Tuesday, September 28, 2010

Weekly Propagation Forecast Bulletins

Product: Weekly Highlights and Forecasts
:Issued: 2010 Sep 28 1921 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact: www.swpc.noaa.gov/weekly.html


# Weekly Highlights and Forecasts

Highlights of Solar and Geomagnetic Activity
20 - 26 September 2010


Solar activity was at very low to low levels during the period. Low levels occurred during 20 - 21 September while very low activity was observed during the remainder of the period. New Region 1109 (N22, L=067, class/area, Ehi/280 on 25 September) rotated onto the disk on
20 September and was responsible for 4 C-class events, the largest a C2.1 x-ray event at 20/1945 UTC. The region grew steadily in area, spot count and magnetic complexity through the summary period. Since the 20th, only B-class activity was observed from Region 1109.
Region 1108 (S30, L=136, class/area, Fko/380 on 20 September) decayed to a large H-type spot on 22 September, and was stable during the summary period. New Region 1110 (N19, L=085, class/area, Axx/10 on 26 September) emerged late in the forecast period and produced only low level B-class activity.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at normal to moderate levels throughout the period. Geomagnetic field activity was at mostly quiet levels during 20 - 23
September. Activity increased to quiet to unsettled levels, with high latitude active levels, beginning early on 24 September and lasting to the end of the period. The increase in activity was associated with a recurrent coronal hole high-speed stream (CH HSS).
Early on 23 September, density, temperature and velocity, as measured on the ACE spacecraft, all increased. These increases were associated with a co-rotating interaction region (CIR) in advance of a recurrent CH HSS. The interplanetary magnetic field (IMF) Bt intensity peaked at 13 nT at 23/1143 UTC, with periods of southward IMF Bz (maximum deflection of -8 nT at 24/0455 UTC) and increased velocities (from 285 km/s at 22/2150 UTC to 659 km/s at 25/0254 UTC). Activity decreased to predominantly quiet levels by midday on 25 September. Activity increased to quiet to unsettled levels on 26 September with isolated active periods observed at high latitudes.

Forecast of Solar and Geomagnetic Activity
29 September - 25 October 2010

Solar activity is expected to be at very low to low levels during the period. Low activity is expected during 29 September - 05 October with C-class flares likely from Region 1109. Activity is expected to decrease to very low levels during 05 - 25 October.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at normal to moderate levels during the period.

Geomagnetic field activity is expected to be at quiet levels on 27 September. Activity is expected to increase to quiet to unsettled levels on 28 - 29 September as a recurrent CH HSS affects the field. Activity is expected to decrease to mostly quiet levels on 30 September - 02 October. Activity is expected to increase to quiet to unsettled levels on 03 - 05 October as another recurrent CH HSS affects the field. Quiet levels are expected during 06 - 10 October. Activity is expected to increase to unsettled levels during 11 - 14 October due to recurrent solar sector boundary and CH HSS effects. Activity is expected to decrease to quiet levels during 15
- 20 October. Activity is expected to increase to quiet to unsettled levels on 21 - 22 October as another recurrent CH HSS begins to disturb the field. Mostly quiet levels are expected for the
remainder of the forecast period.

Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2010 Sep 28 1923 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact: www.swpc.noaa.gov/wwire.html
# 27-day Space Weather Outlook Table

# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2010 Sep 29 84 8 3
2010 Sep 30 84 5 2
2010 Oct 01 83 5 2
2010 Oct 02 83 5 2
2010 Oct 03 82 7 2
2010 Oct 04 82 7 2
2010 Oct 05 80 7 2
2010 Oct 06 78 5 2
2010 Oct 07 76 5 2
2010 Oct 08 76 5 2
2010 Oct 09 76 5 2
2010 Oct 10 75 5 2
2010 Oct 11 75 8 3
2010 Oct 12 75 8 3
2010 Oct 13 76 8 3
2010 Oct 14 76 8 3
2010 Oct 15 76 5 2
2010 Oct 16 77 5 2
2010 Oct 17 77 5 2
2010 Oct 18 78 5 2
2010 Oct 19 80 5 2
2010 Oct 20 81 5 2
2010 Oct 21 82 8 3
2010 Oct 22 82 8 3
2010 Oct 23 82 5 2
2010 Oct 24 82 8 3
2010 Oct 25 82 8 3
(NOAA)