Solar Flare Probability Discrepancy

[Drax Spacex]

Multiple C solar flares have originated from AR 2778.  Clicking on that region, we see probabilities for C, M, X respectively 55%, 10%, 1%.  This seems up to date and correct.  However, under the Solar Flare section below the blue solar disk image, we see probabilities for C, M, X respectively 5%, 1%, 1%.  This seems wrong, perhaps latched with stale data?

[Vancanneyt Sander]

The probabilities are updated around midnight UTC by the SWPC. Those are not updated during the day, and the issue is that regions continue to develop or degrade and thus during the day the odds of C, M and X class flares can change rapidly.

the swpc has two methods: a per region probability forecast and a global probability forecast of the visible solar disk. But with one active region you would indeed expect that the probabilities would be equal to the global solar disk forecast. My guess is that the disk probability is also used for the industries and satellite operators with down to Earth chances to play it safe, I don’t know 🤷‍♂️ 

Sometimes we do our own predictions as well, we do that with interesting regions (you find several on the forum of a few years back) that develop fast and have a lot of potential. I always look at the regions to know the odds and barely look at the prediction 😇 

[Drax Spacex]

Understood - thanks for the quick reply and explanation.  The handwritten whole disk probability in the upper right of the SWPC Synoptic map appears to match the values of the AR region with highest flare probabilities.  That probability, based on latest observations, is what I will refer to.

AR2778 has been a real sparkler since it first started forming around Oct 25th, even before it had been defined as an active region.  Interesting in its evolution how it has blossomed and increased in size and linear extent over the past few days.

[Drax Spacex]

Correction - the whole disk forecast on the SWPC Synoptic map is not based on the single highest probability region.  It is calculated using the "probability of at least one" using the probabilities from all individual regions.

e.g. 29 Oct 2020 1215 UT Synoptic Map:
60/15/1/1 Whole Disk Forecast
45/10/1/1 AR2779
30/5/1/1 AR2778

P(C flare whole disk)=1-(1-.45)(1-.30)=.615≈60%
P(M flare whole disk)=1-(1-.10)(1-.05)=.145≈15%