jns182wx.github.ioNEXRAD Beam AnalysisFebruary 20, 2026
STORM DEEP DIVE · FEB20 · PEAK 2026-02-20T10Z · DATA: IEM RAP BUFKIT + ASOS HOURLY

February 20, 2026

Cold Air Damming Event

0.800"
MDT Hourly-Corrected Total
8,209
Freezing Level ft AGL
8,185
Wet Bulb Zero ft AGL
23.42
Precip Water mm
91
Bulk Shear 0-6km kt
2.63mi
MDT Raindrop Drift
Atmospheric Cross-Section — West to East · MDT Peak Hour Sounding

Wind Hodograph — 0 to 6km AGL

97°/6.5kt
Surface Wind
135°/40.4kt
1km Wind
222°/32.2kt
3km Wind
243°/85.4kt
6km Wind
91
Bulk Shear 0-6km kt
198°
Storm Tilt Dir

Key Findings — Peak Hour Analysis

☁️ Precipitation Type
Surface: 🌧 Rain (marginal freezing) · Sfc temp 2.1°C · Dewpoint 1.8°C
Freezing level 8,209ft AGL · Wet bulb zero 8,185ft AGL
📡 Radar Beam Position (MDT · KLWX · 8,493ft AGL)
Beam is above the freezing level — sampling ice/snow crystals. Z-R relationship wrong for liquid QPE.
💧 Raindrop Trajectory (MDT)
Drop sampled at 8,493ft AGL drifts 2.63 miles SSE before surface impact
Mid-level flow: 222°/32.2kt · Terminal velocity 7 m/s assumed
💨 Wind Shear & Storm Structure
0-6km bulk shear: 91kt · Tilt toward 198° SSW
Low-level lapse rate: 1.5°C/km · Directional shear veering with height → warm air advection
🏜️ Dry Air & Moisture
Precipitable water: 23.42mm · CAPE: 0J/kg
Dry layer (T-Td>10°C) first found at: 30,878ft AGL
Deep moist column — precipitation efficiency high
Hourly Precipitation Timeline — All Stations (corrected hourly totals)
10-Station Ensemble — Peak Hour RAP Thermodynamics
StationRadarBeam AGLEvent Total Freeze ftWBZ ftPW mm Drop DriftShear kt Storm TiltDry Layer ft
MDTHarrisburg Intl KLWX 8,493 0.800" 8,209 8,185 23.42 2.63mi SSE 91 198° SSW 30,878
CXYCapital City KLWX 8,413 0.680" 8,209 8,185 23.42 2.61mi SSE 91 198° SSW 30,878
THVYork KLWX 5,874 0.800" 12,344 9,902 31.29 2.51mi WSW 65 240° WSW 11,085
SEGSelinsgrove KCCX 6,608 0.380" 731 692 19.99 2.56mi SE 64 189° S 33,046
LNSLancaster KDIX 9,420 0.570" 8,339 8,133 22.4 2.44mi SSE 96 210° SSW 30,889
ZERSchuylkill Co. KCCX 8,582 0.230" 8,203 7,416 22.24 2.15mi SE 89 204° SSW 40,621
HZLHazleton KBGM 7,429 0.100" 1,383 1,431 14.92 1.61mi SE 72 211° SSW 8,728
RDGReading KDIX 7,642 0.600" 8,203 7,416 22.24 2.06mi SE 89 204° SSW 40,621
MUIFt. Gap KCCX 9,189 0.340" 8,209 8,185 23.42 2.75mi SSE 91 198° SSW 30,878
N79New Garden KDIX 5,431 0.220" 7,326 7,300 21.41 1.62mi ESE 69 207° SSW 40,947