Detailed Predictions for: Hat Creek Rim
Launch Altitude (f): 4590
LZ Altitude (f): 3575
Sounding

Station:

KOAK

Date/Time:

26 MAY 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)
5 AM Sun 44 44 N 3 6584 5353 763 Blue 7
6 AM Sun 43 43 N 3 5799 5147 557 Blue 6
7 AM Sun 43 43 N 3 5799 5147 557 Blue 6
8 AM Sun 44 44 E 5 6584 5353 763 Blue 7
9 AM Sun 45 45 E 5 7143 5557 967 White 8
10 AM Sun 48 48 E 5 7794 7242 2652 White 11
11 AM Sun 50 50 S 5 8225 7999 3409 White 13
12 Noon Sun 52 52 S 5 8653 8624 4034 White 15
1 PM Sun 53 53 S 5 8870 8870 4280 White 16
2 PM Sun 55 55 SW 7 9306 9306 4716 White 18
3 PM Sun 55 55 SW 7 9306 9306 4716 White 18
4 PM Sun 55 55 SW 7 9306 9306 4716 White 18
5 PM Sun 54 54 W 12 9088 9088 4498 White 17
6 PM Sun 53 53 W 12 8870 8870 4280 White 16
7 PM Sun 52 52 W 12 8653 8624 4034 White 15
8 PM Sun 50 50 W 8 8225 7999 3409 White 13
9 PM Sun 49 49 W 8 8010 7661 3071 White 12
10 PM Sun 48 48 W 8 7794 7242 2652 White 11
11 PM Sun 46 46 W 8 7361 5762 1172 White 9
12 Midnight Mon 46 46 W 8 7361 5762 1172 White 9
1 AM Mon 45 45 W 8 7143 5557 967 White 8
2 AM Mon 44 44 W 7 6584 5353 763 Blue 7
3 AM Mon 44 44 W 7 6584 5353 763 Blue 7
4 AM Mon 44 44 W 7 6584 5353 763 Blue 7
5 AM Mon 44 44 SW 5 6584 5353 763 Blue 7
6 AM Mon 45 45 SW 5 7143 5557 967 White 8
7 AM Mon 46 46 SW 5 7361 5762 1172 White 9
8 AM Mon 48 48 SW 5 7794 7242 2652 White 11
9 AM Mon 50 50 SW 5 8225 7999 3409 White 13
10 AM Mon 52 53 SW 5 8870 8870 4280 White 16
11 AM Mon 55 57 W 7 9737 9737 5147 White 20
12 Noon Mon 57 59 W 7 10155 10155 5565 White 22
1 PM Mon 58 60 W 7 10363 10363 5773 White 23
2 PM Mon 59 61 W 9 10572 10572 5982 White 24
3 PM Mon 60 62 W 9 10779 10779 6189 White 25
4 PM Mon 61 62 W 9 10779 10779 6189 White 25
5 PM Mon 61 62 W 10 10779 10779 6189 White 25
6 PM Mon 59 59 W 10 10155 10155 5565 White 22
7 PM Mon 57 57 W 10 9737 9737 5147 White 20
8 PM Mon 55 55 W 10 9306 9306 4716 White 18
9 PM Mon 53 53 W 10 8870 8870 4280 White 16
10 PM Mon 51 51 W 10 8439 8313 3723 White 14
11 PM Mon 50 50 W 5 8225 7999 3409 White 13
12 Midnight Tue 48 48 W 5 7794 7242 2652 White 11
1 AM Tue 47 47 W 5 7578 6522 1932 White 10
2 AM Tue 46 46 W 5 7361 5762 1172 White 9
3 AM Tue 45 45 W 5 7143 5557 967 White 8
4 AM Tue 45 45 W 5 7143 5557 967 White 8
5 AM Tue 45 45 NE 3 7143 5557 967 White 8
6 AM Tue 46 46 NE 3 7361 5762 1172 White 9
7 AM Tue 48 48 NE 3 7794 7242 2652 White 11
8 AM Tue 50 51 NE 3 8439 8313 3723 White 14
9 AM Tue 53 55 NE 3 9306 9306 4716 White 18
10 AM Tue 56 59 NE 3 10155 10155 5565 White 22
11 AM Tue 59 63 N 8 10986 10986 6396 White 26
12 Noon Tue 62 67 N 8 11815 11612 7022 White 30
1 PM Tue 64 69 N 8 12229 11993 7403 White 32
2 PM Tue 66 71 N 8 12642 12510 7920 White 34
3 PM Tue 68 72 N 8 12848 12767 8177 White 35
4 PM Tue 68 71 N 8 12642 12510 7920 White 34
5 PM Tue 67 68 N 8 12022 11732 7142 White 31
6 PM Tue 66 66 N 8 11608 11537 6947 White 29
7 PM Tue 64 64 N 8 11194 11194 6604 White 27
8 PM Tue 61 61 N 8 10572 10572 5982 White 24
9 PM Tue 58 58 N 8 9946 9946 5356 White 21
10 PM Tue 55 55 N 8 9306 9306 4716 White 18
11 PM Tue 53 53 NE 5 8870 8870 4280 White 16
12 Midnight Wed 52 52 NE 5 8653 8624 4034 White 15
1 AM Wed 51 51 NE 5 8439 8313 3723 White 14
2 AM Wed 50 50 NE 5 8225 7999 3409 White 13
3 AM Wed 49 49 NE 5 8010 7661 3071 White 12
