Space Weather Now

Source: NOAA SWPC real-time solar wind (DSCOVR/ACE) · as of Sep 5, 2026 03:55 UTC

• ▸Geomagnetic field: Kp 2 — below the G1 storm threshold (Kp 5). No storm-level drag or charging concern from the current index.
• ▸Radio blackout: M1.2 flare in the last 72 h reached NOAA R1. Dayside HF and low-frequency navigation signals degrade during flares of this class.
• ▸Solar wind: Bz -4.9 nT — northward or near zero, so the magnetosphere is mostly closed to incoming energy right now.
• ▸Flare outlook (SWPC day 1): 10% chance of an M-class and 1% of an X-class flare.

24 B-class · 32 C-class · 4 M-class

What is the Kp index?

Kp is a 0–9 planetary index of geomagnetic disturbance, computed every three hours from a network of ground magnetometers. Kp 0–3 is quiet, 4 is unsettled, and Kp 5 and above corresponds to NOAA geomagnetic storm levels G1 (Kp 5) through G5 (Kp 9). Higher Kp means more energy entering the magnetosphere from the solar wind.

What does an X-class solar flare do to satellites?

Flares are classed by peak X-ray flux: C, M and X, each ten times stronger than the last. An X-class flare produces an R3 or stronger radio blackout on the sunlit side of Earth within minutes, degrading HF communications and GNSS signal quality. Satellites do not feel the flare directly, but the extra ultraviolet and X-ray energy heats the upper atmosphere, raising drag on low-Earth-orbit spacecraft, and an associated coronal mass ejection or proton event can follow hours to days later.

How do I read Bz?

Bz is the north–south component of the interplanetary magnetic field carried by the solar wind, measured in nanotesla. When Bz is negative (southward) it reconnects with Earth’s northward field and lets solar-wind energy in; sustained Bz below about −5 nT is geoeffective and below −10 nT usually drives a geomagnetic storm within hours. Positive (northward) Bz keeps the magnetosphere largely closed, even when the solar wind is fast.

Where does this data come from and how fresh is it?

Kp and solar-wind readings come from NOAA’s Space Weather Prediction Center (planetary K-index and the DSCOVR/ACE real-time solar wind feed). The 3-day outlook is SWPC’s published flare-probability forecast. The flare log is built from NASA DONKI and NOAA GOES X-ray event lists. Each panel shows its own “as of” timestamp; SWPC feeds are stored every 30 minutes and the flare log every six hours.