Weather
Heat Domes: Persistent High Pressure and Extreme Temperatures
Heat dome is an informal forecast and media label for a persistent ridge of high pressure aloft associated with widespread, long-lasting heat. Sinking air warms and dries, clouds and rain may be suppressed, and strong sunshine can heat the surface repeatedly.
Lake-Effect Snow: Cold Air, Open Water and Narrow Snow Bands
Lake-effect snow forms when cold air crosses relatively warm, open water, gaining heat and moisture that drive shallow convection and snow downwind.
Atmospheric Rivers: How Narrow Moisture Plumes Bring Heavy Rain
An atmospheric river is a long, relatively narrow corridor in which strong winds transport concentrated water vapor through the lower atmosphere. Forecasters use integrated water-vapor transport, or IVT, to describe that horizontal flux.
Katabatic and Anabatic Winds
Anabatic winds flow upslope when sunshine warms a slope and the adjacent air, while katabatic winds flow downslope when air over elevated terrain cools, becomes denser and drains under gravity. They often reverse through the daily cycle, but snow cover, clouds, terrain shape and larger weather systems can change or…
Flash Freezes: Rapid Icing After a Temperature Drop
A flash freeze occurs when liquid water or wet snow on a surface freezes rapidly after the surface temperature drops below its effective freezing point. It often follows a cold front or snow squall and can make apparently wet pavement icy within a short time. Pavement temperature, moisture, treatment, shade and…
Pollen Counts and Allergy Forecasts
A pollen count is an observed concentration from an air sampler, commonly identified over a collection period, while a pollen forecast predicts future levels from observations, plant seasons and weather. Counts differ because stations, locations, time windows, taxa and category scales differ. A nearby total is an…
Cloud Ceilings and Visibility in Aviation Weather
In aviation weather, ceiling is the height above ground of the lowest broken or overcast layer, or vertical visibility into an obscuration; few and scattered layers do not set it. Visibility describes horizontal seeing distance under defined observation rules. Flight-category colors use whichever of ceiling or…
Radiation Fog vs Advection Fog
Radiation fog usually develops when moist air next to land cools overnight as the surface loses heat, whereas advection fog forms when wind carries moist air across a colder surface. Radiation fog is often patchy and clears with daytime heating; advection fog can occur under cloud and stronger wind, travel with the…
Weather Radar Reflectivity: Colors, Intensity and Common Limits
Reflectivity is the strength of energy returned to weather radar, expressed on a logarithmic dBZ scale.
Bomb Cyclone: What Rapid Intensification Means
A bomb cyclone is a midlatitude low-pressure system that meets a latitude-adjusted rapid-deepening criterion over 24 hours.
Polar Vortex: Why It Does Not Mean Every Cold Snap Is the Same
The polar vortex usually refers to strong wintertime westerly winds encircling cold air in the polar stratosphere, while related circumpolar circulation also exists in the troposphere.
Extreme Heat Watch, Warning and Heat Advisory Explained
An Extreme Heat Watch means extremely dangerous heat is possible but timing or occurrence remains uncertain. An Extreme Heat Warning means it is expected or occurring. A Heat Advisory covers dangerous heat below local warning criteria.
Dense Fog Advisory: Visibility, Driving Risk and Safe Decisions
A Dense Fog Advisory means widespread visibility around one-quarter mile or less is expected or occurring, making travel difficult. If a trip cannot be delayed, drivers should reduce speed, use low-beam headlights, increase following distance and keep checking current National Weather Service and road guidance.
Wet-Bulb Temperature: What It Measures and Why It Matters
Wet-bulb temperature is the temperature reached by a ventilated, water-wetted sensor as evaporation removes heat, so it reflects the joint effects of air temperature and moisture on evaporative cooling.
Dew Point vs Humidity: Two Ways to Describe Moisture
Dew point is the temperature to which air must cool to reach saturation at essentially constant pressure, making it a useful indicator of moisture amount.
Wind Chill: How Wind Changes Cold-Weather Risk
Wind chill expresses the cooling effect of air temperature and wind on exposed human skin as an equivalent calm-air temperature under defined assumptions. It helps communicate frostbite and hypothermia risk, but does not replace actual temperature, clothing, wetness, sunshine, activity, health or local warnings.
