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MRMS Weather Grabber v2

Build a hierarchical precipitation-forensics packet from NOAA's public MRMS archive: broad event accumulations first, then progressively finer 6 h → 3 h → 1 h windows where the interesting weather actually happened.

1. Event window

Start UTC
End UTC

Times in this section are treated as UTC. The packet builder can span up to 3 days by default; longer windows are allowed, but browser ZIP memory remains an organism with feelings.

Product families

Overview accumulation intervals

For 24 h products, prefer daily 12Z endpoints Include longest selected accumulation ending nearest event end

How overview scheduling works

72/48 h products are used as event-scale context. 24 h products can be pinned to 12Z daily. 12 h products are sampled at 00/12Z, 6 h at 00/06/12/18Z, 3 h every 3 hours, and 1 h hourly. You decide which levels are worth the bandwidth.

2. Drill into important 6-hour windows

Enter the ending UTC time of each important 6-hour window, one per line. Example: 2026-09-03T12:00Z. The builder can automatically include the parent 6-hour field, its two 3-hour children, and its six 1-hour children.

6 h parent 3 h children 1 h children

For a 6-hour window ending 12Z, the 3-hour children end at 09Z and 12Z; the 1-hour children end at 07, 08, 09, 10, 11, and 12Z. This preserves the nested chronology instead of mixing unrelated rolling accumulations.

3. Optional live storm context

QC composite reflectivity Precipitation rate 5-min CG lightning density

Context products are sampled across the event at the cadence chosen below. Keep these off for a compact QPE packet; turn them on when reconstructing storm morphology.

Context cadence

4. Scan, inspect, download

–files

–estimated

–requested anchors

Scan only inventories NOAA S3 objects and estimates size. Nothing is downloaded until you press Download.

Activity

Ready.

Packet contents

Layer	Purpose
RadarOnly QPE	Radar-only accumulation, independent of gauge adjustment
MultiSensor Pass2	Later-latency gauge-adjusted multi-sensor accumulation
Radar accumulation quality	Non-dimensional quality of the radar accumulation
Gauge influence index	Where/how strongly gauges influence Pass2; this is not itself a rainfall amount

The ZIP also contains MRMS_MANIFEST.json, MRMS_MANIFEST.csv, and README.txt, recording the event window, requested anchors, exact S3 keys, UTC times, roles, and source URLs.

Source: NOAA MRMS public AWS S3 bucket noaa-mrms-pds. Original .grib2.gz files are preserved byte-for-byte in the ZIP. This is a research/data-acquisition helper, not an operational warning service.