GONG/TD is down for Inclement weather

Photo courtesy Pere L. Palle  

Local support team at Teide Observatory, Tenerife, Canary Islands reports that storm "Emilia" reached the islands 24 hours earlier than expected. The storm brought severe and unusual weather conditions to Tenerife, including strong winds, heavy rain, and a rare form of soft hail known as graupel. The observatory will remain closed until the weather improves. 

GONG/LE: Radiometer/Pyranometer Outage

 The local Corella (Australian white cockatoos) have been up to their usual antics, and have once again chewed through the cable from the radiometer. The outage started on 11/12/25. Radiometer data will return after repair parts have been shipped from Boulder HQ to Learmonth.

 

GONG/ML: Shelter Condition

 NOAA/GML staff have provided the project with some recent pictures (12/3/25) of the shelter. The GONG engineering staff is working on plans to get the shelter painted during the restart after the access road and power to the site have been established. (Photos: Paul Fukumura-Sawada, NOAA)

 

UPDATE: Mauna Loa Access Road

 NOAA/GML and the US DOT met the week of 12/1. The road construction contractor is pushing to get the project done as quickly as possible, and plan to have the work completed within the current period of performance that expires on March 31st.

GONG data processing update

Processing of the network-merged daily velocity and magnetogram images, p-mode-coefficient time series, and ring-diagram analysis products for GONG month 308, and the p-mode frequency data products for central GONG month 307 is completed and the data products are now available.

Why Active Regions Appeared Displaced in GONG Far-Side Map Compared to Mars Rover View

 

In two recent posts, we compared an image of the Sun’s far side taken by the Mars rover with the GONG far-side helioseismic map. A large active region is clearly visible in both, though at different apparent locations. This displacement arises solely from differences in viewing geometry. The rover observes the Sun’s far side with distinct values of B0 and L0, which differ from those used in the helioseismic map, and the discrepancies we note result from the combined influence of these parameters. Variations in L0 are driven by the rover’s position in the orbit, which changes over time. 

As mentioned earlier, the rover will provide far-side observations for only the next two months. During this period, its viewing angle will gradually shift, yielding perspectives of different portions of the Sun’s far side. Since Mars completes an orbit around the Sun in about 687 days, the Sun's far side can be observed from Mars roughly every other year, with each transit lasting about two months as determined by its orbital velocity.

Expect a moderate geomagnetic storm and aurora on 5-6 Dec.

A large coronal hole that we wrote about in our post from 7 Nov.  (also see an early post on 14 Sep.) is again crossing the solar central meridian. Image on the left taken by AIA instrument on board NASA's Solar Dynamics Observatory shows the coronal hole early 2 December 2025 (universal time). This coronal hole developed at the end of April, 2025 (8 months ago!) and since then was steadily growing. The coronal hole coincides with a large area of weak unipolar magnetic field of mostly negative polarity (right panel, see white outline  plotted over a magnetogram taken by GONG station at Learmonth, Australia). The magnetic field from this area opens up to the interplanetary space forming a high speed solar wind stream. One should expect that in about 4 days (5-6 Dec), the solar wind from this stream will intersect with Earth's magnetosphere and cause a moderate geomagnetic storm and aurora.

 

More "fireworks" (solar flares) are coming?

Active region observed in GONG farside images and from the surface of Mars is now visible from Earth (see right panel showing GONG broadband image). This region is now assigned 14294 number. Based on image from the NASA's Perseverance Rover and GONG far side maps (white circles on the left and middle panels) the region rapidly developed on the side of Sun not visible from Earth.  A rapidly growing regions may exhibit a significant flare activity, and in fact, AR14294 already produced several moderate (C-class) and major (M-class) flares. So far, the largest flare was M5.9, when the region was crossing the East limb. Based on history of the region's development, it is expected to produce more flares. Other region marked by orange box on farside and the rover's images corresponds to decaying AR14274 from previous solar rotation. Based on the rover's image, the region has decayed significantly, and it may not exhibit a strong flare activity, when crossing to the visible solar hemisphere. Still, there were limb flares in the approximate location of that region too.

