surface analysis charts - are analysed charts of surface weather observations.
surface analysis charts depicts the distribution of several items, including sea-level pressure, position of highs, lows, ridges, and throughs, location and type of fronts, and boundaries like drylines
WPC issues surface analysis chart eight times daily, meaning, valid at 00, 03, 06,09, 12,15,18, 21
components of surface analysis charts are isobars, fronts, high pressure and low-pressure system, and surface weather station plots
isobars are lines on a map that pass through an area with the same pressure
iso means same, bar means unit of measure for pressure
isobars has 4hPa difference between and can range from 870 hPa to 1080 hPa
fronts are weather system that is the boundary separating two different types of air mass
types of fronts includes cold front, warm front, stationary front, occluded front, through, ridge, squall line, dryline, and tropical wave
cold front - cold air mass replacing warmer air mass
warm front - warm air mass replacing colder air mass
stationary front - forms when a cold or warm front stops moving
occluded front - forms when warm air mass gets caught between two cold air masses
through - elongated area of relatively low pressure extending from the center of a region of low pressure
ridge - elongated area of relatively high pressure extending from the center of a high-pressure region
squall line - group of storms arranged in a line
dryline - boundary between moist and dry air masses
tropical wave - areas of low pressure in the tropics, generally from east to west due to trade winds
the large letters (Blue H’s and Red L’s) on weather maps indicate centers, marks the highest and lowest relative to the surrounding air
high pressure and low-pressure system are often labeled with a three or fourdigit pressure reading in millibars
surface weather station plots describes the weather at a station location
surface weather station plots includes reports of a variety of weather data at that location
surface weather station plots shows information like wind speed and direction, temperature and dewpoint, current weather, pressure and pressure trend, sky cover, visibility
current weather symbols are established by NOAA for use in weather station plots
current weather tells what conditions are currently happening at that particular station location
current weather symbols are typically plotted if some type of precipitation is occurring or some weather event is causing reduced visibility at the time of observation
sea-level pressure is plotted in tenths of millibars (mb) with the first two digits (generally 10 or 9) omitted
pressure trend has two components and that is a number and a symbol
pressure trend indicates how sea-level pressure has changed during the past 3 hours
in pressure trend, the number provides the 3-hour change in tenths of millibars, while the symbol provides a graphic illustration of how this change occurred
approximate amount of sky cover can be determined by the circle at the center of the station plot
horizontal surface visibility is measure in statute miles