Daily Report

(last updated 18 Mar 2025 23:30 UT)

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT ISSUED AT 2330UT/18 MARCH 2025 FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE SUMMARY FOR 18 MARCH AND FORECAST FOR 19 MARCH - 21 MARCH STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx ----------------------------------------------------------- 1A. SOLAR SUMMARY Activity 18 Mar: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Mar: 184/137 1B. SOLAR FORECAST 19 Mar 20 Mar 21 Mar Activity R0-R1 R0-R1 R0-R1 Fadeouts Possible Possible Possible 10.7cm/SSN 185/138 185/138 190/143 COMMENT: Solar activity on UT day 18-Mar was at the R0 level, with several low C-class flares. There are currently twelve numbered active regions on the visible solar disk and one unnumbered region. AR4022 (N08W46, beta), AR4031 (N17W22, beta-gamma) and AR4034 (S17E39, beta-gamma). There are no significantly flare-active regions on the solar disk. An unnumbered region has recently rotated onto the solar disk at around N15E65 with beta magnetic characteristics. All other regions were either stable or in decay. Solar activity is expected to be at R0-R1 levels over 19-21 Mar. S0 solar radiation storm conditions were observed on UT day 18-Mar. S0 solar radiation storm conditions are expected over 19-21 Mar. No geoeffective CMEs were observed on 18-Mar. Solar wind speed increased on 18-Mar, with a decline at the end of the day. The wind speed mostly ranged between 350 km/s and 575 km/s. The current wind speed is around 380 km/s. The peak total interplanetary field strength (IMF, Bt) was 12 nT and the north-south IMF component range was +6 to -10 nT. The solar wind environment is expected to be near background levels on 19-Mar. An increase in speed is possible early on 20-Mar due to the arrival of a CME first observed on 16-Mar. Elevated solar wind speeds are possible on 21-Mar. ----------------------------------------------------------- 2A. MAGNETIC SUMMARY Geomagnetic field for Australian Region 18 Mar: G0 Estimated Indices 18 Mar : A K Australian Region 7 22223212 Cocos Island 6 22213210 Darwin 5 21222202 Townsville 7 21223212 Learmonth 8 31223212 Alice Springs 7 22223202 Gingin 8 31223212 Canberra 7 22223221 Kennaook Cape Grim 7 22223212 Hobart 7 22123221 Estimated Antarctic Regional K Indices 18 Mar : Macquarie Island 10 22324320 Casey 12 33332223 Mawson 27 55433344 Observed Regional daily pc3 Indices 18 Mar : Darwin 0 (Quiet) Townsville 0 (Quiet) Learmonth 0 (Quiet) Alice Springs 0 (Quiet) Gingin 0 (Quiet) Canberra 0 (Quiet) 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 18 Mar : A Fredericksburg 12 Planetary 15 Observed AFr/Ap Indices 17 Mar : A K Fredericksburg 14 Planetary 14 3332 3433 2B. MAGNETIC FORECAST Date Ap Conditions 19 Mar 10 G0, chance of G1 20 Mar 18 G0-G1 21 Mar 8 G0 COMMENT: G0 geomagnetic conditions were observed in the Australian region on UT day 18-Mar. Mostly G0 geomagnetic conditions were observed in the Antarctic region, with G1 conditions observed at Mawson. G0 geomagnetic conditions are expected on 19-Mar with a chance of G1 and G0-G1 conditions are expected on 20-Mar due to an anticipated impact from a CME first observed on 16-Mar. G0 conditions are expected on 21-Mar. ----------------------------------------------------------- 3A. GLOBAL HF PROPAGATION SUMMARY Latitude Band Date Low Middle High 18 Mar Normal Normal Normal PCA Event : No event. 3B. GLOBAL HF PROPAGATION FORECAST Latitude Band Date Low Middle High 19 Mar Normal Normal Normal-fair 20 Mar Normal Normal-fair Fair 21 Mar Normal Normal Normal-fair COMMENT: HF radio propagation conditions on UT day 18-Mar were mostly normal. HF radio propagation conditions are expected to be mostly normal over 19-21 Mar, with a chance of mild degradations on 20-Mar at high latitudes due to anticipated geomagnetic activity. Equatorial scintillation is anticipated due to the proximity to the equinox. Minor shortwave fadeouts are possible. ----------------------------------------------------------- 4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY Date T index 18 Mar 141 Observed Australian Regional MUFs Cocos Island Region: Near predicted monthly values during local day. Enhanced by 20% during local night. Niue Island Region: Near predicted monthly values. Northern Australian Region: Mostly near predicted monthly values. Enhanced by 20% after local dawn. Southern Australian Region: Enhanced by 15% during local day. Near predicted monthly values during local night. Enhanced by 20% after local dawn. Antarctic Region (Casey/Davis/Mawson): Depressed by 30% over the UT day. Monthly T index: Month T index Feb 127 Mar 117 Apr 114 4B. AUSTRALIAN REGION IONOSPHERIC FORECAST Date T index MUFs 19 Mar 150 Near to 15% above predicted monthly values 20 Mar 140 Near to 15% above predicted monthly values 21 Mar 150 Near to 15% above predicted monthly values COMMENT: Maximum usable frequencies (MUFs) on UT day 18-Mar were near predicted values to enhanced by 20%. Sporadic-E and spread F were observed at Hobart. MUFs are expected to be near predicted monthly values to 15% enhanced over 19-21 Mar, with the chance of some minor degradations on 20-Mar due to possible geomagnetic activity. Minor shortwave fadeouts are possible. ----------------------------------------------------------- 5. SPACE ENVIRONMENT SUMMARY GOES satellite data for 17 Mar Daily Proton Fluence >1 MeV: 7.7E+05 Daily Proton Fluence >10 MeV: 1.7E+04 Daily Electron Fluence >2 MeV: 1.70E+08 (moderate fluence) Electron Fluence Daily Deep Dielectric Discharge Probability:14% Fluence (flux accumulation over 24hrs)/ cm2-ster-day. X-ray background: C1.2 DSCOVR Satellite Solar Wind Day Averaged Data for 17 Mar Speed: 400 km/sec Density: 3.7 p/cc Temp: 60400 K Bz: -2 nT (Courtesy Space Weather Prediction Center, Boulder USA) -----------------------------------------------------------