Present Weather Flashcards
What does TT mean on the Station Model
Air Temperature
What does TdTd mean
Dew Point Temperature
What does WW mean
Present Weather symbol
What does DD mean
Wind Direction (10s of degrees from where wind is blowing)
What does FF mean
Wind speed (long feathers 10 knots, short feathers 5 knots)
What does PPP mean
Sea level atmospheric pressure
What does a mean
Slope of pressure tendency (last three hours)
What does pp mean
Magnitude of pressure tendency
What are the present weather codes 20 - 26 used to represent
Report precipitation, fog (ice fog) or thunderstorms at the station during the preceding hour but not at the time of precipitation
What do the the 40s and 50s mostly represent as ww
Precipitation and drizzle
What do the 60s and 70s mostly represent as ww
Rain snow and Ice type weather
What do the 80s and 90s mostly represent as ww
Rain shower, snow showers, thunderstorms and tornados
What is the present weather sensor (PWS)
A component of an automatic weather station that detects the presence of hydrometeors and determines their type (rain, snow, drizzle etc) and intensity.
What is the tipping bucket raingauge
The most common instrument for measuring precipitation, in situ, at the surface and cheap. Logs each tip of the bucket (commonly 0.2mm in size but can be larger in the tropics).
What classifies slight rain
<0.5mm/hr
What classifies moderate rain
0.5-4mm/hr
What classifies heavy rain
> 4mm/hr
What is the difference between a rain shower and just raining
showers are of short duration and fall from convection clouds (cumulus/ cumulonimbus)
What does drizzle mean
The Diameter is greater than 5mm
What is continuous precipitation
Falling for an hour or more
What is intermittent precipitation
Falling for less than an hour
What is fog
Visibility < 1000m and relative humidity 95%
What is mist
Visibility 1-10km and relative humidity >95%
What is haze
Visibility <10km and relative humidity 95%. There can b special cases though
