Message 28181 in SPACWX.USA
From: N4SD
Date: Tue, 18 Aug 26 00:31:00 Z
Newsgroups: SPACWX.USA
Subject: Space Weather 3-Day Forecast
Message-ID: <20852_N4SD>
Path: N2MH4|N2MH|W1BKW|N3MEL|N4SD
R:260818/0253Z 35605@N2MH4.#SENC.NC.USA.NOAM LinBPQ6.0.24
R:260818/0252z @:N2MH.#NNJ.NJ.USA.NOAM [via AREDN Mesh] jnos 2.0p $:20852_N4SD
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R:260818/0031Z 20852@N4SD.#TIDE.VA.USA.NOAM BPQ6.0.24
FXXX10 KWNP 180031
DAYTDF
:Product: 3-Day Forecast
:Issued: 2026 Aug 18 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 Aug 18-Aug 20 2026 is 4.67 (NOAA Scale
G1).
NOAA Kp index breakdown Aug 18-Aug 20 2026
Aug 18 Aug 19 Aug 20
00-03UT 3.67 3.67 4.00
03-06UT 4.00 4.67 (G1) 3.33
06-09UT 1.33 4.00 3.33
09-12UT 3.00 3.67 3.00
12-15UT 3.00 3.00 2.33
15-18UT 2.00 2.33 2.00
18-21UT 2.33 2.33 2.33
21-00UT 2.67 3.00 3.00
Rationale: G1 (Minor) geomagnetic storms are likely on 19 Aug due to CH
HSS influences.
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 Aug 18-Aug 20 2026
Aug 18 Aug 19 Aug 20
S1 or greater 5% 5% 5%
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 Aug 18-Aug 20 2026
Aug 18 Aug 19 Aug 20
R1-R2 35% 35% 35%
R3 or greater 5% 5% 5%
Rationale: There is a chance for R1-R2 (Minor-Moderate) radio blackouts
on 18-20 Aug.
------
73 de Sperry N4SD
N4SD@N4SD.#TIDE.VA.USA.NOAM
Received via NOAA GOES-East satellite downlink
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