Space Weather

Space Weather Observations, Alerts, and Forecast

Product: 3-Day Forecast - Issued: 2025 Oct 17 1230 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center.

Geomagnetic Activity Observation and Forecast

The greatest observed 3 hr Kp over the past 24 hours was 3 (below NOAA Scale levels). The greatest expected 3 hr Kp for Oct 17-Oct 19 2025 is 4.67 (NOAA Scale G1).

NOAA Kp index breakdown Oct 17-Oct 19 2025
	Oct 17	Oct 18	Oct 19
00-03UT	2.00	3.00	4.00
03-06UT	1.67	2.33	3.00
06-09UT	2.67	2.00	2.67
09-12UT	3.67	2.00	2.33
12-15UT	3.67	2.00	2.00
15-18UT	3.33	4.00	2.00
18-21UT	3.00	4.00	2.00
21-00UT	4.67 (G1)	4.33	2.33

Rationale: G1 (Minor) geomagnetic storming is likely on 17 Oct due to glancing CME effects from events that left the Sun on 12/13 Oct.

Solar Radiation Activity Observation and Forecast

Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was below S-scale storm level thresholds.

Solar Radiation Storm Forecast for Oct 17-Oct 19 2025
	Oct 17	Oct 18	Oct 19
S1 or greater	10%	10%	5%

Rationale: There is a slight chance for a greater than 10 MeV proton event above the S1 (Minor) levels through 18 Oct.

Radio Blackout Activity and Forecast

Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was at Oct 17 2025 0128 UTC.

Radio Blackout Forecast for Oct 17-Oct 19 2025
	Oct 17	Oct 18	Oct 19
R1-R2	60%	60%	40%
R3 or greater	15%	15%	5%

Rationale: Minor to moderate (R1-R2) radio blackouts are likely through 18 Oct, with a slight chance for an isolated R3 (Strong) event, due to the current and potential flare activity of Regions 4246 and 4248. Probabilities decrease slightly on 19 Oct as AR 4246 rotates beyond the western limb.

Space Weather Overview

Real Time Images of the Sun

eit-171

eit-195

eit-284

eit-304

The sun is constantly monitored for sun spots and coronal mass ejections. EIT (Extreme ultraviolet Imaging Telescope) images the solar atmosphere at several wavelengths, and therefore, shows solar material at different temperatures. In the images taken at 304 Angstrom the bright material is at 60,000 to 80,000 degrees Kelvin. In those taken at 171 Angstrom, at 1 million degrees. 195 Angstrom images correspond to about 1.5 million Kelvin, 284 Angstrom to 2 million degrees. The hotter the temperature, the higher you look in the solar atmosphere.

SDO/HMI
Continuum

SDO/HMI
Magnetogram

Lasco
C2

Lasco
C3

The MDI (Michelson Doppler Imager) images shown here are taken in the continuum near the Ni I 6768 Angstrom line. The most prominent features are the sun spots.

LASCO (Large Angle Spectrometric Coronagraph) is able to take images of the solar corona by blocking the light coming directly from the Sun with an occulter disk, creating an artificial eclipse within the instrument itself.

Real-Time Solar Wind data broadcast from NASA's ACE satellite

Electron Proton Alpha Monitor (EPAM)

Low energy electrons & protons

Magnetic Field

Solar Wind Electron Proton Alpha Monitor

Plasma

Solar Isotope Spectrometer (SIS)

High energy protons

Solar Cycle

The Solar Cycle is observed by counting the frequency and placement of sunspots visible on the Sun. The forecast comes from the Solar Cycle Prediction Panel representing NOAA, NASA and the International Space Environmental Services (ISES). The Prediction Panel has predicted Cycle 25 to reach a maximum of 115 occurring in July, 2025. The solar radio flux at 10.7 cm (2800 MHz) is an excellent indicator of solar activity. Often called the F10.7 index, it is one of the longest running records of solar activity. The F10.7 radio emissions originates high in the chromosphere and low in the corona of the solar atmosphere. The F10.7 correlates well with the sunspot number as well as a number of UltraViolet (UV) and visible solar irradiance records.

Auroral Activity Extrapolated from NOAA POES

Tonight's Auroral Map

Tomorrow's Auroral Map

Instruments on board the NOAA Polar-orbiting Operational Environmental Satellite (POES) continually monitor the power flux carried by the protons and electrons that produce aurora in the atmosphere. SWPC has developed a technique that uses the power flux observations obtained during a single pass of the satellite over a polar region (which takes about 25 minutes) to estimate the total power deposited in an entire polar region by these auroral particles. The power input estimate is converted to an auroral activity index that ranges from 1 to 10.

VHF and HF Band Conditions

Conditions on the Sun and in the solar wind, magnetosphere, ionosphere and thermosphere can influence the performance and reliability of space-borne and ground-based technological systems and can endanger human life or health. This introduction movie in the English language will open on a new tab/window when you click on the image below.

Space Weather links:
Lots of interesting information
3-Day Forecast of Solar and Geophysical Activity
Space Weather overview
LASCO Coronagraph
Solar wind
Forecast discussion
Solar and Heliospheric Observatory (SOHO)

Space Agencies:
National Aeronautics and Space Administration (NASA)
European Space Agency (ESA)

Credits

Space Weather Images and Information (excluded from copyright) courtesy of:
NOAA / NWS Space Weather Prediction Center Mauna Loa Solar Observatory (HAO/NCAR) SOHO (ESA & NASA)

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