Detailed Predictions for: Rainbow Valley
Launch Altitude (f): 1125
LZ Altitude (f): 80
Sounding

Station:

KTUS

Date/Time:

20 AUG 2019

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
6 AM Tue 83 83 SW 3 0 1125 0 Blue 0
7 AM Tue 84 84 S 2 0 1125 0 Blue 0
8 AM Tue 84 85 E 2 0 1125 0 Blue 0
9 AM Tue 90 93 NE 2 2766 2554 1429 Blue 4
10 AM Tue 96 101 NE 1 3322 3108 1983 Blue 12
11 AM Tue 101 108 E 1 6064 4110 2985 Blue 19
12 Noon Tue 104 112 E 1 9641 6632 5507 Blue 23
1 PM Tue 107 115 SE 2 14573 9236 8111 Blue 25
2 PM Tue 109 116 SW 5 15658 10565 9440 Blue 26
3 PM Tue 111 117 W 6 16105 12469 11344 Blue 27
4 PM Tue 112 115 W 7 14573 9236 8111 Blue 25
5 PM Tue 113 115 W 8 14573 9236 8111 Blue 25
6 PM Tue 112 112 W 9 9641 6632 5507 Blue 23
7 PM Tue 110 110 W 8 7623 5230 4105 Blue 21
8 PM Tue 107 107 W 7 5334 3807 2682 Blue 18
9 PM Tue 103 103 W 6 3527 3247 2122 Blue 14
10 PM Tue 100 100 W 6 3252 3038 1913 Blue 11
11 PM Tue 97 97 W 5 3043 2831 1706 Blue 8
12 Midnight Wed 94 94 W 5 2835 2623 1498 Blue 5
1 AM Wed 94 94 W 3 2835 2623 1498 Blue 5
2 AM Wed 91 91 W 3 2627 2470 1345 Blue 2
3 AM Wed 90 90 W 3 2558 2470 1345 Blue 1
4 AM Wed 88 88 W 3 0 1125 0 Blue 0
5 AM Wed 87 87 SW 3 0 1125 0 Blue 0
6 AM Wed 85 85 SW 3 0 1125 0 Blue 0
7 AM Wed 84 84 S 3 0 1125 0 Blue 0
8 AM Wed 86 87 SE 2 0 1125 0 Blue 0
9 AM Wed 92 95 E 2 2904 2692 1567 Blue 6
10 AM Wed 97 102 E 2 3391 3177 2052 Blue 13
11 AM Wed 102 108 E 2 6064 4110 2985 Blue 19
12 Noon Wed 106 113 E 2 10966 7449 6324 Blue 23
1 PM Wed 109 116 E 5 15658 10565 9440 Blue 26
2 PM Wed 111 118 SE 6 16407 13946 12821 Blue 28
3 PM Wed 113 118 S 8 16407 13946 12821 Blue 28
4 PM Wed 114 117 SW 9 16105 12469 11344 Blue 27
5 PM Wed 114 115 W 10 14573 9236 8111 Blue 25
6 PM Wed 113 113 W 10 10966 7449 6324 Blue 23
7 PM Wed 110 110 W 10 7623 5230 4105 Blue 21
8 PM Wed 107 107 W 10 5334 3807 2682 Blue 18
9 PM Wed 103 103 W 9 3527 3247 2122 Blue 14
10 PM Wed 99 99 SW 9 3182 2969 1844 Blue 10
11 PM Wed 96 96 SW 8 2974 2761 1636 Blue 7
12 Midnight Thu 93 93 SW 7 2766 2554 1429 Blue 4
1 AM Thu 91 91 SW 7 2627 2470 1345 Blue 2
2 AM Thu 90 90 SW 6 2558 2470 1345 Blue 1
3 AM Thu 88 88 SW 6 0 1125 0 Blue 0
4 AM Thu 86 86 S 5 0 1125 0 Blue 0
5 AM Thu 84 84 S 5 0 1125 0 Blue 0
6 AM Thu 83 83 S 5 0 1125 0 Blue 0
7 AM Thu 84 84 S 3 0 1125 0 Blue 0
8 AM Thu 86 87 S 3 0 1125 0 Blue 0
9 AM Thu 89 92 S 3 2696 2470 1345 Blue 3
10 AM Thu 93 98 S 3 3113 2900 1775 Blue 9
11 AM Thu 96 103 S 3 3527 3247 2122 Blue 14
12 Noon Thu 100 108 S 5 6064 4110 2985 Blue 19
1 PM Thu 103 111 S 5 8416 5950 4825 Blue 22
2 PM Thu 105 112 S 6 9641 6632 5507 Blue 23
3 PM Thu 107 112 SW 6 9641 6632 5507 Blue 23
4 PM Thu 108 111 SW 7 8416 5950 4825 Blue 22
5 PM Thu 109 110 W 8 7623 5230 4105 Blue 21
6 PM Thu 108 108 W 8 6064 4110 2985 Blue 19
7 PM Thu 106 106 W 9 4446 3501 2376 Blue 17
8 PM Thu 103 103 W 9 3527 3247 2122 Blue 14
9 PM Thu 100 100 SW 10 3252 3038 1913 Blue 11
10 PM Thu 97 97 SW 10 3043 2831 1706 Blue 8
11 PM Thu 94 94 SW 10 2835 2623 1498 Blue 5
12 Midnight Fri 92 92 SW 10 2696 2470 1345 Blue 3
1 AM Fri 90 90 SW 9 2558 2470 1345 Blue 1
