Product: Weekly Highlights and Forecasts
:Issued: 2011 Apr 12 1823 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 04 - 10 April 2011
Solar activity was low. Three C-class events were observed on 06 and 07 April from the East Limb. On 08 April, Region 1185 (N23, L=033, class/area Cso/100 on 05 April) was redefined as two distinct groups, the second of which was designated Region 1189 (N23, L=033, class/area Dso/040 on 08 April). Six regions, numbered 1184 through 1189, populated the visible disk by the end of the period. Of those, Region 1184 (N17, L=110, class/area Dso/170 on 04 April) was the largest. The remaining regions were small B or C type groups with simple Beta magnetic characteristics. While x-ray activity was low, several CMEs were observed during the period. The first CME launched at 02/2347 UTC from Region 1176 (S15, L=200, class/area Eko/490 on 23 March). Additional CMEs were observed on 04 April, including one from the northeast limb at 04/0509 UTC associated with a long duration B-class flare. Two more CMEs were observed on 07 April. The first originated from an active filament channel on the southeast limb and was observed in SOHO/LASCO C3 imagery at 07/0754 UTC. The second, seen at 07/1042 UTC, was thought to originate from old Region 1176 which had rotated around the west limb on 04 April. Finally, a slow partial halo CME was observed in SOHO/LASCO C2 imagery at 09/0024UTC.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at high levels from 04 - 06 April. Moderate levels were observed throughout the rest of the period.
Geomagnetic field activity ranged from quiet to major storm levels. The period began at unsettled to active levels in the midst of a coronal hole high speed stream (CH HSS). The CME observed at 02/2347 UTC arrived at the ACE spacecraft at approximately 06/0854 UTC. A sudden impulse of 24 nT was observed at Boulder at 06/0942 UTC.
Solar wind speeds at ACE jumped from 494 to 559 km/s, then climbed to a peak of 591 km/s at 06/1700 UTC. The Interplanetary Magnetic Field (IMF Bt) initially rose from +07 to +14 nT following the shock and peaked at +17 nT at 06/1030 UTC. The IMF Bz turned southward following shock passage and remained mostly southward until approximately 06/2000 UTC. A maximum southward deflection of -11 nT was observed at 06/1213 UTC. The geomagnetic field was at quiet to unsettled levels in the days prior to the CME arrival (04 - 06 April).
Activity increased to unsettled to major storm levels once the CME arrived. Active to minor storm levels were recorded at Boulder and minor to major storm levels detected at high latitudes. Activity decreased to mostly unsettled levels after 06/1800 UTC as Bt decreased and Bz became variable at +03 to -03 nT. Geomagnetic activity returned to quiet to unsettled levels for the remainder of the week.
Forecast of Solar and Geomagnetic Activity 13 April - 09 May 2011
Solar activity is expected to be at predominantly low levels for the entire period, with a slight chance for an M-class event when old Region 1176 returns on 17 April.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to begin the period at high levels following the increased windspeeds associated with the CH HSS. A return to normal to moderate levels is expected from 17 April until 01 May. High levels are expected to return from 02 - 05 May following a second CH HSS. Normal to moderate levels are expected for the remainder of the period.
Geomagnetic field activity is expected to be at predominantly quiet levels from 12 April until a CH HSS arrives on 17 April. Three days of unsettled to active conditions are anticipated, with a return to mostly quiet conditions on 20 April. Quiet to unsettled conditions with isolated active and minor storm periods are expected from 28 April - 01 May due to a second recurrent CH HSS becoming geoeffective. Quiet conditions are expected to return and persist until 07 May. Unsettled to active conditions with a chance for isolated minor storm periods are expected from 08 - 09 May as a third CH HSS rotates into a geoeffective position.
Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2011 Apr 12 1823 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web www.swpc.noaa.gov/wwire.html
#
# 27-day Space Weather Outlook Table
# Issued 2011-04-12
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2011 Apr 13 100 5 2
2011 Apr 14 105 5 2
2011 Apr 15 110 5 2
2011 Apr 16 110 5 2
2011 Apr 17 110 7 2
2011 Apr 18 110 7 2
2011 Apr 19 105 7 2
2011 Apr 20 105 5 2
2011 Apr 21 110 5 2
2011 Apr 22 115 5 2
2011 Apr 23 115 5 2
2011 Apr 24 120 5 2
2011 Apr 25 120 5 2
2011 Apr 26 120 5 2
2011 Apr 27 115 5 2
2011 Apr 28 110 7 2
2011 Apr 29 110 15 3
2011 Apr 30 115 12 3
2011 May 01 115 8 3
2011 May 02 120 5 2
2011 May 03 120 5 2
2011 May 04 120 5 2
2011 May 05 110 5 2
2011 May 06 105 5 2
2011 May 07 105 5 2
2011 May 08 105 8 3
2011 May 09 100 15 3
(NOAA)
