NOAA SEC Report of Solar-Geophysical Activity 14 Apr 2001


:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Apr 14 2200 UT
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
#Space Environment Center and the U.S. Air Force.
#
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 104 Issued at 2200Z on 14 Apr 2001
IA.  Analysis of Solar Active Regions and Activity from  13/2100Z
to 14/2100Z:  Solar activity was moderate.  Region 9415 (S22W72)
produced an M1/SF event during 14/1715-1828 UTC.  Peak x-ray flux
occurred at 14/1811 UTC, after an extended and variable rise in flux
levels.  Also observed were an associated Type-II sweep, 150 sfu
tenflare, eruptive prominence and bright surging on the limb. 
Imagery from SOHO/LASCO indicated a subsequent CME, however not
appearing earth-directed.  Region 9418 (N26W59) also produced a
subfaint flare during the event, and now exhibits some increase in
areal coverage and magnetic complexity.  Two new regions were
numbered today:  9428 (N14W39) and 9429 (N09E62).
IB.  Solar Activity Forecast:  Solar activity is expected to be low
to moderate.  Regions 9415 and 9418 remain potential sources of
isolated major flares.
IIA.  Geophysical Activity Summary 13/2100Z to 14/2100Z:
The geomagnetic field was at unsettled to active levels, primarily
due to lingering effects of the geomagnetic storm that commenced on
13 April.  Greater-than-2 MeV electron flux at geosynchronous orbit
reached high levels at 1415 UTC, and remained above threshold
through the end of the period.
IIB.  Geophysical Activity Forecast:  Geomagnetic field activity is
expected to increase, with major storm levels possible during the
next 24 hours, due to an expected shock arrival from CME activity
observed on 12 April.  Storm activity is expected to wane during the
following two days, with quiet to unsettled levels expected by the
end of the period.
III.  Event Probabilities 15 Apr-17 Apr
Class M    70/60/50
Class X    20/10/10
Proton     20/10/10
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           14 Apr 139
Predicted   15 Apr-17 Apr  140/145/150
90 Day Mean        14 Apr 166
V.  Geomagnetic A Indices
Observed Afr/Ap 13 Apr  031/036
Estimated Afr/Ap 14 Apr  020/020
Predicted Afr/Ap 15 Apr-17 Apr  030/040-020/030-010/020
VI.  Geomagnetic Activity Probabilities 15 Apr-17 Apr
A.  Middle Latitudes
Active                35/25/20
Minor storm           15/10/05
Major-severe storm    10/05/01
B.  High Latitudes
Active                35/35/30
Minor storm           25/20/10
Major-severe storm    20/10/05

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