SPC Hindcast Lab

CASE

BLIND HINDCAST DATE HIDDEN NIU Practically Perfect Archive • 1979–2023

CASE SOURCE

NIU Practically Perfect 1979–2023 • Tornado / Hail / Wind

OUTLOOK TYPE

PROBABILITY

CONDITIONAL INTENSITY

CIG applies to modern SPC outlooks beginning in 2026.

DRAWING

Brush size

REPORTS

Use the reports to draw your hindcast. The correct SPC outlook stays hidden until you submit.

FORECAST

Main hazard Confidence Notes

TORNADO OUTLOOK

Historical Case

Draw your tornado probabilities.

Derived categorical TSTM

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Tornado 2% 0 strokes

Tornado2%Loading reports…

Hail5%Loading reports…

Wind5%Loading reports…

CategoricalTSTMAutomatically derived

SUBMIT & VERIFY

HOW CATEGORICAL IS DERIVED

TSTMNo severe threshold reached

MRGLLow severe probability threshold

SLGTModerate severe probability threshold

ENHHigher combined hazard signal

MDTVery high hazard probabilities

HIGHExtreme hazard probabilities