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

Station:

KTUS

Date/Time:

17 SEP 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 77 77 E 2 0 1125 0 Blue 0
7 AM Tue 79 79 E 3 2653 2470 1345 Blue 1
8 AM Tue 76 77 SE 5 0 1125 0 Blue 0
9 AM Tue 81 83 SE 6 3118 2702 1577 Blue 5
10 AM Tue 85 89 SE 5 4028 3667 2542 Blue 11
11 AM Tue 88 93 S 3 4683 4134 3009 Blue 15
12 Noon Tue 91 97 S 3 6245 5112 3987 Blue 19
1 PM Tue 94 100 S 3 9205 6193 5068 Blue 22
2 PM Tue 96 101 SW 5 10468 6502 5377 Blue 23
3 PM Tue 98 102 SW 6 10959 6809 5684 Blue 24
4 PM Tue 99 101 SW 7 10468 6502 5377 Blue 23
5 PM Tue 99 100 W 8 9205 6193 5068 Blue 22
6 PM Tue 99 99 W 9 6866 5882 4757 Blue 21
7 PM Tue 98 98 W 8 6557 5568 4443 Blue 20
8 PM Tue 94 94 W 6 5179 4251 3126 Blue 16
9 PM Tue 91 91 W 5 4263 3900 2775 Blue 13
10 PM Tue 89 89 W 5 4028 3667 2542 Blue 11
11 PM Tue 87 87 SW 5 3794 3433 2308 Blue 9
12 Midnight Wed 86 86 SW 6 3677 3091 1966 Blue 8
1 AM Wed 85 85 SW 6 3560 2805 1680 Blue 7
2 AM Wed 83 83 SW 6 3118 2702 1577 Blue 5
3 AM Wed 82 82 SW 6 2808 2650 1525 Blue 4
4 AM Wed 80 80 S 5 2705 2470 1345 Blue 2
5 AM Wed 79 79 S 3 2653 2470 1345 Blue 1
6 AM Wed 78 78 S 3 2586 2470 1345 Blue 0
7 AM Wed 77 77 S 2 0 1125 0 Blue 0
8 AM Wed 77 78 S 2 2586 2470 1345 Blue 0
9 AM Wed 83 85 S 2 3560 2805 1680 Blue 7
10 AM Wed 87 91 S 2 4263 3900 2775 Blue 13
11 AM Wed 91 97 S 2 6245 5112 3987 Blue 19
12 Noon Wed 94 101 S 3 10468 6502 5377 Blue 23
1 PM Wed 97 104 S 6 11409 10128 9003 Blue 26
2 PM Wed 99 105 SW 8 11740 10889 9764 Blue 27
3 PM Wed 101 105 SW 9 11740 10889 9764 Blue 27
4 PM Wed 102 104 SW 10 11409 10128 9003 Blue 26
5 PM Wed 102 103 SW 12 11174 8586 7461 Blue 25
6 PM Wed 100 100 SW 12 9205 6193 5068 Blue 22
7 PM Wed 97 97 SW 10 6245 5112 3987 Blue 19
8 PM Wed 94 94 SW 10 5179 4251 3126 Blue 16
9 PM Wed 91 91 SW 9 4263 3900 2775 Blue 13
10 PM Wed 88 88 SW 9 3911 3550 2425 Blue 10
11 PM Wed 87 87 SW 8 3794 3433 2308 Blue 9
12 Midnight Thu 85 85 SW 8 3560 2805 1680 Blue 7
1 AM Thu 84 84 SW 8 3442 2753 1628 Blue 6
2 AM Thu 82 82 SW 8 2808 2650 1525 Blue 4
3 AM Thu 81 81 SW 7 2756 2575 1450 Blue 3
4 AM Thu 79 79 S 6 2653 2470 1345 Blue 1
5 AM Thu 78 78 SE 5 2586 2470 1345 Blue 0
6 AM Thu 77 77 SE 5 0 1125 0 Blue 0
7 AM Thu 78 78 SE 5 2586 2470 1345 Blue 0
8 AM Thu 79 80 SE 5 2705 2470 1345 Blue 2
9 AM Thu 82 84 S 6 3442 2753 1628 Blue 6
10 AM Thu 86 90 S 7 4146 3784 2659 Blue 12
11 AM Thu 89 94 S 8 5179 4251 3126 Blue 16
12 Noon Thu 93 99 S 9 6866 5882 4757 Blue 21
1 PM Thu 96 102 S 12 10959 6809 5684 Blue 24
2 PM Thu 98 104 SW 13 11409 10128 9003 Blue 26
3 PM Thu 99 103 SW 14 11174 8586 7461 Blue 25
4 PM Thu 99 101 SW 15 10468 6502 5377 Blue 23
5 PM Thu 99 100 SW 15 9205 6193 5068 Blue 22
6 PM Thu 97 97 SW 16 6245 5112 3987 Blue 19
7 PM Thu 94 94 SW 15 5179 4251 3126 Blue 16
8 PM Thu 91 91 SW 14 4263 3900 2775 Blue 13
9 PM Thu 87 87 SW 13 3794 3433 2308 Blue 9
10 PM Thu 84 84 SW 12 3442 2753 1628 Blue 6
11 PM Thu 82 82 SW 9 2808 2650 1525 Blue 4
12 Midnight Fri 80 80 SW 8 2705 2470 1345 Blue 2
1 AM Fri 79 79 SW 7 2653 2470 1345 Blue 1
2 AM Fri 77 77 SW 6 0 1125 0 Blue 0
