Future Floyd–Florence rains could jump sharply
A design-rainfall method applied to three historic tropical cyclones projects large late-century increases in eastern North Carolina extreme rain.
Source
Projecting changes in extreme rainfall from three tropical cyclones using the design-rainfall approach
Study at a glance
- Design
- Computational / modelling — Design-rainfall scaling of Floyd, Matthew, and Florence onto future WRF-downscaled climates
- N
- N=3 · Three historic tropical cyclones; CESM and GFDL-CM3 RCP scenarios for 2025–2054 and 2070–2099
- Population
- Extreme tropical-cyclone rainfall over eastern North Carolina
- Outcome
- Projected late-century increases in storm totals and maximum intensities
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
Authors mapped PRISM rainfall from Hurricanes Floyd, Matthew, and Florence onto Atlas 14 return periods, then scaled each grid cell by changes in precipitation frequency between 2025–2054 and 2070–2099 from WRF-downscaled CESM and GFDL-CM3 RCP scenarios.
What they found
Under CESM RCP4.5, ‘2100’ storm totals rise 22–41% while maximum intensities jump ~89–130% (Florence MI to 1535 mm). Coastal-plain cells see the largest rare-event increases; some inland RCP8.5 cells even decrease. Mean 3-day increases of 24–39% exceed many statistically downscaled estimates.
The limits
What it doesn't show
Atlas 14 omits later storms so return periods may be too rare; 36 km WRF is coarse for TCs; the method does not simulate future storm genesis, tracks, or surge compounding.
Key terms
- Design-rainfall approach (DRA)
- Scaling observed storm rainfall by model-projected changes in precipitation frequency at each cell’s return period.
- Return period (RP)
- Average years between events of a given intensity, from NOAA Atlas 14.
- Maximum intensity (MI)
- Highest point rainfall in the storm over the analysis duration.
- ENC
- Eastern North Carolina coastal plain, highly exposed to tropical cyclones.
- PRISM
- Gridded observational precipitation product used at 4 km then aggregated to 36 km.
Flashcards
Research intelligence for this paper
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Quiz yourself
DRA scales observed TC rain by:
Common questions
Which storms were used?
Floyd (1999), Matthew (2016), and Florence (2018).
Why scale observed storms instead of simulating new ones?
To explore relative future intensity independent of GCM tropical-cyclone biases.
Where are increases largest?
Coastal-plain basins; inland ENC can even see decreases in some RCP8.5 rare events.
Is 1535 mm plausible?
It matches Harvey 2017 point rainfall, but whether NC can host that from a TC is unproven.
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