Transactions of RHASS Volume 1940 - Page 103
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| Year | 1940 |
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THE WEATHER OF SCOTLAND IN 1939. By W. A. HARWOOD, D.Sc. THIS report consists of (1) a general description of the weather from month to month, and (2) a selection of rainfall returns in which each county of Scotland is represented by one or more stations. Temperature readings, unless otherwise stated, are from the thermometers exposed in the regulation “ Stevenson Screen.” JANUARY. The weather of January may be summed up as very cold during the first week, with frequent snow in the course of the month. Conditions were unsettled generally, a series of depressions maintaining disturbed weather, with only short fairer intervals. The depression tracks lay mainly to the south of Scotland, and there was a consequent excess of cold N. and N .E. winds. Gales were reported on sixteen days, the stormiest day being the 15th. On this day the anemometer at Bell Rock recorded a mean speed of 50 miles per hour between 11 P.M. and mid" night. Gusts reached 70 miles per hour at Bell Rock, 67 at Lerwick, and 63 at Kirkwall. The total duration of winds of gale force during the month was 27 hours at Bell Rock and not more than 5 at any other station. The cold spell which affected the whole country in the first week was very intense. During this period the temperature fell to 1° F. (31 degrees of frost) at Braemar and DalWhinnie on the 4th, 6° F. at Logie Coldstone on the 6th, and 7° F. at Balmoral and West Linton. Much milder weather set in sharply on the 7th over the whole country, this day being the warmest day of the month at most stations. The highest temperatures reported were 55° F. at Onich and 54° F. at Ayr and Colmonell, while many stations in the south and west had temperatures of 50° F. or more. Very severe ground frosts were experienced in the first week, and ground frosts of varying intensity were reported from one part or another on all days except the 9th and 20th. In the very cold Spell, temperature on the exposed ground fell to — 2° F. (34 degrees of frost) on the 4th at Braemar and on the 6th at Dalwhinnie. THE WEATHER OF SCOTLAND IN 1939. 195 Rainfall was remarkably persistent in many places, the only relatively dry spells being from the 2nd to the 5th and from the 27th to the end of the month, the earlier of these «oinciding with the period of extreme cold. In various parts of the country twenty-five or more days had measurable rain- fall. The amount of rainfall was above normal in the east and north and also south of the line from Dundee to Renfrew. The excess was very substantial in places, more than twice the normal rainfall being recorded in the Firth of Tay area and in the extreme south-east. On the other hand, the amount was below normal in the west, some places in Argyll having only about half the normal amount. The monthly totals ranged from 1370 inches at Ben Alder to 300 inches at Loch Laggan, and the largest daily fall was 255 inches at Lochgoilhead on 14th, this day being the wettest day of the month. Snow or sleet fell at one place or another on twenty- five days ; many places had snow on the 1st and from 24th to 28th. There was 7 inches of undrifted snow at Braemar in the first week and about 8 inches on the 28th and 29th. Hail occurred locally on twenty-three days, and was fairly widespread on the 24th. There were thunderstorms in some east coast towns on the night of the 25th, and at Stornoway on the 8th-9th. The duration of sunshine was much above the average in parts of the north-west, the totals at Stornoway, Oban, and Onich being more than double that ordinarily experienced. [n the east, on the other hand, the amount of sunshine was below normal. From 65 to 68 hours of bright sunshine were recorded at Turnberry, Oban, and Tiree, while less than 30 hours were registered in the inland area of the north, and Peebles also reported a marked deficiency. FEBRUARY. This month was mild generally and, on the whole, wet. The weather continued to be unsettled during February, but depressions mostly passed to the northward of Scotland between Iceland and Norway, and conditions became rather mild, with frequent and sometimes heavy rainfall. Gales occurred oftener than during January in the north, but less often in the south, Lerwick recording a total of 67 hours on eighteen days against 5 hours in January, and Bell Rock 16 hours against 27 in January. Gales were reported from one part or another on every day except the 1st, 2nd, 17th, and 28th. The stormiest period in the north was the 15th- 16th, when gusts of 80 miles per hour were recorded at Storno- way, 75 at Kirkwall, and 70 at Tiree, but in the south-east the winds were strongest on the 6th, the mean speed in Edin- .. _. M"... mun— w I |
| Title | Transactions of RHASS Volume 1940 - Page 103 |
