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FXXX12 KWNP 280032

:Product: Forecast Discussion
:Issued: 2017 Mar 28 0030 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 at low levels due to occasional C-class flares.
Region 2644 (N13E17, Dai/beta-gamma) grew further as it gained area and
spots. There were mixed polarities among the intermediate spots and some
minor magnetic shear present. The region produced a C1/1f flare at
27/0000 UTC and frequent B-class flares afterwards. New Region 2645
(S09E59, Cso/beta) emerged and was assigned this period. Limb
foreshortening prevented a better analysis, however, the region was
unstable and underwent continued slow growth. The region produced
occasional C-class flares, to include the largest flare of the period, a
C5/Sf at 27/1820 UTC. Region 2646 (N06W60, Hrx/alpha) emerged and was
assigned, but was inactive.

A narrow cone CME first seen in SOHO/LASCO-C2 imagery at 27/1212 UTC was
associated with a C3/Sf from Region 2645 at 27/1112 UTC. Analysis of
SDO/AIA imagery indicated the CME appeared to be on a more eastern
trajectory and is not expected to have an Earth-directed component.

Solar activity is expected to be low, with C-class flares likely, and a
slight chance of M-class flares (R1-R2, Minor-Moderate) the next two
days (28-29 Mar) due to the instability and flare probabilities of
Regions 2644 and 2645. Solar activity is expected to be very low, with
C-class flare probability expected to decrease to a chance, with a
slight chance of M-class flares continuing into day three (30 Mar) as
Region 2646 rotates beyond the limb.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux began the period at moderate
levels, until electron redistribution due to a CIR, decreased the flux
to normal values. The greater than 10 MeV proton flux remained at
background levels.

The greater than 2 MeV electron flux is expected to be at normal to
moderate levels, with a chance for high levels on day one (28 Mar); and
increase to high levels on days two and three (29-30 Mar) due to CH HSS
effects. The greater than 10 MeV proton flux is expected to continue at
background levels all three days.

Solar Wind

.24 hr Summary...
Solar wind parameters were indicative of CIR arrival, followed by onset
of a negative polarity, extension of the south polar CH HSS. Total IMF
strength increased early in the period and reached a maximum value of 19
nT at 27/0755 UTC. Total field strength began a slow and unsteady
decline afterwards. The Bz component was primarily southward oriented as
the CIR progressed, and became more variable with CH HSS onset. Maximum
southward deviation reached was -14 nT at 27/0827 UTC. Solar wind speed
began the period at about 370 km/s, before it increased with CH HSS
onset and reached speeds of over 650 km/s by the end of the period. The
phi angle was negative (towards the Sun).

Solar wind speed is anticipated to reach around 700 km/s on day one (28
Mar) based off recurrence data. IMF strength will likely weaken in the
more rarified space of the CH HSS, while solar wind speeds remain
elevated on day two and three (29-30 Mar) as Earth continues under the
influence of the negative, southern polar CH HSS extension.


.24 hr Summary...
The geomagnetic field reached G2 (Moderate) and G1 (Minor) storming
levels due to CIR and CH HSS effects.

The geomagnetic field is expected to respond with primarily active to
minor (G1-Minor) storm levels, with an isolated period of moderate
(G2-Moderate) storming, on day one (28 Mar) as an enhanced IMF and
elevated solar wind speeds from the CH HSS continue. Overall planetary
geomagnetic response is expected to decrease to unsettled to minor (G1)
storming, with an isolated period of moderate (G2) storming likely on
day two (29 Mar) as elevated solar wind speeds from the CH HSS continue.
The geomagnetic field is expected to react with primarily unsettled to
active levels, with an isolated period of minor (G1) storming remaining
likely on day three (30 Mar) as CH HSS effects continue, but begin
weakening. is the U.S. government's official web portal to all federal, state and local government web resources and services.