National Weather Service United States Department of Commerce

Heat Continues for the East and South-Central U.S.; Strong to Severe Storms Across the Mid-Atlantic and Northeast

The extremely dangerous heat wave continues across the East Coast and much of the South-Central U.S. today. Record high temperatures are expected for some areas especially across the Mid-Atlantic where extreme heat risk conditions reside. There is a Slight Risk (level 2 of 5) of severe thunderstorms today for the northern Mid-Atlantic into portions of southern New England. Read More >

Beaufort Wind Scale

Developed in 1805 by Sir Francis Beaufort of England


Force Wind WMO
Classification
Appearance of Wind Effects
Kts MPH On the Water On Land
0 Less than 1 Less than 1 Calm Sea surface smooth and mirror-like Calm, smoke rises vertically
1 1-3 1-4 Light Air Scaly ripples, no foam crests Smoke drift indicates wind direction, still wind vanes
2 4-6 5-7 Light Breeze Small wavelets, crests glassy, no breaking Wind felt on face, leaves rustle, vanes begin to move
3 7-10 8-12 Gentle Breeze Large wavelets, crests begin to break, scattered whitecaps Leaves and small twigs constantly moving, light flags extended
4 11-16 13-18 Moderate Breeze Small waves 1-4 ft. becoming longer, numerous whitecaps Dust, leaves, and loose paper lifted, small tree branches move
5 17-21 19-24 Fresh Breeze Moderate waves 4-8 ft taking longer form, many whitecaps, some spray Small trees in leaf begin to sway
6 22-27 25-31 Strong Breeze Larger waves 8-13 ft, whitecaps common, more spray Larger tree branches moving, whistling in wires
7 28-33 32-38 Near Gale Sea heaps up, waves 13-20 ft, white foam streaks off breakers Whole trees moving, resistance felt walking against wind
8 34-40 39-46 Gale Moderately high (13-20 ft) waves of greater length, edges of crests begin to break into spindrift, foam blown in streaks Whole trees in motion, resistance felt walking against wind
9 41-47 47-54 Strong Gale High waves (20 ft), sea begins to roll, dense streaks of foam, spray may reduce visibility Slight structural damage occurs, slate blows off roofs
10 48-55 55-63 Storm Very high waves (20-30 ft) with overhanging crests, sea white with densely blown foam, heavy rolling, lowered visibility Seldom experienced on land, trees broken or uprooted, "considerable structural damage"
11 56-63 64-72 Violent Storm Exceptionally high (30-45 ft) waves, foam patches cover sea, visibility more reduced  
12 64+ 73+ Hurricane Air filled with foam, waves over 45 ft, sea completely white with driving spray, visibility greatly reduced