A visual of the solar flare that erupted on the sun Tuesday night (NASA)

UPDATE, 2 p.m.: SpaceWeather.com writes: “Analysts at [NASA’s] Goddard Space Weather Lab .... say the impact [of Tuesday’s solar flare] could spark a strong-to-severe geomagnetic storm. Sky watchers at all latitudes should be alert for auroras.” Note - though - aurora viewing, possible late tonight and/or Thursday night (more likely), may be compromised by a near full moon.

From 11:46 a.m.: The sun is hot and bothered, and exhaling its fury towards Earth. Solar radiation and geomagnetic storms are currently in progress, and a second, more intense geomagnetic storm is forecast to arrive tonight. This second storm is associated with the X-class solar flare spewed out by the sun Tuesday night, second largest this solar cycle, which began early in 2007.

The heightened space weather activity arises from potent sunspot region 1429, which has unleashed two X-class solar flares - the strongest type - in recent days.

The first flare occurred Sunday, and its associated coronal mass ejection (CME) - essentially a wave of plasma - reached the Earth today. The resulting geomagnetic storm rates at the G2 or moderate level on NOAA’s five-point scale.

Tuesday night’s flare registered as class X5.4, besting the class X1.3 flare hurled out Sunday. It generated a strong (S3 rated) solar radiation storm in the Earth’s upper atmosphere that’s still ongoing. Such storms can disrupt high frequency radio communications but pose no threat to people on the ground.

“This was the sun’s version of Super Tuesday,” said Joe Kunches, a scientist at NOAA’s Space Weather Prediction Center in Boulder.

Via NASA: This movie of the March 6, 2012 X5.4 flare was captured by the Solar Dynamics Observatory (SDO)

The flare was complemented by a CME that will blow by the Earth starting around midnight tonight, stirring up already unstable conditions in the Earth’s magnetic field.

The CME is currently speeding toward the Earth at more than two million miles per hour. When it arrives, it will distort the Earth’s magnetic field – which is already being hammered by another plasma wave that arrived early this morning.

“We’ve had these multiple shots,” said Kunches. “They can pile on top of each other, so the second one has a more energetic impact on Earth.”

Kunches said the new CME, when it arrives around midnight, could push the geomagnetic storm to the G3 or strong level.

Link: NOAA model run for incoming CME

Via NOAA, a model of the incoming CME: This animation shows the output from the WSA-Enlil space weather model for solar winds, developed in partnership with NASA and academia and run operationally by NOAA. The white through yellow and orange plumes indicate the density of the coronal mass ejection plasma as it heads towards Earth (orange is the highest density). The sun is centered as an orange circle. The size of Earth is represented in relative scale -- a small dot compared to the size of the Sun or the coronal mass ejection.

Sky watchers at high latitudes should be on the lookout for auroras. NOAA’s Space Weather Prediction Center (SPWC) says aurora may be seen as far south as New York to Wisconsin to Washington State.

Communications satellite operators and power companies are keeping a close eye on the activity, Kunches said. He added that current space weather forecasting can not predict whether the power grid will be impacted.

“It’s like predicting 5 inches of rain,” he said. “We know it’s going to fall, but the real question is how fast will it fall? For the power grid, they want to know how fast the Earth’s magnetic field is going to change. Unfortunately we just don’t have ability to give them that much information.”

Intense solar activity can damage transformers and other power grid equipment; in 1989, a strong solar storm destroyed a transformer in Quebec and knocked part of Canada’s power grid offline for about eight hours.

The flurry of solar weather has NOAA’s SPWC as busy as it gets.

“[A]lmost every type of warning, alert, and watch that SWPC forecasters issue were issued today,” it said.

Related links:

Understanding space weather forecasts and the risk of solar storms

Space weather: are we ready for a solar strike?

As the sun awakens, the power grid stands vulnerable

NASA: Frequently asked questions about space weather

NOAA: Primer on space weather

NOAA: Space Weather Prediction Center updates