Local-Flight
NOW evaluation for a Local-Flight mission.
Parameter Overview
The parameter overview displays a parameter summary, containing all parameter limits considered in the evaluation, as well as additional information on the current weather conditions, which allow the pilot to independently assess the weather situation.
The evaluation, combined with the additional weather information, provide an accurate and reliable decision-making basis for the flight mission.
Components that are part of the parameter overview are the following: a parameter summary, a section for wind direction, wind gusts, precipitation, temperature and pressure, cloud cover & visibility, and METAR/TAF data. These are explained in detail below.
Parameter Sections
This summary provides an overview of all limit parameters considered when assessing the flight capability of the mission. In this example, it includes precipitation, visibility, as well as wind gusts and wind speed, both measured at a standard height of 10 meters above ground level. Based on these parameters, the corresponding indication of flight capability is displayed in the window.
The result of the flight capability analysis can also be seen directly below the displayed mission name and is highlighted in color:
GREEN - GOOD TO FLY (NOMINAL):
All weather parameters lie within the nominal range.
YELLOW - CAUTION (MODERATE):
At least one parameter lies within the moderate range.
RED - DO NOT FLY (SEVERE):
At least one parameter lies within the critical range.
The "WIND DIRECTION" section shows wind direction and speed at the significant heights AGL.
The wind-direction indicator on the left illustrates the wind direction at each altitude, with color-coded arrows corresponding to the heights listed on the right:
10 meters AGL: This is the standard height for wind measurements, as defined by the World Meteorological Organization (WMO).
100 meters AGL: This height is roughly above the atmospheric boundary layer, which typically extends up to about 60 meters AGL. At this level, wind is less affected by surface roughness.
300 meters AGL: Height which is just in the range of a typical flight altitude and wind conditions are more stable.
Due to the logarithmic wind profile, wind speed increases with height. Close to the ground, wind speed is nearly zero because of surface friction, leading to different measurements depending on the height.
The "WIND GUST" section indicates wind gust speeds at the significant heights, similar to wind speed. A wind gust is referred to when the instantaneous wind speed exceeds the mean wind speed by at least 10 knots (5 m/s). It is therefore defined as a brief and sudden increase in wind speed.
The averaging period for determining deviations from the mean wind speed is approx. 3 seconds. This period helps ensure accurate and consistent assessment of wind gusts.
This section provides key precipitation metrics: the precipitation rate in mm/h, the probability of precipitation, the probability of thunder strikes, and the probability of icing.
Precipitation
Accumulated Precipitation: The total amount of moisture that has fallen over a specified period. Various types of precipitation are taken into account: rain, snow, sleet, and hail. Typical intensity ranges are:
Rain (in mm/h):
Light: < 2.5 mm/h
Moderate: 2.5 mm/h to 10 mm/h
Heavy: > 10 mm/h
Sleet (in mm/h):
Light: < 2.5 mm/h
Moderate: 2.5 mm/h to 5 mm/h
Heavy: > 5 mm/h
Precipitation Probability
The likelihood of precipitation occurring within a given time frame, which is derived from complex modeling that incorporates factors such as humidity, temperature, and atmospheric pressure.
TS prob.
Definition
Thunderstorm probability quantifies the likelihood of thunderstorms occurring in a specific area.
Estimation Methodology
TS probability is provided by using estimations conducted by advanced models that analyze atmospheric parameters such as temperature, humidity, and wind patterns to predict the likelihood of thunderstorms. It's based on key indicators, including thermodynamic factors like high humidity (often exceeding 90%) and atmospheric instability, as well as meteorological indices such as the Lifted Index (LI) and Convective Available Potential Energy (CAPE), which assess the potential for thunderstorm development. Additionally, the predictions are enhanced by integrating real-time data from Meteodrones, which provide detailed atmospheric profiles and improve the accuracy of thunderstorm forecasts.
Icing
Icing is a critical concern in aviation as it can lead to severe safety hazards, including loss of control. Icing conditions typically arise when two specific criteria are met: air temperatures drop below 0 °C, and relative humidity exceeds 95%. These conditions can occur even at low altitudes, depending on temperature and moisture levels​.
