Monday, February 24, 2014

Weekly Propagation Forecast Bulletins



Product: Weekly Highlights and Forecasts
:Issued: 2014 Feb 24 0820 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 17 - 23 February 2014

Solar activity reached moderate levels with two M-class flares observed during the week. An M3/Sn was observed on 20 Feb at 0756 UTC from Region 1976 (S15, L=320, class/area=Cho/270 on 18 February). A Type II radio sweep (estimated shock velocity 915 km/s), a Tenflare (420 sfu), and an asymmetric full-halo coronal
mass ejection (CME) were observed with this event. Most of the ejecta with this cornal mass ejection (CME) appeared to be directed westward with a minor Earthward component. On the same day, Region 1982 (S10, L=207, class/area=Ekc/570) produced a C3/Sf flare at 20/0335 UTC associated with a Type II radio sweep (estimated shock velocity 1432 km/s), a Type IV radio sweep, and an asymmetric full-halo CME with most of the ejected directed eastward with a minor Earthward component. Region 1982 was the largest region on the disk during the week, the most magnetically complex (beta-gamma), and the most productive. It was responsible for 11 C-class events and 30 optical flares. 

Old Region 1967 (S12, L=12) was responsible for a C7 flare at 22/1550 UTC and was at least partially responsible for a long-duration M1 flare at 23/0610 UTC. During the M-flare, GOES-15 SXI imagery suggested that old Regions 1967 and 1977 (S10, L=294)flared simultaneously. Subsequent SOHO LASCO C2 coronagraph imagery
showed coronal mass ejections (CMEs) from both region locations with the larger of the two coming from behind the west limb. Throughout the week, old Region 1967 was the source of many CMEs while behind the east limb. 

In addition to the CMEs associated with the flares, a 45-degree filament erupted from the southeast quadrant during 18/0015 - 0158 UTC associated with an Earth-directed, asymmetric, full-halo coronal mass ejection (CME). Analysis of coronagraph imagery suggested the ejecta was moving at 695 km/s, with most directed southward. 

The greater than 10 MeV proton flux at geosynchronous orbit reached the S1 (Minor) threshold at 20/0850 UTC, reached a peak of 22 pfu at 20/0925 UTC, and dropped below the S1 event threshold at 20/1125 UTC as a result of the M3/Sn flare at 20/0756 UTC from Region 1976. 

The greater than 2 MeV electron flux at geosynchronous orbit reached high levels on 20/0906 UTC and again on 21/1700 UTC. High levels were subsequently observed again on the 22nd and 23rd. Peak flux during the week was 2780 pfu observed on 23/1455 UTC. 

Geomagnetic field activity reached major storm levels as successive coronal mass ejections battered the magnetosphere during the past week and produced the most extended period of planetary major storm conditions since June 29, 2013. ACE data indicated the arrival of a CME at approximately 19/0309 UTC, likely associated with a faint full-halo CME on Feb 16. Wind speed jumped from about 380 to 500
km/s with the arrival and remained elevated for the rest of the period (peak 546 km/s at 19/1747 UTC). IMF Bt (total field intensity) increased from 8 to 15 nT with the CME arrival and remained enhanced for the rest of the day (peak 18 nT at 19/0658 UTC), with a gradual decrease after approximately 19/1500 UTC. The
Bz component of the IMF was southward at around -8 nT prior to the arrival, then became further southward following the arrival (maximum reading of -15 nT at 19/0358 UTC). IMF Bz remained southward until approximately 19/0830 UTC, then became variable until approximately 19/1300 UTC, followed by mostly northward Bz conditions. IMF Phi data indicated a variable solar-sector orientation during the period. EPAM data showed a gradual increase during the latter half of the day, likely indicating the approach of the CME observed on Feb 18. In response to the arrival of the CME, the magnetic field reached major storm conditions during 19/0300 - 1500 UTC, with severe storm levels detected at high latitudes. Activity decreased to quiet to unsettled levels after 19/1500 UTC. 

A second shock arrived at approximately 20/0251 UTC, most likely associated with the filament eruption on 18 Feb. Solar wind speed at the ACE spacecraft jumped from about 500 to 640 km/s and was accompanied by a 6 nT increase in IMF Bt, and a southward turn of the Bz component of the IMF (minimum -14 nT at 20/0507 UTC). Wind speed peaked at 743 km/s at 20/0440 UTC with this CME passage, followed by a gradual decrease to about 500 km/s by the end of the period. A geomagnetic sudden impulse was observed at 20/0329 UTC (31nT, Boulder USGS magnetometer) associated with the CMEs arrival at Earth. Major storm levels prevailed from 03-12Z, followed by a minor storm period. Severe storm cinditons were recorded at some
high-latitude stations. 

Finally, the 20 Feb CME likely arrived around 23/0230 UTC. Solar wind speed was initially steady in the 420 - 440 km/s range and increased to around 520 km/s during transient passage. Total field strength values were steady near 5 nT and began a slow rise to 11 nT during CME passage while the Bz component remained predominately north throughout the period. The phi angle began the period in a negative (toward) sector and underwent minor rotation and variability to a positive (away) sector during transient passage. The CME arrival produced unsettled to active geomagnetic conditions with minor to major storm conditions for half the day at high latitudes. 

Forecast of Solar and Geomagnetic Activity 24 February - 22 March 2014

Solar activity is expected to be at low to moderate levels, with high levels of activity likely through 16 March, with the return of Old Regions 1967 (S13, L=112) at the beginning of the period, and 1974 (S12, L=354) after 03 March. STEREO EUVI imagery suggests these regions have maintained their levels of activity. 

No proton events are expected at geosynchronous orbit, however, the threat will increase during the transit of Old Region 1974, particularly after 09 March. 

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at normal to moderate levels for most of the forecast period. High flux levels are anticipated on 09-10 March in response to a coronal hole high speed stream. 

Geomagnetic field activity is expected to be at quiet to unsettled levels in the absence of any transient activity. There is a chance for active conditions 28 Feb-01 March in response to a positive polarity coronal hole high speed stream. A slight chance of active levels exists on 09 March in response to another high speed stream. 

Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2014 Feb 24 0820 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 2014-02-24
#
#   UTC      Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
2014 Feb 24     175          10          3
2014 Feb 25     175           8          3
2014 Feb 26     175           5          2
2014 Feb 27     180           5          2
2014 Feb 28     175          15          3
2014 Mar 01     170          15          3
2014 Mar 02     165           5          2
2014 Mar 03     170           5          2
2014 Mar 04     175           5          2
2014 Mar 05     175           5          2
2014 Mar 06     180           5          2
2014 Mar 07     180           5          2
2014 Mar 08     180           5          2
2014 Mar 09     180          10          3
2014 Mar 10     175           5          2
2014 Mar 11     160           8          3
2014 Mar 12     145           5          2
2014 Mar 13     145           5          2
2014 Mar 14     150           5          2
2014 Mar 15     150           5          2
2014 Mar 16     150           5          2
2014 Mar 17     150           5          2
2014 Mar 18     155           5          2
2014 Mar 19     155           5          2
2014 Mar 20     155           5          2
2014 Mar 21     160           5          2
2014 Mar 22     165           5          2
(NOAA)