Daily Report

(last updated 18 Jul 2026 23:30 UT)

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT ISSUED AT 2330UT/18 JULY 2026 FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE SUMMARY FOR 18 JULY AND FORECAST FOR 19 JULY - 21 JULY STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx ----------------------------------------------------------- 1A. SOLAR SUMMARY Activity 18 Jul: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Jul: 110/60 1B. SOLAR FORECAST 19 Jul 20 Jul 21 Jul Activity R0, chance of R1 R0, chance of R1 R0, chance of R1 Fadeouts None expected None expected None expected 10.7cm/SSN 115/66 120/72 120/72 COMMENT: Solar flare activity on UT day 18-Jul was at the R0 level, with no significant flaring activity. There are currently two numbered regions visible on the solar disk and one unnumbered region. Active Region (AR) 4489 (S07W01, beta) is the most magnetically complex on the disk and has been stable over the UT day. Region 4491 (S11E33, alpha) is also stable. An unnumbered region is rotating over the eastern limb near N15E88 (alpha). This region is possibly the return of region 4479, which produced R3 level flare activity on its previous rotation. Solar flare activity is expected to be at the R0 level over 19-21 Jul, with a chance of R1. S0 solar radiation storm conditions were observed on UT day 18-Jul. S0 solar radiation storm conditions are expected over 19-21 Jul. No Earth-directed coronal mass ejections (CMEs) have been observed. The solar wind speed on UT day 18-Jul decreased, ranging from 355 to 320 km/s and is currently near 325 km/s. The peak total interplanetary magnetic field strength (IMF, Bt) was 5 nT and the north-south IMF component (Bz) range was -3 to +4 nT. A narrow, elongated trans-equatorial coronal hole spanning both solar hemispheres is currently visible in the eastern solar hemisphere, but is not expected to impact the solar wind during the forecast period. The solar wind speed is expected to remain at background levels over 19-21 Jul. ----------------------------------------------------------- 2A. MAGNETIC SUMMARY Geomagnetic field for Australian Region 18 Jul: G0 Estimated Indices 18 Jul : A K Australian Region 0 11000000 Cocos Island 1 01110000 Darwin 1 11100001 Townsville 1 11100011 Learmonth 1 11110010 Alice Springs 0 11000000 Gingin 0 11000000 Canberra 1 11001000 Kennaook Cape Grim 0 01001000 Hobart 0 01001000 Estimated Antarctic Regional K Indices 18 Jul : Macquarie Island 1 01002000 Casey 4 32211000 Mawson 5 33210001 Observed Regional daily pc3 Indices 18 Jul : Darwin 0 (Quiet) Townsville 0 (Quiet) Learmonth 0 (Quiet) Alice Springs 0 (Quiet) Gingin 0 (Quiet) Canberra 0 (Quiet) Hobart 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 Jul : A Fredericksburg 5 Planetary 5 Observed AFr/Ap Indices 17 Jul : A K Fredericksburg 4 Planetary 4 1111 1111 2B. MAGNETIC FORECAST Date Ap Conditions 19 Jul 4 G0 20 Jul 4 G0 21 Jul 5 G0 COMMENT: G0 geomagnetic conditions were observed in the planetary, Australian and Antarctic regions on UT day 18-Jul. G0 planetary geomagnetic conditions are expected over 19-21 Jul. ----------------------------------------------------------- 3A. GLOBAL HF PROPAGATION SUMMARY Latitude Band Date Low Middle High 18 Jul Normal-fair Normal Normal PCA Event : No event. 3B. GLOBAL HF PROPAGATION FORECAST Latitude Band Date Low Middle High 19 Jul Normal Normal Normal 20 Jul Normal Normal Normal 21 Jul Normal Normal Normal COMMENT: Global high-frequency (HF) radio propagation conditions were normal to fair on UT day 18-Jul, with some degradations observed across northern hemisphere regions. Global HF propagation conditions are expected to be normal over 19-21 Jul. ----------------------------------------------------------- 4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY Date T index 18 Jul 60 Observed Australian Regional MUFs Cocos Island Region: No data available during local day. No data available during local night. Niue Island Region: Near predicted monthly values during local day. Depressed by 15% during local night. Northern Australian Region: Near predicted monthly values during local day. Depressed by 15% during local night. Southern Australian Region: Near predicted monthly values. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. Monthly T index: Month T index Jun 81 Jul 66 Aug 63 4B. AUSTRALIAN REGION IONOSPHERIC FORECAST Date T index MUFs 19 Jul 60 Near predicted monthly values 20 Jul 60 Near predicted monthly values 21 Jul 60 Near predicted monthly values COMMENT: Maximum Usable Frequencies (MUFs) in the Australian region on UT day 18-Jul were mostly near predicted monthly values, with depressions up to 15% observed during local night hours in the northern Australian region. Strong spread-F was observed across the Australian region during local night hours. MUFs are forecast to be near predicted monthly values over 19-21 Jul, with some depressions possible during local night hours. ----------------------------------------------------------- 5. SPACE ENVIRONMENT SUMMARY GOES satellite data for 17 Jul Daily Proton Fluence >1 MeV: 1.3E+05 Daily Proton Fluence >10 MeV: 1.8E+04 Daily Electron Fluence >2 MeV: 6.60E+07 (normal fluence) Electron Fluence Daily Deep Dielectric Discharge Probability: 8% Fluence (flux accumulation over 24hrs)/ cm2-ster-day. X-ray background: B4.2 DSCOVR Satellite Solar Wind Day Averaged Data for 17 Jul Speed: 380 km/sec Density: 2.8 p/cc Temp: 101000 K Bz: -1 nT (Courtesy Space Weather Prediction Center, Boulder USA) -----------------------------------------------------------