Monday, April 22, 2013

Weekly Propagation Forecast Bulletins



Product: Weekly Highlights and Forecasts
:Issued: 2013 Apr 22 0431 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 15 - 21 April 2013

Solar activity was at low levels during the period. The first half of the period (15 - 18 April) was dominated with mostly low-level C-class activity from Regions 1719 (N11, L=077, class/area Eki/290 on 12 April) and 1723 (S18, L=001, lass/area Dai/200 on 17 April). The largest event during this time frame was a long duration C6 at 18/1823 UTC from Region 1719. Associated with the event was a Type II signature with an estimated plane-of-sky speed of 1273 km/s and a coronal mass ejection (CME) observed off the west limb. The remainder of the period (19 - 21 April) witnessed the rapid emergence on the disk of Region 1726 (N12, L=326, class/area Ekc/260 on 21 April). During this time frame, Region 1726 produced a total of 20 C-class flares. The largest flare was a C4/Sf at 21/1838 UTC. At the time of this report, Region 1726 was continuing its growth phase and maintaining its complex beta-gamma-delta magnetic configuration. 

No proton events were observed at geosynchronous orbit. However, the greater than 10 MeV proton flux increased slightly above background levels beginning at about 21/1005 UTC and peaked at about 3 pfu at 21/1640 UTC. The enhancement was likely triggered by activity beyond the west limb from old Region 1719 (N11, L=077). 

The greater than 2 MeV electron flux at geosynchronous orbit was at normal to moderate levels. 

Geomagnetic field activity was at predominately quiet levels with an isolated unsettled reading observed during the period 15/1800 - 2100 UTC. The period began under the waning influence of a weak CME. Solar wind speeds were at mostly nominal levels, beginning the period near 450 km/s and exhibited a steady decline to end the period at about 285 km/s. Total interplanetary magnetic field (IMF)
readings ranged from a high of 12 nT early on 15 April, declined to 4 nT by early on 16 April and varied between 4 - 6 nT for the remainder of the period. The Bz component of the IMF ranged from +11 nT early on 15 April and declined to about +5 nT by midday on 15 April. Through the remainder of the period, Bz did not vary much beyond +/-4 nT. The Phi angle was in a negative (toward) orientation through early on 16 April and switched to a predominately positive (away) orientation  through about 20/1900 UTC when it became variable through the remainder of the period. 

Forecast of Solar and Geomagnetic Activity 22 April - 18 May 2013

Solar activity is expected to be at predominately low levels through the outlook period. A chance for M-class activity and a slight chance for x-class activity exists due to active regions that currently populate the visible disk and active regions due to rotate onto the disk throughout the outlook period. 

A slight chance for a 10 MeV proton event at geosynchronous orbit is possible due to active regions that currently populate the visible disk and active regions due to rotate onto the disk throughout the outlook period. 

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at moderate to high levels from 24 April - 02 May in the wake of a coronal hole high speed stream (CH HSS). Normal to moderate levels will predominate from 03 - 18 May. 

Geomagnetic field activity is expected to be at quiet to unsettled levels on 22 April in response to a possible glancing blow from the 18 April CME. Mostly unsettled to active levels with isolated minor storm periods are possible from 23 - 26 April due to recurrent (CH HSS) effects. Predominately quiet levels are expected from 27 April - 18 May. 

Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2013 Apr 22 0431 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC website: www.swpc.noaa.gov/wwire.html
#
#      27-day Space Weather Outlook Table
#                Issued 2013-04-22
#
#   UTC      Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
2013 Apr 22     110           8          3
2013 Apr 23     120          12          4
2013 Apr 24     115          12          4
2013 Apr 25     120          15          4
2013 Apr 26     110          12          4
2013 Apr 27     110           5          2
2013 Apr 28     110           5          2
2013 Apr 29     115           5          2
2013 Apr 30     115           5          2
2013 May 01     120           5          2
2013 May 02     125           5          2
2013 May 03     125           5          2
2013 May 04     125           5          2
2013 May 05     125           5          2
2013 May 06     120           5          2
2013 May 07     115           5          2
2013 May 08     115           5          2
2013 May 09     120           5          2
2013 May 10     120           5          2
2013 May 11     120           5          2
2013 May 12     115           5          2
2013 May 13     115           5          2
2013 May 14     110           5          2
2013 May 15     110           5          2
2013 May 16     105           5          2
2013 May 17     105           5          2
2013 May 18     105           5          2
(NOAA)