Joint USAF/NOAA Report of Solar and Geophysical Activity 25 Dec 2009

:Product: Report of Solar-Geophysical Activity
:Issued: 2009 Dec 25 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
#
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 359 Issued at 2200Z on 25 Dec 2009
IA. Analysis of Solar Active Regions and Activity from 24/2100Z
to 25/2100Z: Solar activity was very low. No flares were observed.
The visible disk was spotless.
IB. Solar Activity Forecast: Solar activity is expected to be very
low.
IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z:
The geomagnetic field was quiet. Solar wind observations from the ACE
satellite decreased gradually after 24/2235Z, from 380 km/s to 282
km/s at 25/1457Z. Velocities then increased to 354 km/s at 25/1708Z
as the density increased to a peak of 13 p/cc. The interplanetary
magnetic field (IMF) increased, with the total field reaching +10 nT
at 25/1852Z. The southward component of the IMF ranged between -8 nT
and +7 nT, with the peak of -8 nT at 25/1609Z. This activity is
consistent with the arrival of the partial halo coronal mass
ejection (CME) observed on 22 December.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be predominantly quiet, with isolated unsettled periods
possible at high latitudes, on day one (26 December). Quiet levels
are expected on days two and three (27-28 December).
III. Event Probabilities 26 Dec-28 Dec
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 25 Dec 076
Predicted 26 Dec-28 Dec 072/072/072
90 Day Mean 25 Dec 074
V. Geomagnetic A Indices
Observed Afr/Ap 24 Dec 001/002
Estimated Afr/Ap 25 Dec 003/005
Predicted Afr/Ap 26 Dec-28 Dec 007/007-005/005-005/005
VI. Geomagnetic Activity Probabilities 26 Dec-28 Dec
A. Middle Latitudes
Active 10/05/05
Minor storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/05/05
Minor storm 01/01/01
Major-severe storm 01/01/01