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Thursday, July 18, 2013

Weekly propagation forecast bulletins


Product: Weekly Highlights and Forecasts
:Issued: 2013 Jul 15 0430 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 08 - 14 July 2013

Solar activity was low. The largest flare of the period was a C9/Sf at 08/0122 UTC from Region 1785 (S09, L=7, class/area=Ekc/570 on 08 July). This region was responsible for the majority of the C-class flares during the period. Region 1787 (S15, L=348, class/area=Eai/230 on 09 July) was the second most prolific flare producer and is credited with a C4/1n flare at 10/0643 UTC. The remaining regions were relatively small and inactive. A 12-degree filament occurred at 09/1400 UTC resulting in an Earth-directed coronal mass ejection (CME) with an estimated  speed of 400 km/s. Another slow-moving CME with a potential Earth-directed component was observed at 12/1824 UTC, however, the quality of available coronagraph imagery prevented meaningful analysis. The remainder of the week was devoid of potentially geoeffective events. 

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit reached high levels on 10 - 14 July and was at moderate levels before that. A peak flux value of 22,500 pfu was reported on 12 July at 1850 UTC. 

Geomagnetic field activity ranged from quiet to minor (NOAA Scale G1) geomagnetic storm conditions during the week. An Earth-directed CME which left the Sun on 06 July arrived at the ACE spacecraft at approximately 09/1958 UTC. A 25 nT sudden impulse was subsequently recorded at the Fredericksburg magnetometer at 09/2049 UTC. By 09/2359 UTC, the geomagnetic field had reached active levels, and by
10/0257 UTC, minor (NOAA Scale G1) geomagnetic storm conditions were observed. Minor (G1) storm conditions prevailed for two periods, after which, active to unsettled conditions were observed. The College magnetometer (high latitude) reported major (NOAA Scale G2) geomagnetic storm levels. The following day, there was an isolated minor (G1) storm period nestled among otherwise quiet to active conditions. By 12 July, the field had returned to mostly quiet levels when a co-rotating interaction region (CIR) ahead of a small negative polarity coronal hole high speed stream (CH HSS) arrived. By 13 July, the diffuse remnants of the CME from 09 July had arrived, bringing Bt values at the ACE spacecraft to 17 nT. Bz remained positive for the majority of 13 July, so, with the exception of a single active period, the geomagnetic field was at quiet to unsettled levels. Active conditions returned on 14 July, after an extended period of southward Bz, reaching about -10 nT.  Minor (G1) to Major (G2) storm levels were observed at high latitude. 

Forecast of Solar and Geomagnetic Activity 15 July - 10 August 2013

Solar activity is expected to remain low with a slight chance for isolated low (R1) radio blackouts throughout the 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 levels from 20 July through the end of the month due to a coronal hole high speed stream (CH HSS). 

Geomagnetic field activity is expected to be at active to minor (G1) storm conditions early on 15 July due to transient passage, decreasing back to quiet to unsettled levels with a chance for active conditions for the remainder of 25 July. Generally quiet to unsettled conditions are expected to persist until 17 - 21 July, when a recurrent CH HSS is expected to bring unsettled to active
conditions with a chance for minor (G1) storm conditions. Generally quiet to unsettled conditions are once again expected until 25 - 27 July, when another recurrent CH HSS is expected to bring active to minor (G1) storm conditions with a chance for major (G2) storm conditions. 


Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2013 Jul 15 0430 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/wwire.html
#
#      27-day Space Weather Outlook Table
#                Issued 2013-07-15
#
#   UTC      Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
2013 Jul 15     125          12          3
2013 Jul 16     120           8          3
2013 Jul 17     120          10          3
2013 Jul 18     125          15          4
2013 Jul 19     125          15          4
2013 Jul 20     125          15          4
2013 Jul 21     120          15          4
2013 Jul 22     110           8          3
2013 Jul 23     105           5          2
2013 Jul 24     100           5          2
2013 Jul 25     100          18          4
2013 Jul 26     105          30          5
2013 Jul 27     110          10          3
2013 Jul 28     110           5          2
2013 Jul 29     120           5          2
2013 Jul 30     125           5          2
2013 Jul 31     130           5          2
2013 Aug 01     135           5          2
2013 Aug 02     135           5          2
2013 Aug 03     130           5          2
2013 Aug 04     125           5          2
2013 Aug 05     125           5          2
2013 Aug 06     125           5          2
2013 Aug 07     125           5          2
2013 Aug 08     125           5          2
2013 Aug 09     120           8          3
2013 Aug 10     120           5          2
(NOAA)