The summer solstice occurred on June 20th this year (2025). The summer solstice is the day with the longest period of daylight and the shortest night of the year in a given hemisphere, and marks the beginning of astronomical summer. In the Northern Hemisphere, it typically falls on June 20 or 21.

GOES satellite imagery provides a unique view of the earth as we pass through the various seasons. The angle of the shadow at sunrise or sunset (satellite time, or at the satellite nadir point) shows how earth progresses through the seasons from summer solstice to fall equinox. Watch the reflection of the sun migrate through the imagery, in this case from the southern hemisphere to the northern hemisphere in this animation of GOES-East from the winter solstice (Dec 21, 2024) to the summer solstice (Jun 20, 2025).

Webapps about the Seasons

These images were made using NOAA data with geo2grid software, from UW-Madison, SSEC. T. Whittaker is thanked for the web apps.

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Total Precipitable Water (TPW) fields across the western Pacific (source), show a band of abundant moisture between 10^o and 20^o N latitude. In addition, the remnants of Sepat are moving to the north and east of Japan, and a tropical depression is making landfall over China to the north of Hainan Island. Do you expect tropical cyclogenesis from the rotation apparent in the MIMIC TPW fields centered near 138^oE and 15^oN?

Scatterometry data from MetopB and OSCAT, below (from here, and here, respectively) shows a circulation moving to the west, from about 141^oE to 139^oE in 12 hours.

NOAA-21 overflew Guam around 0345 UTC on 26 June, and the direct broadcast antenna at the NWS forecast office there acquired data used to create the images (created with CSPP software) below. ATMS rain rate data shows concentrated convection under a region of active convection to the west of Guam; parallel lines of convection are east and north of Guam.

Himawari-9 imagery (more-or-less centered on Guam), below, shows a region of convection associated with the circulation detected by scatterometry. (There are many other interesting features in this animation too!)

Mid-level water vapor imagery shows now distinct regions of mid-level dry air that could act to impede development of this system.

The Joint Typhoon Weather Center (JTWC) show this system as an invest (#97W). Imagery from this site shows the system in a narrow region of low shear.

Refer to the webpages of the Joint Typhoon Warning Center and JMA for more information on this system.

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Grand Island, Nebraska received 6.41″ of rainfall during the calendar day on 25 June 2025 — which set a new record for the date and for any single day during the month of June. 1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Infrared images centered at Grand Island (above) included an overlay of the Total Precipitable Water derived product, GLM Flash Points and 1-hour Precipitation during the 11-hour period  from 0001-1100 UTC on 26 June (which was a period during which a large portion of the 25 June record rainfall occurred — with rainfall rates as high as 1.22 inches per hour).

The same set of GOES-19 imagery that also includes Flood Watch/Warning/Advisory polygons is shown below. Note the appearance of the bold red Flash Flood Emergency for Grand Island area, beginning at 0445 UTC (image | text).

The GOES-19 imagery at 1100 UTC (below) included plots of 24-hour precipitation — which displayed 7.13 inches at Grand Island (ending at 1200 UTC on 26 June).

Prior to the onset of this period of heavy rain, the GOES-19 Total Precipitable Water value in the vicinity of Grand Island was as high as 1.74 inches (below).

 

Wow! The grand total for Grand Island for June 25th is going in the record books at 6.41". Along with breaking the record for June 25th AND the single day record for ANY day in June…it was 0.09" away from tying the all-time single day record for the entire year! ?

— NWS Hastings (@NWSHastings) June 26, 2025

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5-minute CONUS Sector GOES-19 (GOES-East) Visible images with an overlay of GLM Flash Extent Density (FED) and contours of LightningCast Probability (above) showed two isolated thunderstorms which passed over the eastern portion of Lake Murray (located in central South Carolina, just northwest of Columbia KCAE) during the late afternoon hours on 24 June 2025. GLM FED highlighted the presence of satellite-detected lightning activity with each of those two storms — and with the second storm, a lightning strike on the lake around 2043 UTC resulted in 20 injuries, with 12 of those being hospitalized (media report).

A sequence of GOES-19 Infrared and Visible images with LightningCast contours (plus Visible images with both LightningCast contours and GLM FED) is shown below. Note that the LightningCast Probability began to increase in advance of the appearance of FED pixels. The coldest cloud-top infrared brightness temperatures of the isolated thunderstorms were around -55 to -57ºC.

A time series plot of LightningCast Probability and GOES-19 GLM flash counts at Columbia Metropolitan Airport KCAE (below) showed how the LightningCast Probability dramatically ramped up after 1926 UTC, with GLM flash counts within a 10-mile radius of the airport beginning at 1956 UTC. The LightningCast values dipped briefly at 2021 UTC, as the first storm moved farther from the airport (and before the second storm began to produce GLM flash counts as it moved closer).

Cursor samples of LightningCast Probability near the eastern edge of Lake Murray — where the lightning-related injuries occurred — revealed values of 96% from 2026-2041 UTC (below).

For the storms that affected Lake Murray, lightning was first explicitly mentioned in a METAR report from Fairfield County Airport in Winnsboro at 2015 UTC (below).

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