This section provides an overview of cloud cover and visibility conditions during the mission timeframe. It lists low cloud coverage, cloud base, cloud ceiling, and visibility.
Low Cloud Cover
Definition: This parameter refers to the portion of the sky covered by low clouds (typically below 2,000 feet or approximately 600 meters).
Determination: Data on low cloud cover is collected through satellite-based observations, radar, and automated weather stations, which analyze both the altitude and extent of the clouds. Numerical Weather Prediction (NWP) models are used to simulate precipitation and cloud formation, enabling accurate forecasts. The classification of "Low Cloud Cover" is expressed in percentages and divided into intervals, with the coverage reported in octas (1 octa represents 1/8 of the sky).
Classification
0-12.5%: No to very little cloud cover (0 octas))
12.5-37.5%: Slightly cloudy (1-3 octas)
37.5-62.5%: Moderately cloudy (4-5 octas)
62.5-87.5%: Heavily cloudy (6-7 octas)
87.5-100%: Overcast to completely cloudy (8 octas)
Cloud Base
The cloud base refers to the height at which the lower boundary of the clouds begins, measured in feet or meters above sea level.
Cloud Ceiling
The cloud ceiling is the height of the highest cloud base above the ground that causes visibility impairment. This is important for aviation and meteorological reporting.
Visibility
Visibility refers to the distance at which an object can be clearly seen and identified through the atmosphere. Visibility measurements do not take terrain or day time into account; they focus solely on atmospheric clarity, considering factors such as haze, precipitation, fog, and other meteorological phenomena that can affect sightlines.
Here, the METAR and TAF data for the surrounding airports around the flight location are illustrated, listed by airport designation, along with the distance to the flight location (horizontal arrow) and the altitude at which the METAR data is measured.
Based on the latitude and longitude coordinates, a ranking is created with airports sorted by increasing distance. The first three airports from this list are selected.
Structure
METAR: METAR [Station Identifier] [Date and Time of Observation] [Wind] [Visibility] [Weather Conditions] [Sky Condition] [Temperature and Dew Point] [Pressure] [Other Remarks]
TAF: TAF [Station Identifier] [Date and Time of Forecast] [Wind] [Visibility] [Weather Conditions] [Sky Condition] [Forecast Changes] [Other Remarks]
Common Abbreviations
Cloud Cover States:
SKC – Sky Clear (no clouds).
CLR – Clear (no significant clouds).
FEW – Few clouds (1/8 to 2/8 of the sky covered).
SCT – Scattered clouds (3/8 to 4/8 of the sky covered).
BKN – Broken clouds (5/8 to 7/8 of the sky covered).
OVC – Overcast (8/8 of the sky covered).
CB – Cumulonimbus (thunderstorm clouds).
TCU – Towering Cumulus (potential for thunderstorms).
Weather Conditions:
-RA – Light rain.
RA – Rain.
+RA – Heavy rain.
-SN – Light snow.
SN – Snow.
+SN – Heavy snow.
SHRA – Showers of rain.
+SHRA – Heavy showers of rain.
SHSN – Showers of snow.
+SHSN – Heavy snow showers.
TS – Thunderstorms.
+TS – Severe thunderstorms.
SQ – Squall (strong wind gusts).
HZ – Haze (reduces visibility).
FG – Fog (reduces visibility).
BR – Mist (light fog).
DU – Dust (reduces visibility).
SA – Sand (reduces visibility).
VA – Volcanic ash (reduces visibility).
UP – Unknown precipitation (precipitation not specified).
Phenomena:
FZFG – Freezing fog.
FZRA – Freezing rain.
G – Gusts (wind gusts).
LGT – Light (used to describe light intensity of rain, snow, etc.).
MOD – Moderate (used for moderate intensity of rain, snow, etc.).
HEAVY – Heavy (used for intense weather conditions like heavy rain, snow, etc.).
WVA – Wind variable (wind direction is variable).
RVR – Runway Visual Range (visibility along a runway).
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