ROCKTUCATION
Weather Terms.
Every word the sky uses, explained plainly, with the rock's commentary.
Weather Terms · 190 entries
Every term a forecast can throw at you, defined plainly, with the rock's commentary. The same dictionary that powers the app's Rocktionary, now with a permanent address for every word.
Forecast talk
The models are arguing
Different weather computers disagree about a future day, usually over whether rain falls. When the badge shows on the 10-day, the vote was split and the rock says so instead of pretending.
“The future is a rumor. I only guarantee the present.” — the rock
Sky cover
Clear / Sunny 1 of 5
Zero to one okta of cloud. Full sun.
“My favorite forecast: nothing.” — the rock
Mostly clear 2 of 5
One to two oktas of cloud.
“A cloud or two. I'll allow it.” — the rock
Partly cloudy 3 of 5
Three to five oktas. Sun and cloud trade places.
“The sky is half committed.” — the rock
Mostly cloudy 4 of 5
Six to seven oktas. More cloud than sun.
“Sun's losing the argument.” — the rock
Overcast 5 of 5
Eight oktas. Full gray ceiling.
“The sky put a lid on it.” — the rock
Rain
Mist 1 of 7
Visible fine droplets, lighter than drizzle, visibility better than fog.
“Weather you feel more than see.” — the rock
Drizzle 2 of 7
Fine drops under 0.02 inch across, usually from stratus. Light, moderate, and dense grades.
“Rain that mumbles.” — the rock
Light rain / Sprinkle 3 of 7
Up to 0.10 inch per hour.
“The sky is counting these out one by one.” — the rock
Moderate rain 4 of 7
0.11 to 0.30 inch per hour.
“Now it means it.” — the rock
Heavy rain / Downpour 5 of 7
More than 0.30 inch per hour.
“The faucet position.” — the rock
Cloudburst 6 of 7
Informal term for extreme short-burst rainfall, roughly 4 inches per hour or more.
“The cloud just gave up carrying it.” — the rock
Torrential rain 7 of 7
Sustained extreme rainfall. Flood maker.
“I have never been this rinsed.” — the rock
Rain shower type
Convective rain: starts fast, stops fast, sun between.
“Rain with commitment issues.” — the rock
Sun shower type
Rain falling while the sun shines, usually from a distant cloud.
“The sky can't pick a lane. Respect.” — the rock
Virga type
Rain that evaporates before reaching the ground.
“All that effort and nothing lands. Relatable.” — the rock
Freezing drizzle type
Drizzle that freezes on contact with cold surfaces.
“A slow glaze. Like being shellacked politely.” — the rock
Freezing rain type
Supercooled rain that ices everything it touches. The ice storm ingredient.
“Rain that turns the world to glass.” — the rock
Monsoon seasonal
Seasonal wind reversal bringing a months-long wet season.
“Rain with a subscription plan.” — the rock
Atmospheric river AR 1 to 5
A ribbon of concentrated vapor aloft, rated AR Cat 1 weak to AR Cat 5 exceptional.
“A river in the sky, and I live under the faucet.” — the rock
Pineapple Express type
The atmospheric river running from near Hawaii to the West Coast.
“Tropical water, delivered overnight.” — the rock
Thunderstorm
Thunderstorm 1 of 3
Any storm producing thunder and lightning.
“The sky's drum solo.” — the rock
Severe thunderstorm 2 of 3
Hail 1 inch or larger, gusts 58 mph or more, or a tornado.
“When the sky starts throwing furniture.” — the rock
Destructive severe storm 3 of 3
Phone-alert tier: 80 mph gusts or baseball hail.
“Your phone screams. Listen to it.” — the rock
Supercell type
A rotating storm with a mesocyclone. Produces the giant hail and violent tornadoes.
“The storm other storms are afraid of.” — the rock
Squall line type
A solid line of storms, often ahead of a cold front.
“Storms holding hands. Rude.” — the rock
Bow echo type
A squall line bowing outward on radar. Damaging straight-line wind.
“The radar draws a bow. The wind is the arrow.” — the rock
Derecho type
A widespread long-lived windstorm: 240+ mile damage swath with 58+ mph gusts.