A Large Solar Active Region Seen on the Sun’s Far Side by Helioseismology and NASA’s Perseverance Rover

 Helioseismic mapping of the Sun’s far side has been instrumental in providing early warnings of medium to-large active regions before they rotate into Earth’s view. The most recent helioseismic map (left image), derived from NSF’s GONG observations, reveals several active regions on the far hemisphere, with the most prominent located in the southern hemisphere and highlighted by the white circle. This region is estimated to rotate onto the Earth-facing side on November 30. 

 A complementary perspective comes from Mars, which currently lies behind the Sun and will remain in that position for the next two months. NASA’s Perseverance Rover, part of the Mars 2020 mission, has also detected a large active region in the southern hemisphere of the Sun (white circle in the right image) 

The apparent locations of active regions in far side and direct imaging may appear different. This is because difference in image orientation and a viewing angle for Mars rover images. Some features that appear in far side images may have a low probability. Nonetheless, both methods consistently confirm the existence of a substantially large active region on the Sun’s far side at its precise location.

Image Credits: Left image: NSF/NSO/GONG; Right image: Spaceweather.com

Blank magnetograms from LE, UD, and BB

Starting 7 Nov. 2025, there were occasional blank magnetograms produced by some GONG network sites. So far, this had happened at least once at LE, UD, and BB. GONG duty responder identifies these instances and restarts the system, which corrects the issue. The root-cause of these events is under investigation.

 

Update: Mauna Loa Access Road

The Mauna Loa road construction contract has been awarded! The award notification has been posted on Sam.gov. A Notice to Proceed is pending. The construction period of performance has been set, January 1 to March 31, 2026. Once a construction schedule has been officially published, Hawaiian Electric will start work on their schedule for restoring utility power to the site.

This image, taken midday during a helicopter overflight of Mauna Loa's eruption on December 5, 2022, shows a lava flow branching after it cuts across the Mauna Loa Access Road. The large blocks in channel are called lava boats. These are termed lava balls or lava boats and form when portions of the fissure 3 cone or levees break away and are rafted down stream. As they move along in the channel, additional lava can cool to their surface to form accretionary lava balls. USGS image by L. Gallant.

GONG refurbishment project update

NISP Data Center, scientists, and engineers completed vetting eleventh GONG EVT (Emergent Vision Technologies) camera in frame of the GONG refurbishment project. Vetting of one more EVT camera is going to start soon, which will be the last new camera that the NISP group will need to evaluate.

One of the strongest flares of cycle 25 and aurora

Active regions 14274, 14272, and 14275 predicted  by GONG's farside imaging continue producing strong flares and CMEs. This enhanced solar activity also produces strong geomagnetic storms and aurora. Last  night (11 Nov 2025), the aurora was observed as far south as Santa Fe, New Mexico, USA. Photo shows aurora in Denver, Colorado. On 11 November 2025, AR14274 produced a very large solar flare of X5.1 class. More aurora displays to come! Video shows flare as observed in H-alpha by GONG station at Teide Observatory, Canary Islands, Spain.

 

Aurora and recurrent geomagnetic storm

Geomagnetic activity associated with long-lasting coronal hole on the Sun (see, our previous post at https://gongnisp.blogspot.com/2025/09/recurrent-geomagnetic-storms.html) seem to continue. Last night (7 November 2025), a moderate geomagnetic storm hit the Earth and produced some beautiful aurora. The geomagnetic activity associated with this long-lasting coronal hole is approximately marked by black ovals. Geomagnetic storm on previous night (also included to the last oval) is related to solar flare activity.
 

As expected, all three predicted active regions appeared and contributed to elevated solar activity on the front side

 

Over a week ago, GONG far-side helioseismic maps forecasted the rotation of three prominent active regions to the front side in early November 2025. These regions have now emerged, contributing to a marked increase in magnetic activity. They are clearly visible in the latest line-of-sight magnetogram from a GONG site (top image).  

After nearly two weeks of minimal activity, these regions produced two X-class and several high-energy M-class flares. It is noted that the X-class flares were observed after a gap of about four months. This flaring activity, along with associated CMEs, has also elevated the chances of auroral sightings on 6-7 November.

