Daily Report

(last updated 24 Apr 2024 23:30 UT)

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT ISSUED AT 2330UT/24 APRIL 2024 FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE SUMMARY FOR 24 APRIL AND FORECAST FOR 25 APRIL - 27 APRIL STATUS INDICATORS SOL:** YELLOW ** MAG:GREEN ION: GREEN ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx ----------------------------------------------------------- 1A. SOLAR SUMMARY Activity 24 Apr: R1 Flares Max Fadeout Freq. Sectors M1.7 0029UT possible lower West Pacific M1.8 0239UT possible lower E. Asia/Aust. M1.4 1214UT possible lower European M1.1 2250UT possible lower East Pacific/ North American M2.0 2259UT possible lower East Pacific/ North American Observed 10.7 cm flux/Equivalent Sunspot Number for 24 Apr: 199/151 1B. SOLAR FORECAST 25 Apr 26 Apr 27 Apr Activity R1-R2 R1-R2 R1-R2 Fadeouts Possible Possible Possible 10.7cm/SSN 195/147 185/138 170/124 COMMENT: Solar activity on UT day 24-Apr was R1, with five M-class solar flares. All of the M flares came from either AR3645 (S08W70, beta) or AR3638 (S18W75, beta). Some high level C class solar flares were also observed from AR3646 (N22W28, beta). There are a total of twelve numbered sunspot regions on the solar disk. The complex cluster of sunspots that has featured in recent forecasts in the solar southwest quadrant is nearing the western limb and suffering from projection effects, although analysis indicates these regions are either stable or decaying. AR3648 (N18W40, beta) and AR3654 (S09E24, beta) have shown growth over the past day, but otherwise all other sunspots are either stable or in decay. Solar activity is expected to be R1-R2 over 25-27 Apr. A CME was observed to the solar southwest, which was associated with a C9 level solar flare from AR3638 at 24/1410 UT but is not expected to be geoeffective. No other CMEs of interest were observed on 24-Apr. S0 solar radiation storm conditions were observed on 24-Apr. S0 solar radiation storm conditions are expected over 25-27 Apr. The solar wind was at background levels on 24-Apr. The solar wind speed ranged between 350 and 400 km/s. The peak total interplanetary field strength (IMF, Bt) was 5 nT and the north-south IMF component range (Bz) was +5 to -2 nT. There are a series of coronal holes beginning near S00W30 stretching to S40W00. These coronal holes may increase the solar wind speed from 25-Apr and over 26-27 Apr. ----------------------------------------------------------- 2A. MAGNETIC SUMMARY Geomagnetic field for Australian Region 24 Apr: G0 Estimated Indices 24 Apr : A K Australian Region 0 10000001 Cocos Island 1 21010000 Darwin 1 10110001 Townsville 2 20011012 Learmonth 1 11100000 Alice Springs 0 10000001 Gingin 1 11100000 Canberra 0 10000001 Kennaook Cape Grim 0 10000001 Hobart 1 11000001 Estimated Antarctic Regional K Indices 24 Apr : Macquarie Island 0 00000000 Casey 4 33200000 Mawson 4 22210003 Observed Regional daily pc3 Indices 24 Apr : 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 24 Apr : A Fredericksburg 4 Planetary 4 Observed AFr/Ap Indices 23 Apr : A K Fredericksburg 9 Planetary 7 1122 2233 2B. MAGNETIC FORECAST Date Ap Conditions 25 Apr 12 G0, chance G1 26 Apr 12 G0, chance G1 27 Apr 12 G0, chance G1 COMMENT: G0 geomagnetic conditions were observed in Australian and Antarctica on UT day 24-Apr. Mostly G0 geomagnetic conditions are expected over 25-27, with a chance for G1 on these days due to coronal holes. ----------------------------------------------------------- 3A. GLOBAL HF PROPAGATION SUMMARY Latitude Band Date Low Middle High 24 Apr Normal Normal-fair Fair PCA Event : No event. 3B. GLOBAL HF PROPAGATION FORECAST Latitude Band Date Low Middle High 25 Apr Normal Normal-fair Fair 26 Apr Normal Normal-fair Fair 27 Apr Normal Normal-fair Fair COMMENT: HF radio communication on UT day 24-Apr was generally normal. Some degraded conditions were observed in high latitudes and equatorial scintillation was common. HF radio communication conditions are expected to be normal to mildly degraded over 25-27 Apr due to an anticipated coronal hole high speed wind stream. ----------------------------------------------------------- 4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY Date T index 24 Apr 147 Observed Australian Regional MUFs Cocos Island Region: Enhanced by 15% during local day. Enhanced by 55% during local night. Niue Island Region: Enhanced by 20% during local day. Enhanced by 70% during local night. Northern Australian Region: Near predicted monthly values during local day. Enhanced by 25% during local night. Southern Australian Region: Enhanced by 15% during local day. Enhanced by 15% during local night. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. Monthly T index: Month T index Mar 120 Apr 114 May 115 4B. AUSTRALIAN REGION IONOSPHERIC FORECAST Date T index MUFs 25 Apr 140 Near predicted monthly values 26 Apr 135 Near predicted monthly values 27 Apr 130 Near predicted monthly values COMMENT: Maximum usable frequencies (MUFs) in the Australian region were near predicted values to 25% enhanced on UT day 24-Apr. Spread F was observed in Hobart and Perth during local night and dawn hours. Scintillation was observed at Darwin, Weipa and Niue between 24/0911-1350 UT. MUFs are expected to be near monthly predicted values over 25-27 Apr, although some mild depressions may be observed due to the oncoming coronal hole wind stream over this period. ----------------------------------------------------------- 5. SPACE ENVIRONMENT SUMMARY GOES satellite data for 23 Apr Daily Proton Fluence >1 MeV: 6.4E+04 Daily Proton Fluence >10 MeV: 1.6E+04 Daily Electron Fluence >2 MeV: 3.10E+07 (normal fluence) Electron Fluence Daily Deep Dielectric Discharge Probability: 5% Fluence (flux accumulation over 24hrs)/ cm2-ster-day. X-ray background: C3.0 DSCOVR Satellite Solar Wind Day Averaged Data for 23 Apr Speed: 383 km/sec Density: 0.4 p/cc Temp: 33300 K Bz: 0 nT (Courtesy Space Weather Prediction Center, Boulder USA) -----------------------------------------------------------