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

Station:

KTUS

Date/Time:

21 JUL 2018

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 Sat 86 86 S 6 1152 1125 0 White 0
7 AM Sat 86 86 SW 7 1152 1125 0 White 0
8 AM Sat 88 88 W 8 1152 1125 0 White 0
9 AM Sat 90 91 NW 8 1152 1125 0 White 0
10 AM Sat 90 91 NW 7 1152 1125 0 White 0
11 AM Sat 92 94 W 6 1152 1125 0 White 0
12 Noon Sat 94 96 W 6 1152 1125 0 White 0
1 PM Sat 97 100 W 7 1152 1125 0 White 0
2 PM Sat 100 103 W 8 1152 1125 0 White 0
3 PM Sat 101 103 W 10 1152 1125 0 White 0
4 PM Sat 103 105 W 12 1152 1125 0 White 0
5 PM Sat 103 104 W 13 1152 1125 0 White 0
6 PM Sat 103 103 W 13 1152 1125 0 White 0
7 PM Sat 101 101 W 12 1152 1125 0 White 0
8 PM Sat 100 100 W 10 1152 1125 0 White 0
9 PM Sat 97 97 W 9 1152 1125 0 White 0
10 PM Sat 95 95 W 9 1152 1125 0 White 0
11 PM Sat 93 93 SW 9 1152 1125 0 White 0
12 Midnight Sun 93 93 SW 9 1152 1125 0 White 0
1 AM Sun 91 91 SW 8 1152 1125 0 White 0
2 AM Sun 90 90 SW 7 1152 1125 0 White 0
3 AM Sun 89 89 SW 6 1152 1125 0 White 0
4 AM Sun 87 87 SW 6 1152 1125 0 White 0
5 AM Sun 86 86 SW 6 1152 1125 0 White 0
6 AM Sun 85 85 SW 6 1152 1125 0 White 0
7 AM Sun 84 84 SW 6 1152 1125 0 White 0
8 AM Sun 87 88 W 6 1152 1125 0 White 0
9 AM Sun 92 95 W 5 1152 1125 0 White 0
10 AM Sun 94 98 W 6 1152 1125 0 White 0
11 AM Sun 97 102 W 6 1152 1125 0 White 0
12 Noon Sun 99 104 W 6 1152 1125 0 White 0
1 PM Sun 102 108 W 7 1152 1125 0 White 0
2 PM Sun 104 109 W 8 1152 1125 0 White 0
3 PM Sun 106 110 W 9 1152 1125 0 White 0
4 PM Sun 107 110 W 10 1152 1125 0 White 0
5 PM Sun 108 109 W 12 1152 1125 0 White 0
6 PM Sun 108 108 W 12 1152 1125 0 White 0
7 PM Sun 107 107 W 12 1152 1125 0 White 0
8 PM Sun 104 104 W 9 1152 1125 0 White 0
9 PM Sun 102 102 W 8 1152 1125 0 White 0
10 PM Sun 100 100 W 8 1152 1125 0 White 0
11 PM Sun 98 98 SW 9 1152 1125 0 White 0
12 Midnight Mon 96 96 SW 9 1152 1125 0 White 0
1 AM Mon 94 94 SW 8 1152 1125 0 White 0
2 AM Mon 93 93 SW 8 1152 1125 0 White 0
3 AM Mon 91 91 SW 7 1152 1125 0 White 0
4 AM Mon 89 89 SW 7 1152 1125 0 White 0
5 AM Mon 88 88 SW 7 1152 1125 0 White 0
6 AM Mon 88 88 SW 6 1152 1125 0 White 0
7 AM Mon 89 89 SW 6 1152 1125 0 White 0
8 AM Mon 91 92 SW 6 1152 1125 0 White 0
9 AM Mon 94 97 W 6 1152 1125 0 White 0
10 AM Mon 97 101 W 6 1152 1125 0 White 0
11 AM Mon 101 107 W 7 1152 1125 0 White 0
12 Noon Mon 104 110 W 7 1152 1125 0 White 0
1 PM Mon 106 113 W 8 1152 1125 0 White 0
2 PM Mon 109 115 W 8 1152 1125 0 White 0
3 PM Mon 111 116 W 9 1152 1125 0 White 0
4 PM Mon 113 117 W 10 1152 1125 0 White 0
5 PM Mon 114 116 W 12 1152 1125 0 White 0
6 PM Mon 114 114 W 12 1152 1125 0 White 0
7 PM Mon 112 112 W 12 1152 1125 0 White 0
8 PM Mon 109 109 W 12 1152 1125 0 White 0
9 PM Mon 106 106 W 10 1152 1125 0 White 0
10 PM Mon 103 103 W 10 1152 1125 0 White 0
11 PM Mon 100 100 SW 9 1152 1125 0 White 0
12 Midnight Tue 98 98 SW 9 1152 1125 0 White 0
1 AM Tue 97 97 SW 8 1152 1125 0 White 0
2 AM Tue 95 95 SW 7 1152 1125 0 White 0
3 AM Tue 93 93 SW 7 1152 1125 0 White 0
4 AM Tue 91 91 SW 6 1152 1125 0 White 0
