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

Station:

KOAK

Date/Time:

18 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)
5 AM Wed 50 50 S 5 3869 4590 0 Blue 0
6 AM Wed 48 48 S 5 3839 4590 0 Blue 0
7 AM Wed 46 46 S 5 3839 4590 0 Blue 0
8 AM Wed 48 48 W 5 3839 4590 0 Blue 0
9 AM Wed 52 52 W 5 4133 4590 0 Blue 0
10 AM Wed 50 50 W 5 3869 4590 0 Blue 0
11 AM Wed 50 50 W 8 3869 4590 0 Blue 0
12 Noon Wed 52 52 W 8 4133 4590 0 Blue 0
1 PM Wed 55 55 W 8 5001 4590 0 Blue 2
2 PM Wed 56 56 SW 12 5065 4867 277 Blue 3
3 PM Wed 57 57 SW 12 5128 4936 346 Blue 4
4 PM Wed 57 57 SW 12 5128 4936 346 Blue 4
5 PM Wed 55 55 W 13 5001 4590 0 Blue 2
6 PM Wed 53 53 W 13 4265 4590 0 Blue 0
7 PM Wed 52 52 W 13 4133 4590 0 Blue 0
8 PM Wed 50 50 SW 5 3869 4590 0 Blue 0
9 PM Wed 50 50 SW 5 3869 4590 0 Blue 0
10 PM Wed 51 51 SW 5 4001 4590 0 Blue 0
11 PM Wed 50 50 SE 3 3869 4590 0 Blue 0
12 Midnight Thu 49 49 SE 3 3839 4590 0 Blue 0
1 AM Thu 49 49 SE 3 3839 4590 0 Blue 0
2 AM Thu 48 48 E 3 3839 4590 0 Blue 0
3 AM Thu 47 47 E 3 3839 4590 0 Blue 0
4 AM Thu 46 46 E 3 3839 4590 0 Blue 0
5 AM Thu 45 45 E 3 3839 4590 0 Blue 0
6 AM Thu 44 44 E 3 3839 4590 0 Blue 0
7 AM Thu 43 43 E 3 3839 4590 0 Blue 0
8 AM Thu 46 46 E 3 3839 4590 0 Blue 0
9 AM Thu 49 49 E 3 3839 4590 0 Blue 0
10 AM Thu 49 50 E 3 3869 4590 0 Blue 0
11 AM Thu 49 51 NE 7 4001 4590 0 Blue 0
12 Noon Thu 51 54 NE 7 4938 4590 0 Blue 1
1 PM Thu 54 57 NE 7 5128 4936 346 Blue 4
2 PM Thu 57 60 N 7 5413 5126 536 Blue 7
3 PM Thu 59 61 N 7 5609 5190 600 Blue 8
4 PM Thu 60 61 N 7 5609 5190 600 Blue 8
5 PM Thu 59 60 N 7 5413 5126 536 Blue 7
6 PM Thu 57 57 N 7 5128 4936 346 Blue 4
7 PM Thu 55 55 N 7 5001 4590 0 Blue 2
8 PM Thu 53 53 NE 5 4265 4590 0 Blue 0
9 PM Thu 52 52 NE 5 4133 4590 0 Blue 0
10 PM Thu 52 52 NE 5 4133 4590 0 Blue 0
11 PM Thu 51 51 NE 5 4001 4590 0 Blue 0
12 Midnight Fri 50 50 NE 5 3869 4590 0 Blue 0
1 AM Fri 49 49 NE 5 3839 4590 0 Blue 0
2 AM Fri 47 47 E 5 3839 4590 0 Blue 0
3 AM Fri 46 46 E 5 3839 4590 0 Blue 0
4 AM Fri 44 44 E 5 3839 4590 0 Blue 0
5 AM Fri 43 43 E 5 3839 4590 0 Blue 0
6 AM Fri 43 43 E 5 3839 4590 0 Blue 0
7 AM Fri 44 44 E 5 3839 4590 0 Blue 0
8 AM Fri 45 45 E 5 3839 4590 0 Blue 0
9 AM Fri 48 49 E 5 3839 4590 0 Blue 0
10 AM Fri 51 53 E 5 4265 4590 0 Blue 0
11 AM Fri 55 58 N 7 5192 4999 409 Blue 5
12 Noon Fri 58 62 N 7 6021 5266 676 Blue 9
1 PM Fri 62 66 N 7 7474 6667 2077 Blue 13
2 PM Fri 65 69 N 7 8166 7445 2855 Blue 16
3 PM Fri 67 70 N 7 8687 7702 3112 Blue 17
4 PM Fri 67 69 N 7 8166 7445 2855 Blue 16
5 PM Fri 66 67 NE 5 7733 6928 2338 Blue 14
6 PM Fri 63 63 NE 5 6689 5407 817 Blue 10
7 PM Fri 60 60 NE 5 5413 5126 536 Blue 7
8 PM Fri 58 58 NE 5 5192 4999 409 Blue 5
9 PM Fri 56 56 NE 5 5065 4867 277 Blue 3
10 PM Fri 56 56 NE 5 5065 4867 277 Blue 3
11 PM Fri 56 56 E 5 5065 4867 277 Blue 3
12 Midnight Sat 55 55 E 5 5001 4590 0 Blue 2
1 AM Sat 53 53 E 5 4265 4590 0 Blue 0
2 AM Sat 51 51 E 5 4001 4590 0 Blue 0
3 AM Sat 50 50 E 5 3869 4590 0 Blue 0
4 AM Sat 48 48 E 5 3839 4590 0 Blue 0