“A hurricane's wind bill, no ocean required.” — the rock
Mesoscale convective system type
A storm complex bigger than any single cell, often rolling through overnight.
“The storms formed a committee.” — the rock
Pulse storm type
A single brief storm that surges and dies within the hour.
“One song and it leaves the stage.” — the rock
Dry thunderstorm type
Lightning whose rain evaporates before landing. Starts wildfires.
“All spark, no soak. The bad combo.” — the rock
Hailstorm by stone size
Any storm producing hail. Graded pea to grapefruit; 1 inch is severe.
“The sky is throwing rocks at a rock.” — the rock
Downburst / Macroburst type
A violent column of sinking air spreading damage over 2.5+ miles.
“The sky slammed the door downward.” — the rock
Microburst type
A downburst under 2.5 miles wide. Aviation's nightmare.
“Small on radar. Not small in person.” — the rock
Gust front type
The leading edge of a storm's cool outflow.
“The storm sends its wind ahead to knock.” — the rock
Gustnado type
A brief spin-up along a gust front. Not a true tornado.
“A tornado costume, worn badly.” — the rock
Thundersnow type
A thunderstorm that snows instead of rains. Rare, muffled, and loud all at once.
“Snow with a bass line.” — the rock
Heat lightning visual
Ordinary lightning from a storm too far away to hear.
“Somebody else's storm, free light show.” — the rock
Ball lightning visual
Rare reported glowing spheres during storms. Still being studied.
“Even scientists shrug at this one.” — the rock
Tornado
Funnel cloud pre-stage
A rotating funnel that has not touched ground yet.
“The sky reaching for the doorknob.” — the rock
Tornado EF0 EF0
65 to 85 mph estimated gusts. Light damage.
“Entry-level. Still not staying to watch.” — the rock
Tornado EF1 EF1
86 to 110 mph. Moderate damage.
“Gone. Ask my dirt patch.” — the rock
Tornado EF2 EF2
111 to 135 mph. Considerable damage.
“This is where roofs change addresses.” — the rock
Tornado EF3 EF3
136 to 165 mph. Severe damage.
“Severe is the polite word for it.” — the rock
Tornado EF4 EF4
166 to 200 mph. Devastating damage.
“Houses leave. Rocks leave faster.” — the rock
Tornado EF5 EF5
Over 200 mph. Incredible damage.
“The scale stops. So should you. Underground.” — the rock
Tornado watch alert 1 of 3
Conditions favor tornadoes. Be ready.
“The sky is loading the dice.” — the rock
Tornado warning alert 2 of 3
A tornado is spotted or radar-indicated. Shelter now.
“I'm gone. Copy me.” — the rock
Tornado emergency alert 3 of 3
A confirmed violent tornado threatening lives.
“The rarest words. The fastest feet.” — the rock
Landspout type
A weak tornado from a non-rotating storm.
“A tornado that skipped the audition.” — the rock
Waterspout type
A tornado over water. Fair-weather ones are weaker.
“How fish learn to fly.” — the rock
Dust devil type
A fair-weather whirlwind of dust. Not storm-related.
“The desert doing a little dance.” — the rock
Fire whirl type
A whirlwind of flame and ash over intense fire.
“Fire learned to spin. Nobody asked for this.” — the rock
Tropical
Tropical wave 1 of 9
A westward-moving trough that can seed development.
“A ripple with ambitions.” — the rock
Tropical disturbance / Invest 2 of 9
An organized area being watched, assigned an invest number.
“The forecasters are staring at it. So am I.” — the rock
Tropical depression 3 of 9
Closed circulation, winds up to 38 mph.
“A storm learning to walk.” — the rock
Tropical storm 4 of 9
39 to 73 mph sustained winds. It gets a name.
“Once it has a name, take it personally.” — the rock
Hurricane Category 1 5 of 9
74 to 95 mph. Very dangerous winds.
“Category one, rock zero. I'm gone.” — the rock
Hurricane Category 2 6 of 9
96 to 110 mph. Extremely dangerous.
“Shutters up. Rock down the block.” — the rock
Hurricane Category 3 (Major) 7 of 9
111 to 129 mph. Devastating damage. Major begins here.
