Daily Report

(last updated 26 Jul 2024 23:30 UT)

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT ISSUED AT 2330UT/26 JULY 2024 FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE SUMMARY FOR 26 JULY AND FORECAST FOR 27 JULY - 29 JULY STATUS INDICATORS SOL:** YELLOW ** MAG:** YELLOW ** ION: GREEN ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx ----------------------------------------------------------- 1A. SOLAR SUMMARY Activity 26 Jul: R1 Flares Max Fadeout Freq. Sectors M1.7 0442UT possible lower E. Asia/Aust. Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Jul: 176/130 1B. SOLAR FORECAST 27 Jul 28 Jul 29 Jul Activity R0-R1 R0-R1 R0-R1 Fadeouts Possible Possible Possible 10.7cm/SSN 170/124 165/119 165/119 COMMENT: Solar activity on UT day 26-Jul was R1, with an isolated M1 solar flare from AR3761(S10W80, beta). This small region is about to rotate off disk. There are currently ten numbered sunspot regions on the solar disk. Solar region AR3762(S12W12, beta-gamma) is currently the largest region on the visible solar disk and has shown decay in its trailers and development in some of its leader spots. This region produced C class flare activity. In the southeast solar quadrant a group of solar regions AR3765(S11E36, beta), AR3766(S22E37, beta) and AR3767(S09E48, beta-gamma) are growing. All other sunspot regions are either stable or in decay. Solar activity is expected to be R0-R1 over 27-29 Jul. A small 7 degree long solar filament located at S25W08 erupted over the interval 26/1900-2000UT. No Earth-directed CMEs were observed on 26-Jul. Two very narrow west directed CMEs were observed in LASCO imagery from 26/0312UT and 26/0948UT. These CMEs could not be correlated to on disk activity and are currently assumed to be associated with either solar limb or far side activity. No CME appeared associated with the small filament eruption. S0 solar radiation storm conditions were observed on 26-Jul. S0 solar radiation storm conditions are expected over 27-29 Jul. The solar wind speed gradually increased on 26-Jul from near 450 to 600 km/s during the interval 26/0000-0500UT and is currently near 500km/sec. The peak total interplanetary field strength (IMF, Bt) was 16 nT and the north-south IMF component range (Bz) was +8 to -13 nT. The solar wind IMF Bz component showed an interval of oscillation 26/0000-0240UT followed by a southward interval 26/0325-0520UT. The increase in wind speed and later drop in density implies a coronal hole wind stream, though none appears currently evident on the solar disk west of the solar central meridian, whilst the interval of oscillation of the IMF Bz component early in the UT day possibly suggests a solar sector boundary crossing, though the solar wind toward and way ecliptic plane magnetic field vector angle does not show a sustained change in orientation following the oscillating Bz interval. The solar wind is expected to remain enhanced for today with a slight declining trend and is expected to be somewhat disturbed at times during 27-29 Jul due to the possible arrival of weak glancing blows from recent CMEs. ----------------------------------------------------------- 2A. MAGNETIC SUMMARY Geomagnetic field for Australian Region 26 Jul: G0 Estimated Indices 26 Jul : A K Australian Region 13 34332322 Cocos Island 11 34322221 Darwin 12 34322322 Townsville 17 35432322 Learmonth 19 35433332 Alice Springs 13 34332321 Gingin 15 44422322 Canberra 13 34332322 Kennaook Cape Grim 13 34332322 Hobart 15 34332422 Estimated Antarctic Regional K Indices 26 Jul : Macquarie Island 32 35444642 Casey 13 34332232 Mawson 38 46543355 Observed Regional daily pc3 Indices 26 Jul : Darwin 0 (Quiet) Townsville 2 (Quiet) Learmonth 0 (Quiet) Alice Springs 0 (Quiet) Gingin 8 (Quiet) Canberra 17 (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 26 Jul : A Fredericksburg 19 Planetary 26 Observed AFr/Ap Indices 25 Jul : A K Fredericksburg 9 Planetary 9 2101 2234 2B. MAGNETIC FORECAST Date Ap Conditions 27 Jul 16 G0, chance G1 28 Jul 13 G0, slight chance G1 29 Jul 13 G0, slight chance G1 COMMENT: G0 geomagnetic conditions were observed in the Australian region on UT day 26-Jul, with an isolated period of G1 observed at Townsville and Learmonth. The planetary Kp reached G1 during the period 26/03-06UT. Mostly G0 conditions were observed in Antarctica, with isolated periods of G1 and G2 observed at Macquarie Island and Mawson. Mostly G0 geomagnetic conditions are expected over 27-29 Jul, with periods of G1 conditions possible due to weak CME glancing blows. ----------------------------------------------------------- 3A. GLOBAL HF PROPAGATION SUMMARY Latitude Band Date Low Middle High 26 Jul Normal Fair-normal Fair PCA Event : No event. 3B. GLOBAL HF PROPAGATION FORECAST Latitude Band Date Low Middle High 27 Jul Normal Fair-normal Fair 28 Jul Normal Fair-normal Fair 29 Jul Normal Fair-normal Fair COMMENT: HF radio communication conditions on UT day 26-Jul were mostly fair to normal, with fair conditions at high latitudes due to a mild increase in geomagnetic activity. HF radio communication conditions are expected to be be similar over 27-29 Jul, with mild degradations at times for middle to high latitudes particularly during local night hours. Isolated minor fadeouts are possible. ----------------------------------------------------------- 4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY Date T index 26 Jul 145 Observed Australian Regional MUFs Cocos Island Region: Enhanced by 20% during local day. Near predicted monthly values during local night. Niue Island Region: Near predicted monthly values. Northern Australian Region: Near predicted monthly values. Southern Australian Region: Enhanced by 20%. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. Monthly T index: Month T index Jun 120 Jul 118 Aug 117 4B. AUSTRALIAN REGION IONOSPHERIC FORECAST Date T index MUFs 27 Jul 130 Near predicted monthly values to 15% enhanced 28 Jul 130 Near predicted monthly values to 15% enhanced 29 Jul 130 Near predicted monthly values to 15% enhanced COMMENT: ASWFC SWF HF Communications Warning 79 was issued on 26 July and is current for 26-27 Jul. Maximum usable frequencies (MUFs) on UT day 26-Jul were near predicted values to 20% enhanced in the Australian region. Strong spread F was observed at Hobart during local night hours. MUFs are expected to be near predicted values to 15% enhanced over 27-29 Jul. Isolated minor fadeouts are possible. ----------------------------------------------------------- 5. SPACE ENVIRONMENT SUMMARY GOES satellite data for 25 Jul Daily Proton Fluence >1 MeV: 5.1E+06 Daily Proton Fluence >10 MeV: 2.2E+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: C1.3 DSCOVR Satellite Solar Wind Day Averaged Data for 25 Jul Speed: 335 km/sec Density: 1.4 p/cc Temp: 88200 K Bz: 3 nT (Courtesy Space Weather Prediction Center, Boulder USA) -----------------------------------------------------------