4 AM Wed 47 47 NE 5 7578 6522 1932 White 10
5 AM Wed 47 47 NE 5 7578 6522 1932 White 10
6 AM Wed 48 48 NE 5 7794 7242 2652 White 11
7 AM Wed 51 51 NE 5 8439 8313 3723 White 14
8 AM Wed 55 56 NE 5 9523 9523 4933 White 19
9 AM Wed 58 60 NE 5 10363 10363 5773 White 23
10 AM Wed 62 65 NE 5 11401 11401 6811 White 28
11 AM Wed 65 67 N 6 11815 11612 7022 White 30
12 Noon Wed 68 70 N 6 12436 12252 7662 White 33
1 PM Wed 69 71 N 6 12642 12510 7920 White 34
2 PM Wed 71 73 N 6 13053 13022 8432 White 36
3 PM Wed 71 73 N 6 13053 13022 8432 White 36
4 PM Wed 71 72 N 6 12848 12767 8177 White 35
5 PM Wed 69 70 W 6 12436 12252 7662 White 33
6 PM Wed 68 68 W 6 12022 11732 7142 White 31
7 PM Wed 65 65 W 6 11401 11401 6811 White 28
8 PM Wed 63 63 W 6 10986 10986 6396 White 26
9 PM Wed 60 60 W 6 10363 10363 5773 White 23
10 PM Wed 58 58 W 6 9946 9946 5356 White 21
11 PM Wed 56 56 NE 2 9523 9523 4933 White 19
12 Midnight Thu 54 54 NE 2 9088 9088 4498 White 17
1 AM Thu 53 53 NE 2 8870 8870 4280 White 16
2 AM Thu 51 51 NE 2 8439 8313 3723 White 14
3 AM Thu 50 50 NE 2 8225 7999 3409 White 13
4 AM Thu 48 48 NE 2 7794 7242 2652 White 11
5 AM Thu 48 48 SE 2 7794 7242 2652 White 11
6 AM Thu 50 50 SE 2 8225 7999 3409 White 13
7 AM Thu 52 52 SE 2 8653 8624 4034 White 15
8 AM Thu 56 56 SE 2 9523 9523 4933 White 19
9 AM Thu 59 60 SE 2 10363 10363 5773 White 23
10 AM Thu 62 64 SE 2 11194 11194 6604 White 27
11 AM Thu 64 66 W 5 11608 11537 6947 White 29
12 Noon Thu 67 70 W 5 12436 12252 7662 White 33
1 PM Thu 68 71 W 5 12642 12510 7920 White 34
2 PM Thu 70 73 W 5 13053 13022 8432 White 36
3 PM Thu 70 72 W 5 12848 12767 8177 White 35
4 PM Thu 70 72 W 5 12848 12767 8177 White 35
5 PM Thu 69 70 W 8 12436 12252 7662 White 33
6 PM Thu 67 67 W 8 11815 11612 7022 White 30
7 PM Thu 65 65 W 8 11401 11401 6811 White 28
8 PM Thu 62 62 W 8 10779 10779 6189 White 25
9 PM Thu 60 60 W 8 10363 10363 5773 White 23
10 PM Thu 57 57 W 8 9737 9737 5147 White 20
11 PM Thu 55 55 W 3 9306 9306 4716 White 18
12 Midnight Fri 54 54 W 3 9088 9088 4498 White 17
1 AM Fri 52 52 W 3 8653 8624 4034 White 15
2 AM Fri 51 51 W 3 8439 8313 3723 White 14
3 AM Fri 50 50 W 3 8225 7999 3409 White 13
4 AM Fri 48 48 W 3 7794 7242 2652 White 11
5 AM Fri 48 48 NE 3 7794 7242 2652 White 11
6 AM Fri 49 49 NE 3 8010 7661 3071 White 12
7 AM Fri 51 51 NE 3 8439 8313 3723 White 14
8 AM Fri 55 56 NE 3 9523 9523 4933 White 19
9 AM Fri 58 60 NE 3 10363 10363 5773 White 23
10 AM Fri 62 65 NE 3 11401 11401 6811 White 28
11 AM Fri 66 70 N 5 12436 12252 7662 White 33
12 Noon Fri 69 74 N 5 13254 13254 8664 White 37
1 PM Fri 71 76 N 5 13656 13656 9066 White 38
2 PM Fri 73 78 N 5 14056 14056 9466 White 40
3 PM Fri 73 77 N 5 13856 13856 9266 White 39
4 PM Fri 73 76 N 5 13656 13656 9066 White 38
5 PM Fri 72 74 NW 6 13254 13254 8664 White 37
6 PM Fri 70 71 NW 6 12642 12510 7920 White 34
7 PM Fri 68 68 NW 6 12022 11732 7142 White 31
8 PM Fri 66 66 NW 6 11608 11537 6947 White 29
9 PM Fri 63 63 NW 6 10986 10986 6396 White 26
10 PM Fri 60 60 NW 6 10363 10363 5773 White 23
11 PM Fri 58 58 N 3 9946 9946 5356 White 21
12 Midnight Sat 55 55 N 3 9306 9306 4716 White 18
1 AM Sat 54 54 N 3 9088 9088 4498 White 17
2 AM Sat 52 52 N 3 8653 8624 4034 White 15
3 AM Sat 51 51 N 3 8439 8313 3723 White 14
4 AM Sat 50 50 N 3 8225 7999 3409 White 13

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