FXXX12 KWNP 121231

DAYDIS



:Product: Forecast Discussion

:Issued: 2025 Dec 12 1230 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

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#             Forecast Discussion

#

Solar Activity



.24 hr Summary...

Solar activity reached moderate levels with an M2.0 flare at 12/0505 UTC

from Region 4296 (S15W83, Eho/beta-gamma), which triggered a sympathetic

M1.1 from Region 4294 (S16W93, Dkc/beta-gamma-delta) at 12/0544 UTC;

these regions is moving beyond the west limb now and is becoming too

difficult to characterize due to foreshortening. The M-class events were

accompanied by Type II and Type IV radio sweeps and a CME became visible

in LASCO C2 at 12/0524 and is currently under analysis.



Region 4307 (S12W05, Cri/beta-gamma) showed continued flux emergence in

its intermediary region, developing new spots along its southern edge. A

new region rapidly developed along the eastern limb and was numbered as

Region 4308 (N08E59, Bxo/beta). All other regions were stable or in

decay.



.Forecast...

Probabilities for flare activity decrease through 14 Dec as major flare

producing regions move beyond the west limb. Chances for R1-R2

(Minor-Moderate) flares decrease from 75% to 55%, and chances for R3

(Strong) decrease from 10% to 5% over the three days.



Energetic Particle



.24 hr Summary...

The greater than 2 MeV electron flux remained at moderate levels

throughout the period. The greater than 10 MeV proton flux remained at

background.



.Forecast...

The electron flux is expected to become elevated through 14 Dec as a

coronal hole (CH) high speed stream (HSS) originating from the negative

polarity CH in the northern hemisphere becomes geoeffective. The flux is

likely to surpass the 1,000 pfu threshold during the diurnal maxima.



As complex regions in the western hemisphere move beyond the limb,

chances for the proton flux to become elevated decrease. There is a 10%

chance for an S1 (Minor) radiation storming event on 12 Dec, with

chances decreasing to 1% by 14 Dec.



Solar Wind



.24 hr Summary...

Solar wind parameters remained elevated due to what is assumed to be

multiple transients and undulations between current sheets. The total

magnetic field (Bt) decreased from near 22 nT to just under 10 nT. The

north-south (Bz) component was predominantly positive for the first half

of the reporting period, slowly decreasing from near 15 nT. After

11/2100 UTC, Bz sustained an average southward orientation of

approximately -8 nT. Solar wind speeds remained between

400-450 km/s. The phi angle was predominantly positive until roughly

11/1300 UTC when rotation into the negative sector occurred.



.Forecast...

Solar wind will likely experience additional enhancements in the later

half of 12 Dec with the arrival of an incoming co-rotating interacting

region (CIR) associated with a negative polarity CH HSS. Wind speeds

with the HSS are expected to rise towards 650 km/s through 13-14 Dec.



Geospace



.24 hr Summary...

The geomagnetic field had an isolated period of G1 (Minor) storming

levels late on 11 Dec due to the sector boundary crossing, and

afterwards was largely unsettled to active.



.Forecast...

Additional enhancements are likely by the end of 12 Dec through early 13

Dec with the arrival of a CIR/HSS. Unsettled to active levels are likely

to continue into 14 Dec as CH HSS influence lingers.