Joint USAF/NOAA Report of Solar and Geophysical Activity 19 Apr 2005
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 Apr 19 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 109 Issued at 2200Z on 19 Apr 2005
IA. Analysis of Solar Active Regions and Activity from 18/2100Z
to 19/2100Z: Solar activity was very low. Region 755 (S12E49),
which was responsible for three C-class flares on 17 April,
continues to decay. A CME was observed on LASCO imagery at 19/1226
UTC directed to the northwest. The CME most likely occurred on the
backside and is not expected to be geoeffective. No new regions
were numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low.
IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z:
The geomagnetic field was quiet to unsettled with an isolated active
period between 0600 UTC and 0900 UTC on 19 April. The greater than
2 MeV electron flux at geosynchronous orbit was at high levels again
today.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled with the possibility of isolated
active conditions on 20 and 21 April. On 22 April, there is a
chance for increased active periods due to a recurrent coronal hole
high speed stream moving into geoeffective position.
III. Event Probabilities 20 Apr-22 Apr
- Class M 05/01/01
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 19 Apr 078
- Predicted 20 Apr-22 Apr 080/080/080
- 90 Day Mean 19 Apr 092
V. Geomagnetic A Indices
- Observed Afr/Ap 18 Apr 005/008
- Estimated Afr/Ap 19 Apr 008/010
- Predicted Afr/Ap 20 Apr-22 Apr 008/012-008/010-012/015
VI. Geomagnetic Activity Probabilities 20 Apr-22 Apr
A. Middle Latitudes
- Active 20/20/25
- Minor storm 10/10/10
- Major-severe storm 01/01/05
B. High Latitudes
- Active 25/25/30
- Minor storm 10/10/15
- Major-severe storm 05/01/05
