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4 October 2015
20151003 Week Rotation Today Rotation Week 20151005

4 Active Regions

Flare Forecast
Welcome to the Flare Prediction System. This page lists the active regions present on the Sun today, together with their probability of producing C-, M-, or X-class events. Flare probabilities are calculated using NOAA Space Weather Prediction Center data combined over 1969-1976 and 1988-1996 (details of which can be found in Bloomfield et al., 2012, The Astrophysical Journal Letters, 747, L41, along with full forecast verification testing). The percentage probabilities are based on the number of flares produced by regions classified using the McIntosh classification scheme (McIntosh, P., 1990, Solar Physics, 125, 251) during cycles 21 and 22. For example, over both time periods there were 377 regions classified Eai. As this class produced 131 M-class events, the mean M-class flare rate is ~131/377 or ~0.347 flares per day. Assuming the number of flares per unit time is governed by Poisson statistics, we can estimate a flaring probability for the following 24-hours using P( one or more flares ) = 1 - exp( -mean ), i.e., P = 1 - exp( -0.347 ) ~ 0.29, or 29% for an Eai class region to produce one or more M-class flares in the next 24-hours.

See Gallagher, P. T., Moon, Y.-J., Wang, H., Solar Physics, 209, 171, (2002),
Wheatland, M. S., 2001, Solar Physics, 203, 87 and Moon et al., 2001, Journal of Geophysical Research-Space Physics, 106(A12) 29951 for further details.

Click here for a description of the various active region classifications from the Royal Observatory of Belgium.

Region Flare Probabilities (%)
Number McIntosh C-class M-class X-class
12420 Hax 8(10) 3(1) 0(1)
12422 Dko 56(65) 23(25) 3(5)
12427 Dai 66(40) 16(10) 2(1)

NOTE: Occurrence of '...' indicates that McIntosh class was not observed in the period over which the Poisson flare rate statistics were determined. Values in parantheses/brackets give the NOAA/SWPC forecast probabilities for the occurrence of one or more C-, M-, or X-class flares. When viewed in real-time and before 22:00 UT, NOAA predictions are valid up to 22:00 UT on the current date. When viewed in real-time after 22:00 UT (or when viewing past dates), NOAA predictions are valid up to 22:00 UT on the following date. The most recent data can also be found at NOAA's 3-day Space Weather Predictions page.

Please contact Peter Gallagher if you have any comments or questions regarding this research.

IDL Access

Today's NOAA Active Regions
Group Number
McIntosh Class
Number of Spots
12420 N14W91
α/β Hax/Bxo 0030/0010 01/03 -
12422 S20W91
β/βγδ Dko/Fkc 0270/0480 05/11 M1.0(02:34)
12427 N18W35
βγ/β Dai/Cai 0180/0180 11/14 -
12426 N16W67
/ / / / -

Events not associated with currently named NOAA regions: /C1.7(08:15) C1.1(16:23)

Note: The tabulated data are based on the most recent NOAA/USAF Active Region Summary issued on 4-Oct-2015 00:30 UT , the values to the right of the forward slashes representing yesterdays values or events. Regions with no data in above property fields have decayed and exhibit no spots. The region positions are valid on 4-Oct-2015 08:35 UT .