“Major. As in majorly not here.” — the rock
Hurricane Category 4 8 of 9
130 to 156 mph. Catastrophic damage.
“Four says leave yesterday.” — the rock
Hurricane Category 5 9 of 9
157 mph or higher. Catastrophic.
“The top of the scale. The bottom of my patience.” — the rock
Typhoon regional
The same storm, western Pacific name.
“Same monster, different accent.” — the rock
Super typhoon regional
A typhoon at 150 mph or more.
“When typhoon needed a bigger word.” — the rock
Cyclone regional
Same storm, Indian Ocean and South Pacific name.
“Third name, same bad news.” — the rock
Medicane regional
A rare Mediterranean tropical-like cyclone.
“Even the Mediterranean tries it sometimes.” — the rock
Subtropical storm type
A hybrid with tropical and non-tropical traits.
“A storm with dual citizenship.” — the rock
Post-tropical cyclone stage
A former tropical storm that changed structure. Can stay dangerous.
“Retired, still throwing punches.” — the rock
Rapid intensification process
Winds jumping 35+ mph within 24 hours.
“The storm hit the gym overnight.” — the rock
Storm surge hazard
Ocean pushed ashore by the storm. The deadliest tropical hazard.
“The ocean makes a house call.” — the rock
Landfall moment
The eye's center crossing the coastline.
“The moment the map stops being theoretical.” — the rock
Winter
Flurries 1 of 6
Intermittent light snow, little accumulation.
“Winter's screensaver.” — the rock
Light snow 2 of 6
Visibility over 1/2 mile in snow.
“A gentle burial begins.” — the rock
Moderate snow 3 of 6
Visibility 1/4 to 1/2 mile.
“Now we're accumulating.” — the rock
Heavy snow 4 of 6
Visibility under 1/4 mile. Warning-level totals.
“My hat has a hat now.” — the rock
Blizzard 5 of 6
35+ mph winds AND under 1/4 mile visibility for 3+ hours. Wind defines it, not amount.
“Buried is a lifestyle now.” — the rock
Severe blizzard 6 of 6
45+ mph winds, near-zero visibility, 10 F or lower.
“The blizzard's blizzard.” — the rock
Snow shower type
Convective snow, on and off like a rain shower.
“Snow that pops in unannounced.” — the rock
Snow squall type
A brief violent burst of snow and wind. Whiteout in minutes; has its own NWS warning.
“Fifteen minutes of pure chaos.” — the rock
Ground blizzard type
No falling snow: wind lofts what's already down.
“Recycled snow. Still counts.” — the rock
Lake-effect snow type
Cold air over warm lakes builds narrow intense snow bands.
“The lake exhales and a town disappears.” — the rock
Nor'easter NESIS 1 to 5
An East Coast coastal storm with northeast winds. Impact rated NESIS 1 notable to 5 extreme.
“New England's recurring subscription.” — the rock
Bomb cyclone process
Bombogenesis: pressure drops 24+ millibars in 24 hours.
“The storm speedran its own resume.” — the rock
Alberta clipper type
A fast dry Canadian system: quick light snow, sharp cold behind.
“Canada's express delivery. No signature needed.” — the rock
Panhandle hook type
A storm curving up from the Texas panhandle. Big Midwest snows.
“Texas sends winter north, with interest.” — the rock
Polar vortex outbreak type
The Arctic's cold pool wobbles south. Multi-day extreme cold.
“The Arctic came to visit and brought luggage.” — the rock
Ice storm by glaze depth
Freezing rain event. Warnings near 1/4 inch of glaze (varies by region); 1/2 inch snaps trees.
“The world gets dipped in glass.” — the rock
Sleet (ice pellets) type
Raindrops that freeze into pellets before landing. They bounce.
“Rain that arrives pre-frozen. Efficient.” — the rock
Graupel type
Snowflakes coated in rime: soft crunchy pellets. Not hail, not sleet.
“Snow dipped in more snow.” — the rock
Snow grains type
The frozen equivalent of drizzle. Tiny opaque grains.
“Winter's dandruff.” — the rock
Wintry mix type
Snow, sleet, freezing rain, and rain trading places all day.
