WMOD00377

• Contract/Permit #: 14-06-D-5640
• Project Name: Park Range Atmospheric Water Resources Program
• Title: Park Range Atmospheric Water Resources Program - Phase II - Part A
• Date: 11/15/1966
• Weather Modification - Doc Type: Report

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12-13 NOVEMBER 1965 CASE (Analysis period No. I)

This was a classic orographic upslope flow snow-producer with al-
most saturated westnorthwest flow from 750 rob to 350 mb from the west
coast to the Park Range, The cyclonic side of the 500 mb westnorthwest jet
was over the Park Range and there was no upper trough in the vicinity,

Figures 31, 32, and 33 show the 500 mb, 700 mb, and surface patterns,
re spectively, for this snow storm. Figu re 34: depicts the general topography
and elevation along the streamline of incoming moist air to the Park Range.
Note from Figure 33 what a non-de script, flat pressure field prevailed on
the surface chart. Figure 35 shows the deep moist layer that accompanied
this storm"

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22 DECEMBER 1965 CASE (Not an analysis period)

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The precipitation shadow from the White River Plateau :-vas quite ef-
fective on this date, producing ceilings above 10,000 feet MSL. It was snow-
ing continuously much of the day as close as Eagle (EGE) on the south flank

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of the Plateau to the southwest, and the San Juans' of southwestern Colorado
received heavy snow.

Figures 36, 37, and 38 depict the 500 mb, 700 mb and surface analy-
ses respectively. Figure 39 shows the terrain elevations along a streamline
from Winslow; Arizona, to the Park Range. The sounding in' Figure 40, show s
the incoming moi st layer.

15 JANUARY 1966 CASE (Analysis Period No.7)

This started out as a good we stnorthwest orographic flow pattern on
the 14th; but by midnight MST of the 15th, winds at 700 m b we re turning to
northnorthwest on the macroscale. A seeding operation was in progress from
1300 MST on the 14th until 1530 of the 15th even though snow stopped at Rab-
bit Ears at 1200 MST, implying a possible precipitation shadow from the Elk-
head Mountains, 25 miles to the northwest"

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