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

Station:

KTUS

Date/Time:

27 MAY 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 Sun 65 65 S 2 0 1125 0 Blue 0
7 AM Sun 62 63 S 2 0 1125 0 Blue 0
8 AM Sun 68 70 S 2 0 1125 0 Blue 0
9 AM Sun 72 76 S 3 3151 2820 1695 Blue 5
10 AM Sun 76 82 S 3 4725 3468 2343 Blue 11
11 AM Sun 80 88 S 5 6764 5452 4327 Blue 17
12 Noon Sun 83 91 SW 5 7614 6720 5595 Blue 20
1 PM Sun 85 93 SW 6 8270 7216 6091 Blue 22
2 PM Sun 87 94 SW 7 8568 7545 6420 Blue 23
3 PM Sun 89 95 W 8 8864 7872 6747 Blue 24
4 PM Sun 89 93 W 9 8270 7216 6091 Blue 22
5 PM Sun 90 92 W 10 7944 6961 5836 Blue 21
6 PM Sun 91 91 W 10 7614 6720 5595 Blue 20
7 PM Sun 90 90 W 10 7282 6478 5353 Blue 19
8 PM Sun 89 89 W 9 7007 5979 4854 Blue 18
9 PM Sun 85 85 W 9 5527 4690 3565 Blue 14
10 PM Sun 83 83 W 8 5011 3576 2451 Blue 12
11 PM Sun 80 80 SW 7 3584 3252 2127 Blue 9
12 Midnight Mon 80 80 SW 6 3584 3252 2127 Blue 9
1 AM Mon 78 78 SW 5 3367 3036 1911 Blue 7
2 AM Mon 75 75 SW 5 3043 2652 1527 Blue 4
3 AM Mon 73 73 SW 5 2826 2470 1345 Blue 2
4 AM Mon 72 72 SW 3 2660 2470 1345 Blue 1
5 AM Mon 70 70 SW 3 0 1125 0 Blue 0
6 AM Mon 69 69 SW 2 0 1125 0 Blue 0
7 AM Mon 68 69 SW 2 0 1125 0 Blue 0
8 AM Mon 73 75 SW 1 3043 2652 1527 Blue 4
9 AM Mon 80 84 SW 1 5187 4144 3019 Blue 13
10 AM Mon 83 89 SW 1 7007 5979 4854 Blue 18
11 AM Mon 87 95 W 2 8864 7872 6747 Blue 24
12 Noon Mon 90 99 W 3 9868 9081 7956 Blue 28
1 PM Mon 92 100 W 5 10063 9370 8245 Blue 29
2 PM Mon 94 101 W 6 10266 9617 8492 Blue 30
3 PM Mon 96 102 W 7 10476 9812 8687 Blue 31
4 PM Mon 97 100 W 8 10063 9370 8245 Blue 29
5 PM Mon 98 100 W 9 10063 9370 8245 Blue 29
6 PM Mon 98 98 W 9 9672 8790 7665 Blue 27
7 PM Mon 97 97 W 9 9448 8496 7371 Blue 26
8 PM Mon 95 95 W 9 8864 7872 6747 Blue 24
9 PM Mon 92 92 W 8 7944 6961 5836 Blue 21
10 PM Mon 90 90 SW 8 7282 6478 5353 Blue 19
11 PM Mon 87 87 SW 8 6520 5164 4039 Blue 16
12 Midnight Tue 85 85 SW 8 5527 4690 3565 Blue 14
1 AM Tue 83 83 SW 7 5011 3576 2451 Blue 12
2 AM Tue 81 81 SW 7 4221 3360 2235 Blue 10
3 AM Tue 79 79 W 6 3476 3144 2019 Blue 8
4 AM Tue 76 76 W 5 3151 2820 1695 Blue 5
5 AM Tue 74 74 W 3 2934 2472 1347 Blue 3
6 AM Tue 73 73 W 3 2826 2470 1345 Blue 2
7 AM Tue 75 75 W 3 3043 2652 1527 Blue 4
8 AM Tue 78 80 SW 5 3584 3252 2127 Blue 9
9 AM Tue 83 87 SW 5 6520 5164 4039 Blue 16
10 AM Tue 87 92 SW 5 7944 6961 5836 Blue 21
11 AM Tue 91 98 SW 3 9672 8790 7665 Blue 27
12 Noon Tue 94 101 W 3 10266 9617 8492 Blue 30
1 PM Tue 97 104 W 3 11009 10203 9078 Blue 33
2 PM Tue 99 105 W 6 11589 10412 9287 Blue 34
3 PM Tue 101 106 W 7 12146 10620 9495 Blue 35
4 PM Tue 102 105 W 8 11589 10412 9287 Blue 34
5 PM Tue 103 104 W 9 11009 10203 9078 Blue 33
6 PM Tue 102 102 W 10 10476 9812 8687 Blue 31
7 PM Tue 100 100 W 9 10063 9370 8245 Blue 29
8 PM Tue 97 97 W 8 9448 8496 7371 Blue 26
9 PM Tue 94 94 W 7 8568 7545 6420 Blue 23
10 PM Tue 91 91 W 8 7614 6720 5595 Blue 20
11 PM Tue 89 89 SW 8 7007 5979 4854 Blue 18
12 Midnight Wed 87 87 SW 8 6520 5164 4039 Blue 16
1 AM Wed 84 84 SW 7 5187 4144 3019 Blue 13
2 AM Wed 82 82 SW 7 4725 3468 2343 Blue 11
3 AM Wed 80 80 SW 6 3584 3252 2127 Blue 9
4 AM Wed 77 77 SW 6 3259 2928 1803 Blue 6
