Wednesday, July 03, 2013

Weekly Propagation Forecast Bulletin


Product: Weekly Highlights and Forecasts
:Issued: 2013 Jul 01 0420 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 24 - 30 June 2013

Solar activity was at low levels during the period. Numerous low-level C-class activity was recorded from a variety of regions, the largest a C9/1n at 24/1132 UTC from Region 1778 (S16, L=129, class/area Hsx/110 on 22 June). The largest region on the disk, Region 1775 (S26, L=223, class/area Dkc/410 on 18 June) was responsible for a few low-level C-class flares. Numerous filament eruptions were recorded during the period with possibly three observed to have Earth-directed CME components. The first Earth-directed eruption occurred during 24/1104 - 1204 UTC when a 15 degree long filament, centered near S14W26, erupted. The second Earth-directed eruption occurred during 28/0129 - 0250 UTC associated with a C4/Sf parallel-ribbon flare at 28/0159 UTC from Region 1777 (S15, L=162, class/area Cso/200 on 22 June). ENLIL model analysis suggested a possible weak impact from the resultant CME late on 30 June to early on 01 July. The third Earth-directed CME occurred during 29/0921 - 2342 UTC when a 16 degree long filament, centered near S17W22, erupted. ENLIL model analysis suggested a possible glancing blow from the resultant CME mid to late on 04 July. 

A greater than 10 MeV proton event at geosunchronous orbit was observed during the period. In response to an M2 flare observed on 21 June, protons became enhanced at approximately 21/1600 UTC. At 23/2010 UTC, flux levels exceeded the 10 pfu threshold, reached a maximum of 14 pfu at 24/0520 UTC and ended at 24/0850 UTC. 

The greater than 2 MeV electron flux at geosynchronous orbit was at high levels from 24 - 28 June, reaching a maximum flux of 17,678 at 27/1640 UTC. Electron flux levels decayed to moderate levels on 29 - 30 June. 

Geomagnetic field activity was at quiet to severe storm levels. The period began with quiet to active levels from 24 June to early on 25 June due to waning effects from a coronal hole high speed stream (CH HSS). During this period, solar wind speeds averaged about 550 km/s with total field (Bt) measurements in the 4 to 6 nT range and the Bz component mostly negative to -6 nT. Through midday on 27 June, wind speeds gradually decreased to about 375 km/s, Bt relaxed to about
2-3 nT while Bz was mostly neutral. The geomagnetic field responded with quiet to isolated unsettled levels. At 27/1353 UTC, wind speeds increased sharply from about 380 km/s to 460 km/s for a short period and then gradually declined to about 350 km/s through early on 29 June. Bt increased to 8 nT while the Bz component ranged from -5 to -7 nT. This discontinuity at the ACE satellite was possibly due to effects from the 24 June CME. A 44 nT sudden impulse was recorded at the Hartland magnetometer at 27/1440 UTC. The geomagnetic field responded with quiet to active conditions which persisted through early on 28 June. This was followed by a short interval of quiet levels through midday on 28 June. At about 28/0800 UTC, the Bz component began a slow, negative dive reaching a maximum of -12 nT at 27/1905 UTC. It remained between -10 nT to -12 nT through about 29/1100 UTC. Bt reached a maximum of 13 nT during this time frame. Through the remainder of the period, Bz generally indicated fluctuations of +/- 5 nT. By about 29/0400 UTC, solar wind began a gradual increase from 350 km/s to end the period near 500 km/s. From midday on 28 June through 29 June, the geomagnetic field responded  with unsettled to severe storm conditions. Indications are that this activity was a result of the 28 June slow-moving transient coupled with a corotating interaction region in advance of a recurrent, positive CH HSS. Additional indications of a transition from a transient feature to the CH HSS was a change in the Phi orientation from negative (toward) to positive (away) late on 28 June coupled with increases in temperature and density. By 30 June, the geomagnetic field had relaxed to quiet to unsettled conditions. Finally, a 24 nT shock passage was observed at the Hartland magnetometer at 30/1125 UTC, likely an indication of the arrival of the expected CME that erupted on 28 June. 

Forecast of Solar and Geomagnetic Activity 01 July - 27 July 2013

Solar activity is expected to be at predominately low levels with a slight chance for M-class activity through the outlook period. 

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at high to very high levels from 01 - 06 July, at normal to moderate levels from 07 - 19 July and high to very levels from 20 - 27 July. 

Geomagnetic field activity is expected to be unsettled to active levels due to combined effects from a positive CH HSS and effects from the 29 June CME. Predominately quiet conditions are expected from 06 - 16 July. Unsettled to active conditions are expected from 17 - 21 July as a recurrent, negative CH HSS rotated into a geoeffective position. Mostly quiet conditions are expected from 22 - 27 July. 

Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2013 Jul 01 0421 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
#                Issued 2013-07-01
#
#   UTC      Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
2013 Jul 01     110           8          3
2013 Jul 02     110           5          2
2013 Jul 03     105          10          3
2013 Jul 04     100          15          3
2013 Jul 05     100           7          2
2013 Jul 06      95           5          2
2013 Jul 07     100           5          2
2013 Jul 08     110           5          2
2013 Jul 09     115           5          2
2013 Jul 10     115           5          2
2013 Jul 11     120           5          2
2013 Jul 12     120           5          2
2013 Jul 13     120           5          2
2013 Jul 14     125           5          2
2013 Jul 15     125           5          2
2013 Jul 16     125           5          2
2013 Jul 17     130          10          3
2013 Jul 18     130          15          4
2013 Jul 19     130          15          4
2013 Jul 20     120          15          4
2013 Jul 21     115          18          4
2013 Jul 22     110           5          2
2013 Jul 23     110           5          2
2013 Jul 24     105           5          2
2013 Jul 25     105           5          2
2013 Jul 26     100           5          2
2013 Jul 27     100          10          3
(NOAA)