Already quite a few trails appearing and there are likely to become more prevalent over the weekend as thousands of aircraft fly through the moister
air aloft ahead of the front stretched out across Ireland and Scotland slowly creeps southeastwards.
This is the midnight sounding from Cambourne, showing the situation well (note the very high humidity levels):-
PRES HGHT TEMP DWPT RELH MIXR DRCT SKNT THTA THTE THTV
hPa m C C % g/kg deg knot K K K
486.0 6036 -14.5 -16.3 86 2.22 195 24 317.9 325.4 318.3
480.0 6131 -15.1 -16.6 88 2.19 199 26 318.3 325.7 318.7
470.0 6290 -16.1 -17.1 92 2.15 205 30 318.9 326.2 319.3
457.0 6501 -17.5 -17.7 98 2.09 195 31 319.8 326.9 320.2
446.0 6684 -18.6 -18.8 98 1.95 190 27 320.6 327.4 321.0
445.0 6701 -18.7 -18.9 98 1.94 191 27 320.7 327.4 321.1
438.0 6819 -19.9 -20.3 97 1.75 196 28 320.6 326.7 321.0
432.0 6921 -20.1 -21.1 92 1.65 200 29 321.6 327.4 321.9
419.0 7148 -21.2 -22.3 91 1.53 210 31 323.0 328.4 323.3
414.0 7237 -21.7 -22.8 91 1.49 213 32 323.5 328.8 323.8
410.0 7308 -22.1 -23.8 86 1.37 215 32 323.9 328.8 324.2
401.0 7472 -23.3 -25.1 85 1.25 206 34 324.4 328.9 324.6
400.0 7490 -23.3 -25.1 85 1.25 205 34 324.6 329.1 324.9
396.0 7563 -24.0 -25.6 87 1.21 200 32 324.7 329.1 324.9
394.0 7600 -24.3 -25.8 87 1.19 201 32 324.7 329.0 325.0
392.0 7637 -24.9 -26.8 84 1.09 202 33 324.4 328.4 324.6
385.0 7767 -25.7 -28.7 76 0.93 205 33 325.0 328.5 325.2
374.0 7976 -27.2 -29.4 81 0.90 210 35 325.8 329.1 326.0
373.0 7995 -27.3 -29.5 82 0.90 210 35 325.9 329.2 326.0
365.0 8150 -28.5 -33.2 64 0.64 210 36 326.3 328.7 326.4
363.0 8189 -28.9 -33.8 63 0.61 210 36 326.3 328.6 326.4
358.0 8288 -29.5 -33.9 66 0.61 210 36 326.7 329.0 326.9
355.0 8348 -29.9 -34.0 67 0.61 210 35 327.0 329.3 327.1
342.0 8611 -31.8 -35.0 74 0.58 210 33 327.9 330.1 328.0
337.0 8714 -32.6 -35.4 76 0.56 210 33 328.2 330.4 328.4
335.0 8756 -32.9 -35.5 77 0.56 210 33 328.4 330.5 328.5
332.0 8819 -33.3 -35.0 85 0.59 210 34 328.7 330.9 328.8
326.0 8946 -34.3 -36.3 82 0.53 210 35 329.0 331.1 329.1
316.0 9161 -36.0 -38.4 78 0.44 205 33 329.6 331.3 329.7
306.0 9384 -37.7 -40.6 74 0.36 220 34 330.2 331.6 330.3
304.0 9429 -38.1 -41.1 73 0.35 220 34 330.3 331.7 330.4
300.0 9520 -38.9 -41.6 75 0.33 220 34 330.4 331.8 330.5
296.0 9612 -39.6 -42.0 78 0.32 220 34 330.8 332.0 330.8
294.0 9659 -39.9 -42.2 79 0.32 219 33 330.9 332.2 331.0
288.0 9800 -40.9 -44.2 70 0.26 215 29 331.5 332.6 331.6
284.0 9895 -41.5 -45.6 64 0.23 212 29 331.9 332.9 332.0
281.0 9967 -42.1 -46.1 65 0.22 210 29 332.0 332.9 332.1
Oh, and before anyone asks, the fact it's 29c at sea level has no bearing on the temperatures 6 miles up
edit on 1-10-2011 by Essan because: (no reason given)