Storm Surge Watch vs Warning: Coastal Flooding Alerts Explained
A Storm Surge Watch means life-threatening inundation from rising water moving inland from the shoreline is possible, generally within 48 hours. A Storm Surge Warning means the danger is expected, generally within 36 hours.
Cyclone Alfred 2025: Track and Timeline Explained
Alfred formed northeast of Cooktown, moved east and then south over the Coral Sea, briefly tracked southeast, turned abruptly west toward southeast Queensland, crossed Moreton Island, weakened near Bribie Island and moved onto the mainland as a subtropical system.
California 2025 Fire Season: How the Palisades Fire Compared
The Palisades Fire burned 23,448 acres, making it the fifth-largest incident by acreage in CAL FIRE’s displayed 2025 archive. Its 6,845 destroyed structures and 12 confirmed civilian deaths show why acreage alone understates its impact.
Lightning Safety: Why Blue Sky and No Rain Do Not Mean You’re Safe
Lightning can extend miles beyond a storm’s rain area, so hearing thunder or seeing lightning is the signal to enter a substantial building or enclosed hard-topped vehicle and remain sheltered for at least 30 minutes after the last thunder.
Hurricane Milton: Wind, Rain, Surge and Tornado Hazards
Milton struck near Siesta Key as a category 3 hurricane, but its impacts came from several overlapping hazards: destructive wind, Gulf Coast storm surge, extreme rainfall and flooding, a major tornado outbreak, large waves and hazardous surf.
Why a Hurricane Forecast Cone Does Not Show Every Hazard
The National Hurricane Center cone describes uncertainty in the forecast track of a tropical cyclone’s center. It does not show the storm’s full size or the complete reach of wind, surge, rain and tornado hazards, as Hurricane Milton demonstrated when its wind field expanded approaching Florida.
Hurricane Melissa 2025: Track, Strength and Jamaica Impacts
Melissa rapidly intensified to Category 5 and made landfall in southwestern Jamaica on October 28, 2025 with estimated 185 mph winds and a central pressure of 892 millibars. It then crossed eastern Cuba and parts of the Bahamas after producing catastrophic wind, surge and flood impacts.
Why Hurricane Melissa’s 892 mb Pressure Was Exceptional
Hurricane Melissa reached an analyzed minimum central pressure of 892 millibars and peak winds of 165 knots before Jamaica landfall. NHC’s final analysis tied 892 mb for the Atlantic basin’s third-lowest minimum pressure and listed 897 mb at landfall as the second-lowest Atlantic landfall pressure.
How Strong Was Tropical Cyclone Alfred?
Alfred peaked as an Australian category 4 severe tropical cyclone far offshore, with 10-minute sustained winds of 165 km/h. It later weakened, briefly re-intensified, reached Moreton Island at category 1 strength and fell below tropical-cyclone strength before the remnant crossed mainland southeast Queensland.
Winter Storm Watch vs Warning vs Advisory
A Winter Storm Watch means significant winter weather is possible, a Warning means it is expected or occurring and calls for protective action, and an Advisory describes hazardous conditions below warning criteria that can still disrupt travel.
Hail Size and Damage: How Storm Reports Classify It
Storm reports classify hail by the largest stone's diameter, while actual damage also depends on fall speed, horizontal wind, stone shape and density, exposure duration, impact angle and the age, material and condition of what is struck.
Atmospheric Rivers: How They Move Water Through the Sky
Atmospheric rivers are long, narrow corridors of concentrated water-vapor transport whose strong winds carry moisture toward land, where lift can convert it to rain or snow that replenishes water supplies or causes floods and landslides.
Rip Currents: How to Escape and Help Safely
A rip current is a narrow flow moving away from shore; a caught swimmer should conserve energy, float or tread water, signal for help and, if able, swim parallel to shore out of the current before returning at an angle.
Flash Flood Warning: What to Do Immediately
A Flash Flood Warning means dangerous rapid flooding is occurring or imminent in the warned area; move away from low ground, never enter floodwater on foot or in a vehicle, and follow current National Weather Service and local emergency instructions.
Red Flag Warning: What Fire Weather Conditions Mean
A Red Flag Warning means critical fire-weather conditions are occurring or expected soon, usually from some combination of dry fuels, low humidity and strong wind; it does not necessarily mean a wildfire already exists.
