttime glow of this lava flow could be seen in NOAA-21 VIIRS Day/Night Band imagery (below).

GOES-18 SO₂ RGB images from the RealEarth site (below) indicated that a low-altitude plume of SO₂ (pale shades of green) was drifting southwest from Kilauea — the cluster of dark blue pixels denoted the thermal anomaly associated with the eruption site.

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Dust RGB imagery (here is a larger version) from GK2A at 1720 UTC on 5 May 2025, above, show the distinct bright pink signature of dust along the east coast of China. Airmass RGB imagery (larger version) at the same time shows a rust/orange color as might be expected from a potential vorticity anomaly (GK2A imagery is from this KMA website). NOAA-21 overflew eastern China just after the imagery above. What did the atmospheric spectra from the CrIS instrument on NOAA-21 show? As discussed here and here, Hydra software within McIDAS-V can be used to display CrIS spectra. The partial NOAA-21 data swath is shown below within Hydra.

The plots below show two (identical) longwave infrared spectra (in white and in cyan) as a function of wavenumber at the two points that are plotted on the two different greyscale plots at the bottom of the figure. One point, depicted by a red cross-hatch, corresponds to the white line in the spectral plots; the second, depicted by the cyan cross-hatch, corresponds to the cyan line in the spectral plots. The probed brightness temperature near the region of the bright pink dust RGB signature is warmer at 12.2 µm (283.84 K) than at 10.3 µm (279.99 K); the brightness temperature over the western Pacific at some distance from that pink dust RGB signature is colder at 12.2 µm (283.12 K) than at 10.3 µm (284.7 K). This difference in the differences reflects more absorption by dust of 10.3 µm radiation at the red cross-hatch, and more absorption by water vapor of 12.2 µm radiation at the cyan cross-hatch. Note in the spectral plot how the spectra that has the warmed brightness temperatures is a function of wavenumber. If you had a geostationary sounder viewing this event, the spectrum you see as dust starts to move over will be affected in noticeable ways, just as in this case.

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GOES-19 True-Color animations on 5 May and 4 May 2025 (from the CSPP Geosphere site) show a circulation cut off from the main westerlies and slowly meandering across the Ohio River Valley. The system has become a bit more symmetric on the 5th as it separates more completely from the front along the east coast. A MIMIC Total Precipitable Water animation for the 24 hours ending 1600 UTC on 5 May, below, shows the system surrounded by relatively dry air.

Advected Layer Precipitable Water (ALPW) fields, below, from ca. 0300 UTC 4 May 2025 and 1500 UTC 5 May 2025 (from this site) shows that the system is stacked in the vertical and moving very very slowly.

Airmass RGB shows the system drifting across northern Kentucky in the 38 hours ending at 1400 UTC 5 May 2025. It is spawning clouds and showers over a large portion of the eastern United States as the storm meanders, as shown in this radar animation from here.

The animation below shows the evolution of the surface system from 2100 UTC 3 May through 1200 UTC 5 May 2025.

500-mb heights on 5 May 2025 (below, at 0000 and 1200 UTC), clearly show the system over Kentucky. A system over the southwestern United States is poised to kick the storm over the Ohio River valley to the east.

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A significant outbreak of tornadoes occurred across Oklahoma and Kansas during the afternoon and evening hours on 03 May 1999 — and hail as large as 4.50 inches in diameter was reported in parts of Texas and Oklahoma (Storm Reports). NWS damage surveys indicated that widespread F4 and F5 tornado damage occurred. NOAA GOES-8 Visible images (above) and Infrared images (below) centered on Oklahoma City (KOKC) showed the explosive development of convection across southwestern Oklahoma after 2045 UTC. Several overshooting tops were evident in the visible imagery, and Enhanced-V cloud-top signatures were seen in the Infrared imagery.

A toggle between GOES-8 Visible and Infrared images at 2302 UTC (below) displayed distinct overshooting top and Enhanced-V signatures associated with the supercell thunderstorm that was southwest of Oklahoma City — about 50 minutes prior to the first tornado reports in the Newcastle area (10 miles south of KOKC).

GOES-8 Water Vapor images (below) showed the approach of an upper-level shortwave trough during the afternoon hours.

Strong upper-level divergence indicated that forcing for synoptic-scale lift was likely being enhanced as a jet streak moved over Oklahoma (below).

GOES-8 Sounder lifted index (LI) and total precipitable water (PW) derived products are shown below. During the morning hours preceding convective development, a trend of rapid destabilization was evident from central Texas into Oklahoma (LI’s decreased to -8 C and lower, red enhancement); in addition, the moisture gradient appeared to increase slightly along the dryline that was located across western Oklahoma.

AERI retrieval data was combined with GOES-8 Sounder data to produce Skew-t/log-p thermodynamic diagrams for the atmosphere over Purcell (in south-central Oklahoma) at 1934 UTC and 2043 UTC UTC (below), during the hour preceding convective development. Note how the low-level “capping inversion” near 850 hPa was eroded, allowing organized surface-based updrafts to ascend above the level of free convection. In that 1-hour period, the CAPE increased from 4111 to 4681 J/kg, and the lifted index (LI) decreased from -7.48 to -8.22 C; convective inhibition (CIN) decreased from -259 to -69 J/kg.

A time series of convective indices for the 4 Oklahoma AERI + GOES Sounder sites (below) showed the trend of rapid destabilization during the afternoon hours leading up to the development of supercell convection.

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