Joint USAF/NOAA Report of Solar and Geophysical Activity 24 Apr 2003
SDF Number 114 Issued at 2200Z on 24 Apr 2003
IA. Analysis of Solar Active Regions and Activity from 23/2100Z
to 24/2100Z: Solar activity was at moderate levels this period.
Region 338 (N18W45) produced an M3/1n at 24/1253Z with associated
Type II (830 km/s) and Type IV radio sweeps. A partial halo CME was
also detected on LASCO imagery. Region 339 (N16,L=337) was active
during the period, producing several C-class flares as it crossed
the west limb, the largest being a C8 flare at 24/1553Z. No
significant changes were observed in the remaining active regions.
New Regions 344 (N16E39), 345 (S17E74), and 346 (N16E74) were
numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be at
moderate levels. Region 338 may produce futher M-class flares.
IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z:
The geomagnetic field was at unsettled to active levels with isolated
minor storm periods at high latitudes. Elevated solar wind speeds
up to near 600 km/s are responsible for the disturbed periods. The
greater than 2 MeV electrons at geosynchronous orbit reached high
levels today.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at unsettled to minor storm levels. High speed
coronal hole flow may be enhanced by transient flow over the next
three days. Weak CME impact from an M5 flare on April 23 are
possible on days one and two. A CME impact produced by today’s M3
flare may arrive on day three.
III. Event Probabilities 25 Apr-27 Apr
- Class M 40/40/30
- Class X 05/05/05
- Proton 05/05/05
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 24 Apr 128
- Predicted 25 Apr-27 Apr 130/135/135
- 90 Day Mean 24 Apr 125
V. Geomagnetic A Indices
- Observed Afr/Ap 23 Apr 013/018
- Estimated Afr/Ap 24 Apr 020/023
- Predicted Afr/Ap 25 Apr-27 Apr 020/020-020/025-020/025
VI. Geomagnetic Activity Probabilities 25 Apr-27 Apr
A. Middle Latitudes
Active 30/30/30
- Minor storm 30/20/20
- Major-severe storm 10/10/05
B. High Latitudes
- Active 50/40/40
- Minor storm 35/35/35
- Major-severe storm 15/15/15