5 AM Wed 75 75 S 6 3043 2652 1527 Blue 4
6 AM Wed 74 74 S 6 2934 2472 1347 Blue 3
7 AM Wed 76 76 S 6 3151 2820 1695 Blue 5
8 AM Wed 79 81 S 6 4221 3360 2235 Blue 10
9 AM Wed 84 88 S 6 6764 5452 4327 Blue 17
10 AM Wed 88 94 S 6 8568 7545 6420 Blue 23
11 AM Wed 91 99 S 6 9868 9081 7956 Blue 28
12 Noon Wed 94 103 S 7 10686 10006 8881 Blue 32
1 PM Wed 97 106 S 8 12146 10620 9495 Blue 35
2 PM Wed 99 106 S 9 12146 10620 9495 Blue 35
3 PM Wed 101 107 S 10 12684 10828 9703 Blue 36
4 PM Wed 102 106 SW 12 12146 10620 9495 Blue 35
5 PM Wed 102 104 SW 13 11009 10203 9078 Blue 33
6 PM Wed 101 101 SW 14 10266 9617 8492 Blue 30
7 PM Wed 99 99 SW 13 9868 9081 7956 Blue 28
8 PM Wed 96 96 SW 12 9157 8195 7070 Blue 25
9 PM Wed 93 93 SW 10 8270 7216 6091 Blue 22
10 PM Wed 90 90 SW 9 7282 6478 5353 Blue 19
11 PM Wed 87 87 SW 8 6520 5164 4039 Blue 16
12 Midnight Thu 84 84 S 7 5187 4144 3019 Blue 13
1 AM Thu 82 82 S 6 4725 3468 2343 Blue 11
2 AM Thu 79 79 S 6 3476 3144 2019 Blue 8
3 AM Thu 77 77 S 7 3259 2928 1803 Blue 6
4 AM Thu 74 74 S 7 2934 2472 1347 Blue 3
5 AM Thu 72 72 SE 7 2660 2470 1345 Blue 1
6 AM Thu 72 72 SE 7 2660 2470 1345 Blue 1
7 AM Thu 74 74 SE 7 2934 2472 1347 Blue 3
8 AM Thu 77 79 SE 8 3476 3144 2019 Blue 8
9 AM Thu 81 85 S 8 5527 4690 3565 Blue 14
10 AM Thu 85 91 S 8 7614 6720 5595 Blue 20
11 AM Thu 89 96 S 8 9157 8195 7070 Blue 25
12 Noon Thu 92 100 S 9 10063 9370 8245 Blue 29
1 PM Thu 94 101 S 10 10266 9617 8492 Blue 30
2 PM Thu 96 102 S 12 10476 9812 8687 Blue 31
3 PM Thu 98 102 S 13 10476 9812 8687 Blue 31
4 PM Thu 99 102 SW 14 10476 9812 8687 Blue 31
5 PM Thu 100 101 SW 15 10266 9617 8492 Blue 30
6 PM Thu 99 99 SW 15 9868 9081 7956 Blue 28
7 PM Thu 97 97 SW 15 9448 8496 7371 Blue 26
8 PM Thu 94 94 SW 14 8568 7545 6420 Blue 23
9 PM Thu 90 90 SW 12 7282 6478 5353 Blue 19
10 PM Thu 87 87 SW 10 6520 5164 4039 Blue 16
11 PM Thu 85 85 SW 9 5527 4690 3565 Blue 14
12 Midnight Fri 83 83 SW 8 5011 3576 2451 Blue 12
1 AM Fri 80 80 SW 7 3584 3252 2127 Blue 9
2 AM Fri 78 78 S 7 3367 3036 1911 Blue 7
3 AM Fri 75 75 S 7 3043 2652 1527 Blue 4
4 AM Fri 72 72 S 7 2660 2470 1345 Blue 1
5 AM Fri 69 69 S 7 0 1125 0 Blue 0
6 AM Fri 69 69 S 7 0 1125 0 Blue 0
7 AM Fri 71 71 S 7 2480 2470 1345 Blue 0
8 AM Fri 74 76 S 7 3151 2820 1695 Blue 5
9 AM Fri 78 82 S 6 4725 3468 2343 Blue 11
10 AM Fri 82 88 S 6 6764 5452 4327 Blue 17
11 AM Fri 85 93 SW 6 8270 7216 6091 Blue 22
12 Noon Fri 89 98 SW 6 9672 8790 7665 Blue 27
1 PM Fri 92 101 SW 6 10266 9617 8492 Blue 30
2 PM Fri 94 102 SW 7 10476 9812 8687 Blue 31
3 PM Fri 96 102 SW 7 10476 9812 8687 Blue 31
4 PM Fri 97 101 W 8 10266 9617 8492 Blue 30
5 PM Fri 98 100 W 8 10063 9370 8245 Blue 29
6 PM Fri 97 97 W 9 9448 8496 7371 Blue 26
7 PM Fri 95 95 W 8 8864 7872 6747 Blue 24
8 PM Fri 93 93 W 8 8270 7216 6091 Blue 22
9 PM Fri 90 90 W 7 7282 6478 5353 Blue 19
10 PM Fri 87 87 W 6 6520 5164 4039 Blue 16
11 PM Fri 84 84 W 5 5187 4144 3019 Blue 13
12 Midnight Sat 81 81 W 5 4221 3360 2235 Blue 10
1 AM Sat 79 79 W 3 3476 3144 2019 Blue 8
2 AM Sat 77 77 NW 3 3259 2928 1803 Blue 6
3 AM Sat 75 75 NW 3 3043 2652 1527 Blue 4
4 AM Sat 72 72 NW 3 2660 2470 1345 Blue 1
5 AM Sat 70 70 NW 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