“The sky's sampler platter. All bad.” — the rock
Whiteout condition
Snow and scattered light erase contrast and horizon.
“The world, factory reset.” — the rock
Diamond dust type
Clear-sky ice crystals glittering in extreme cold.
“The air itself starts sparkling. Show-off.” — the rock
Rime ice type
Freezing fog deposits feathery white ice on every surface.
“The fog leaves fingerprints.” — the rock
Hoar frost type
Vapor freezing straight to feathery crystals on cold clear nights.
“Overnight the world grows fur.” — the rock
Frost cold 1 of 3
Surface ice crystals near 32 F. Kills tender plants.
“The garden's eviction notice.” — the rock
Freeze cold 2 of 3
Air at or below 32 F.
“Water stops negotiating.” — the rock
Hard freeze cold 3 of 3
At or below about 28 F. Season-ender.
“The growing season taps out.” — the rock
Flash freeze type
Temperatures crash so fast wet roads ice in minutes.
“The puddle you stepped over is a rink on the way back.” — the rock
Avalanche danger 1 to 5
Mountain scale: Low, Moderate, Considerable, High, Extreme.
“The mountain keeps its own forecast.” — the rock
Obscuration
Haze 1 of 4
Dry particles soften the sky. Visibility mostly fine.
“The sky in soft focus.” — the rock
Mist (visibility) 2 of 4
Visibility 5/8 mile to 6 miles in fine droplets.
“Fog's opening act.” — the rock
Fog 3 of 4
A cloud on the ground. Visibility under 5/8 mile.
“I live in the sky now. Involuntarily.” — the rock
Dense fog 4 of 4
Visibility 1/4 mile or less. Advisory territory.
“Just the eyes today. The rest is rumor.” — the rock
Freezing fog type
Fog below 32 F that rimes every surface it touches.
“Fog with teeth.” — the rock
Ice fog type
Fog made of ice crystals in extreme Arctic cold.
“The air froze mid-thought.” — the rock
Radiation fog formation
Forms overnight under clear calm skies as the ground cools.
“The night brews it fresh by morning.” — the rock
Advection fog formation
Warm moist air sliding over a cold surface. San Francisco's brand.
“Imported fog, sea to door.” — the rock
Valley fog formation
Cold air pools in valleys overnight.
“The valley keeps it like a secret.” — the rock
Upslope fog formation
Air cooling as terrain forces it uphill.
“Fog that hikes.” — the rock
Steam fog / Sea smoke formation
Cold air over warm water. The lake steams.
“The lake's morning coffee.” — the rock
Smoke AQI graded
Wildfire particulate, graded by AQI and PM2.5.
“The sky's been smoking again.” — the rock
Smog AQI graded
Urban ozone haze. The city kind of bad air.
“The city's morning breath.” — the rock
Vog type
Volcanic smog from eruption gases. Hawaii's version.
“The volcano contributes to the group chat.” — the rock
Dust storm type
Strong winds lofting dust; visibility can crash below 1/4 mile.
“The county, airborne.” — the rock
Sandstorm type
The desert version, heavier grains.
“Exfoliation at highway speed.” — the rock
Haboob type
A dramatic dust wall on storm outflow. Arizona's wall of dirt.
“A wall of dirt with a cool name.” — the rock
Wind
Calm to light breeze Beaufort 0-2
0 to 7 mph. Smoke drifts, leaves rustle.
“The air, politely existing.” — the rock
Gentle to fresh breeze Beaufort 3-5
8 to 24 mph. Flags fly, small trees sway.
“Kite economy: booming.” — the rock
Strong breeze to near gale Beaufort 6-7
25 to 38 mph. Umbrellas fail, whole trees move.
“Umbrella funerals begin.” — the rock
Gale Beaufort 8-9
39 to 54 mph. Twigs snap, walking is work.
“Walking becomes a group project.” — the rock
Storm-force wind Beaufort 10-11
55 to 73 mph. Trees down, structural damage.
“Everything unbolted is now traveling.” — the rock
Hurricane-force wind Beaufort 12
74+ mph sustained.
“I stopped being furniture.” — the rock
Gust type
A brief spike above the sustained wind.
