Weather Field Guide

Vertical velocity at 700 hPa (upward motion = negative values)

Vertical velocity at 500 hPa (upward motion = negative values)

Bulk wind shear in the 0-6 km layer (storm organization indicator)

Bulk wind shear in the 0-3 km layer (low-level rotation indicator)

Model-simulated composite radar reflectivity at location

Relative humidity at 700 hPa (~3000m, mid-cloud level)

Relative humidity at 850 hPa (~1500m, low cloud level)

Storm-relative helicity in 0-3 km layer (rotation potential)

Absolute vorticity at 500 hPa (rotation in mid-troposphere)

Fraction of precipitation that is convective (0-1)

Fraction of condensate that is ice in mid-level clouds

Height of tropopause above sea level (cloud top limit)

Overall cloud coverage across all altitudes

Cloud coverage below 2km altitude

Cloud coverage between 2-6km altitude

Cloud coverage above 6km altitude (cirrus)

Estimated height of cloud base above ground level

Combines aurora activity with viewing conditions (darkness, cloud cover, visibility) to provide photography-ready aurora quality scores. Aurora activity is OVATION-aware from the compute step.

Evaluates atmospheric conditions for blue hour photography quality. Scores sky clarity, cloud type suitability (high thin clouds ideal), visibility, and calm conditions.

Atmospheric suitability for fiery red sky conditions across extended time window around sunrise/sunset periods. Enhanced with CAMS aerosol data (AOD, particle composition, Ångström exponent) and GFS upper-air humidity for improved color prediction.

Multi-factor fog formation likelihood combining visibility, dewpoint spread, humidity, and time-of-day analysis

Atmospheric suitability for golden hour photography across extended time window around golden hour periods

Cloud formation suitability for golden hour photography across extended time window around golden hour periods

Analysis of cloud formations and atmospheric conditions for dramatic sky photography

Storm intensity analysis combining precipitation, wind conditions, atmospheric pressure, visibility, GFS simulated radar reflectivity, and wind shear for enhanced storm organization detection.

Frost formation probability combining temperature, dewpoint spread, cloud cover, and wind analysis

Probability of visible rainbow formation based on solar geometry and precipitation patterns

Analysis of coastal conditions combining wave dynamics, atmospheric conditions, and lighting for dramatic seascape photography. Evaluates wave height, swell patterns, spray potential, and atmospheric drama factors.

Comprehensive atmospheric clarity analysis for landscape and astrophotography using CAMS aerosol optical depth, particle composition (dust, smoke, sea salt), particle size distribution (Ångström exponent), and visibility conditions.

Likelihood of sun breaking through clouds creating dramatic rays and dappled light patterns. Best with partial cloud cover (40-70%) and some sunshine reaching the surface.

Quality of diffused light for portrait and product photography. High scores indicate soft, even lighting that minimizes harsh shadows - the 'giant softbox' effect.

Rates how visually interesting the clouds are - distinguishing dramatic formations from boring flat overcast. High scores indicate structured clouds with good light transmission.

How flat and boring the overcast is. HIGH scores indicate uniform gray sky with no breaks or texture - generally unfavorable for most photography. LOW scores indicate breaks, texture, or clearing.

Probability of clear sky based on GEFS ensemble (TCDC < 30%)

Spread/volatility in cloud cover predictions across GEFS members (0=consensus, 100=high disagreement)

Height of 0°C isotherm above sea level

Snow depth accumulated on ground

Seconds of direct sunlight per hour

Shortwave solar radiation from sun

Direct (beam) solar radiation reaching the surface. Higher values indicate harsh, directional light with defined shadows.

Scattered solar radiation from clouds and atmosphere. Higher values indicate soft, even lighting ideal for portraits.

UV radiation index (0-15+)

Sun's angle above horizon (0° = horizon, 90° = zenith)

Sun's compass direction (0° = North, 180° = South)

Combined wind wave and swell height (significant wave height)

Height of primary swell waves (organized long-period waves)

Height of wind-driven waves (locally generated)

Time interval between consecutive wind wave crests

Direction wind waves are coming from (meteorological convention)

Direction of primary wave component (meteorological convention)

Moisture content relative to saturation

Dew point temperature at 2 meters

Temperature difference between air temperature and dew point

Difference between saturation and actual vapor pressure

Darkest period between astronomical dusk and dawn

Specific moon phase requirements

Moon must be above the horizon

When Galactic Center or MW band is photographable

Moon's elevation angle above horizon

Moon's compass direction (0° = North, 180° = South)

Percentage of moon disc illuminated (0% = new, 100% = full)

Galactic Center elevation angle above horizon

Predicted aurora Kp index for geomagnetic activity

Aurora geomagnetic activity score (0-100%) based on Kp index and geomagnetic latitude

Real-time NOAA OVATION Prime satellite aurora probability (0-100%). Available for near-term forecasts only (0-2 hours).

Combined rain and snow precipitation

Liquid precipitation amount

Shower-type precipitation (brief, heavy bursts)

Snow precipitation amount per hour in centimeters

Probability of any precipitation occurring

Atmospheric pressure at surface level

Convective Available Potential Energy

Temperature difference measure for atmospheric stability

Air temperature at 2 meters above ground

Temperature accounting for wind chill and humidity

Ground/surface temperature at 0cm depth

Golden hour periods with warm, soft light

Deep blue sky after sunset/before sunrise

Sun 0-6° below horizon

Sun 6-12° below horizon

Sun 12-18° below horizon

Daylight period conditions (day/night)

Horizontal visibility distance

Total aerosol optical depth at 550nm. Lower values indicate clearer skies and more vivid colours.

Dust component of aerosol optical depth. High dust reduces air clarity and can create warm-toned haze.

Smoke component of aerosol optical depth (black carbon + organic matter). Indicates wildfire smoke or urban pollution affecting air quality and visibility.

Sea salt component of aerosol optical depth. Indicates marine aerosols from ocean spray, common in coastal areas.

Ångström exponent (α) computed from AOD at 550nm and 865nm. Indicates aerosol particle size: higher values = smaller particles (pollution, smoke), lower values = larger particles (dust, sea salt).

Wind speed at 10 meters above ground

Wind direction in degrees (0° = North)

Maximum wind gust speed