2 AM Fri 89 89 S 8 0 1125 0 Blue 0
3 AM Fri 88 88 S 7 0 1125 0 Blue 0
4 AM Fri 86 86 S 6 0 1125 0 Blue 0
5 AM Fri 85 85 SE 5 0 1125 0 Blue 0
6 AM Fri 84 84 SE 3 0 1125 0 Blue 0
7 AM Fri 84 84 SE 3 0 1125 0 Blue 0
8 AM Fri 86 87 SE 3 0 1125 0 Blue 0
9 AM Fri 88 91 SE 3 2627 2470 1345 Blue 2
10 AM Fri 91 96 S 3 2974 2761 1636 Blue 7
11 AM Fri 94 101 S 5 3322 3108 1983 Blue 12
12 Noon Fri 97 105 S 5 4142 3386 2261 Blue 16
1 PM Fri 100 108 S 5 6064 4110 2985 Blue 19
2 PM Fri 102 108 S 6 6064 4110 2985 Blue 19
3 PM Fri 104 109 S 7 6765 4412 3287 Blue 20
4 PM Fri 105 108 SW 7 6064 4110 2985 Blue 19
5 PM Fri 105 106 SW 7 4446 3501 2376 Blue 17
6 PM Fri 104 104 SW 8 3836 3316 2191 Blue 15
7 PM Fri 102 102 SW 8 3391 3177 2052 Blue 13
8 PM Fri 100 100 SW 7 3252 3038 1913 Blue 11
9 PM Fri 97 97 SW 7 3043 2831 1706 Blue 8
10 PM Fri 95 95 SW 7 2904 2692 1567 Blue 6
11 PM Fri 93 93 SW 6 2766 2554 1429 Blue 4
12 Midnight Sat 92 92 SW 6 2696 2470 1345 Blue 3
1 AM Sat 90 90 SW 6 2558 2470 1345 Blue 1
2 AM Sat 89 89 SW 5 0 1125 0 Blue 0
3 AM Sat 88 88 SW 5 0 1125 0 Blue 0
4 AM Sat 86 86 SW 5 0 1125 0 Blue 0
5 AM Sat 85 85 SW 5 0 1125 0 Blue 0
6 AM Sat 84 84 SW 5 0 1125 0 Blue 0
7 AM Sat 84 84 SW 5 0 1125 0 Blue 0
8 AM Sat 85 85 SW 5 0 1125 0 Blue 0
9 AM Sat 87 88 SW 5 0 1125 0 Blue 0
10 AM Sat 89 92 SW 5 2696 2470 1345 Blue 3
11 AM Sat 92 96 SW 5 2974 2761 1636 Blue 7
12 Noon Sat 95 100 SW 6 3252 3038 1913 Blue 11
1 PM Sat 97 102 SW 6 3391 3177 2052 Blue 13
2 PM Sat 99 104 SW 6 3836 3316 2191 Blue 15
3 PM Sat 101 104 W 7 3836 3316 2191 Blue 15
4 PM Sat 102 104 W 7 3836 3316 2191 Blue 15
5 PM Sat 102 103 W 8 3527 3247 2122 Blue 14
6 PM Sat 102 102 W 8 3391 3177 2052 Blue 13
7 PM Sat 101 101 W 8 3322 3108 1983 Blue 12
8 PM Sat 99 99 W 8 3182 2969 1844 Blue 10
9 PM Sat 97 97 W 7 3043 2831 1706 Blue 8
10 PM Sat 95 95 W 7 2904 2692 1567 Blue 6
11 PM Sat 93 93 SW 7 2766 2554 1429 Blue 4
12 Midnight Sun 91 91 SW 7 2627 2470 1345 Blue 2
1 AM Sun 90 90 SW 6 2558 2470 1345 Blue 1
2 AM Sun 88 88 SW 6 0 1125 0 Blue 0
3 AM Sun 87 87 SW 6 0 1125 0 Blue 0
4 AM Sun 85 85 SW 6 0 1125 0 Blue 0
5 AM Sun 84 84 SW 6 0 1125 0 Blue 0
6 AM Sun 83 83 SW 6 0 1125 0 Blue 0
7 AM Sun 83 83 SW 6 0 1125 0 Blue 0
8 AM Sun 85 86 SW 6 0 1125 0 Blue 0
9 AM Sun 87 89 W 6 0 1125 0 Blue 0
10 AM Sun 90 93 W 6 2766 2554 1429 Blue 4
11 AM Sun 93 98 W 6 3113 2900 1775 Blue 9
12 Noon Sun 95 100 W 6 3252 3038 1913 Blue 11
1 PM Sun 98 103 W 6 3527 3247 2122 Blue 14
2 PM Sun 100 105 W 7 4142 3386 2261 Blue 16
3 PM Sun 101 104 W 7 3836 3316 2191 Blue 15
4 PM Sun 102 104 W 8 3836 3316 2191 Blue 15
5 PM Sun 103 104 W 8 3836 3316 2191 Blue 15
6 PM Sun 103 103 W 9 3527 3247 2122 Blue 14
7 PM Sun 102 102 W 10 3391 3177 2052 Blue 13
8 PM Sun 100 100 W 10 3252 3038 1913 Blue 11
9 PM Sun 97 97 W 10 3043 2831 1706 Blue 8
10 PM Sun 95 95 W 12 2904 2692 1567 Blue 6
11 PM Sun 92 92 SW 12 2696 2470 1345 Blue 3
12 Midnight Mon 91 91 SW 12 2627 2470 1345 Blue 2
1 AM Mon 89 89 SW 10 0 1125 0 Blue 0
2 AM Mon 88 88 SW 9 0 1125 0 Blue 0
3 AM Mon 87 87 SW 8 0 1125 0 Blue 0
4 AM Mon 85 85 SW 8 0 1125 0 Blue 0
5 AM Mon 84 84 SW 7 0 1125 0 Blue 0