“The wind's sucker punch.” — the rock
Squall type
A sudden wind jump of 16+ knots lasting minutes.
“A tantrum with a timestamp.” — the rock
Wind shear type
Wind changing speed or direction with height.
“The sky disagreeing with itself.” — the rock
Chinook / Foehn type
Warm dry downslope wind. Can erase snow overnight; the snow eater.
“The wind that eats winter.” — the rock
Santa Ana winds type
Hot dry offshore winds in Southern California. Fire weather.
“California's hair dryer.” — the rock
Katabatic wind type
Cold dense air draining downhill, sometimes violently.
“Gravity, but make it wind.” — the rock
Jet stream driver
The high-altitude wind river steering weather systems.
“The conveyor belt upstairs runs everything.” — the rock
Heat
Warm spell 1 of 4
Informal: pleasantly above normal.
“The good kind of warning sign.” — the rock
Heat advisory 2 of 4
Heat index near 100 to 104 F (varies by region).
“The air has opinions now.” — the rock
Excessive heat warning 3 of 4
Heat index 105+ F (varies). Dangerous for everyone.
“Officially too hot for heroics.” — the rock
Heat wave 4 of 4
Multiple consecutive days of excessive heat.
“The heat moved in and unpacked.” — the rock
Heat dome pattern
A parked high-pressure lid trapping heat for days.
“The sky put a casserole lid on us.” — the rock
Heat burst rare
A rare nighttime blast of hot dry wind from a dying storm. Temps jump in minutes.
“Midnight opens an oven door.” — the rock
Heat index scale
What temperature plus humidity feels like. Caution to extreme danger.
“The feels-like is the real bill.” — the rock
Drought D0 to D4
US Drought Monitor: Abnormally Dry through Exceptional.
“The rain is on strike.” — the rock
Flash drought type
Drought developing in weeks instead of months.
“Dry, but in a hurry.” — the rock
Red flag warning fire weather
Hot, dry, windy: fires spread explosively.
“The forest is one spark from headlines.” — the rock
Cold
Cold snap 1 of 3
A brief sharp turn cold.
“Winter's jump scare.” — the rock
Cold wave 2 of 3
Extended dangerous cold.
“The cold settled in for a season pass.” — the rock
Extreme cold warning 3 of 3
Dangerous wind chills (thresholds vary by region).
“Skin has a countdown timer out here.” — the rock
Wind chill scale
What wind makes the cold feel like on skin.
“The wind's markup on winter.” — the rock
Indian summer pattern
A warm calm stretch after the first frost.
“Summer forgot its keys, came back for a week.” — the rock
January thaw pattern
A midwinter mild spell.
“Winter blinks.” — the rock
Flood
Flood watch 1 of 4
Flooding is possible. Stay aware.
“The water is thinking about it.” — the rock
Flood warning 2 of 4
Flooding is happening or imminent.
“The water stopped thinking. It's moving.” — the rock
Flash flood warning 3 of 4
Rapid life-threatening flooding within hours of the rain.
“Never drive into it. I can't drive and even I know.” — the rock
Flash flood emergency 4 of 4
Catastrophic flooding underway. The rare top tier.
“High ground. Now. Higher than me.” — the rock
River flood type
A river over its banks: minor, moderate, major at each gauge.
“The river forgot its lane.” — the rock
Coastal flood type
Ocean water into normally dry coastal land.
“The tide overstays.” — the rock
Urban flood type
Drainage overwhelmed in built-up areas.
“The street applies for lake status.” — the rock
Ice jam flood type
River ice dams the channel and backs water up.
“The river's own ice gets in its way.” — the rock
King tide type
The year's highest astronomical tides.
“The moon flexes; the ocean obeys.” — the rock
Seiche type
Water sloshing in a closed basin like the Great Lakes.
“The lake as a tilted soup bowl.” — the rock
Rip current risk low / moderate / high
Beach hazard scale for surf-zone currents.
“Swim sideways, not homeward.” — the rock
Air quality
Good air AQI 0-50
Air poses little risk.
“Breathe freely. I'll sit here.” — the rock
Moderate air AQI 51-100
Acceptable; a note for the unusually sensitive.
