Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 25 May 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 145 Issued at 2200Z on 25 May 2013

IA. Analysis of Solar Active Regions and Activity from 24/2100Z to
25/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C2 event observed at
25/1049Z from Region 1755 (N11E12). There are currently 6 numbered
sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares on days one, two, and three (26 May, 27 May,
28 May).

IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic
field has been at unsettled to minor storm levels for the past 24 hours.
Solar wind speed, as measured by the ACE spacecraft, reached a peak
speed of 725 km/s at 25/2100Z. Total IMF reached 13 nT at 25/2040Z. The
maximum southward component of Bz reached -11 nT at 25/2048Z. Protons
greater than 10 MeV at geosynchronous orbit reached a peak level of 16
pfu at 24/2110Z. Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 943 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (26 May) and quiet to
unsettled levels on days two and three (27 May, 28 May).

III. Event probabilities 26 May-28 May
Class M 25/25/25
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 25 May 121
Predicted 26 May-28 May 120/120/125
90 Day Mean 25 May 123

V. Geomagnetic A Indices
Observed Afr/Ap 24 May 017/023
Estimated Afr/Ap 25 May 020/029
Predicted Afr/Ap 26 May-28 May 015/020-010/010-007/008

VI. Geomagnetic Activity Probabilities 26 May-28 May
A. Middle Latitudes
Active 35/20/10
Minor Storm 15/05/01
Major-severe storm 05/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/25/20
Major-severe storm 50/25/20