Daily Report

(last updated 15 Apr 2021 23:30 UT)

SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT ISSUED AT 2330UT/15 APRIL 2021 BY Space Weather Services FROM THE AUSTRALIAN SPACE FORECAST CENTRE SUMMARY FOR 15 APRIL AND FORECAST FOR 16 APRIL - 18 APRIL STATUS INDICATORS SOL:GREEN MAG:** YELLOW ** ION: GREEN ----------------------------------------------------------- 1A. SOLAR SUMMARY Activity 15 Apr: Very low Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 15 Apr: 72/8 1B. SOLAR FORECAST 16 Apr 17 Apr 18 Apr Activity Very low to low Very low to low Very low to low Fadeouts None expected None expected None expected 10.7cm/SSN 74/11 74/11 74/11 COMMENT: Solar activity was very low on UT day 15 April. There are currently three spotted regions on the visible disk, AR 2814(S24W32) and two new as yet unnumbered spot groups. Solar activity is expected to be very low to low for the next three days, 16-18 April. No Earth directed CMEs were observed in the available images up to 15/1645UT. On 15 April, a brief transient was observed in solar wind parameters. The total IMF (Bt) was initially weak, below 5nT but increased after 15/04UT to 10 nT while Bz deflected south up to -7 nT between 15/04-06UT. The origin of this disturbance is possibly related to a slow faint CME on 10 April. The solar wind speed remained under 400 km/s. The solar wind speed is expected to be enhanced over the next three days 16-18 April due to coronal hole effects. ----------------------------------------------------------- 2A. MAGNETIC SUMMARY Geomagnetic field for Australian Region 15 Apr: Quiet to Active Estimated Indices 15 Apr : A K Australian Region 9 23412211 Cocos Island 7 23312210 Darwin 9 23412211 Townsville 9 23422211 Learmonth 12 33512211 Alice Springs 9 23412211 Gingin 9 33412110 Canberra 7 23412100 Hobart 7 23411100 Estimated Antarctic Regional K Indices 15 Apr : Macquarie Island 7 22500000 Casey 12 34511100 Mawson 20 53622100 Observed Regional daily pc3 Indices 15 Apr : Darwin 0 (Quiet) Townsville 0 (Quiet) Learmonth 0 (Quiet) Alice Springs 0 (Quiet) Gingin 0 (Quiet) Canberra 0 (Quiet) Melbourne NA Pc3 pulsations are high frequency (10-45 second period) variations of the Earths magnetic field. Daily pc3-indices are the daily sum of 20 minute pc3-indices for that station and have been shown to be well correlated with rejection of high resolution aeromagnetic survey flight-line data. NOTE: Indices may have been generated from data obtained in cooperation with the following organisations: Geoscience Australia, University of Newcastle Space Physics Group, Australian Government Antarctic Division and International Center for Space Weather Science and Education, Japan. Estimated AFr/Ap Indices 15 Apr : A Fredericksburg 12 Planetary 15 Observed AFr/Ap Indices 14 Apr : A K Fredericksburg 7 Planetary 6 1101 1223 2B. MAGNETIC FORECAST Date Ap Conditions 16 Apr 20 Quiet to active with a possible minor storm period. 17 Apr 20 Quiet to active with a possible minor storm period. 18 Apr 15 Quiet to active. COMMENT: SWS Geomagnetic Warning 13 was issued on 14 April and is current for 16 Apr only. Quiet to active geomagnetic conditions were observed in the Australian region on UT day 15 April. The active period was associated with the southward Bz between 15/04-06 UT. Storm levels were briefly observed in the Antarctic region. Geomagnetic activity is expected to increase to Active levels with a chance of an isolated minor storm period from late 16 April due to coronal hole effects. ----------------------------------------------------------- 3A. GLOBAL HF PROPAGATION SUMMARY Latitude Band Date Low Middle High 15 Apr Normal Normal Normal PCA Event : No event. 3B. GLOBAL HF PROPAGATION FORECAST Latitude Band Date Low Middle High 16 Apr Normal Normal-fair Normal-fair 17 Apr Normal Fair Fair 18 Apr Normal Fair-normal Fair COMMENT: Mildly degraded conditions may be observed on 17-18 April. ----------------------------------------------------------- 4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY Date T index 15 Apr 17 Observed Australian Regional MUFs Cocos Island Region: No data available. Niue Island Region: No data available. Northern Australian Region: Near predicted monthly values. Southern Australian Region: Near predicted monthly values. Antarctic Region (Casey/Scott Base/Davis/Mawson): Near predicted monthly values over the UT day. Monthly T index: Month T index Mar 9 Apr 19 May 23 4B. AUSTRALIAN REGION IONOSPHERIC FORECAST Date T index MUFs 16 Apr 10 Near predicted monthly values 17 Apr 0 Near predicted monthly values/depressed 10 to 30% 18 Apr 0 Near predicted monthly values/depressed 10 to 30% COMMENT: MUFs over the Australian regions were mostly near predicted monthly levels on UT day 15 April. Mild to moderate MUFs depressions may be observed on 17-18 April due to anticipated increase in geomagnetic activity. ----------------------------------------------------------- 5. SPACE ENVIRONMENT SUMMARY GOES satellite data for 14 Apr Daily Proton Fluence >1 MeV: 7.2E+04 Daily Proton Fluence >10 MeV: 4.3E+04 Daily Electron Fluence >2 MeV: 1.10E+06 (normal fluence) Electron Fluence Daily Deep Dielectric Discharge Probability: 1% Fluence (flux accumulation over 24hrs)/ cm2-ster-day. X-ray background: A3.7 DSCOVR Satellite Solar Wind Day Averaged Data for 14 Apr Speed: 403 km/sec Density: 6.7 p/cc Temp: 104000 K Bz: 2 nT (Courtesy Space Weather Prediction Center, Boulder USA) -----------------------------------------------------------