Aviation Wx Charts Flashcards
Give some examples of the various NWS wx charts you’ll be using during preflight planning.
a) Surface analysis chart
b) Weather depiction chart
c) Short-range surface prognostic chart
d) Significant weather prognostic chart
e) Convective outlook chart
f) Constant pressure analysis chart
What is a surface analysis chart?
Surface analysis charts are analyzed charts of surface weather observations. The chart depicts the distribution of several items including sea level pressure, the position of high, lows, ridges, troughs, the location and character of fronts, and the various boundaries such as drylines, outflow, boundaries, sea-breeze fronts, and convergence lines. The chart is produced eight times daily.
What information does a wx depiction chart provide?
The wx depiction chart contains a plot of wx conditions at selected METAR stations and an analysis of wx flying category (VFR, MVFR, IFR). It is designed primarily as a briefing tool to alert aviation interests to the location of critical or near critical operational minimums at terminals in the US and surrounding land areas. The chart is issued eight times daily.
Define the terms: LIFR, IFR, MVFR, VFR
a) Low IFR - ceiling less than 500ft and/or visibility less than 1 mile
b) IFR - Ceiling 500 to less than 1,000ft and/or visibility 1 to less than 3 miles
c) MVFR - Marginal VFR - ceiling 1000 to 3000ft and.or visibility 3 to 5 miles inclusive.
d) VFR - ceiling greater than 3000ft and visibility great than 5 miles; including sky clear
What are short range surface prognostic charts?
Short-range surface prognostic charts provide a forecast of surface pressure systems, fronts, and precipitation for a 2 1/2 day period. Predicated conditions are divided into five forecast periods: 12, 18, 24, 48, and 60 hours. Charts are issued four times a day and can be used to obtain an overview of the progression of surface wx features during the included periods.
Describe a US low-level significant wx prog chart
The low-level significant wx (SIGWX) charts provide a forecast of aviation wx hazards primarily intended to be used as guidance products for pre-flight briefings. The charts depict wx flying categories, turbulence, and freezing levels, and are issued four times a day in teo types: 12 hour prog, 24 hour prog
Describe a mid-level significant wx (SIGWX) chart
The mid-level significant wx chart provides a forecast and an overview of significant en route wx phenomena over a range of flight levels from 10,000ft MSL to FL450 and associated surface wx features. Four times daily
What is a convective outlook chart?
The convective outlook chart depicts areas forecast to have the potential severe (tornado, wind gusts 50 knots or greater, or hail 3/4” diameter size or greater) and non-severe convection and specific sever wx threats during the following three days.The chart depicts areas of slight risk (SLGT), moderate risk (MDT) or high risk (HIGH) of sever thunderstorms for a 24 hour period beginning at 1200 UTC.
What are constant pressure analysis charts?
Any surface of equal pressure in the atmosphere is a constant pressure surface. A constant pressure analysis chart is an upper air wx map where all information depicted is at the specified pressure of the chart.
From these charts, a pilot can approximate the observed air temperature, wind, and temperature-dewpoint spread along a proposed route. They also depict highs, lows, troughs, ridges aloft by the height contour patterns resembling isobars on a surface map. Issued twice daily.
