Meteorology 101-02

Laboratory 2

Surface SYNOP observation format• Comes in a numerical format like:72365 11966 82504 10074 21001 39875 40157 52008 69901

70206 8807/Where 72365 is the WMO Index number (station code)11966 is coded visibility and cloud height values82504 is total cloud cover in eighths, wind direction & speed10074 is code for temperature in deg C21001 is code for dew point, etc.

Not a very human-friendly format. The station model format is more illuminating and compact

WMO codes for some US Weather Stations

OAK 72493 Oakland International, CA

MFL 72202 Miami, FL

CRP 72251 Corpus Christi, TX

BUF 72528 Buffalo, NY

RAP 72662 Rapid City, SD

OTX 72786 Spokane, WA

SLC 72572 Salt Lake City, CA

TUS 72274 Tucson, AZ09/09/09

Automated Observing Systems• AWOS (Automated Weather System)

Oldest, operated by FAA (Federal Aviation Administration) as well as by state and local governments. Collects T, DP in deg C, wind speed & direction, ceiling up to 12 thousand feet and altimeter settings. Reports at 20 minute intervals. Recently added present weather, freezing rain, and thunderstorm activity.

09/09/09

• ASOS (Automated Surface Observing System) operated by NWS, FAA, and DOD.

Reports at hourly intervals, in addition to AWOS data, degrees Fahrenheit, present weather, icing, lightning, sea level pressure and precipitation accumulation.

Serves as primary climatological observing network in the United States.

09/09/09

Surface Plot Model

Fahrenheit, Celsius, & Kelvin Conversions

09/09/09

 

Tf =95Tc + 32

Tc =59(Tf - 32)

Tk = Tc + 273.15

Remember the parentheses! The 32 goes with the Fahrenheit degrees;

 

Tf - 32 =95Tc

Is it reasonable? 32°F=0°C, 68°F=20°C, 86°F=30°C.

Basic Weather Symbols

Wind Direction and Speed

Cloud Cover

Sea-level pressure

• Sea-level pressure is plotted in tenths of millibars (mb), with the leading 10 or 9 omitted. For reference, 1013 mb is equivalent to 29.92 inches of mercury. Below are some sample conversions between plotted and complete sea-level pressure values:

• 410: 1041.0 mb 103: 1010.3 mb

• 987: 998.7 mb 872: 987.2 mb

Upper-level plot model

Heights (in meters) of constant pressure surfaces (typically 500mb and 300mb) are plotted in place of sea level pressure (on upper-level plots) when these are available; i.e., when soundings have been with weather balloons. These heights are typically also shortened.

UNIVERSITY OF WISCONSIN WEB SITEFOR STATION MODEL PRACTICE

http://profhorn.meteor.wisc.edu/wxwise/AckermanKnox/chap1/decoding_ surface.html

09/09/09