When reporting severe weather to the NWS or on a Skywarn net, here are guidelines to follow.
(these charts are from the NWS Jacksonville site)
Red indicates severe criteriaPlease do not refer to “marble size” hail! It’s ambiguous; please try to reference coin sizes.PLEASE NOTE: As of January 5, 2010, the severe criterion for hail diameter changed from 3/4″ to 1″.
| Hail Size Reference Chart
| Hail Diameter (Inches)
|| Reference Object
||Ping Pong Ball
Red indicates severe criteria
| Beaufort Wind Speed Estimate Scale
|| Wind Speed
|| On Land
|| On Water Surfaces
||Calm. Smoke rises vertically.
||Waters are mirror smooth.
||Smokes drift indicates wind direction. Still wind vanes.
||Waters have a ripple.
||Wind is felt on face, leaves rustle, wind vanes begin to move.
||Small wavelets, crests glassy, no breaking.
||Leaves and small twigs constantly move, light flags are extended.
||Large wavelets, crests begin to break, scattered whitecaps.
||Dust, leaves and loose paper lifted, small tree branches move.
||Small waves (1-4 ft) becoming longer with numerous whitecaps.
||Small trees in leaf begin to sway.
||Moderate waves (4-8 ft) taking longer form, many whitecaps, some spray.
||Larger trees begin moving, whistling in wires.
||Larger waves (8-13 ft), whitecaps common, more spray.
||Whole trees moving, resistance felft walking against wind.
||Mounting sea (seas heaps) (waves 13-20 ft), foam streaks off of breakers.
||Whole trees in motion, resistance felt walking in wind.
||Moderately high waves (13-20 ft) of greater length, edges of crests begin to break into spindrift, foam blown in streaks.
||Branches break from trees, slate blows off roofs, slight structural damage.
||High waves (20 ft), sea begins to roll, dense streaks of foam, visibility affected by spray.
|| Trees broken or uprooted, considerable structural damage.
|| Very high waves (20-30 ft) with overhanging crests, sea white with dense blown foam, heavy sea roll, visibility impaired.
|| Violent Storm
||Exceptionally high waves (30-45 ft), foam patches cover the sea, poor visibility.
||Storm waves (> 45 ft), air filled with foam and spray, sea completely white, visibility bad.