 In the accompanying illustration below, the top panel shows newly assigned active region numbers, while the bottom panel references their previous front-side identifications during far-side transit. 

The atmospheric blast wave associated with the Hunga Tonga-Hunga Ha'apai volcano eruption.

The Hunga Tonga-Hunga Ha'apai volcano erupted on January 15, 2022. A blast wave from the eruption went around the globe. Each GONG station is equipped with a very sensitive barometer, which record barometric pressure every minute. A pulse in the atmospheric pressure associated with this wave was recorded by each station. Figure shows daily variations of the barometric pressure on 15 January 2022 at the GONG station at Big Bear Lake, California, USA. Red oval marks the passage of the blast wave. Records of the barometric pressure and temperature for all GONG network and engineering stations for 14-17 January 2022 are now available at DOI: 10.5281/zenodo.17493218

Solar Activity Expected to Intensify Next Week

Over the past ten days, solar magnetic activity has remained low, with no major high-energy flares recorded. On October 21, however, fast-propagating shocks were detected within a coronal mass ejection (CME), originating from active region 14246 on the far side of the Sun. This region had previously produced dozens of M-class flares while Earth-facing, before rotating beyond the west limb on October 19.

NSF/NSO/GONG far-side helioseismic maps show that AR 14246 — along with regions 14248 and 14258 — has continued to grow and is likely to reappear on the Earth-facing side. These regions are expected to rotate into view on November 1, 3, and 5, respectively.  Upon rotating into the Earth-facing hemisphere, these regions will be assigned new NOAA active region numbers in accordance with standard tracking protocols. Large active regions like these are known sources of intense magnetic activity and CMEs, which can significantly disturb Earth’s magnetic field and trigger space weather events.

In the visualization, the far side of the Sun is depicted against a dark background, while the grey background represents the front-side magnetogram.

GONG data processing update

Processing of the network-merged daily velocity and magnetogram images, p-mode-coefficient time series, and ring-diagram analysis products for GONG month 307, and the p-mode frequency data products for central GONG month 306 is completed and the data products are now available.

Filament eruptions and flare

 As solar activity continues declining after the peak of Cycle 25, Sun produces various eruptive events. On 24 October, 2025, there were multiple filament eruptions and flares; some were associated with Coronal Mass Ejections. Image on the left outlines locations of two filament eruptions (white ovals) and one flare (white square) which occurred during this period. Watch the attached video to see these eruptions in progress.  

GONG station at Learmonth is back to operation

On 11 October 2025, GONG station at Learmonth (Australia) stopped recording Doppler velocities and magnetic field. H-alpha observations were not affected. The remote diagnostics identified that the camera trigger cable was broken. The cable was repaired with the help of site support personnel and reconnected. Data acquisition was restored on 17 October and a calibration set passed. GONG/LE is now back to full operation. The most recent magnetogram is shown on the right.

Failed filament eruption

GONG observations of active region 14246 show a spectacular but failed eruption of the chromospheric filament. Dark material appears to be erupting following untwisting magnetic field lines, but then expands and falls back to the chromosphere. Observations were taken by GONG/Udaipur (India) on 14 October 2025 between 02:01 UT and 11:33 UT.

GONG/UD has restarted its operations

 After about 3 months of dormancy, GONG station in Udaipur, India has restarted its daily operations. The station was shut down at the end of June due to monsoon season.  Transitionally, monsoon in India is divided into the Southwest Monsoon and the Northeast Monsoon. Udaipur area is affected by the Southwest monsoon, which usually starts in June and ends in September. Even though the entrance window in GONG turret is sealed, during the monsoon season with heavy rains, the turret has to be covered by a special bag, to prevent any water leakage. The 2025 monsoon season in India officially ended on September 30, and GONG/UD resumed observations on 9 Oct. During the initial restart, one can see H-alpha images rapidly rotating at the beginning of observing day. The image orientation will be corrected later. After the image rotation is completed, a very large prominence can been seen on the North-East (upper-left).

