Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 26 November 2012


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 331 Issued at 2200Z on 26 Nov 2012

IA. Analysis of Solar Active Regions and Activity from 25/2100Z to
26/2100Z: 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
26/1526Z from Region 1620 (S13W28). The region grew significantly
overnight and is now considered an Esi-type region with a beta-gamma
magnetic configuration. Region 1618 (N08W69) continued to decay,
however, it maintained a weak delta in its trailing spot. There are
currently 4 numbered sunspot regions on the disk. A filament eruption
was observed south of Region 1620 in SDO/AIA 304 imagery beginning at
26/0343Z. A model run is in progress to determine geoeffectiveness.
IB. Solar Activity Forecast: Solar activity is expected to be at low to
moderate levels on days one, two, and three (27 Nov, 28 Nov, 29 Nov).

IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. A
shock passage was observed at 26/0437Z indicating the possible early
arrival of the 23 November CME followed by an 8 nT Sudden Impulse (SI)
observed at the Boulder magnetometer at 26/0514Z. Solar wind speed, as
measured by the ACE spacecraft, reached a peak speed of 558 km/s at
26/0709Z. Total IMF reached 12.8 nT at 26/0749Z. The maximum southward
component of Bz reached -7.8 nT at 26/0729Z although it has remained
positive since about 26/1000Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels with a chance for isolated active
periods on day one (27 Nov) as CME effects begin to wane. Mostly quiet
conditions are expected on days two and three (28 Nov, 29 Nov).

III. Event probabilities 27 Nov-29 Nov
Class M 35/35/35
Class X 05/05/05
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 26 Nov 122
Predicted 27 Nov-29 Nov 120/120/115
90 Day Mean 26 Nov 123

V. Geomagnetic A Indices
Observed Afr/Ap 25 Nov 004/004
Estimated Afr/Ap 26 Nov 005/005
Predicted Afr/Ap 27 Nov-29 Nov 011/012-006/005-006/005

VI. Geomagnetic Activity Probabilities 27 Nov-29 Nov
A. Middle Latitudes
Active 25/10/05
Minor Storm 10/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/15/10
Major-severe storm 35/15/05

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