Message 30149 in SPACWX.USA
From: N4SD
Date: Thu, 17 Sep 26 00:32:00 Z
Newsgroups: SPACWX.USA
Subject: Space Weather 3-Day Forecast
Message-ID: <22580_N4SD>
Path: K7EK|K5DAT|N3MEL|KA3VSP|N4SD
R:260917/0047z @:K7EK.#NOKY.KY.USA.NOAM $:22580_N4SD
R:260917/0046Z 53404@K5DAT.#NEWI.WI.USA.NOAM LinBPQ6.0.25
R:260917/0046Z 26990@N3MEL.#EPA.PA.USA.NOAM LinBPQ6.0.25
R:260917/0042Z 8213@KA3VSP.DE.USA.NOAM BPQ6.0.25
R:260917/0032Z 22580@N4SD.#TIDE.VA.USA.NOAM BPQ6.0.24
FXXX10 KWNP 170031
DAYTDF
:Product: 3-Day Forecast
:Issued: 2026 Sep 17 0030 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
#
# 3-Day Forecast
#
A. NOAA Geomagnetic Activity Observation and Forecast
The greatest observed 3 hr Kp over the past 24 hours was 4 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Sep 17-Sep 19 2026 is 4.67 (NOAA Scale
G1).
NOAA Kp index breakdown Sep 17-Sep 19 2026
Sep 17 Sep 18 Sep 19
00-03UT 4.00 3.67 2.67
03-06UT 4.67 (G1) 2.00 2.00
06-09UT 3.67 2.00 2.33
09-12UT 3.33 2.67 2.33
12-15UT 3.33 2.67 2.33
15-18UT 3.33 2.67 2.33
18-21UT 3.33 2.67 2.33
21-00UT 3.33 3.00 2.67
Rationale: G1 (Minor) geomagnetic storms are likely on 17 Sep. No
significant transient or recurrent solar wind features are forecast for
18-19 Sep.
B. NOAA Solar Radiation Activity Observation and Forecast
Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was
below S-scale storm level thresholds.
Solar Radiation Storm Forecast for Sep 17-Sep 19 2026
Sep 17 Sep 18 Sep 19
S1 or greater 1% 1% 1%
Rationale: No S1 (Minor) or greater solar radiation storms are expected.
No significant active region activity favorable for radiation storm
production is forecast.
C. NOAA Radio Blackout Activity and Forecast
No radio blackouts were observed over the past 24 hours.
Radio Blackout Forecast for Sep 17-Sep 19 2026
Sep 17 Sep 18 Sep 19
R1-R2 5% 5% 5%
R3 or greater 1% 1% 1%
Rationale: No R1 (Minor) or greater radio blackouts are expected. No
significant active region flare activity is forecast.
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