GONG refurbishment project update

 

NISP Data Center, scientists, and engineers started vetting another EVT camera installed at one of the GONG engineering sites in Boulder. This camera is eleventh EVT camera that is being tested by NISP group. 

Solar cycle variation of oscillation frequencies

The figure shows the temporal variation of the oscillation frequencies incorporating the latest data set (GONG month 306) as well as solar activity represented by 10.7 cm radio flux.  The frequency shifts are calculated from 36 days time series.  The light blue and orange curves are smoothed over a 1 year period.   The correlation between the frequency shifts and solar activity is very high.   

GONG operations during U.S. government shutdown

During U.S. government shutdown, GONG will continue regular operations. The data will be provided both for the operational space weather forecast to SWPC/NOAA, and to the research community via NISP Data Center. Currently, four GONG stations are in operations with GONG/Udaipur station is down for a monsoon season, and GONG/Mauna Loa - in aftermath of the volcanic eruption (see blog post about ML road access). For a real-time information about GONG stations, see https://monitor.nso.edu/

GONG data processing update

Processing of the network-merged daily velocity and magnetogram images, p-mode-coefficient time series, and ring-diagram analysis products for GONG month 306, and the p-mode frequency data products for central GONG month 305 is completed and the data products are now available.

next-generation Ground-based Solar Observing Network

NSO has issued a press release announcing receiving funding from NSF to Design the Next-Generation Solar Observing Network to Advance Solar Science and Space Weather Forecasting.

The U.S. National Science Foundation National Solar Observatory (NSF NSO) will receive $19 million for design work for the Next-Generation Ground-based Solar Observing Network (ngGONG), a state-of-the-art solar observing network that will provide multi-decade, 24/7 monitoring and observing of the Sun.

ngGONG will be capable to:

• Provide continuous measurements of the Sun to study the processes driving solar activity from the Sun’s interior through the heliosphere, improving our understanding of solar structure and space weather.
• Deliver critical quantitative context for high-resolution solar and in-situ measurements, as well as advanced modeling efforts.
• Bridge solar and stellar research, shedding light on the impacts of stellar activity on planetary habitability both in our solar system and beyond.
• Serve as a platform for instrument innovation and long-term scientific discovery, creating a multi-decade record of solar variability for future generations of researchers.

The official award is now listed at NSF.gov. 

 

AGU calls for nominations of impactful datasets

Recently,  the American Geophysical Union (AGU) called for nominations of impactful datasets. It is highlighting and celebrating datasets that support the broad spectrum of research, analysis, and decision making by Earth and space sciences communities. AGU is looking for the impacts in three dimensions: people, planet, and prosperity. Nominations are due October 10th!For complete details and to submit your nomination see http://lite.spr.ly/6009zklz. 

 

 

 

 

 

New Ceph cluster for NISP data storage

Work has started on replacing the current NISP Isilon cluster by a new Ceph cluster for data storage. Last week, the base hardware for a "sandbox" (test) cluster was successfully installed and tested (see figure on the right).  The testing will continue as the main cluster is built. The plan is to complete the transition to the new cluster by the end of FY2026. The new cluster will increase the storage space available for NISP observations by approximately 50%, which include GONG, SOLIS, and legacy observations from various NSO and non-NSO instruments.

Update on the GONG/TD LCVR temperature control issue

This is an update on the note about GONG/Teide (TD) site (Canary Islands, Spain) LCVR temperature control issue, posted back in July. Once the LCVR temperature controller was disabled on June 24th, the TD-EVT data has been stable. Science tests of the TD Doppler velocity and magnetic field images before and after the LCVR temperature control was turned off did not uncover any significant problems with the data. The GONG/TD-EVT images have been accepted for downstream processing.

GONG refurbishment project update

NISP Data Center, scientists, and engineers completed vetting tenth GONG EVT (Emergent Vision Technologies) camera in frame of the GONG refurbishment project. This camera will upgrade one of the engineering sites in Boulder.  

