Forecast update, 2 Jul #2


Mark Conner <n9xtn@...>
 

The Eta and AVN now cover the launch time. Unfortunately, the
Eta indicates a more unidirectional wind profile and a bit
stronger one.

For a 95,000 ft burst, the landing is 352 degrees at 19 miles.
This is not far where US77 crosses the Kansas River and is only a
mile or two south of Junction City. For a 75,000 ft burst, the
landing is at 014 degrees at 20 miles, which is comfortably south
of I-70.

If this continues, I plan to switch NSTAR to a 600 or a 350g
balloon (have one each of 800, 600, and 350) to get a lower burst
altitude and move the landing east, and really gassing the
balloon up to shorten the trip.

The AVN model, on the other hand, is more consistent with the
previous MRF predictions (297 at 9 miles for 95kft and 355 at 5
miles for 75 kft). It should be consistent, however, as it has
the same physics.

In my experience, the Eta is better at the lower levels and the
AVN is better higher up. What I did was come up with a hybrid
wind profile using the Eta below 20,000 ft, the AVN from 20 to 60
kft, and the latest Topeka sounding data above 60 kft. Doing
this gave landings to the NNW and NNE at 10-12 miles in both
cases.

Still time for things to change. The wind profile I used is
below.

- Mark

1237,156,6
1240,161,7
1988,194,23
2766,206,26
3556,206,25
4364,206,23
5190,207,21
6030,207,21
6893,206,21
7776,206,19
8678,206,17
9606,195,11
10561,174,11
12552,194,17
14685,207,17
16962,215,17
19419,220,15
25066,186,7
31962,266,6
36106,292,9
40945,300,9
46834,337,7
54800,60,7
60311,81,11
61712,95,10
62910,92,10
63533,91,11
65200,87,11
67404,83,12
68602,80,12
70328,78,16
76597,90,17
79199,90,18
84812,77,17
87795,85,17
92611,64,17
94025,62,19
97178,66,23
100885,72,27
103018,75,29
105367,75,29
109501,75,29

Join GPSL@groups.io to automatically receive all group messages.