5 AM Sat 47 47 E 5 3839 4590 0 Blue 0
6 AM Sat 47 47 E 5 3839 4590 0 Blue 0
7 AM Sat 48 48 E 5 3839 4590 0 Blue 0
8 AM Sat 49 49 E 5 3839 4590 0 Blue 0
9 AM Sat 52 53 E 5 4265 4590 0 Blue 0
10 AM Sat 56 58 E 5 5192 4999 409 Blue 5
11 AM Sat 60 64 NE 5 6952 5598 1008 Blue 11
12 Noon Sat 64 69 NE 5 8166 7445 2855 Blue 16
1 PM Sat 68 73 NE 5 9598 8606 4016 White 20
2 PM Sat 71 76 NE 5 10266 9958 5368 White 23
3 PM Sat 73 77 NE 5 10477 10477 5887 White 24
4 PM Sat 73 76 NE 5 10266 9958 5368 White 23
5 PM Sat 71 72 W 5 9376 8124 3534 White 19
6 PM Sat 68 68 W 5 7970 7187 2597 Blue 15
7 PM Sat 65 65 W 5 7213 5973 1383 Blue 12
8 PM Sat 62 62 W 5 6021 5266 676 Blue 9
9 PM Sat 60 60 W 5 5413 5126 536 Blue 7
10 PM Sat 59 59 W 5 5272 5063 473 Blue 6
11 PM Sat 58 58 S 5 5192 4999 409 Blue 5
12 Midnight Sun 57 57 S 5 5128 4936 346 Blue 4
1 AM Sun 54 54 S 5 4938 4590 0 Blue 1
2 AM Sun 52 52 S 5 4133 4590 0 Blue 0
3 AM Sun 51 51 S 5 4001 4590 0 Blue 0
4 AM Sun 50 50 S 5 3869 4590 0 Blue 0
5 AM Sun 50 50 S 5 3869 4590 0 Blue 0
6 AM Sun 50 50 S 5 3869 4590 0 Blue 0
7 AM Sun 51 51 S 5 4001 4590 0 Blue 0
8 AM Sun 52 52 S 5 4133 4590 0 Blue 0
9 AM Sun 54 54 S 5 4938 4590 0 Blue 1
10 AM Sun 57 58 S 5 5192 4999 409 Blue 5
11 AM Sun 59 61 SW 8 5609 5190 600 Blue 8
12 Noon Sun 63 65 SW 8 7213 5973 1383 Blue 12
1 PM Sun 66 69 SW 8 8166 7445 2855 Blue 16
2 PM Sun 69 71 SW 8 9159 7947 3357 White 18
3 PM Sun 70 72 SW 8 9376 8124 3534 White 19
4 PM Sun 70 71 SW 8 9159 7947 3357 White 18
5 PM Sun 68 69 W 9 8166 7445 2855 Blue 16
6 PM Sun 65 65 W 9 7213 5973 1383 Blue 12
7 PM Sun 63 63 W 9 6689 5407 817 Blue 10
8 PM Sun 61 61 W 9 5609 5190 600 Blue 8
9 PM Sun 60 60 W 9 5413 5126 536 Blue 7
10 PM Sun 59 59 W 9 5272 5063 473 Blue 6
11 PM Sun 58 58 N 7 5192 4999 409 Blue 5
12 Midnight Mon 57 57 N 7 5128 4936 346 Blue 4
1 AM Mon 54 54 N 7 4938 4590 0 Blue 1
2 AM Mon 52 52 N 7 4133 4590 0 Blue 0
3 AM Mon 50 50 N 7 3869 4590 0 Blue 0
4 AM Mon 49 49 N 7 3839 4590 0 Blue 0
5 AM Mon 48 48 N 6 3839 4590 0 Blue 0
6 AM Mon 47 47 N 6 3839 4590 0 Blue 0
7 AM Mon 47 47 N 6 3839 4590 0 Blue 0
8 AM Mon 48 48 N 6 3839 4590 0 Blue 0
9 AM Mon 49 49 N 6 3839 4590 0 Blue 0
10 AM Mon 52 54 N 6 4938 4590 0 Blue 1
11 AM Mon 55 58 NE 10 5192 4999 409 Blue 5
12 Noon Mon 59 63 NE 10 6689 5407 817 Blue 10
1 PM Mon 62 66 NE 10 7474 6667 2077 Blue 13
2 PM Mon 65 69 NE 10 8166 7445 2855 Blue 16
3 PM Mon 67 70 NE 10 8687 7702 3112 Blue 17
4 PM Mon 68 70 NE 10 8687 7702 3112 Blue 17
5 PM Mon 67 68 NE 12 7970 7187 2597 Blue 15
6 PM Mon 65 65 NE 12 7213 5973 1383 Blue 12
7 PM Mon 63 63 NE 12 6689 5407 817 Blue 10
8 PM Mon 60 60 NE 12 5413 5126 536 Blue 7
9 PM Mon 59 59 NE 12 5272 5063 473 Blue 6
10 PM Mon 59 59 NE 12 5272 5063 473 Blue 6
11 PM Mon 58 58 NE 8 5192 4999 409 Blue 5
12 Midnight Tue 57 57 NE 8 5128 4936 346 Blue 4
1 AM Tue 55 55 NE 8 5001 4590 0 Blue 2
2 AM Tue 52 52 NE 8 4133 4590 0 Blue 0
3 AM Tue 51 51 NE 8 4001 4590 0 Blue 0
4 AM Tue 50 50 NE 8 3869 4590 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