Joint USAF/NOAA Report of Solar and Geophysical Activity 20 Nov 2003

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.

Updated 2003 Nov 20 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 324 Issued at 2200Z on 20 Nov 2003

IA. Analysis of Solar Active Regions and Activity from 19/2100Z
to 20/2100Z: Solar activity has been high. Region 501 (N02W18)
produced an M9.6/2b flare at 20/0747 UTC with an associated Type IV
radio sweep and a 9700 pfu tenflare. This flare also produced a CME
with an estimated velocity of 700 km/s. Region 507 (N07E49)
produced a C8.6 at 20/1929 UTC. All regions on the disk were stable
in size. Two regions increased in complexity: Region 501 developed
into a Beta-Gamma-Delta magnetic configuration, and Region 508
(S20E58) developed into a Beta-Gamma configuration.

IB. Solar Activity Forecast: Solar activity is expected to be
moderate to high. Regions 501, 507 and 508 are capable of producing
major flares.

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field has been at quiet to severe storm levels. A
CME shock arrived at SOHO/MTOF and was observed at 20/0740 UTC, and
a geomagnetic sudden impulse was observed at 0805 UTC. A very
strong (55 nT) southward component of the interplanetary magnetic
field resulted in severe geomagnetic storming during the latter half
of the day. Magnetopause crossings were observed at both main GOES
satellites, at 1301 UTC for GOES 12 and at 1628 UTC for GOES 10.
The greater than 2 MeV electrons at geosynchronous orbit dropped
below high levels early in the day and have remained below
threshold. The M9 flare produced elevated 10 MeV proton levels at
geosynchronous orbit, but this activity did not cross event
thresholds.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be unsettled to active all three days, with major storm
conditions possible early on 21 November from the lingering effects
of the geomagnetic storm in progress. Minor storming is possible on
22-23 November from a CME shock arrival originating from the M9
flare observed earlier today.

III. Event Probabilities 21 Nov-23 Nov

• Class M 70/75/80
• Class X 15/20/25
• Proton 10/20/20
• PCAF yellow

IV. Penticton 10.7 cm Flux

• Observed 20 Nov 175
• Predicted 21 Nov-23 Nov 180/190/200
• 90 Day Mean 20 Nov 128

V. Geomagnetic A Indices

• Observed Afr/Ap 19 Nov 012/014
• Estimated Afr/Ap 20 Nov 105/115
• Predicted Afr/Ap 21 Nov-23 Nov 040/045-025/035-015/020

VI. Geomagnetic Activity Probabilities 21 Nov-23 Nov

A. Middle Latitudes

• Active 35/35/35
• Minor storm 35/25/15
• Major-severe storm 20/15/05

B. High Latitudes

• Active 35/35/40
• Minor storm 35/40/35
• Major-severe storm 30/25/15