Predicting the ISON experience ... 1/2 year in advance (yikes)

Key factors and the - geometrical - visibility conditions at 50°N

Including 3 brightness models fitting the present and making assumptions ...

Brightness predictions as of May 21 by JPL Horizons (data), the Minor Planet Center and for the BAA (data),
heliocentric & geocentric distances [au], solar elongation [°], phase angle [°], constellation,
lunar interference (rough; * = in best of several windows), altitude [°]in the morning
at the switch from night to astronomical / astronomical to nautical / nautical to civilian twilight and sunrise
and everything in reverse for the evening (all from JPL Horizons or Minor Planet Center)

Date(s) JPL MPC BAA r Delta Elong. Phase Const. Moon */A A/N N/C C/o o/C C/N N/A A/*
Aug. 1-10 13.8-13.5 13.2-12.9 13.0-12.7 2.6-2.5 3.6-3.5 12-18 5-7 Gem-Cnc none / /-3 5-10 10-16
Aug. 11-20 13.5-13.2 12.9-12.6 12.7-12.3 2.5-2.4 3.4-3.3 18-24 8-10 Cnc none /-2 4-9 11-16 16-21
Aug. 21-31 13.1-12.7 12.5-12.1 12.3-11.8 2.3-2.2 3.2-3.0 25-31 10-14 Cnc mod. 3-10 10-16 16-24 22-27
Sep. 1-10 12.7-12.2 12.1-11.6 11.7-11.3 2.2-2.0 3.0-2.7 32-37 14-17 Cnc none 11-15 17-22 24-29 28-33
Sep. 11-20 12.2-11.7 11.6-11.1 11.1-10.6 2.0-1.8 2.7-2.5 38-42 18-22 Cnc (none) 16-20 22-27 29-34 33-38
Sep. 21-30 11.6-11.1 11.0-10.5 10.6-10.0 1.8-1.7 2.4-2.2 43-47 22-27 Cnc-Leo (bad) 20-26 27-31 34-38 38-41
Oct. 1-10 11.0-10.3 10.4-9.7 9.8-9.1 1.7-1.5 2.2-1.9 47-51 27-32 Leo none 26-29 31-34 38-40 42-44
Oct. 11-20 10.2-9.4 9.6-8.8 9.0-8.0 1.4-1.3 1.9-1.6 51-53 32-39 Leo none-bad 29-30 34-35 40-41 44-44
Oct. 21-31 9.3-8.1 8.7-7.6 7.9-6.6 1.2-1.0 1.6-1.3 53-52 40-50 Leo bad-o.k. 31-28 35-33 41-38 44-41
Nov. 1-5 8.0-7.5 7.4-6.9 6.3-5.4 1.0-0.9 1.2-1.1 52-50 52-58 Leo none 28-24 32-31 38-34 40-38
Nov. 6-10 7.3-6.7 6.7-6.1 5.6-4.8 0.9-0.8 1.1-1.0 50-45 58-67 Vir none 23-21 30-25 33-30 37-33
Nov. 11-15 6.5-5.7 5.9-5.1 4.7-3.8 0.7-0.6 1.0-0.9 44-38 69-78 Vir none 19-12 23-18 29-22 31-26
Nov. 16-18 5.5-5.0 4.9-4.5 3.5-2.9 0.6-0.5 0.9 36-32 81-86 Vir bad 10-6 17-12 20-18 25-21
Nov. 19-21 4.8-4.2 4.2-3.6 2.6-1.9 0.5-0.4 0.9 30-25 89-95 Vir bad 6-2 10-5 16-11 18-14
Nov. 22-24 n.a. 3.3-2.5 1.5-0.6 0.4-0.3 0.9 23-17 98-104 Vir-Lib bad / 3-/ 9-4 12-9
Nov. 25 n.a. 2.0 -0.1 0.3 0.9 14 107 Lib (bad) / / 2 6
Nov. 26 n.a. 1.3 -0.9 0.2 0.9 11 109 Lib (bad) / / / 4
Nov. 27 n.a. 0.2 -2.2 0.1 0.9 8 110 Lib none / / / 1
Nov. 28 n.a. -1.8 -4.4 0.1 1.0 5 107 n.a. none
Nov. 29 n.a. -4.9 -11.8 0.0 1.0 2 108 Sco none / / / 0 2 / / /
Nov. 30 n.a. -0.7 -4.0 0.1 0.9 5 127 Sco none / / / 3 3 / / /
Dec. 1 n.a. 0.7 -2.1 0.2 0.9 8 128 Sco none / / 3 6 4 / / /
Dec. 2 n.a. 1.5 -1.0 0.2 0.8 11 127 Sco none / / 5 8 4 1 / /
Dec. 3 n.a. 2.0 -0.2 0.3 0.8 13 126 Sco none / / 7 11 5 1 / /
Dec. 4 n.a. 2.5 0.4 0.3 0.8 15 125 Oph none / 3 9 15 6 2 / /
Dec. 5 n.a. 2.8 0.8 0.4 0.7 18 123 Oph none / 5 11 17 6 3 / /
Dec. 6 3.8 3.1 1.2 0.4 0.7 20 122 Oph none 2 7 14 19 7 3 / /
Dec. 7 4.0 3.3 1.5 0.4 0.7 22 120 Ser none 4 11 16 22 8 4 / /
Dec. 8-10 4.1-4.5 3.5-3.8 1.8-2.3 0.5 0.7-0.6 25-30 119-116 Ser none 6-11 14-18 18-23 24-28 9-10 5-7 / /
Dec. 11-15 4.6-5.0 4.0-4.4 2.4-3.0 0.6-0.7 0.6-0.5 32-43 113-106 Ser none 13-23 20-30 27-37 31-41 11-16 8-12 1-5 /
Dec. 16-20 5.0-5.3 4.4-4.7 3.1-3.5 0.7-0.8 0.5 45-57 104-94 Her-CrB bad 25-38 33-43 40-50 43-56 18-24 14-20 7-14 1-8
Dec. 21-25 5.4-5.7 4.8-5.0 3.6-4.0 0.9-1.0 0.5-0.4 61-74 92-80 CrB-Her none* 41-50 46-55 53-62 59-69 26-34 22-29 16-25 11-21
Dec. 26-31 5.8-6.3 5.1-5.6 4.1-4.6 1.0-1.1 0.4 77-93 77-63 Her-Dra none* 52-56 57-59 64-63 70-66 36-45 31-42 28-39 24-37
Jan. 1-15 6.3-8.1 5.7-7.4 4.7-6.7 1.1-1.4 0.4-0.7 96-118 60-38 Dra-Cam none* 56-36 58-35 62-34 64-34 46-58 44-60 41-62 40-64
Jan. 16-31 8.1-9.7 7.5-9.1 6.8-8.5 1.4-1.7 0.7-1.1 118-115 37-31 Cam none* 34-20 34-19 33-18 33-18 59-66 60-71 63-75 65-80