Forecasters Guide - (IMD), Pune

2.2 CHANGES IN SHIPS’ AND UPPER AIR CODES
DDGM (WF) UOI NO.W-318/ dated 19 November 1991.
As per recommendation of Extra-Ordinary Session of W.M.O. held at London from
24-9-1990 to 5-10-1990 the follow ing changes in the ships and upper air codes have been
introduced w ith effect from 0001 UTC of 1 st November, 1991.
1) All ships equipped w ith raingauge w ill report 7 R 24 R 24 R 24 R 24 group giving
rainfall in mm during the past 24 hours at the time of observations. At present
this group is not used by I.V.O.F.
2) All upper Air Observatories, in India w ill report w inds at 925 hPa in part TTAA of
temp-message as standard level. 92 is an indicator for 925 hPa level and is
follow ed by height in gpm. Then the temperature and w ind groups are reported
for this level as per the usual practice. All forecasting offices will prepare C.P.
charts for 925 hPa level and analyse them follow ing the usual procedure.
Sd/
( M. R. Tikhe )
For D.D.G.F.
37