noaa-cpc

name

noaa-cpc

description

Fetch climate and ENSO data from NOAA Climate Prediction Center — Niño SST anomaly indices (weekly/monthly), Oceanic Niño Index (ONI), Southern Oscillation Index (SOI), and ENSO diagnostic advisory text. Use this skill when the user asks about El Niño, La Niña, ENSO status, Pacific sea surface temperatures, Southern Oscillation, or climate patterns affecting weather, agriculture, or commodity markets, even if they don't name ENSO, NOAA, or CPC explicitly.

NOAA CPC Indices

Fetch climate indices from the NOAA Climate Prediction Center — Niño SST anomalies, the Oceanic Niño Index (ONI), Southern Oscillation Index (SOI), and ENSO diagnostic advisories.

Source: https://www.cpc.ncep.noaa.gov/data/indices/

Scripts

enso-indices

Fetch weekly (OISSTv2.1) or monthly (ERSSTv5) Niño SST anomaly indices for all four Niño regions.

Usage:
  enso-indices [--index <name>] [--period weekly|monthly] [--json] [--months <n>]

Option	Description
--index	Single index: nino12, nino3, nino34, nino4 (default: all)
--period	weekly (OISSTv2.1) or monthly (ERSSTv5) [default: weekly]
--json	Output as JSON
--months	Number of recent weeks/months (default: 1 weekly, 3 monthly)

Examples:

enso-indices --index nino34
enso-indices --period monthly --months 6
enso-indices --json

enso-oni

Fetch the Oceanic Niño Index — 3-month running mean of Niño 3.4 SST anomalies. Thresholds: El Niño ≥ +0.5°C for 5 consecutive overlapping seasons, La Niña ≤ -0.5°C.

Usage:
  enso-oni [--months <n>] [--json] [--threshold <t>]

Option	Description
--months	Number of recent seasons (default: 6)
--json	Output as JSON
--threshold	Only show seasons with |anomaly| >= this (e.g. 0.5)

Examples:

enso-oni --months 4
enso-oni --threshold 0.5 --months 12

enso-soi

Fetch the Southern Oscillation Index (SOI) — standardized Tahiti minus Darwin sea level pressure. Confirms atmospheric coupling. Negative SOI → El Niño, positive SOI → La Niña.

Usage:
  enso-soi [--months <n>] [--json] [--standardized]

Option	Description
--months	Number of recent months (default: 6)
--json	Output as JSON
--standardized	Use standardized values (default: anomalies)

Examples:

enso-soi --months 12
enso-soi --json

enso-advisory

Fetch the latest ENSO Diagnostic Discussion and extract key fields (status, synopsis, Niño 3.4 value, probability).

Usage:
  enso-advisory [--text] [--json]

Examples:

enso-advisory
enso-advisory --text

Workflows

Check current ENSO status

enso-advisory
enso-indices --index nino34
enso-soi --months 3

Track ENSO evolution

enso-indices --period monthly --index nino34 --months 12
enso-oni --months 8
enso-soi --months 12

Gotchas

• Weekly vs monthly base periods — Weekly indices use OISSTv2.1 (1991–2020 base period). Monthly ERSSTv5 and ONI also use 1991–2020. ONI uses centered 30-year base periods updated every 5 years.
• Anomaly, not absolute SST — The anomaly (SSTA) is the departure from the 30-year average. An absolute SST of 28°C in Niño 3.4 is normal; the anomaly is what matters.
• Niño 3.4 is the benchmark — CPC uses Niño 3.4 (170°W–120°W, 5°N–5°S) for official ENSO classification. Niño 1+2 is the easternmost region and can spike independently.
• ONI lags weekly data — ONI is a 3-month running mean and smooths weekly noise. Weekly indices show the current state; ONI shows the sustained signal.
• SOI confirms coupling — Negative SOI (Tahiti lower pressure, Darwin higher) confirms El Niño atmospheric coupling. SST anomalies without SOI confirmation may indicate a weak or uncoupled event.
• Weekly data has leading spaces — The fixed-width SST file has leading spaces on data lines. Parsing must account for this.
• SOI has two data blocks — The SOI file contains anomaly values followed by standardized values below a STANDARDIZED DATA header. The script defaults to anomalies.
• SSTA concatenation — In the weekly data, when SSTA is negative the SST and SSTA are concatenated (e.g., 20.6-0.1). When positive they are space-separated (25.3 0.1).

Base directory: file:///Users/shane/.config/opencode/skills/noaa-cpc