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

Station:

KTUS

Date/Time:

17 JAN 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)
5 AM Wed 47 47 E 7 0 1125 0 Blue 0
6 AM Wed 45 45 E 7 0 1125 0 Blue 0
7 AM Wed 43 43 E 6 0 1125 0 Blue 0
8 AM Wed 44 44 E 6 0 1125 0 Blue 0
9 AM Wed 47 47 E 7 0 1125 0 Blue 0
10 AM Wed 53 54 E 8 2583 2472 1347 Blue 3
11 AM Wed 58 60 E 9 2826 2691 1566 Blue 9
12 Noon Wed 62 64 E 9 3343 2878 1753 Blue 13
1 PM Wed 65 68 E 8 4129 3524 2399 Blue 17
2 PM Wed 67 69 E 7 4325 3720 2595 Blue 18
3 PM Wed 69 70 E 6 4520 3915 2790 Blue 19
4 PM Wed 70 70 NE 3 4520 3915 2790 Blue 19
5 PM Wed 69 69 NE 2 4325 3720 2595 Blue 18
6 PM Wed 67 67 NE 2 3933 3329 2204 Blue 16
7 PM Wed 63 63 NE 2 3145 2823 1698 Blue 12
8 PM Wed 59 59 N 3 2770 2654 1529 Blue 8
9 PM Wed 56 56 NE 3 2656 2545 1420 Blue 5
10 PM Wed 54 54 NE 3 2583 2472 1347 Blue 3
11 PM Wed 52 52 E 3 2510 2470 1345 Blue 1
12 Midnight Thu 51 51 E 3 2474 2470 1345 Blue 0
1 AM Thu 50 50 E 3 0 1125 0 Blue 0
2 AM Thu 49 49 E 3 0 1125 0 Blue 0
3 AM Thu 48 48 E 5 0 1125 0 Blue 0
4 AM Thu 48 48 E 5 0 1125 0 Blue 0
5 AM Thu 47 47 E 5 0 1125 0 Blue 0
6 AM Thu 45 45 E 5 0 1125 0 Blue 0
7 AM Thu 44 44 E 5 0 1125 0 Blue 0
8 AM Thu 45 45 E 6 0 1125 0 Blue 0
9 AM Thu 49 49 E 6 0 1125 0 Blue 0
10 AM Thu 55 56 E 7 2656 2545 1420 Blue 5
11 AM Thu 60 62 E 8 2947 2767 1642 Blue 11
12 Noon Thu 65 67 E 8 3933 3329 2204 Blue 16
1 PM Thu 68 70 E 8 4520 3915 2790 Blue 19
2 PM Thu 70 72 E 7 4909 4304 3179 Blue 21
3 PM Thu 72 73 E 6 5098 4498 3373 Blue 22
4 PM Thu 73 73 E 5 5098 4498 3373 Blue 22
5 PM Thu 72 72 E 3 4909 4304 3179 Blue 21
6 PM Thu 69 69 E 2 4325 3720 2595 Blue 18
7 PM Thu 65 65 E 1 3540 2935 1810 Blue 14
8 PM Thu 62 62 E 1 2947 2767 1642 Blue 11
9 PM Thu 59 59 E 1 2770 2654 1529 Blue 8
10 PM Thu 57 57 E 1 2693 2581 1456 Blue 6
11 PM Thu 55 55 E 2 2620 2509 1384 Blue 4
12 Midnight Fri 54 54 E 2 2583 2472 1347 Blue 3
1 AM Fri 53 53 E 3 2547 2470 1345 Blue 2
2 AM Fri 52 52 E 5 2510 2470 1345 Blue 1
3 AM Fri 51 51 E 5 2474 2470 1345 Blue 0
4 AM Fri 50 50 E 6 0 1125 0 Blue 0
5 AM Fri 49 49 E 7 0 1125 0 Blue 0
6 AM Fri 48 48 E 7 0 1125 0 Blue 0
7 AM Fri 47 47 E 7 0 1125 0 Blue 0
8 AM Fri 48 48 E 7 0 1125 0 Blue 0
9 AM Fri 53 53 E 7 2547 2470 1345 Blue 2
10 AM Fri 59 60 E 7 2826 2691 1566 Blue 9
11 AM Fri 65 66 E 7 3737 3132 2007 Blue 15
12 Noon Fri 69 71 SE 7 4714 4110 2985 Blue 20
1 PM Fri 72 74 SE 7 5267 4691 3566 Blue 23
2 PM Fri 74 75 S 7 5436 4885 3760 Blue 24
3 PM Fri 76 77 SW 7 5773 5244 4119 Blue 26
4 PM Fri 77 77 SW 7 5773 5244 4119 Blue 26
5 PM Fri 76 76 W 7 5605 5076 3951 Blue 25
6 PM Fri 73 73 W 8 5098 4498 3373 Blue 22
7 PM Fri 68 68 SW 8 4129 3524 2399 Blue 17
8 PM Fri 63 63 SW 8 3145 2823 1698 Blue 12
9 PM Fri 60 60 SW 8 2826 2691 1566 Blue 9
10 PM Fri 57 57 SW 8 2693 2581 1456 Blue 6
11 PM Fri 55 55 SW 8 2620 2509 1384 Blue 4
12 Midnight Sat 53 53 SW 9 2547 2470 1345 Blue 2
1 AM Sat 52 52 SW 10 2510 2470 1345 Blue 1
