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controlled. by an upper level pressure trough which tends to be located during
trade weather just west of Eniwetok. The difficulties of forecasting variations
‘In trade weather, then, are associated with small movements of the trough line
‘to ‘ond ‘fro across the northern Marshalls. .
The second ‘type of weather ‘situation ‘is very easily ‘confused with ‘the
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first. especially if an adequate upper alr observational network is not established.
In the lower atmosphere the winds are,-as in the trade situation between eastnortheeast and northeast.
However, the fluctuctions in speed, in time, and space
may be quite large and the winds do not vary lIatitudinally in the regular manner
that is typical of the trodes.
For a period of two or three days, for example,
although the winds remain in the northeast, almost the entire Marshall Islands may
show wind speeds less than 10 knots.
The cloud cover,-instead of being recorded
as 5/10 trade cumulus may consist over most of the area of only 2 to 4/10 of
small cumulus below 4,000 feet.
Here and there, a more or less stationary line
of large cumulocnimbus with heavy showers, or on occasion thunderstorms, may be
The greatest difference,
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however, lies not in the lower cloud but in the middle and upper regions.
very extensive sheet of -alto-stratus breaking here and fhere to alto-cumuluswill
observed from aitcraft or lie across individual atolls.
Blanket the southern Marshalls and extend from time to fime to the Eniwetok -
Bikini area,
From this sheet, wherever it -is thick. will fall a continuous and
often heavy rain.
Cirrus cloud is much more extensive than normal and in the
south may form continuous overcasts lying above and: sometimes fusing with the
altoestratus decks.
Cloud and weather moke aircraft operations ‘above 20.000 feet
difficult and occasionally hazardous.
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1500 Ft Eniwetok Winds Under Cold Low Aloft
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