Joint USAF/NOAA Report of Solar and Geophysical Activity 13 May 2003

SDF Number 133 Issued at 2200Z on 13 May 2003

IA. Analysis of Solar Active Regions and Activity from 12/2100Z
to 13/2100Z: Solar activity has been very low.

IB. Solar Activity Forecast: Solar activity is expected to be very
low for the next 24 hours. A new active area on the east limb
(returning Region 336 at latitude N13) appears to be fairly well
developed, and may effect an increased chance of isolated C-class
flares in the following days.

IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z:
The geomagnetic field has been at unsettled to minor storm levels due
to a favorably positioned coronal hole. The greater than 2 MeV
electron flux at geosynchronous orbit reached very high levels
today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at unsettled to minor storm levels for the next two
days, falling off to unsettled to active on day three. The current
coronal hole is rotating out of geoeffective position. With that,
the associated high-speed solar wind stream should abate.

III. Event Probabilities 14 May-16 May

• Class M 10/15/15
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 13 May 096
• Predicted 14 May-16 May 100/105/110
• 90 Day Mean 13 May 125

V. Geomagnetic A Indices

• Observed Afr/Ap 12 May 014/018
• Estimated Afr/Ap 13 May 025/025
• Predicted Afr/Ap 14 May-16 May 025/025-020/020-015/015

VI. Geomagnetic Activity Probabilities 14 May-16 May

A. Middle Latitudes

• Active 35/35/25
• Minor storm 25/20/15
• Major-severe storm 10/10/05

B. High Latitudes

• Active 35/35/35
• Minor storm 15/15/15
• Major-severe storm 15/10/05