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Lt. Col. Ernest J. Fawbush
and
Maj. Robert C. Miller

From sixty-two cases of non-frontal thunderstorms passing over reporting stations, a relation is found between peak wind gusts and the temperature difference between the surface air underneath and in advance of the thunderstorm. The temperature under the thunderstorm is forecast by lowering the wet-bulb temperature at the freezing level to the surface along a saturation adiabat on a pseudoadiabatic chart, permitting use of the relation as an aid to thunderstorm gust forecasting.

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Bernhard Haurwitz
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Willis L. Webb
,
James Giraytys
,
Harold B. Tolefson
,
R. C. Forsberg
,
Robert I. Vick
,
Orville H. Daniel
, and
Leon R. Tucker

The status of the Meteorological Rocket Network (MRN) is presented at the end of the first six years operation. A total of twenty stations were active at the end of 1965 and almost 6000 observations had been collected. The latest instrumentation systems employed in the MRN are described, and the general results of certain MRN data analyses are presented. The MRN data illustrate very clearly the need for a global MRN to adequately observe the stratospheric circulation.

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Alan Robock

While tropical sea surface temperatures certainly influence the atmosphere; winter circulation, temperature, and precipitation over Northen Hemisphere continents are also influenced by circulation patterns related to the stratosphere. In particular, large tropical volcanic eruptions produce winter warming patterns over Northern Hemisphere continents because of a dynamical effect forced by gradients of radiative heating from sulfate aerosols in the lower stratosphere. These effects must be included for accurate dynamical seasonal predictions of Northern Hemisphere winter temperature over both North America and Eurasia.

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James R. Scoggins
and
Christopher N. K. Mooers
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C. L. Jordan
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Iver A. Lund

The coefficient of rank correlation was computed between daily weather charts and “ideal” map types. This coefficient was used as a predictor to specify the ceiling height at a station. The effectiveness of this predictor was compared to that of a slightly different predictor which weighted the differences in rank. It was found that weighting the differences improved the predictor. A “weather index” was derived from a combination of three predictors which weighted the differences in rank and one predictor which gave the difference in pressure between two points. This index was used to obtain an estimate of the occurrence probability of several categories of ceiling height.

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Edwin Kessler III
and
Raymond Wexler

Observations of a sharp cold front and closely associated squall line in New England are analyzed. A striking feature is a line of convective clouds and heavy precipitation, which does not extend above 10,000 ft. The radar indication of the true plan-position and vertical extent of such disturbances is of special importance to air operations.

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Edwin Kessler III

Hurricanes Edna, 1954, and Ione, 1955 were observed by radar at South Truro, Massachusetts. Both storms are associated with convective shower bands near the northern extremities of their circulations. Shower characteristics in the two cases are virtually identical in most respects, but the bands which they comprise propagate in grossly dissimilar ways. The differences are attributed to the presence of a convergence line or zone (cold front) at the boundary between two large scale air streams in the case of Ione, and the absence of a corresponding feature in the case of Edna.

The Ione observations are in general accord with the Bjerknes cold frontal model, as recently modified by Sanders, in which warm air is entrained into the frontal zone and converges and rises there and above it. While the showers thereby formed move with the warm air in which they are embedded, the convergence zone moves with the winds northwest of the wind shift line. The Edna showers develop in an almost horizontally homogeneous wind field, and there is some question as to the persistence of the small scale lines of convergence which produce them.

This note also contains some brief discussion of banded structures associated with altostratus clouds and rain which occur in the outskirts of both Edna and Ione.

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Eberhard W. Wahl

An investigation of temperature and additional records shows the existence of a pronounced January thaw in New England. This singularity can be connected to the existence of typical changes in the circulation over the United States. Further world-wide relations indicate important consequences valuable for further research on singularities.

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