Report of Solar Geophysical Activity (RSGA)

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 140 Issued at 2200Z on 20 May 2013

IA.  Analysis of Solar Active Regions and Activity from 19/2100Z to
20/2100Z: Solar activity has been at moderate levels for the past 24
hours. The largest solar event of the period was a M1 event observed at
20/0525Z. There are currently 7 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is likely to be moderate
with a chance for X-class flares on days one, two, and three (21 May, 22
May, 23 May).

IIA.  Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed, as measured by the ACE spacecraft, reached a peak speed of
493 km/s at 19/2257Z. Total IMF reached 14 nT at 19/2256Z. The maximum
southward component of Bz reached -5 nT at 20/1953Z. Protons greater
than 10 MeV at geosynchronous orbit reached a peak level of 4 pfu at
19/2255Z.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on days one and two (21 May, 22 May)
and unsettled to active levels on day three (23 May). Protons have a
chance of crossing threshold on days one, two, and three (21 May, 22
May, 23 May).

III.  Event probabilities 21 May-23 May
Class M    65/65/65
Class X    25/25/25
Proton     25/25/25
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           20 May 132
Predicted   21 May-23 May 130/125/125
90 Day Mean        20 May 121

V.  Geomagnetic A Indices
Observed Afr/Ap 19 May  011/014
Estimated Afr/Ap 20 May  006/006
Predicted Afr/Ap 21 May-23 May  007/008-011/012-012/015

VI.  Geomagnetic Activity Probabilities 21 May-23 May
A.  Middle Latitudes
Active                15/20/30
Minor Storm           01/05/10
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           25/25/30
Major-severe storm    20/30/40

Radio Events Observed 20 May 2013
A.  245 MHz Bursts
Start  End   Peak Flux  Time of Peak  Duration
1121   1130    120          1123        0009  
1503   1503    300          1503        0000  
1626   1626    110          1626        0000  
1821   1821    100          1821        0000  
B.  245 MHz Noise Storms
No 245 MHz Noise Storms Observed.

SUMMARY: Geomagnetic Sudden Impulse
Observed: 2013 May 18 0112 UTC
Deviation: 31 nT
Station: Boulder

SUMMARY: Geomagnetic Sudden Impulse
Observed: 2013 May 19 2306 UTC
Deviation: 39 nT
Station: Boulder

SPACE WEATHER ADVISORY OUTLOOK #13-20
2013 May 20 at 2:28 a.m. MDT (2013 May 20 0828 UTC)

**** SPACE WEATHER OUTLOOK ****

Summary For May 13-19

Multiple category R3 (Strong)  and R1 (Minor) radio blackouts were observed from 13 - 17 May due to flare activity from active sunspot Region 1748. 

A category S1 (Minor) solar radiation storm was observed from 15 - 18 May due to solar activity associated with Region 1748.

Several category G1 (Minor) geomagnetic storm periods occurred on 18 May as a CME, from 15 May,  became geoeffective.

Outlook For May 20-26

R1 (Minor) and R2 (Moderate), with R3 (Strong) radio blackouts are possible through the outlook period as Region 1748 persists and a new yet to be numbered active region rotates onto the visible disk.

Category S1 (Minor) solar radiation storms are possible through the outlook period as solar activity is expected to remain elevated.