Lake-Effect Snow: Why Narrow Bands Become So Intense
Lake-effect snow develops when cold air crosses relatively warm, open water, gains heat and moisture, becomes unstable and organizes into downwind snow bands whose position and intensity depend strongly on wind, fetch, terrain and ice cover.
Storm Surge: Why Water Is Often a Hurricane’s Greatest Threat
Storm surge is an abnormal rise in seawater driven mainly by a storm's winds; storm size, intensity, speed, track, seafloor and coastline shape determine local inundation, while tide, waves and rainfall add to the total water hazard.
Bangladesh and Pakistan Set to Clash in Asian Games 2026 Cricket Semi-Final After Rain Washouts
On October 1, 2026, Bangladesh and Pakistan will face off in the men's cricket semi-final at the Asian Games after both teams advanced due to rain-abandoned quarter-finals. The match will be held at 9:00 AM JST at Korogi Sports Park, Japan.
Flood Watch vs Warning vs Advisory: What Each Alert Means
A flood watch means flooding is possible and preparation is needed; a warning means flooding is imminent or occurring and immediate protective action is required; an advisory covers less severe flooding that can still create danger and disruption.
Lightning Safety: When to Go Inside and What to Avoid
Hearing thunder means lightning is close enough to threaten; move to a substantial building or hard-top enclosed vehicle, avoid conductive paths indoors, and wait at least 30 minutes after the last thunder.
Tornado Watch vs Warning vs Emergency: What to Do
A tornado watch means conditions favor tornadoes, a warning means a tornado is occurring or imminent, and a tornado emergency is rare enhanced warning language for a confirmed severe threat to a populated area.
Tsunami Warning vs Watch vs Advisory: When to Evacuate
A tsunami warning signals possible widespread inundation and calls for evacuation as directed; an advisory warns of dangerous currents; a watch means the danger level is uncertain; natural signs can require immediate movement inland before any official alert arrives.
Wind Chill vs Temperature: Frostbite Risk and Cold Safety Explained
Wind chill estimates how quickly exposed skin loses heat in cold wind; it does not change the thermometer reading or cool objects below the actual air temperature.
Heat Index vs Temperature: How Humidity Changes the Risk
The heat index combines air temperature and relative humidity to estimate apparent heat under shaded, light-wind conditions; sun, exertion, clothing and individual health can make real exposure more dangerous.
Dew Point vs Relative Humidity: What Each Number Means
Dew point is the temperature at which air becomes saturated when cooled, while relative humidity compares current moisture with the temperature-dependent saturation level.
How to Choose and Use an Air Purifier for Wildfire Smoke
For smoke particles, choose a portable cleaner sized for the room with an effective mechanical filter, avoid ozone-producing devices, close openings when safe and run the cleaner continuously at the highest tolerable setting.
What Hurricane Categories Measure—and What They Leave Out
The Saffir-Simpson scale classifies hurricanes only by maximum sustained wind, so category numbers do not describe storm surge, rainfall flooding, tornadoes or every local impact.
UV Index Scale: What the Number Means and How to Protect Yourself
The UV Index forecasts the intensity of skin-damaging ultraviolet radiation on a 1-to-11+ scale, with stronger protection needed from index 3 upward.
What Accumulated Cyclone Energy Says About 2025
The 2025 Atlantic hurricane season produced an ACE of 130.8, seven percent above the 1991–2020 normal, despite having fewer named storms and hurricanes than average.
How Active Was the 2024 Atlantic Hurricane Season?
The 2024 Atlantic season produced 18 named storms, 11 hurricanes and five major hurricanes, with basin accumulated cyclone energy about 32 percent above the 1991–2020 normal.
Why the 2025 Hurricane Season Had Three Category 5 Storms
Erin, Humberto and Melissa all reached Category 5 intensity in 2025, giving the Atlantic its second-highest single-season total even though the overall number of storms was near average.
Palisades Fire 2025: Final Size and Containment Timeline
The Palisades Fire began on January 7, 2025, burned 23,448 acres in Los Angeles County and was recorded as fully contained on January 31 after 24 active days.
How Hurricane Milton Intensified So Quickly
Milton strengthened over very warm Gulf water and under light wind shear, increasing by roughly 90 mph in 24 hours and eventually reaching an analyzed peak of 180 mph.
2025 Atlantic Hurricane Season: Final Storm Count
The final Atlantic tally was 13 named storms, five hurricanes and four major hurricanes, including three systems that reached Category 5 intensity.