DISCLAIMER: These estimates are intended to assist in daily site selection only.  No warranty is made concerning the accuracy of these estimates.  These estimates cannot be used to determine if conditions are safe for flying.  Conditions should be evaluated at the launch site by experienced pilots before launching.

Sounding: This is the site at which the weather balloon was released.  If the flying site predicted is far from the sounding site, the estimate is not valid.  Also, the sounding is done at 12Z (4AM PST).  If a front comes through, the sounding is no longer valid. The sounding becomes less valid later in the day.

Thermal Ceiling: the lower of the height at which the thermal stops rising and the cloud level.  We can't fly into the clouds, so it doesn't matter how much higher the thermal goes.  Remember that we can't get to the top of the thermal because of our sink rate.  Our upper limit will be lower than the reported ceiling.

Soaring Ceiling: We will stop going up when the thermal is rising just fast enough to offset our sink.  It is estimated that this happens when the temperature difference between the thermal and the surrounding air is about 2 degrees F. This number is an estimate of the maximum altitude we might reach if we start at launch height, and should be more reflective of our chances of soaring than the thermal top. Please let me know how this compares with actually flying, and I will adjust it as necessary.

Above Launch: The difference between how high we might get and how high we start. This estimate does not account for ridge lift.

High Temp: This estimate is taken from the National Weather Service website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service estimate of cloudiness, and the angle of the sun.  When the sun is directly overhead on a sunny day, the puddle temp is esimated to be 25 degrees warmer than the high ambient temperature. This estimate now includes a rigorous calculation of the Sun Angle, and accounts for the seasonal differences in zenith and daylight hours.

Wind: This estimate is taken from the National Weather Service website.

Thermal Type: Blue (no cloud formation) or White (Cloud formation)

Thermal Index: This is the maximum difference in temperature between the rising packet of air (the thermal) and the surrounding air.  The difference in temperature is responsible for the buoyancy of the thermal, and larger temperature differences mean faster rising thermals.  A value of about 10 F or greater often means that the conditions are soarable.  Values above 20 could indicate rowdy thermals.

Validity of estimate: Many factors (including strong wind, fronts, cloud shadows, incorrectly predicted temperatures, etc) can affect the validity of the estimates. 

Author: Tad Hurst

Supported By: Alan Crouse ac_soaring@yahoo.com