Laserfiche WebLink
<br />8 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />the soundings. March and April had the greatest variety in wind directions, but even <br />then, when upslope storms are common on the Front Range, the Gunnison project area <br />rarely received amounts over 0.4" from easterly-type events. November - February <br />events were almost exclusively from a westerly direction. Many of the soundings were <br />dry below 650 or 700 mb. Some showed only a 100- or 200-mb thick moist layer, <br />usually found between 500 and 700 mb. The clouds that were formed in these situations <br />over the proposed target area were no doubt thicker than these numbers would indicate, <br />due to the forced lifting of the air mass by the mountairi barriers. <br /> <br />Of the soundings examined, the 700-mb temperature was -5 oC or below slightly <br />less than half of the time, with the average being -4,1 oC. However, the 700-mb <br />temperature was -2 DC or colder approximately 80% of the time. Figure 2.9 provides a <br />plot of the mean storm 700-mb temperature averaged by month. As expected, these <br />average temperatures drop during the heart of the winter season. Although a -5 oC <br />temperature is commonly used as a maximum threshold for wintertime seeding proj ects, <br />much of the Gunnison project area is at elevations higher (colder) than the 700-mb level, <br />with some peaks rising to near 600mb. Thus the seeding material can be expected to rise <br />significantly higher than 700mb iftargeted correctly. This means that seeding is likely to <br />be effective even when the 700-mb temperature is as wann as -2 oC, in which case the <br />vast majority of these events are cold enough to be seeded. <br />