Recurrent geomagnetic storms

Recurrent geomagnetic storms are associated with large coronal holes (CH). As Sun rotates, the same area of open magnetic field is brought up to face Earth every about 26 days. A large CH that was observed crossing solar central meridian early this week existed for several solar rotations. Upper row of images show solar corona observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) on 19 June, 15 August, and 11 September 2025. A large CH is seeing near central meridian on these days. In all cases, about four days later, there were moderate geomagnetic storms associated with this CH. Lower panel shows Kp (ap) index from the International Service of Geomagnetic Indices (ISGI)  database. It appears that a geomagnetic storm associated with this CH is now in development. 

GONG supports Parker Solar Probe's 25th encounter

Parker Solar Probe is approaching its 25th encounter, with perihelion expected on September 15 at 20:22 UT. The magnetic connectivity prediction issued on 12 Sep 2025 includes modeling predictions based on GONG magnetic field observations. For image on the right - Helioprojective PSP predicted footpoints: one footpoint per day plotted on the solar disk. Colored dots show predictions from a range of models. Gold squares show the consensus value for each day. Black contours show the full width half maximum for the Kent distribution (en.wikipedia.org/wiki/Kent_distribution) fitted to each set of footpoints (Courtesy of Sam Badman). This is the first of seven updates (for future updates see here).

UPDATED: Large coronal hole is crossing solar central meridian - when we will see a geomagnetic storm?

 A large coronal hole that was described earlier  is now crossing solar central meridian. High-speed solar wind streams (HSSs) originating in coronal holes may have velocities as high as 800 km/s, and reach Earth in about 2 days. Disturbance storm time (Dst) index is used to measure the impact of solar activity on Earth environment. A moderate geomagnetic storm has Dst index between -50 nT and -100 nT. Dst can be predicted from the magnetic field (polarity) associated with the coronal hole and the velocity of HSS. The later could be estimated from area of CH. Using this approach (see Nitti et al, 2023, doi: 10.1093/mnras/stac3533) one could expect to see a moderate-strength geomagnetic storm associated with this CH in about 2-3 days. Negative polarity magnetic field associated with this CH measured by GONG suggests stronger geomagnetic storm as compared with positive polarity field. Let's wait and see ... 

UPDATED on 14 Sep 2025: 

The Wang-Sheeley-Arge (WSA) model of solar wind predicts Earth entering HSS originating from this CH on about 14 Sep 2025, and reaching its middle point on 16 Sept 2025.  A snap-shot of  NOAA's WSA–Enlil model on the right shows predicted plasma density (top) and radial velocity (bottom) across the inner solar system. The sun is at the center (yellow), Earth is green, and STEREO A is red. As an input parameter, WSA-Enlil uses GONG magnetograms. Image credit: NOAA Space Weather Prediction Center.

It seems, the geomagnetic storms associated with this CH is now in development.  

Chromospheric H-alpha surge as observed by GONG

On 9 September 2025, GONG/Learmonth station captured H-alpha  surge (H-alpha jet) in a close proximity to the main sunspot of active region 14207. H-alpha jets appear as eruptions along narrow collimated path. The surges are accompanied by micro-flares at its base, followed by the eruption of a dark material. Some surges show rotational motions. The surges are modeled as a reconnection events between the opened magnetic fields and closed magnetic fields of emerging regions (see below for magnetic field configuration by Yuandeng Shen (2021, doi: 10.1098/rspa.2020.0217)).  Small-scale solar jets play an important role in supplying material and energy to the solar wind. Larger jet may contribute to space weather.

 

 

Large coronal hole and future space weather event?

Solar magnetic fields usually come in pairs: active regions have two opposite polarities, similar to bar magnets. One can identify some of these bipolar structures in a solar magnetogram from GONG on the right with positive/negative polarity fields shown as white/black halftones. Sometimes, the patterns are more complex with multiple positive and negative polarities.  Magnetic flux in these twin or multi-polarity regions is usually well-balanced: magnetic field lines originating in one polarity connect to the opposite polarity in the same active region or its surroundings. Corona is bright above closed magnetic field areas (active regions, see SDO/AIA image on far right). There are, however, areas which have predominantly single polarity magnetic field. Magnetic field lines originating in these unipolar areas may not connect to the solar surface, but extend to the interplanetary space. These areas of opened magnetic field coincide with coronal holes, areas were the corona appears much darker. One of these large coronal holes is now crossing solar visible disk. Coronal holes are associated with streams of fast solar wind, which cause moderate geomagnetic storms. We should expect a moderate geomagnetic storm activity in several days after the corona hole passes solar central meridian. 

