Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 25 November 2012


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 330 Issued at 2200Z on 25 Nov 2012

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 C1 event observed at
25/2014Z from the west limb. Region 1618 (N08W55) was responsible for a
B9 flare at 24/0617Z. Region 1618 was classified as an Ekc type group
covering 270 millions of the visible solar disk. Further magnetic
simplification was observed in Region 1618's leader spot, however it
contained a delta in its larger trailing spot earlier in the period.
Region 1620 (S13W14) appeared to develop gamma characteristics over the
past 24 hours. New flux emergence was noted in the southeast quadrant
near S17E38 and S24E30. These regions were small, simple beta type
groups and will be monitored for continued development before being
numbered.

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

IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. There were no
obvious signs the 21 November CME passage in the time series data from
the ACE spacecraft in the past 24 hours. Solar wind speed began rising
slowly from 350 km/s around 25/0400 UTC and peaked at 487 km/s 11 hours
later. The Phi angle was near 225 degrees until 25/1000 UTC when it
became variable. It came to rest at 315 degrees (negative sector) about
90 minutes later. Coincident with the variable period, Bz became
negative. In the hours prior, it had been between 0 and +10nT. The
temperature also began rising about the same time as the wind speed, but
peaked around 25/1100 UTC. The EPAM instrument reported low energy
particle flux rose from around 25/0600 to 0900 UTC, but abruptly leveled
off afterwards and only minor fluctuations have followed. Total IMF
reached 12.3 nT at 25/0303Z. The maximum southward component of Bz
reached -8.1 nT at 25/1259Z.

IIB. Geophysical Activity Forecast: The geomagnetic field should begin
at mostly quiet levels with some isolated unsettled periods. WSA-ENLIL
model runs place the 23 Nov CME at earth at the earliest by 15 UTC on
the 26th and at the latest by about 00 UTC on the 27th. With the CME
arrival, conditions are expected to be unsettled to active with a slight
chance for isolated minor storm levels, particularly at high latitudes.

III. Event probabilities 26 Nov-28 Nov
Class M 30/30/30
Class X 05/05/05
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 25 Nov 121
Predicted 26 Nov-28 Nov 120/115/110
90 Day Mean 25 Nov 123

V. Geomagnetic A Indices
Observed Afr/Ap 24 Nov 011/015
Estimated Afr/Ap 25 Nov 005/006
Predicted Afr/Ap 26 Nov-28 Nov 009/010-013/015-008/008

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

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