WMOD00594

• Title: Investigations of Winter Mountain Storms in Utah during the 1987 Utah/NOAA Field Program
• Date: 1/1/1990
• State: UT
• Weather Modification - Doc Type: Report

1.

INTRODUCTION

A.W. Huggins and A.B. Long (DRI)

This is the third in a series of Final Reports which describes
the results of field research conducted as part of a cooperative
weather modification program between the Utah Division of Water
Resources (UDWR) and the National Oceanic and Atmospheric Adminis-
tration (NOAA). Previous programs were conducted in 1983 and 1985.
This current report is concerned with the most recent field research

~_uf ," _-' - _u_ ---------_______

conducted between 1 February and 15 March 19s7-:-., j. y ~\.-1.0 ..~

'-- __,___ __ 'un __ _____

The key findings from prior years are contained in the Final
Reports of Long (1984) and Long (1986) and in numerous conference
and journal articles by the participating groups; e.g., Long et al.

(1986), Rauber and Grant (1987), Sassen et al. (1986), and Uttal et
al. (1986). A complete list of project papers is contained in the

References section.

A number of the conclusions from prior years are worth
, - -

repeating.

The 1983 and 1985 seasons both revealed that the

greatest amounts of supercooled liquid water were found in shallow

cloud systems when natur~l precipitation and radar echo were

relatively weak.

Lidar data indicated that the liquid water was

often very near ground level, fre~ently having a base bel~~~~~st
height. The liqu~d wat:er _ frequently existed at temperatures between

-5 and -lOoe. In addition to shallow cloud systems, liquid water
- -- - -

was also found to exist localized in convective clouds. The least

amounts of liquid were found in deep, cold, areally extensive clouds

associated with synoptic features.
Temporally within a storm, liquid water was found to form

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