5 AM Tue 90 90 SW 5 1152 1125 0 White 0
6 AM Tue 89 89 SW 5 1152 1125 0 White 0
7 AM Tue 90 90 SW 3 1152 1125 0 White 0
8 AM Tue 93 94 SW 3 1152 1125 0 White 0
9 AM Tue 97 100 S 3 1152 1125 0 White 0
10 AM Tue 101 106 S 3 1152 1125 0 White 0
11 AM Tue 105 112 SE 3 1152 1125 0 White 0
12 Noon Tue 108 115 SE 3 1152 1125 0 White 0
1 PM Tue 111 119 SE 5 1152 1125 0 White 0
2 PM Tue 113 120 S 6 1152 1125 0 White 0
3 PM Tue 115 120 S 7 1152 1125 0 White 0
4 PM Tue 116 120 SW 8 1152 1125 0 White 0
5 PM Tue 117 119 W 9 1152 1125 0 White 0
6 PM Tue 117 117 W 10 1152 1125 0 White 0
7 PM Tue 115 115 W 10 1152 1125 0 White 0
8 PM Tue 113 113 W 10 1152 1125 0 White 0
9 PM Tue 109 109 W 10 1152 1125 0 White 0
10 PM Tue 106 106 W 9 1152 1125 0 White 0
11 PM Tue 103 103 SW 9 1152 1125 0 White 0
12 Midnight Wed 101 101 SW 8 1152 1125 0 White 0
1 AM Wed 99 99 SW 8 1152 1125 0 White 0
2 AM Wed 97 97 SW 7 1152 1125 0 White 0
3 AM Wed 95 95 SW 6 1152 1125 0 White 0
4 AM Wed 93 93 SW 6 1152 1125 0 White 0
5 AM Wed 92 92 SW 5 1152 1125 0 White 0
6 AM Wed 91 91 SW 5 1152 1125 0 White 0
7 AM Wed 92 92 SW 5 1152 1125 0 White 0
8 AM Wed 94 95 SW 5 1152 1125 0 White 0
9 AM Wed 97 99 SW 5 1152 1125 0 White 0
10 AM Wed 100 104 SW 6 1152 1125 0 White 0
11 AM Wed 103 108 W 6 1152 1125 0 White 0
12 Noon Wed 105 111 W 7 1152 1125 0 White 0
1 PM Wed 107 113 W 8 1152 1125 0 White 0
2 PM Wed 109 114 W 9 1152 1125 0 White 0
3 PM Wed 111 115 W 10 1152 1125 0 White 0
4 PM Wed 113 115 W 12 1152 1125 0 White 0
5 PM Wed 114 115 W 13 1152 1125 0 White 0
6 PM Wed 114 114 W 13 1152 1125 0 White 0
7 PM Wed 112 112 W 13 1152 1125 0 White 0
8 PM Wed 109 109 W 14 1152 1125 0 White 0
9 PM Wed 106 106 SW 13 1152 1125 0 White 0
10 PM Wed 103 103 SW 13 1152 1125 0 White 0
11 PM Wed 102 102 SW 13 1152 1125 0 White 0
12 Midnight Thu 100 100 SW 12 1152 1125 0 White 0
1 AM Thu 98 98 SW 10 1152 1125 0 White 0
2 AM Thu 96 96 S 9 1152 1125 0 White 0
3 AM Thu 95 95 S 8 1152 1125 0 White 0
4 AM Thu 93 93 S 7 1152 1125 0 White 0
5 AM Thu 91 91 S 6 1152 1125 0 White 0
6 AM Thu 91 91 SE 5 1152 1125 0 White 0
7 AM Thu 91 91 S 5 1152 1125 0 White 0
8 AM Thu 92 93 S 6 1152 1125 0 White 0
9 AM Thu 94 96 S 7 1152 1125 0 White 0
10 AM Thu 96 99 S 7 1152 1125 0 White 0
11 AM Thu 99 103 SW 8 1152 1125 0 White 0
12 Noon Thu 101 106 SW 9 1152 1125 0 White 0
1 PM Thu 103 108 SW 10 1152 1125 0 White 0
2 PM Thu 104 109 SW 10 1152 1125 0 White 0
3 PM Thu 106 110 SW 12 1152 1125 0 White 0
4 PM Thu 107 109 SW 12 1152 1125 0 White 0
5 PM Thu 107 108 SW 13 1152 1125 0 White 0
6 PM Thu 107 107 SW 13 1152 1125 0 White 0
7 PM Thu 105 105 SW 13 1152 1125 0 White 0
8 PM Thu 103 103 SW 13 1152 1125 0 White 0
9 PM Thu 100 100 SW 13 1152 1125 0 White 0
10 PM Thu 98 98 SW 13 1152 1125 0 White 0
11 PM Thu 96 96 SW 12 1152 1125 0 White 0
12 Midnight Fri 94 94 SW 12 1152 1125 0 White 0
1 AM Fri 92 92 SW 10 1152 1125 0 White 0
2 AM Fri 91 91 SW 9 1152 1125 0 White 0
3 AM Fri 89 89 SW 8 1152 1125 0 White 0
4 AM Fri 88 88 SW 6 1152 1125 0 White 0
5 AM Fri 87 87 SW 5 1152 1125 0 White 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