- Press Release
- Nov 30, 2022
Joint USAF/NOAA Report of Solar and Geophysical Activity 25 July 2012
:Product: Report of Solar-Geophysical Activity
:Issued: 2012 Jul 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 207 Issued at 2200Z on 25 Jul 2012
IA. Analysis of Solar Active Regions and Activity from 24/2100Z
to 25/2100Z: Solar activity was very low. Slight growth was
observed in Region 1526 (S17W00). The remainder of the disk and
limb was quiet and stable. A relatively slow moving CME
(approximate plane-of-sky speed of 350 km/s) was observed off the
southern limb in SOHO/LASCO C2 imagery beginning at 25/0236Z.
Correlations with STEREO-A COR2 imagery indicated ejecta movement
was slightly south of the ecliptic plane with a possible
Earth-directed component. This CME was likely the result of a small
filament eruption just south of central disk observed in H-alpha
imagery at approximately 24/2235Z. A preliminary WSA ENLIL model
run of the event indicated a weak impact early on 29 July.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low.
IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z:
The geomagnetic field was quiet to unsettled. Solar wind speed
measured at the ACE spacecraft continued to decline from
approximately 500 km/s to 440 km/s. The greater than 10 MeV proton
flux at geosynchronous orbit continued to be enhanced around 8 pfu.
The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels during the period.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be mostly quiet on days 1 – 2 (26 – 27 July). By mid to
late on day 3 (28 July), a recurrent coronal hole high speed stream
is expected to rotate into a geoeffective position resulting in
unsettled to active conditions.
III. Event Probabilities 26 Jul-28 Jul
Class M 05/05/05
Class X 01/01/01
IV. Penticton 10.7 cm Flux
Observed 25 Jul 105
Predicted 26 Jul-28 Jul 110/115/115
90 Day Mean 25 Jul 125
V. Geomagnetic A Indices
Observed Afr/Ap 24 Jul 010/009
Estimated Afr/Ap 25 Jul 006/007
Predicted Afr/Ap 26 Jul-28 Jul 006/005-006/005-011/015
VI. Geomagnetic Activity Probabilities 26 Jul-28 Jul
A. Middle Latitudes
Minor storm 01/01/10
Major-severe storm 01/01/01
B. High Latitudes
Minor storm 10/10/25
Major-severe storm 05/05/30