Wind Analysis — Harrisburg Winter Weather

10,336h

Total Snow Hours (All Stations)

WNW

Dominant Snow-Wind Direction

11.0:1

Avg Snow-to-Liquid Ratio

23.1:1

Highest Ratio Recorded

🌹 Overview — All 4 Stations During Snow Hours

Each panel shows the wind direction frequency and speed distribution during all hours when snow was reported at that station. Color represents wind speed band. Outer rings = more frequent. Note: dominant flow for all 4 stations comes from the west-northwest, consistent with continental air masses delivering cold, dry powder events. KMDT shows the most variable wind direction.

🎯 All 4 Stations Overlaid — Snow Wind Rose

Direct comparison of all four stations on a single polar plot. The directional signature is remarkably consistent across stations, confirming that regional-scale synoptic flow (rather than local terrain) dominates wind direction during snowfall at all four airports.

📐 Per-Station Wind Roses by Storm Category

Each station broken down by snowfall storm category. Larger storms (6-10", 10-15", 15+") tend to have stronger and more directionally consistent winds, typically from the NW–WNW quadrant. Note how light snow events (3-6") show much more scattered wind directions — consistent with clipper systems approaching from all angles.

KYORK / THV

KLNS / Lancaster

KMDT / Harrisburg

KCXY / Capital City

🌀 Major Storm Category Overlays

Overlaid wind roses for the three largest storm categories — showing how wind direction shifts and focuses with increasing snowfall. The 15+" category (single event: Blizzard Jonas) shows an intensely focused NW flow that drove the historic accumulations.

6–10" Storm Overlay

20 storm events

10–15" Storm Overlay

5 storm events

15+" Storm Overlay

1 storm event (Jonas)

👁 Precip vs Visibility Scatter

Hourly precipitation rate vs. reported visibility during snow. Lower visibility strongly correlates with higher precip rates, validating snow intensity estimation from visibility.

🧭 Snow Ratio by Wind Direction

Polar plot of average snow-to-liquid ratio by wind direction. NW winds produce the highest ratios (lightest, fluffiest snow). SE winds during snow events tend toward heavier, wetter snow with lower ratios — typical of Nor'easters.

📅 Annual Snow Hours by Station

Year-over-year variation in total snow hours per station. 2009-10 stands out dramatically with the Snowpocalypse + Snowmageddon double-event dominating that winter.

📊 Storm Summary by Category

Summary statistics for each storm size category: average duration, snow hours, wind speeds, and ratio distributions. Larger storms consistently show higher average wind speeds and tighter directional spreads.

💡 Key Wind Findings

🌬

WNW is the dominant snow-wind direction at all 4 stations — The West-Northwest quadrant accounts for the majority of snow hours across all stations and categories. This reflects the typical northwest-flow pattern behind departing coastal lows that produces heavy, banded snow across the Harrisburg region.

❄️

NW winds produce the highest snow ratios (fluffiest snow) — When wind is from the NW, snow ratios average well above 15:1, indicating very low-density, fluffy powder. These are classic Arctic airmass snows with temperatures well below freezing at all levels. SE winds during Nor'easters typically yield ratios of 8-10:1.

🔍

Larger storms show more directionally-focused wind patterns — 3-6" storms show scattered wind directions consistent with clipper systems, Alberta Clippers, and disorganized precipitation. 10-15" events show a tight NW signature — these are almost exclusively organized Nor'easters or major cutoff lows with strong and consistent winds.

📏

Visibility < 0.5 miles reliably indicates heavy snow rates — The precip vs. visibility scatter confirms that hourly precipitation above 0.15" correlates with visibility below 0.5 miles over 80% of the time. This validates using visibility as a proxy for snow intensity when radar data isn't available for historical events.