Solar Activity

» 24 hr Summary: Solar activity was low with occasional low-level C-class flaring. The largest flare of the period was a C1.2/Sf flare from new Region 4503 (S18E65, Axx/alpha) at 04/1158 UTC.

There are six numbered regions on the visible disk. Region 4498 (N14W29, Dso/beta) showed fragmentation in its leader spot and flux cancellation in its trailing spots. Region 4499 (N04W65, Cai/beta) underwent penumbral decay in its leading spot and overall decay in its trailing spots, including the loss of negative polarity penumbra. Region 4500 (N18W25, Cso/beta) saw minor penumbral decay in its leading spot and continued to exhibit transitory trailing pores of both polarities. Region 4501 (S07W67, Cso/beta) showed some submergence in its trailing spots. Region 4502 (S07W25, Dao/beta) had some slight new emergence but was primarily characterized by consolidation. Region 4503 was newly numbered this period after rotating onto the southeast limb.

Eruptions to the northeast and southeast were observed in STEREO COR2 imagery at approximately 04/1330 UTC and later in GOES-19 CCOR1 imagery at 04/1400 UTC. Dimming, field line movement, and post-eruptive arcades observed in SUVI 195 and 284 imagery suggest a source location to the northeast of Region 4498 for the northward eruption, while no obvious source was identified for the eruption to the southeast. While most of the ejective material was directed out of the ecliptic, minor glancing impacts from the northward eruption are anticipated on 09 August.

No other Earth-directed CMEs were observed in available coronagraph imagery.

» Forecast: Solar activity is expected to be low with a slight chance for M-class (R1-R2/Minor-Moderate) flares 05-07 Aug, primarily due to the flare potential of Regions 4498, 4499, and 4502.

Energetic Particle

» 24 hr Summary: The greater than 2 MeV electron flux at geosynchronous orbit was at moderate levels, reaching a peak flux of 371 pfu observed at 04/1705 UTC. The greater than 10 MeV proton flux at geosynchronous orbit remained at background levels.

» Forecast: The greater than 2 MeV electron flux is expected to remain at low to moderate levels through 07 Aug. The greater than 10 MeV proton flux is expected to remain at background levels 05-07 Aug.

Solar Wind

» 24 hr Summary: Solar wind parameters reflected a general return to ambient levels following previous CME influences. Total magnetic field strength (Bt) opened the period around 10 nT before undergoing a steady decline to around 3 nT by 04/0930 UTC. The North-South (Bz) component was mostly southward early in the period with a maximum deflection of -9 nT. Following the drop in Bt, Bz turned weakly variable. Solar wind speeds held relatively steady between 375 and 425 km/s. The phi angle was predominantly in the positive (away from the Sun) sector.

» Forecast: Solar wind parameters are expected to continue toward a slow wind regime until early to mid-day on 07 Aug, when enhancements associated with CMEs that departed the Sun on 03 Aug arrive.

Geospace

» 24 hr Summary: The geomagnetic field began the period with a single synoptic period of active conditions before declining to quiet levels in the latter half of the period.

» Forecast: Geomagnetic conditions are expected to remain quiet over 05-06 Aug. Active conditions with a chance for G1 (Minor) geomagnetic storming or greater are likely on 07 Aug in response to CME effects.


Prepared by:
The U.S. Dept. of Commerce, NOAA, SWPC