Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 November 2012


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 332 Issued at 2200Z on 27 Nov 2012

IA. Analysis of Solar Active Regions and Activity from 26/2100Z to
27/2100Z: Solar activity has been at moderate levels for the past 24
hours. The largest solar event of the period was a M1/Sf event observed
at 27/1557Z from Region 1618 (N09W81). The region appears to be decaying
but it is difficult to determine size and magnetic configuration with
its proximity to the west limb. Region 1620 (S12W43) continued to show
growth in its intermediate spots and developed magnetically into a
beta-gamma-delta configuration. Two CMEs were observed this morning. The
first became visible as an EUV wave in SDO/AIA 193 imagery beginning
around 27/0245Z near N28E46 and appears to have been associated with a
disappearing filament. The second CME appears in SDO/AIA 193 imagery at
27/0530Z near N00W27. Further analysis is being conducted on these two
events to determine geoeffectiveness.
IB. Solar Activity Forecast: Solar activity is expected to be at low to
moderate levels on days one, two, and three (28 Nov, 29 Nov, 30 Nov).

IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed,
as measured by the ACE spacecraft, continued to decrease from
approximately 500 km/s to 415 km/s as the effects from the 23 November
CME subside. Total IMF reached 5.7 nT at 26/2105Z. The maximum southward
component of Bz reached -2.8 nT at 27/1722Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be mostly quiet on day one (28 Nov). Quiet to unsettled conditions
with a chance for isolated active periods are expected on day two (29
Nov) due to the anticipated arrival of the 26 November CME. Quiet to
unsettled conditions are expected on day three (30 Nov) at this time due
to coronal hole high speed stream effects, however, the results of the
analysis on the events discussed above may change the latter half of
this forecast slightly.

III. Event probabilities 28 Nov-30 Nov
Class M 35/35/35
Class X 05/05/05
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 27 Nov 117
Predicted 28 Nov-30 Nov 115/110/105
90 Day Mean 27 Nov 123

V. Geomagnetic A Indices
Observed Afr/Ap 26 Nov 006/004
Estimated Afr/Ap 27 Nov 004/005
Predicted Afr/Ap 28 Nov-30 Nov 006/005-012/015-007/010

VI. Geomagnetic Activity Probabilities 28 Nov-30 Nov
A. Middle Latitudes
Active 10/30/20
Minor Storm 05/10/10
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 15/30/25
Major-severe storm 15/40/30

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