Northern lights in South Plainfield tonight
No tonight
Not tonight. The forecast Kp of 2 is well below what it takes for the aurora to reach this far south. The sky is forecast mostly cloudy.
- The aurora reaches this place at about Kp 7, which is 50 degrees geomagnetic latitude on NOAA's storm scales.
- SWPC forecasts a highest Kp of 2 (2.00) during tonight's dark hours: quiet.
- The forecast for the dark hours is mostly cloudy, 81% sky cover on average.
- The moon is waxing gibbous, 79% lit, and up for part of the dark hours.
South Plainfield forecastLive radar hereKp forecast
From NOAA’s Space Weather Prediction Center and the National Weather Service forecast for this grid cell, read Sep 21, 21:05 UTC. Times are Eastern Daylight Time.
The oval right now
NOAA’s OVATION model: the chance of aurora overhead 30 to 90 minutes from now, valid Sep 21, 22:15 UTC. Green is a low chance, red a high one.
Rain and snow mean cloud, and cloud is the last thing between a forecast aurora and the sky you are standing under. Each town page carries that town’s own sky cover forecast for the dark hours.
Open the live map with the aurora forecast
Aurora forecast from NOAA’s Space Weather Prediction Center. Original at SWPC
Alerts in force
Space weather watches, warnings and alerts from NOAA's Space Weather Prediction Center.
-
WATCH: Geomagnetic Storm Category G1 Predicted
Issued Sep 21, 18:32 UTC
Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.
- Induced Currents: Weak power grid fluctuations can occur.
- Spacecraft: Minor impact on satellite operations possible.
A watch is issued days ahead, a warning hours ahead, and an alert when the threshold has been reached.
Tonight at South Plainfield
- Geomagnetic latitude
- 49.8° (40.58°N, 74.41°W)
- The aurora reaches here at
- Kp 7
- Highest Kp forecast tonight
- 2 (2.00), quiet
- Cloud cover in the dark hours
- 81% on average, mostly cloudy
- Moon
- 79% lit, some interference
| Hour | Kp | Sky cover | Sky | Aurora |
|---|---|---|---|---|
| 1 | 73% | mostly cloudy | Below the line | |
| 1 | 73% | mostly cloudy | Below the line | |
| 1 | 79% | mostly cloudy | Below the line | |
| 1 | 79% | mostly cloudy | Below the line | |
| 1 | 83% | mostly cloudy | Below the line | |
| 1 | 78% | mostly cloudy | Below the line | |
| 2- | 84% | mostly cloudy | Below the line | |
| 2- | 85% | mostly cloudy | Below the line | |
| 2- | 87% | mostly cloudy | Below the line | |
| 2 | 90% | overcast | Below the line |
Darkness and the moon
8.8 hours of full darkness tonight. The moon is waxing gibbous, 79% lit, and up for part of the dark hours.
- Sunset
- Mon 6:56 PM
- Civil twilight ends
- Mon 7:24 PM
- Nautical twilight ends
- Mon 7:56 PM
- Full darkness begins
- Mon 8:28 PM
- Full darkness ends
- Tue 5:13 AM
- Sunrise
- Tue 6:45 AM
- Moonrise
- Mon 4:36 PM
- Moonset
- Tue 2:16 AM
Full darkness is astronomical twilight’s end, the sun 18 degrees below the horizon. Town lights matter as much as the moon: a few minutes’ drive away from them is usually the difference between seeing an arc and not.
The best hours tonight
Mon 10:28 PM to Tue 1:28 AM. Chosen for the darkest, clearest stretch nearest local midnight, which is when the auroral oval swings furthest toward the equator over any one place. Face north, away from town lights, and give your eyes twenty minutes.
The next three days
The highest Kp forecast each UTC day, against the Kp 7 this town needs. A UTC day runs from early evening to early evening in North America, so the night of the 21th sits in two of these rows.
| Day (UTC) | Highest Kp | Level | Here |
|---|---|---|---|
| Mon, Sep 21 | 2 | Quiet | Below the line |
| Tue, Sep 22 | 2 | Quiet | Below the line |
| Wed, Sep 23 | 4+ | Active | Below the line |
| Thu, Sep 24 | 4+ | Active | Below the line |
What this means
This town is at 49.8 degrees geomagnetic latitude, measured from the geomagnetic dipole pole. NOAA’s space weather scales state where a storm of each level is seen: a G1 (Kp 5) at about 60 degrees geomagnetic, a G2 at 55, a G3 at 50, a G4 at 45 and a G5 (Kp 9) at 40, five degrees a step. Reading that backwards gives the Kp 7 this town needs. Below Kp 5 the line runs from 66 degrees geomagnetic at Kp 0 to the scale’s 60 at Kp 5.
Against that go three things the sky does: how dark it gets, from the sun’s altitude here; the moon, from its phase and whether it is above the horizon in those hours; and the cloud cover in this town’s own National Weather Service forecast. The Kp forecast runs three days and is a forecast of the planet’s magnetic field, not of one sky. Only OVATION knows whether an aurora is out right now, and it sees 30 to 90 minutes ahead, because that is how long the solar wind takes to arrive from the spacecraft that measures it.
At the viewing line the aurora is low on the northern horizon, not overhead, and often only a camera sees color in it. Sources: SWPC 3-day forecast, NOAA space weather scales.
Sources
From NOAA’s Space Weather Prediction Center: the OVATION aurora forecast, the planetary K index forecast, the 3-day forecast, the 27-day outlook, its watches, warnings and alerts, and the real-time solar wind. Read Sep 21, 21:05 UTC.