Sounding - NOAA interactive (uses recent balloon data)  revised November 2007

Link on right is also on the main weatherjack weather pageSounding NOAA

Generate soundings from MAPS or RUC Analyses and Forecasts, RAOBS, Profilers, Radiometers, or Aircraft (restricted)

This is the header you get when you get to the web page (via link above)   http://rucsoundings.noaa.gov/
You now get a table with click boxes.  ('RAOB' = (RAwinsonde OBservation).  This example below is from an excellent day Thursday, 9th August 2007

example

Some can be left alone, but some of those starred will probably need to be altered.   RAOB is the usual selection.

Start time can be latest or a particular time for archive study.
The example is for Year 2007, month August, date 8th, time 23:00 UTC, ie the final sounding before the start of 9th August.
Number of hours can be left at 3.0 (number is in connection with animated soundings but not available for UK stations) but this covers the uncertainty exactly when the balloon is sent up.
Site is selected from list below but note is is IMPORTANT to include the leading zero.
IN PRACTICE you will probably want to make a forecast for the coming day.  Use the midnight sounding (probably in practice 2300 from day before).
Use up to date forecast maximum temperatures, expected dewpoint (likely similar to dewpoint at 0700 hours) and sea level pressure.


diagram This is a Skew-T and you can work out a great deal simply by looking at this graph. 

But there is much more.


diagram By positioning the mouse, left clicking and dragging, you can zoom in on the main area of interest

Right click. This box appears.

If necessary, click or fill in the boxes.  It is easy to forget to click Celsius.
In this box, Td means dewpoint, T means (dry) temperature.
Archive temperatures, dewpoints and pressure best found from this website

Alternatively, you can move the mouse pointer to an appropriate place, usually ground level and a surface temperature, and left click. (playing with high level instability is instructive). 
But this method does not allow change in surface dewpoint .

You can try various surface temperatures to see what happens, eg determine the trigger temperature, or the temperature to give cloud base of 3,000 feet.  Experiment.

diagram

This the result. The solid horizontal black line is cloud base for the Tdry and Tdew that had been used.
Small shallow cumulus should occur at around 4,600'

Tdry/Tdew split * 400 gives similar answer but the Bradbury Rule does not work for blue thermals so this SkewT is useful in that it shows that small cu are likely to form and that thermals are not blue.

You can alter the temperature, work out trigger, cloud tops, etc.

It is a superb program.  You can try various "what ifs".  Experiment and have fun.
There are many other features that have not been covered.  This explanation is just to get you started. 
Help and instructions available on the website itself. 

diagram

British Isles stations
Those in bold normally report midnight and midday UTC. 
Others are occasional although Larkhill (for the Salisbury Plain gunnery) usually sends up a balloon at 0600 GMT Monday to Friday.

Name WMO Lat / Long other code Name WMO Lat / Long other code
LERWICK 03005 60N 01W 9999 MUCKLE FLUGGA 03001 61N 01W 9999
STORNOWAY 03026 58N 07W EGPO KINLOSS 03066 58N 04W EGQK
NOTTINGHAM 03354 53N 01W 9999 WEST FREUGH 03130 55N 05W EGOY
LARKHILL 03743 51N 02W 9999 ESKMEALS 03213 55N 04W 9999
CAMBORNE 03808 50N 06W 9999 ALBERMARLE 03238 56N 02W 9999
H'MONCEUX 03882 51N 01W 9999 LEEMING 03257 54N 02W EGXE
CASTOR BAY 03918 54N 06W 9999 WADDINGTON 03377 53N 01W EGXW
VALENTIA 03953 52N 10W 9999 SHAWBURY 03414 53N 03W EGOS
ABERPORTH 03502 52N 05W EGUC BRIZE NORTON 03649 52N 02W EGVN
WATTISHAM 03590 52N 01E EGUW SHOEBURYNESS 03693 56N 01E 9999