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26 September 2011
20110925 Week Rotation Today Rotation Week 20110927

7 Active Regions

Flare Forecast

Coronal Holes
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
11295 Hsx 4(15) 1(1) 0(1)
11301 Esi 49(35) 5(5) 0(1)
11302 Ekc 54(90) 41(70) 13(35)
11303 Cso 12(75) 2(50) 0(10)
11304 Bxo 5(15) 1(1) 0(1)
11305 Hsx 4(15) 1(1) 0(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.

Today's/Yesterday's NOAA Active Regions
NOAA Number
McIntosh Class
Sunspot Area
Number of Spots
11295 N25W91
αγδ/βγ Hsx/Ekc 0180/0500 01/07 -
11301 N18W27
βγδ/βγ Esi/Fso 0090/0090 18/16 -
11302 N12E22
βγδ/βγδ Ekc/Fkc 0980/1300 18/12 C4.8(16:43)
/ M2.2(16:51)
11303 S28W91
βγδ/βγδ Cso/Csi 0070/0030 06/01 - / M1.5(09:25)
11304 N12W07
βγδ/βγδ Bxo/Bxo 0020/0010 04/02 -
11305 N12E56
αγδ/αγδ Hsx/Hsx 0060/0060 01/01 -
11306 N13E60
αγδ/- Hsx/--- 0030/---- 01/-- -

Class (HH:MM) -Today
Class (HH:MM) -Yesterday

Events not associated with currently named NOAA regions: C1.8(20:04) C8.6(22:14) C8.6(22:29) M4.4(02:27)

Note: The tabulated data are based on the most recent NOAA/USAF Active Region Summary issued on 26-Sep-2011 00:30 UT . The greyed out and light-blue entries are values from the previous day. Slashed cells indicate that the active region has no spots. The latest positions of the active regions are given in both heliographic and heliocentric co-ordinates. The region positions are valid on 26-Sep-2011 21:30 UT .