Rare "double-decker" filament eruption

Traditional model represents the chromospheric filaments as dense, cold (relative to its surroundings) material seating in the lower part of horizontal magnetic flux tubes. In this model, the magnetic forces support the filament material against gravity, keeping it from falling down to the solar surface. The model explains many properties of filaments including their relation with the coronal mass ejections. However, the magnetic flux tube is continuous structure, and when the filament erupts, it is expected that the entire flux tube erupts with it. There are, however, instances when only a portion of filament material erupts leaving other part intact. Such filament splitting was explained in the framework of so-called double-decker filaments, when the magnetic reconnection results in splitting of magnetic flux tube into two separate tubes. A filament eruption on 6 September 2025 at 14:51 UT observed by GONG at Cerro Tololo, Chile  captured the filament splitting into two separate filaments. There are some small flare-like brightennings, but no X-ray class flare.  Also, no CME was associated with this event, and so, this is a failed filament eruption. These observations provide a strong support for the double-decker filament model. See for yourself.

What is a double-decker filament?

It refers to two separate filaments situated above the same polarity inversion line. Rui Liu et al (2012, doi:10.1088/0004-637X/756/1/59) proposed two magnetic configuration of a double-decker filament: (a) the upper and lower branches are flux ropes, (b) the upper branch is the flux rope and the lower one is the sheared arcade. Such configuration allows the eruption of one of the filaments, without impacting the other filament.  The filament eruption could be triggered by a loss of equilibrium due to flux imbalance, the torus or kink instabilities. Sunspot rotation was observed prior to some double-decker filament eruptions. More recent studies (e.g., Dongxu Liu et al 2025, doi: 10.3847/2041-8213/addfca) provide support to torus instability as a trigger for the filament eruption.

UPDATED: New data product in development: GONG H-Alpha Integral Carrington synoptic maps

NISP group is seeking feedback on a new data product currently in development: GONG H-Alpha integral Carrington synoptic maps. We are especially interested in suggestions regarding the appropriate set of keywords to include in the FITS file headers, as well as comments on the current map format.

At present, the maps are provided in Carrington sin(latitude)–longitude coordinates, with a resolution of 360 × 720 pixels. Observations from selected GONG sites are corrected for limb darkening and uniformly scaled in intensity before being merged into the final synoptic map.

A selection of FITS files is available at the following link: https://drive.google.com/drive/folders/1M0ZwpBA_SW8JuMwlDP0Se75M2IQkCGQ3?usp=sharing

Please email your comments to nispdata@nso.edu by 15 October 2025.

C-class two-ribbon flare with filament eruption

 

On 4 September 2025 at 19:10 UT, C3.4 class flare erupted from NOAA active region 14206. The flare was captured by GONG station at Cerro Tololo, Chile. A portion of an active region filament situated near the main sunspot of this region starts slowly rising about 30 minutes before the eruption. After the eruption,  dark filament material can be seen in a low part of image as material is leaving the Sun. After the filament erupts, two bright ribbons develop, moving apart from the past filament location. This is a classical two-ribbon flare, which is usually accompanied by a coronal mass ejection (CME). The eruption took place near the solar central meridian, and if it was a CME, it would likely be Earth-directed. In this movie  created with different image scaling, one can briefly see a dark circular front centered at the eruption site (see image below). This is a signature of the Moreton (blast) wave, which maybe another indication of CME.  Unfortunately, LASCO C3 coronagraph has about 4 hour gap in observations between 16:54 UT and 21:06 UT, and thus, similar to previous event, it is not clear if it was a CME or not.

