Message:21046 In: SPACWX.USA
From: N4SDDate: Sat, 18 Apr 26 00:32:00 Z
Newsgroups: SPACWX.USA
Subject: Space Weather 3-Day Forecast
Message-ID: <11387_N4SD>
Path: N2MH4|NS2B|KE0GB|W9GM|KA3BVJ|KA3VSP|N4SD
R:260418/1843Z 30366@N2MH4.#SENC.NC.USA.NOAM LinBPQ6.0.24
R:260418/1842Z 49459@NS2B.#WNY.NY.USA.NOAM BPQ6.0.25
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R:260418/1841Z 80238@KA3BVJ.#EPA.PA.USA.NOAM BPQ1.4.65
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R:260418/0032Z 11387@N4SD.#TIDE.VA.USA.NOAM BPQ6.0.24
FXXX10 KWNP 180031
DAYTDF
:Product: 3-Day Forecast
:Issued: 2026 Apr 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 2 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Apr 18-Apr 20 2026 is 6.00 (NOAA Scale
G2).
NOAA Kp index breakdown Apr 18-Apr 20 2026
Apr 18 Apr 19 Apr 20
00-03UT 6.00 (G2) 5.00 (G1) 3.67
03-06UT 6.00 (G2) 4.67 (G1) 3.67
06-09UT 5.00 (G1) 4.00 3.33
09-12UT 4.00 3.33 3.33
12-15UT 3.67 3.67 3.33
15-18UT 3.33 3.00 2.00
18-21UT 3.00 3.00 3.33
21-00UT 4.33 3.33 3.33
Rationale: G1 (Minor) to G2 (Moderate) geomagnetic storming is likely on
18 Apr, with G1 (Minor) storming likely continuing on into the early
portions of 19 Apr, due to negative polarity coronal hole high speed
stream 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 Apr 18-Apr 20 2026
Apr 18 Apr 19 Apr 20
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 Apr 18-Apr 20 2026
Apr 18 Apr 19 Apr 20
R1-R2 25% 25% 25%
R3 or greater 5% 5% 5%
Rationale: R1-2 (Minor-Moderate) radio blackouts due to isolated M-class
flare activity are likely through 28 Apr.
------
73 de Sperry N4SD
N4SD@N4SD.#TIDE.VA.USA.NOAM
Received via NOAA GOES-East satellite downlink
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