Joint USAF/NOAA Report of Solar and Geophysical Activity 18 May 2004
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 May 18 2200 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 139 Issued at 2200Z on 18 May 2004
IA. Analysis of Solar Active Regions and Activity from 17/2100Z
to 18/2100Z: Solar activity was low. Several small flares occurred
throughout the day. The largest was a C3 at 18/0827 UTC in Region
615 (N17E38). Small flares also occurred in Regions 612 (N10W59),
614 (S06W90), and 617 (S11W04). Region 609 (S03W46) continued to
decay but did not produce any flares.
IB. Solar Activity Forecast: Solar activity is expected to be low.
Small B and C-class flares are possible from several areas on the
disk, including Regions 609, 612, 615, and 617.
IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field was quiet to unsettled.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled. NOTE: The ACE spacecraft orbit
will bring ACE nearly in line with the Sun from about May 30 to June
2, 2004. During that time solar radio noise is expected to interfere
with spacecraft telemetry resulting in the loss of solar wind
plasma, magnetic field, and particle data.
III. Event Probabilities 19 May-21 May
- Class M 30/30/30
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 18 May 108
- Predicted 19 May-21 May 105/105/100
- 90 Day Mean 18 May 105
V. Geomagnetic A Indices
- Observed Afr/Ap 17 May 003/005
- Estimated Afr/Ap 18 May 006/007
- Predicted Afr/Ap 19 May-21 May 008/010-008/015-008/010
VI. Geomagnetic Activity Probabilities 19 May-21 May
A. Middle Latitudes
- Active 15/15/15
- Minor storm 05/05/05
- Major-severe storm 01/01/01
B. High Latitudes
- Active 25/25/25
- Minor storm 10/10/10
- Major-severe storm 05/05/05