3 AM Fri 76 76 S 5 0 1125 0 Blue 0
4 AM Fri 74 74 S 5 0 1125 0 Blue 0
5 AM Fri 73 73 S 3 0 1125 0 Blue 0
6 AM Fri 72 72 S 3 0 1125 0 Blue 0
7 AM Fri 73 73 S 2 0 1125 0 Blue 0
8 AM Fri 75 76 S 2 0 1125 0 Blue 0
9 AM Fri 78 80 S 2 2705 2470 1345 Blue 2
10 AM Fri 82 86 S 2 3677 3091 1966 Blue 8
11 AM Fri 86 92 S 2 4380 4017 2892 Blue 14
12 Noon Fri 89 96 S 2 5931 4626 3501 Blue 18
1 PM Fri 92 99 S 3 6866 5882 4757 Blue 21
2 PM Fri 93 99 S 3 6866 5882 4757 Blue 21
3 PM Fri 95 99 SW 3 6866 5882 4757 Blue 21
4 PM Fri 96 98 SW 5 6557 5568 4443 Blue 20
5 PM Fri 97 98 W 5 6557 5568 4443 Blue 20
6 PM Fri 96 96 W 5 5931 4626 3501 Blue 18
7 PM Fri 93 93 W 5 4683 4134 3009 Blue 15
8 PM Fri 90 90 W 5 4146 3784 2659 Blue 12
9 PM Fri 86 86 W 5 3677 3091 1966 Blue 8
10 PM Fri 83 83 W 3 3118 2702 1577 Blue 5
11 PM Fri 81 81 W 3 2756 2575 1450 Blue 3
12 Midnight Sat 80 80 W 3 2705 2470 1345 Blue 2
1 AM Sat 79 79 W 2 2653 2470 1345 Blue 1
2 AM Sat 78 78 SW 2 2586 2470 1345 Blue 0
3 AM Sat 76 76 SW 2 0 1125 0 Blue 0
4 AM Sat 74 74 S 1 0 1125 0 Blue 0
5 AM Sat 73 73 S 1 0 1125 0 Blue 0
6 AM Sat 72 72 S 1 0 1125 0 Blue 0
7 AM Sat 73 73 S 1 0 1125 0 Blue 0
8 AM Sat 75 76 SE 1 0 1125 0 Blue 0
9 AM Sat 78 80 E 1 2705 2470 1345 Blue 2
10 AM Sat 82 86 E 1 3677 3091 1966 Blue 8
11 AM Sat 86 91 NE 1 4263 3900 2775 Blue 13
12 Noon Sat 90 96 NE 1 5931 4626 3501 Blue 18
1 PM Sat 93 99 NE 2 6866 5882 4757 Blue 21
2 PM Sat 95 100 N 2 9205 6193 5068 Blue 22
3 PM Sat 97 101 N 3 10468 6502 5377 Blue 23
4 PM Sat 98 100 NW 3 9205 6193 5068 Blue 22
5 PM Sat 98 99 NW 5 6866 5882 4757 Blue 21
6 PM Sat 97 97 W 5 6245 5112 3987 Blue 19
7 PM Sat 94 94 W 5 5179 4251 3126 Blue 16
8 PM Sat 91 91 W 3 4263 3900 2775 Blue 13
9 PM Sat 87 87 W 3 3794 3433 2308 Blue 9
10 PM Sat 84 84 W 2 3442 2753 1628 Blue 6
11 PM Sat 82 82 SW 1 2808 2650 1525 Blue 4
12 Midnight Sun 80 80 SW 1 2705 2470 1345 Blue 2
1 AM Sun 79 79 SW 1 2653 2470 1345 Blue 1
2 AM Sun 78 78 SW 1 2586 2470 1345 Blue 0
3 AM Sun 77 77 SW 1 0 1125 0 Blue 0
4 AM Sun 76 76 S 1 0 1125 0 Blue 0
5 AM Sun 74 74 S 1 0 1125 0 Blue 0
6 AM Sun 74 74 S 1 0 1125 0 Blue 0
7 AM Sun 75 75 S 1 0 1125 0 Blue 0
8 AM Sun 77 77 S 1 0 1125 0 Blue 0
9 AM Sun 80 82 SE 1 2808 2650 1525 Blue 4
10 AM Sun 84 87 SE 1 3794 3433 2308 Blue 9
11 AM Sun 87 91 E 2 4263 3900 2775 Blue 13
12 Noon Sun 91 96 E 2 5931 4626 3501 Blue 18
1 PM Sun 94 99 E 3 6866 5882 4757 Blue 21
2 PM Sun 96 100 SE 3 9205 6193 5068 Blue 22
3 PM Sun 98 101 S 5 10468 6502 5377 Blue 23
4 PM Sun 99 101 S 6 10468 6502 5377 Blue 23
5 PM Sun 99 99 SW 6 6866 5882 4757 Blue 21
6 PM Sun 98 98 W 7 6557 5568 4443 Blue 20
7 PM Sun 96 96 W 7 5931 4626 3501 Blue 18
8 PM Sun 92 92 W 6 4380 4017 2892 Blue 14
9 PM Sun 89 89 SW 6 4028 3667 2542 Blue 11
10 PM Sun 86 86 SW 5 3677 3091 1966 Blue 8
11 PM Sun 84 84 SW 5 3442 2753 1628 Blue 6
12 Midnight Mon 82 82 SW 3 2808 2650 1525 Blue 4
1 AM Mon 81 81 SW 3 2756 2575 1450 Blue 3
2 AM Mon 79 79 SW 3 2653 2470 1345 Blue 1
3 AM Mon 78 78 S 3 2586 2470 1345 Blue 0
4 AM Mon 77 77 S 3 0 1125 0 Blue 0
5 AM Mon 76 76 SE 3 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