Aurora forecast: the oval now, Kp for three nights, and where it reaches
The aurora oval as NOAA's OVATION model has it right now, drawn from the grid rather than copied from a picture; the Kp index now, for the next hour and for three nights; the solar wind that decides the next sixty minutes; and a map that turns any place you click into tonight's verdict. Nothing here is a guess dressed as a number: every figure names its feed and its time.
Azimuthal view from the pole to 40°, your meridian at the bottom. Green: probability of aurora overhead in the next 30–90 minutes. Dashed: how far tonight's forecast Kp reaches. Shaded: the night.
Reading NOAA…
Tromsø, Norway
rows: dark · oval · clear · no Moon — the window is the run of green hours
Reading NOAA…
The full verdict page for this pin → · This place on the light pollution map →
The oval on the map
Click anywhere to move the pin and recompute. The glow is NOAA OVATION, sampled between cells the same way the verdict samples it; the dashed line is the viewline for tonight's forecast Kp. Base map: this site's own vector tiles (OpenStreetMap contributors, Natural Earth).
Kp: now, next hour, three nights, 27 days
The Kp index, explained with your line on it → · Geomagnetic storm today? →
Camera settings for this aurora
From the oval's brightness right now (hemispheric power in gigawatts) and the exposure law.
Bright, moving aurora smears at anything over about 4 s: open the aperture or raise ISO rather than lengthen the shutter.
Plan the sequence · stack the night when you are back · the photography guide →
What OVATION is
NOAA's Oval Variation, Assessment, Tracking, Intensity and Online Nowcasting model turns the solar wind measured at L1 into a probability of aurora over each one-degree cell, 30–90 minutes ahead, every five minutes. It is the best short-term picture there is, and it is a probability of aurora overhead — this page adds the horizon geometry so it answers for places under the oval's edge and well south of it.
What the dashed line is
The viewline: the magnetic latitude the oval's edge reaches at the night's forecast Kp, from NOAA's table (Kp 5 → 56°, Kp 7 → 52°, Kp 9 → 48°). Aurora can be seen on the horizon from up to ~1000 km further toward the equator than the line.
Now versus tonight
The grid is now. The 3-day forecast is the forecaster's Kp in three-hour bins; "tonight" on the strip is the largest of the bins over your dark hours, and the card quotes the forecaster's own sentence about why.
Solar wind at Earth
Speed, density and the magnetic field's north–south component Bz, propagated from the L1 spacecraft to the magnetosphere. Sustained Bz below −5 nT with speed above 500 km/s is the classic loading signature; Kp reacts an hour later.
Hemispheric power
Gigawatts deposited into each hemisphere by precipitating particles: the oval's total brightness. Under 20 GW the aurora is a camera-only grey arc; over 100 GW it is a storm you photograph at 1–2 s.
The 27-day outlook
The Sun rotates in ~27 days, so a coronal hole that gave a storm last month tends to give one again. The strip is NOAA's largest daily Kp; green bars are days that reach your threshold.
Tonight, by place
Sources
Everything on this page is read by your browser directly from NOAA SWPC (public domain): the OVATION grid, the 1-minute estimated Kp, the geospace model's hourly prediction, the 3-day and 27-day forecasts, the propagated solar wind, hemispheric power, NOAA scales and alerts. Cloud for the pin: MET Norway (CC BY 4.0). Ground darkness: this site's atlas. Coastlines on the disc: Natural Earth. NOAA's own aurora pictures are at spaceweather.gov; this page draws its own from the same grid so a click can read the value under it.