Space Weather Watch

Monday PM/Tue AM US forecast: Red line shows Kp=7 oval. Clouds high in NE/Midwest; better in West/North. Storm hits ~18:00Z Mon (ET daytime). "Show me" event—may underperform models. Visibility limited by clouds. Check our site for updates!

Where to see auroras: G3-G4 storm could light up Alaska, N. Canada, Iceland, Scandinavia, N. US states (WA, ID, MT, Dakotas, MN, WI, MI, ME). Southern Hemisphere: NZ, Tasmania, S. Australia. Look N horizon under clear skies. Track Kp on NOAA site. Possible live YouTube coverage!

Side view from NASA's STEREO-A shows good Earth alignment in the ecliptic plane. High confidence of impact, but storm intensity uncertain. Models predict Kp 7-9 (strong-extreme), but NOAA & I think it'll be milder: Kp=6 Sep 1, Kp=7 Sep 2. Manage expectations!

Incoming CME alert! A fast-moving solar storm (~1300 km/s) blasted from the Sun yesterday—Earth-directed halo type. Low mass, so moderate-strong impact expected. Arrival: Afternoon Sep 1 (Labor Day). Monitoring closely! #Aurora #SpaceWeather

Strong M8-class flare occurring now, initating a very large-scale eruption on the Earth-facing solar disk which is at least likely partially Earth-directed. A full halo CME is expected.

TONIGHT'S AURORA/CLOUD FORECAST:

X1.1-class flare solar flare occurring now

Incredible eruption associated with today's X1.2-class flare off the western limb. Imagery of the solar storm is still coming in, but expecting it to look like a partial halo. The storm itself will probably miss Earth, but energetic particles are currently streaming towards Earth

YouTube video by Shelbydiamondstar - The Aurora Wrangler Space Weather Unplugged - A chat with Chris Stubenrauch

In case you missed our space weather chat from last night, get your popcorn because we went long! 🤩

www.youtube.com/watch?v=_rj_...

AURORA/CLOUD FORECAST TONIGHT:
A significant CME has arrived and geomagnetic effects are likely this evening. We may choose to move our auroral line farther south this PM, so stay tuned to our page for details. The red line represents southern extent of aurora visibility on the northern horizon.

A strong interplanetary shock (solar storm) arrival near Earth is now ongoing, per ACE/DSCOVR satellites. Moderate to strong geomagnetic storms possible this evening

A Moderate (G2, Kp=6) Geomagnetic Storm Watch has been issued by NOAA/SWPC for 16 April due to anticipated CME impacts.

Cloud wise, low clouds will likely be present over the Great Lakes region and Northeast with high clouds generally present over the Pacific Northwest. Your best shot looks to be the upper Midwest.
Follow us for the latest forecast updates and space weather alerts!

Arrival of one or more of these events seems likely during the second half of the day on Tuesday the 15th, but storm intensity is very uncertain. Here's where aurora visibility could make it down to Tuesday evening if we see an arrival of one or more CMEs that lead to moderate geomagnetic storms.

TUESDAY NIGHT (4/15) AURORA FORECAST: A pair of filament eruptions occurred today on the Earth-facing disk, both of which may potentially be Earth-directed. The first appears to be more Earth-directed in EUV imagery, but the second appears to have a wider extent, indicating likely Earth-directedness

A gigantic eruption occurred today, and it was one of the significant eruptions in recent memory. I think it's safe to say that we dodged an extreme geomagnetic storm here.
If all of the power in today's eruption could be harnessed, it would probably power all of humanity for over 100 billion years

With magnetic field already enhanced above 10 nT, it could potentially be a great night for aurora, especially when wind speeds start to pick up a bit.

As the fast CH HSS overtakes the slower ambient solar wind, plasma and magnetic fields are compressed at the leading edge. The compression leads to a pileup of solar wind plasma, causing an increase in density--a good sign the high speed stream will be following shortly after this region.

A coronal hole high speed stream (abbreviated CH HSS) typically has a velocity of 500–800 km/s, whereas the slow solar wind ahead of it moves at 300–400 km/s. This speed difference causes compression when the fast wind catches up to the slow wind.

TONIGHT: We're seeing the pileup out ahead of our anticipated coronal hole high speed stream.

(This will hit hard if you were a 90s baby or a parent of one)

Moderate geomagnetic storms expected later in the Zulu day as Earth connects to this high speed stream, potentially lasting 2 days or more. Yep yep yep.

If you could take any one person, celebrities included, on a 7-day, all-inclusive Northern Lights adventure and tour, complete with a cabin that has a crystal clear view of the sky from your bedroom... who would it be?

The CME we were expecting late last night still hasn’t reached Earth yet—I’ll keep you posted if anything changes!

In the meantime, thanks for sticking with real space weather experts and not the "armchair" meteorologists who were confidently predicting auroras deep into the U.S. last night! 😉

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(4/5) Meanwhile, a very large coronal hole structure is about 2.5 to 3 days out from being geoeffective; Tuesday the 25th could bring about moderate geomagnetic storms.

(3/5) We're not decreasing our Kp "forecast" yet, however. Kp from 5-7 is expected with the arrival of any solar storm near Earth--it might be very late tonight or daytime hours for the U.S. tomorrow.

(2/5) Particles at ACE which can sometimes be used as a diagnostic for a CME arrival to come are on a decreasing trend, signaling not much is on the horizon in the next few hours, most likely.