Storm Radar

Storm Radar makes a warning inspectable through evidence. It pairs the warning context with MRMS observations, source times, spatial relationships, units, and limitations. Radar can support or differ from a warning's stated threat; record the relationship instead of treating either as interchangeable proof.

The repository's org/apps/data/worker/products.ts defines MESH and lowest-altitude reflectivity. The data Worker polls the public NOAA MRMS S3 bucket on its configured two-minute schedule and sends bounded discovery jobs through ingestion. Polling frequency does not guarantee a new complete observation every two minutes.

Each evidence item needs the native object key/version, observation time, retrieval time, product, native unit, geometry or raster bounds, derived artifact, transformation version, and caveat. The dataset inventory owns supported products; the journey contract links code.

Retain a versioned temporal and spatial association between the warning and radar evidence. A warning polygon is not a hail swath. MRMS is not a direct measurement of a roof or a report of replacement need.

Show separate states for evidence pending, available, partial, stale, and unavailable. State whether an observation falls before, during, or after the warning interval. Missing radar coverage is not a finding of no hail.

1. Forecast and anticipation
   Where is severe weather likely?

2. Radar-derived evidence
   What does radar indicate is occurring?

3. Ground confirmation
   What was actually reported?

4. Derived storm event
   What coherent geographic event do these signals represent?

5. Property impact
   Which structures were probably exposed?

6. Action
   Where should teams deploy, and who may they contact?

7. Outcome
   What happened after the action?

Storm Forecast owns pre-event outlooks and their predicted classification. Watches and warnings belong to Storm Alert with their native status, validity, and protective instructions. They are not classified as forecast products merely because they precede radar evidence. Storm Radar preserves observations and their source-specific relationship to those messages.

The NOAA MRMS distribution registry ↗ identifies the public noaa-mrms-pds bucket in us-east-1 and its notification resource. Preserve native source attribution and distinguish derived outputs.

The existing Worker uses polling. An SNS integration would be a separate source-delivery change, not a configuration implied by this documentation.

MESH and lowest-altitude reflectivity are the two products in the current code catalog. POSH, SHI, accumulated MESH products, and radar-quality layers are candidate supporting inputs, not an inventory of implemented ingestion. Verify native definitions and cadence before adding a product contract.

Maximum Estimated Size of Hail (MESH) is the primary hail-size signal. StormTrust displays United States-facing values in inches while retaining source units in provenance:

25.4 mm = 1.00 in
38.1 mm = 1.50 in
50.8 mm = 2.00 in

MESH is a radar-derived estimate, not a surface hailstone measurement. StormTrust labels MESH-derived conclusions accordingly.

Probability of Severe Hail may support event qualification, prioritization, alerts, confidence, and disagreement detection. It does not independently prove physical hail at the ground.

Severe Hail Index may support interpretation, debugging, methodology, and model features. The product surface should expose it only when useful to the user.

The evidence model should retain radar-quality context and lower confidence when coverage is weak, radar beams are high above the surface, source files are missing, products disagree, or quality masks indicate uncertainty.

Supporting context may include Radar Quality Index, reflectivity at the lowest altitude, reflectivity around freezing levels, hydrometeor classification, warnings, ground reports, and selected NEXRAD review.

These layers improve interpretation. They are not interchangeable evidence.

A hail swath represents spatial accumulation through time:

Frame 1      Frame 2      Frame 3
   \            |            /
    \           |           /
     └──── temporal max ────┘
               ↓
          Hail swath

StormTrust preserves the accumulation window, product, start and end, grid resolution, source, threshold, and transformation method.

NEXRAD provides station-level radar data for deeper analysis, validation, research, and selected forensic workflows. MRMS remains the primary national derived hail layer for Release 1 because it avoids requiring StormTrust to compose every radar volume for baseline coverage.

The warning integration uses authoritative interfaces. The proposed shared warning contract preserves alert ID, issuing office, event type, effective time, onset, expiration, geometry, area, severity, certainty, urgency, and the source representation.

SPC preliminary reports, NWS Local Storm Reports, and later National Centers for Environmental Information (NCEI) records provide ground context. Preliminary observations retain a preliminary state until reconciliation.

NCEI Storm Events supports historical verification, retrospective analysis, research, reconciliation, and test fixtures. It is not the primary real-time alert feed.

The proposed source-health contract includes telemetry such as this fictional example:

{
	"source": "noaa-mrms",
	"status": "degraded",
	"lastExpectedAt": "2026-08-16T19:20:00Z",
	"lastReceivedAt": "2026-08-16T19:14:00Z",
	"lagSeconds": 360,
	"missingPartitions": 2
}

Source states include healthy, delayed, partial, degraded, unavailable, and recovering.

Reconciliation records later evidence without erasing history. A late ground report, removed preliminary report, delayed file, corrected product, or approved algorithm reprocessing creates a revision.