2 AM Sat 50 50 SW 10 0 1125 0 Blue 0
3 AM Sat 49 49 SW 12 0 1125 0 Blue 0
4 AM Sat 48 48 SW 13 0 1125 0 Blue 0
5 AM Sat 48 48 SW 13 0 1125 0 Blue 0
6 AM Sat 49 49 SW 13 0 1125 0 Blue 0
7 AM Sat 50 50 SW 13 0 1125 0 Blue 0
8 AM Sat 51 51 SW 12 2474 2470 1345 Blue 0
9 AM Sat 51 51 W 12 2474 2470 1345 Blue 0
10 AM Sat 51 52 W 10 2510 2470 1345 Blue 1
11 AM Sat 52 53 W 10 2547 2470 1345 Blue 2
12 Noon Sat 55 57 W 12 2693 2581 1456 Blue 6
1 PM Sat 58 60 W 12 2826 2691 1566 Blue 9
2 PM Sat 60 62 W 13 2947 2767 1642 Blue 11
3 PM Sat 60 61 W 14 2881 2727 1602 Blue 10
4 PM Sat 58 58 W 15 2729 2618 1493 Blue 7
5 PM Sat 57 57 W 15 2693 2581 1456 Blue 6
6 PM Sat 56 56 W 14 2656 2545 1420 Blue 5
7 PM Sat 55 55 W 13 2620 2509 1384 Blue 4
8 PM Sat 53 53 W 12 2547 2470 1345 Blue 2
9 PM Sat 50 50 W 10 0 1125 0 Blue 0
10 PM Sat 45 45 W 8 0 1125 0 Blue 0
11 PM Sat 42 42 W 7 0 1125 0 Blue 0
12 Midnight Sun 42 42 W 6 0 1125 0 Blue 0
1 AM Sun 43 43 W 6 0 1125 0 Blue 0
2 AM Sun 43 43 W 6 0 1125 0 Blue 0
3 AM Sun 42 42 NW 5 0 1125 0 Blue 0
4 AM Sun 38 38 NW 5 0 1125 0 Blue 0
5 AM Sun 36 36 NW 5 0 1125 0 Blue 0
6 AM Sun 35 35 NW 3 0 1125 0 Blue 0
7 AM Sun 36 36 NW 3 0 1125 0 Blue 0
8 AM Sun 38 38 NW 3 0 1125 0 Blue 0
9 AM Sun 41 41 NW 3 0 1125 0 Blue 0
10 AM Sun 45 46 N 2 0 1125 0 Blue 0
11 AM Sun 49 51 N 2 2474 2470 1345 Blue 0
12 Noon Sun 53 56 N 3 2656 2545 1420 Blue 5
1 PM Sun 57 60 NW 3 2826 2691 1566 Blue 9
2 PM Sun 60 62 NW 3 2947 2767 1642 Blue 11
3 PM Sun 62 63 NW 3 3145 2823 1698 Blue 12
4 PM Sun 62 62 W 5 2947 2767 1642 Blue 11
5 PM Sun 61 61 W 5 2881 2727 1602 Blue 10
6 PM Sun 60 60 W 5 2826 2691 1566 Blue 9
7 PM Sun 57 57 W 5 2693 2581 1456 Blue 6
8 PM Sun 54 54 NW 3 2583 2472 1347 Blue 3
9 PM Sun 50 50 NW 3 0 1125 0 Blue 0
10 PM Sun 46 46 NW 3 0 1125 0 Blue 0
11 PM Sun 44 44 NW 3 0 1125 0 Blue 0
12 Midnight Mon 44 44 NW 3 0 1125 0 Blue 0
1 AM Mon 44 44 N 3 0 1125 0 Blue 0
2 AM Mon 44 44 N 3 0 1125 0 Blue 0
3 AM Mon 42 42 NE 3 0 1125 0 Blue 0
4 AM Mon 40 40 NE 3 0 1125 0 Blue 0
5 AM Mon 37 37 NE 3 0 1125 0 Blue 0
6 AM Mon 37 37 NE 3 0 1125 0 Blue 0
7 AM Mon 38 38 NE 3 0 1125 0 Blue 0
8 AM Mon 40 40 NE 3 0 1125 0 Blue 0
9 AM Mon 44 44 NE 3 0 1125 0 Blue 0
10 AM Mon 48 49 NE 3 0 1125 0 Blue 0
11 AM Mon 53 54 NE 3 2583 2472 1347 Blue 3
12 Noon Mon 57 59 NE 5 2770 2654 1529 Blue 8
1 PM Mon 61 63 N 5 3145 2823 1698 Blue 12
2 PM Mon 64 66 N 5 3737 3132 2007 Blue 15
3 PM Mon 65 66 N 5 3737 3132 2007 Blue 15
4 PM Mon 65 65 NW 6 3540 2935 1810 Blue 14
5 PM Mon 64 64 NW 6 3343 2878 1753 Blue 13
6 PM Mon 62 62 NW 5 2947 2767 1642 Blue 11
7 PM Mon 60 60 NW 5 2826 2691 1566 Blue 9
8 PM Mon 56 56 NW 5 2656 2545 1420 Blue 5
9 PM Mon 52 52 NW 3 2510 2470 1345 Blue 1
10 PM Mon 47 47 NW 3 0 1125 0 Blue 0
11 PM Mon 45 45 NW 3 0 1125 0 Blue 0
12 Midnight Tue 44 44 NW 3 0 1125 0 Blue 0
1 AM Tue 45 45 NW 2 0 1125 0 Blue 0
2 AM Tue 45 45 N 2 0 1125 0 Blue 0
3 AM Tue 43 43 N 2 0 1125 0 Blue 0
4 AM Tue 40 40 N 2 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