Routine Space Environment Product (Daily)
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FXXX12 KWNP 271230

:Product: Forecast Discussion
:Issued: 2016 May 27 1230 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
#             Forecast Discussion
Solar Activity

.24 hr Summary...
Solar activity was low. Region 2548 (N13W43, Dai/beta) produced a C1/Sf
flare at 26/1336 UTC. Shortly after this event Region 2546 (S07, L=224),
which rotated around the western limb, produced a C1 flare at 26/1351
UTC with an associated Type IV radio sweep. As mentioned in the previous
discussion product an Earth-directed component is not anticipated from
either event due to the narrow signature and southwestern trajectory of
the visible CME. A disappearing solar filament (DSF) was observed
lifting off of the visible disk at approximately 27/0100 UTC in SDO/AIA
304 imagery. The majority of the ejecta appeared to get reabsorbed,
however, SWPC forecasters await additional LASCO chronograph imagery to
complete analysis of this event. There were no additional CMEs observed
in satellite imagery during the reporting period.

Solar activity is expected to be low with a chance for C-class flares
throughout the forecast period (27-29 May) due to the flare history of
Regions 2546 and 2548.

Energetic Particles

.24 hr Summary...
The greater than 2 MeV electron flux was at moderate levels until
approximately 27/0000 UTC when flux values decreased to normal levels
due to particle redistribution after the arrival of an anticipated weak
CH HSS. The greater than 10 MeV proton flux continued at background

The greater than 2 MeV electron flux is expected to be at normal to
moderate levels on days one through three (27-29 May) due to continued
effects from the CH HSS. The greater than 10 MeV proton flux is expected
to remain at background values.

Solar Wind

.24 hr Summary...
The solar wind environment was nominal until approximately 27/0100 UTC
when a SSBC occurred which changed the phi angle from a positive to a
negative solar sector orientation. At the same time an enhancement was
noted in the interplanetary magnetic field when Bt jumped from 2 to 8 nT
and the Bz component dropped to a period low of -7 nT. Wind speed
displayed a steady increase starting the period near 330 km/s and ending
the period at approximately 450 km/s. This solar wind signature,
measured at the ACE spacecraft, is indicative of a weak,
negative-polarity CH HSS.

The solar wind environment is expected to remain slightly enhanced under
the effects of the above mentioned CH HSS throughout day one (27 May)
and into the early part of day two (28 May). On day three (29 May) an
additional enhancement is anticipated due to the arrival of another
negative-polarity CH HSS located in the northwest quadrant of the solar


.24 hr Summary...
The geomagnetic field was quiet to unsettled.

The geomagnetic field is expected to be quiet to unsettled with an
isolated active period likely on day one (27 May) due to continued CH
HSS effects. Quiet to unsettled conditions are expected on day two (28
May) due to waning CH HSS influence. The geomagnetic response on day
three (29 May) is expected to be mostly quiet to unsettled with active
periods late in the day due to the anticipated arrival of another
negative polarity CH HSS. is the U.S. government's official web portal to all federal, state and local government web resources and services.