lunedì 4 settembre 2017

Propagation outlook from Boulder

:Product: Weekly Highlights and Forecasts
:Issued: 2017 Sep 04 0551 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/weekly.html
#
#                Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity 28 Aug - 03 Sept 2017

Solar activity ranged from very low to low levels. Very low levels
were observed on 31 Aug while low levels dominated the period from
28-30 Aug and again from 01-03 Sep. The period began as Regions 2673
(S10, L=117, class/area Dsc/130 on 03 Sep) and 2674 (N14, L=103,
class/area Fhc/930 on 03 Sep) were rotating onto the east limb as
simple alpha and beta magnetic configurations on 28-29 Sep,
respectively. Region 2672 (N08, L=227, class/area Dao/270 on 22 Aug)
was in decay as it approached the west limb on 01 Sep. By midday on
01 Sep, Region 2674 began a growth phase which increased its overall
area to approximately 930 millionths and produced 12 C-class flares
including a C5/Sf at 30/1845 UTC. Region 2673 began a slow growth
phase on 02 Sep, however rapid spot development occurred on 03 Sep
increasing its area to approximately 130 millionths with a
Dsc/beta-gamma spot classification. The largest flare of the period
was a C7 observed at 02/1541 UTC, with an associated Type II (976
km/s) radio burst and non-Earth directed coronal mass ejection
(CME), from Region 2672.

An earlier CME was observed off the west limb on SOHO/LASCO C3
imagery at approximately 28/1930 UTC. This CME was analyzed and it
was determined there was a possibility of a glancing blow on 01 Sep,
however no definitive signs were observed in solar wind data.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal levels on 30-31 Aug, moderate levels on 28 Aug, and at high
levels on 29 Aug and 01-03 Sep. The largest flux of the period was
12,319 pfu observed at 03/1705 UTC.

Geomagnetic field activity ranged from quiet to G1 (Minor) storm
levels during the period. Solar wind speed appeared to be in decline
from approximately 500 km/s to around 350 km/s by 29 Aug with total
field around 6-8 nT. Solar wind speed, temperature, and density was
unreliable in DSCOVR solar wind data between 28/0600 UTC and 29/1655
UTC. A solar sector boundary crossing into a negative sector was
observed at approximately 29/1925 UTC with a brief increase in total
field to 13 nT. The Bz component deflected southward to -10 nT. The
geomagnetic field responded with quiet levels on 28 and 30 Aug while
quiet to active levels were observed on 29 Aug. At approximately
31/0100 UTC total field began to increase, phi angle switched into a
positive sector, and solar wind speed and temperature began to rise
as a positive polarity coronal hole high speed stream (CH HSS) moved
into a geoeffective position. Total field reached a maximum of 30 nT
at 31/0615 UTC. Solar wind speed was mostly between 530 km/s to 680
km/s through 03 Sep and then began to decline to approximately 480
km/s by the end of the period. The geomagnetic field responded with
quiet to G1 (Minor) storm levels on 31 Aug and 02 Sep, quiet to
active levels on 01 Sep, and quiet to unsettled levels on 03 Sep.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY 04 - 30 SEPTEMBER 2017

Solar activity is expected to be at low levels with a chance for
M-class (R1-R2, Minor-Moderate) flares from 04-11 Sep and again from
14-30 Sep due to potential significant flare activity from Region
2673, 2674, and the return of old Region 2672. Very low levels are
expected from 12-13 Sep.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at normal to moderate levels on 07, 13, 21-27 Sep.
High levels are expected on 04-06, 08-12, 14-20, and 28-30 Sep due
to CH HSS influence.

Geomagnetic field activity is expected to be at unsettled to active
levels on 04, 07-09, 13-17, 27-30 Sep with G1 (Minor) geomagnetic
storm levels likely on 13-16, 27-29 Sep and G2 (Moderate) storm
levels likely on 14-15 Sep due to recurrent CH HSS activity.

:Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2017 Sep 04 0551 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/wwire.html
#
#      27-day Space Weather Outlook Table
#                Issued 2017-09-04
#
#   UTC      Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
2017 Sep 04     120          10          4
2017 Sep 05     118           8          3
2017 Sep 06     116           5          2
2017 Sep 07     116          15          4
2017 Sep 08     116          15          4
2017 Sep 09     105           8          3
2017 Sep 10      90           5          2
2017 Sep 11      85           5          2
2017 Sep 12      80           5          2
2017 Sep 13      80          25          5
2017 Sep 14      85          30          6
2017 Sep 15      85          30          6
2017 Sep 16      85          25          5
2017 Sep 17      85          12          4
2017 Sep 18      88           5          2
2017 Sep 19      92           5          2
2017 Sep 20      92           8          3
2017 Sep 21      92           5          2
2017 Sep 22      95           5          2
2017 Sep 23      98           8          3
2017 Sep 24     100           5          2
2017 Sep 25     105           8          3
2017 Sep 26     110           5          2
2017 Sep 27     110          20          5
2017 Sep 28     110          20          5
2017 Sep 29     110          20          5
2017 Sep 30     110          12          4
(SWPC via DXLD)