“Fine print air.” — the rock
Unhealthy for sensitive groups AQI 101-150
Sensitive groups limit exertion.
“Some lungs sit this one out.” — the rock
Unhealthy air AQI 151-200
Everyone may feel effects.
“Air quality: chewy.” — the rock
Very unhealthy air AQI 201-300
Health alert conditions.
“The air has a warning label.” — the rock
Hazardous air AQI 301+
Emergency conditions.
“Even I hold my breath. I'm very good at it.” — the rock
Air stagnation advisory
A stale air mass parks and pollution builds for days.
“The atmosphere hit pause. The exhaust didn't.” — the rock
Optical
Rainbow visual
Sunlight refracted through rain opposite the sun. Always a full circle; the ground hides half.
“The sky apologizing for the rain.” — the rock
Double rainbow visual
A second, reversed, fainter bow outside the first.
“The apology, in writing, twice.” — the rock
Moonbow visual
A rainbow made by moonlight. Ghost-white to the eye.
“The night runs the rainbow on low power.” — the rock
Fogbow visual
A white rainbow in droplets too small for color.
“A rainbow that forgot the crayons.” — the rock
Sundog (parhelion) visual
Bright spots flanking the sun, made by ice crystals.
“The sun brings backup dancers.” — the rock
22-degree halo visual
A ring around sun or moon from cirrus ice. Often a front is coming.
“The sun wears a ring; pack an umbrella.” — the rock
Light pillar visual
A vertical beam above lights or sun in ice-crystal air.
“The cold builds columns out of light.” — the rock
Crepuscular rays visual
Sunbeams fanning through cloud gaps.
“The sky showing its work.” — the rock
Green flash visual
A momentary green glint at the sun's last edge at sunset.
“Blink and the sun keeps the secret.” — the rock
Mirage / Fata Morgana visual
Refraction bends distant images; Fata Morgana stacks them into castles.
“The horizon starts lying.” — the rock
Aurora G-scale driven
Solar particles lighting the upper atmosphere. Strength follows the geomagnetic scale.
“The sky's neon sign, powered by the sun's mood.” — the rock
Noctilucent clouds visual
Electric-blue night-shining clouds at the edge of space.
“Clouds that glow after hours.” — the rock
Clouds
Cumulonimbus storm engine
The thunderstorm tower, anvil top and all.
“The skyscraper that makes its own weather.” — the rock
Mammatus visual
Pouches hanging under a storm anvil. Turbulent air.
“The storm's bubble wrap.” — the rock
Shelf cloud visual
A low wedge on a storm's leading edge. Wind arrives behind it.
“The storm's front bumper.” — the rock
Wall cloud visual
A lowering under a supercell where rotation concentrates.
“When the storm grows a chin, watch it.” — the rock
Lenticular visual
Smooth lens clouds parked over mountains.
“The mountain's UFO collection.” — the rock
Asperitas visual
Rolling wave-like undersides. Newest officially named cloud (2017).
“The sky tries an ocean impression.” — the rock
Morning Glory visual
A rare rolling tube cloud, famous in Australia.
“The sky rolls itself a cigar.” — the rock
Climate patterns
El Nino ENSO warm
Warm equatorial Pacific phase. Shifts global storm tracks.
“The Pacific runs a fever; everyone's forecast sneezes.” — the rock
La Nina ENSO cool
The cool phase. Different global fingerprints.
“The Pacific chills out; the jet stream rearranges the furniture.” — the rock
ENSO neutral neutral
Neither phase dominant.
“The ocean, for once, has no notes.” — the rock
Dog days seasonal
The hottest, most sultry stretch of summer.
“Even the dogs supervise from the shade.” — the rock
Space weather
Geomagnetic storm G1 to G5
Solar wind rattling Earth's magnetic field, G1 minor to G5 extreme. Aurora fuel.
“The sun sneezes; compasses everywhere flinch.” — the rock
Solar radiation storm S1 to S5
Energetic particles from solar eruptions.
“Weather from ninety-three million miles away.” — the rock
Radio blackout R1 to R5
Solar flares disrupting radio on Earth's day side.
“The sun talks over everyone.” — the rock