 

 

 

Blast from the past

 In August 1972, a series of solar flares and associated geomagnetic storms led to widespread communications disturbances and power outages. On August 4th, the geomagnetic storm caused a nearly instantaneous detonation of dozens of sea mines installed by the US during the Vietnam War south of Hai Phong. The August 4th flare, which occurred between the Apollo 16 and Apollo 17 missions, led to a significant increase in the radiation level in the interplanetary space. It was estimated that for the astronauts on the moonwalk, the radiation dose equivalents would have been clinically significant, including nausea, vomiting, a very high probability of cataract formation, with a slight increase in the probability of death. This flare, which occurred more than 50 years ago, was well-observed by the H-alpha flare patrol telescope at the National Solar Observatory at Sacramento Peak. Image on the left shows the Sun before the flare, and on the right is the flare in progress. You can also see that a portion of filament left of the flaring region had disappeared. These are the signs of a coronal mass ejection erupting from this area of the Sun. Study of the past events may bring invaluable information  about how such strong eruptions develop and help us to prepare for traveling to the Moon and Mars.

GONG Big Bear station

Broadband image from GONG/BB

GONG Big Bear station is exhibiting an unusually large number of camera resets. Each reset interrupts normal observing sequence, and impact the continuity of observations. This happen after recent unplanned power outage.  Engineering team is developing a mitigation approach to resolve the issue.

Flares, filament eruptions, but no CME?

Major (M- and X-class) flares and filament eruptions are usually accompany CMEs, but not always. On 31 August 2025 at about 14:00 UT, M1.3-class flare was recorded in NOAA active regions 14197. This is the region that had about hundred sunspots early this week. The flare activated large quiescent filament south of this region with a partial filament eruption at about 16:15 UT  (upper panel). Then, at about 18:00 UT a small two-ribbon flare and filament eruption were observed in NOAA region 14202 to the East of region 14197 (second panel from the top). See GONG video of these events at the bottom panel.  Despite this activity, there was no obvious sign of CMEs in LASCO coronagraph. There is gap in observations in LASCO C2 between 17:24 UT and 18:36 UT, and coronal streamers appear to be pushed apart during this gap. So, maybe it was a CME but LASCO missed it? Or maybe these were the  failed filament eruptions? 

Sunspot group with hundred sunspots

 Sunspots are organized in groups (or active regions). On average, active regions have only about 6-8 sunspots, but sometimes there are groups with much more sunspots. Sunspot drawing from the National Solar Observatory at Sacramento Peak Observatory taken 2 Sep. 1959 shows two groups with 81 and 93 sunspots. Early this week, an active region with about hundred sunspots was observed by GONG (see colored image showing a zoomed-in portion of solar broaband image of the Sun taken by GONG/Big Bear station in California. GONG telescopes have relatively small aperture, and thus, some small sunspots may not be visible. Observations with larger aperture telescopes suggest that there were close to 100 sunspots in this active region. 

C-class flare as observed by GONG/LE

On 26 August 2025, GONG at Learmonth (Australia) caught C6.2 flare in active region 14199 near solar East limb. Only a small eruption associated with this flare could be seeing in LASCO C2 coronagraph at about 1:26 UT. Video of this flare created by Niles Oien is available in GONG gallery.

Adverse Weather Conditions Interrupt GONG’s Continuous Observations

 Recent adverse weather conditions at multiple GONG sites have significantly disrupted observations, resulting in a markedly low duty cycle. Consequently, the seismic far side maps exhibit elevated noise levels.

GONG refurbishment project update

NISP Data Center, scientists, and engineers started vetting next EVT (Emergent Vision Technologies) camera installed at one of the GONG engineering sites in Boulder. This camera is one of the two that still need to be tested. Both cameras will upgrade the engineering sites. Five of the EVT cameras have already replaced old SMD (Silicon Mountain Design company) cameras at five sites of the GONG network.

Huge prominence eruption

 A huge prominence erupts from South-East limb in early hours of August 20, 2025. Day earlier, this region produced a major M-class flare. Such large prominence eruptions could be associated with a major geomagnetic storms impacting Earth's global infrastructure and satellites. This time, however, no geomagnetic storm is expected as the coronal mass ejection associated with this prominence eruption would miss the Earth. These observations are taken by GONG station at Learmonth, Australia. Erupting prominences (filaments on the disk) are closely associated with the coronal mass ejections - the major source of space weather.

Solar tornado

Solar prominence - a large dense plasma "cloud" suspended by the magnetic field in the chromosphere and corona is one of the hallmarks of active sun. Erupting prominence may become the coronal mass ejections, the prime sources of the geomagnetic storms and space weather.  Observations taken by GONG station at Learmonth, Australia on 18 August 2025 show dramatic evolution of a prominence on solar North-East limb with a rotating material forming solar tornado. Can you see a cloud funnel extending from the lower part of the prominence down to the chromosphere (thin bright layer above visible solar surface, the photosphere)? When it touches down it becomes a tornado.
 

From "solar maximum" to "minimum" in one week

The number of sunspots changes with about 11 year cycles, and Sun is on the declining phase of its cycle 25. However, the solar activity may vary significantly even on a shorter time scales. Nine days ago (8 Aug. 2025, left) there were number of sunspots located mostly in the Northern hemisphere (upper part of the solar disk). This level of activity is typical for a solar maximum. However, today (17 August, 2025, right) there are only very few small pores situated mostly in the Southern hemisphere. Such low sunspot activity is more typical for the period of solar minimum. Why does it matter? The ultraviolet (UV) flux, which strongly correlates with sunspot activity, heats the Earth atmosphere. More sunspots mean the Earth’s atmosphere expands to higher altitudes, where it creates additional drug for low-Earth orbit (LEO) satellites. Such swings in number of sunspots may result in more LEO satellites being prematurely lost due to space weather. 

GONG H-alpha data transfer incident resolved

Saturday morning (16 Aug), one of NISP web servers stopped, and it did not auto-recover on-time. This delayed the transfer of H-alpha data between NISP to NOAA/SWPC data centers. The team was informed about the issue, and worked remotely on resolving it. As of 10:40 am (local time) the issue was resolved, and the flow of data to NOAA/SWPC was restored. GONG magnetogram data transfer were not impacted by this incident. 

GONG data processing update

Processing of the network-merged daily velocity and magnetogram images, p-mode-coefficient time series, and ring-diagram analysis products for GONG month 305, and the p-mode frequency data products for central GONG month 304 is completed and the data products are now available. 

Formation of an active region

 

See formation of an active region as observed by GONG (video created by Niles Oien) - https://gong2.nso.edu/products/misc/devGallery/viewSingleEvent.php?eventDir=event_20250802

 

GONG/BB - Power Outage

 A notification was posted on the BVES website regarding the outage:

 

Southern California Edison (SCE)- Restoration and Continued Public Safety Power Shutoff Warning August 4, 2025

Bear Valley Electric Service (BVES) is notifying customers that Southern California Edison (SCE) has restored power from the Public Safety Power Shutoff (PSPS) affecting BVES supply lines. Power restoration typically takes 8 hours. Southern California Edison (SCE) has placed one of the supply lines on standby for re-energization due to a nearby fire.

Additional period of concern begins August 5th, at 12:00 p.m. until 9:00 p.m. If SCE de-energizes this line, BVES customers will not experience an outage due to redundancy in the transmission lines. However, this condition does create the potential for large scale outages should one of the other transmission lines experience an outage during the PSPS event.

This precaution is mainly due to high winds and aims to reduce wildfire risk. Power restoration typically takes 8 hours and will start after the wind subsides. Delays may occur if daylight is required for safe inspections.

Bear Valley Electric Service (BVES) is reaching out to customers who may be impacted if Southern California Edison (SCE) implements a Public Safety Power Shutoff (PSPS). Updates will be provided through Facebook, voice and text messages, www.bvesinc.com, and local media.

As a reminder, the State of California allows electric utilities like SCE to proactively shut off power in high-risk areas during extreme weather conditions to reduce wildfire risk and ensure the safety of customers, their families, and property.

 

Also of note is the developing Gold Fire that is located north of Big Bear in the Holcomb Valley.