Detailed Predictions for: Hat Creek Rim
Launch Lat, Long, Altitude (f): 40.843037, -121.427406, 4590
LZ Altitude (f): 3575
Sounding

Station:

KOAK

Date/Time:

12 MAY 2021

Temp/Wind data from:

NOAA Digital Forecast

Site Forecasts
Time
(Local)
High
Temp

Puddle
Temp

Wind
(mph)
Wind
Gust
Thermal
Ceiling

(ft)
Soaring
Ceiling

(ft)
Above
Launch

(ft)
Thermal
Type
Thermal
Index

(F)
12 Midnight Wed 58 58 SSE 4 8 4488 4590 0 Blue 0
1 AM Wed 54 54 SSE 3 8 4488 4590 0 Blue 0
2 AM Wed 50 50 SSE 3 8 4488 4590 0 Blue 0
3 AM Wed 50 50 SSE 4 8 4488 4590 0 Blue 0
4 AM Wed 49 49 SSE 4 8 4488 4590 0 Blue 0
5 AM Wed 49 49 SSE 4 8 4488 4590 0 Blue 0
6 AM Wed 54 54 S 3 6 4488 4590 0 Blue 0
7 AM Wed 58 58 S 2 4 4488 4590 0 Blue 0
8 AM Wed 63 64 S 1 1 4488 4590 0 Blue 0
9 AM Wed 66 69 SW 2 3 6154 4945 355 Blue 3
10 AM Wed 69 73 WSW 4 5 9216 7278 2688 Blue 7
11 AM Wed 73 79 W 6 7 12940 10290 5700 Blue 13
12 Noon Wed 73 77 W 8 9 11365 9304 4714 Blue 11
1 PM Wed 74 76 W 10 11 10466 9193 4603 Blue 10
2 PM Wed 75 75 WSW 12 13 9652 8659 4069 Blue 9
3 PM Wed 74 76 WSW 11 13 10466 9193 4603 Blue 10
4 PM Wed 73 76 WSW 11 12 10466 9193 4603 Blue 10
5 PM Wed 73 75 WSW 10 12 9652 8659 4069 Blue 9
6 PM Wed 71 72 WSW 8 11 8731 6140 1550 Blue 6
7 PM Wed 69 69 SW 6 11 6154 4945 355 Blue 3
8 PM Wed 67 67 SW 5 10 5578 4590 0 Blue 1
9 PM Wed 66 66 SSW 5 11 5286 4590 0 Blue 0
10 PM Wed 65 65 SSW 5 11 4488 4590 0 Blue 0
11 PM Wed 64 64 S 5 11 4488 4590 0 Blue 0
12 Midnight Thu 60 60 S 5 11 4488 4590 0 Blue 0
1 AM Thu 56 56 S 4 10 4488 4590 0 Blue 0
2 AM Thu 52 52 S 4 9 4488 4590 0 Blue 0
3 AM Thu 51 51 S 4 9 4488 4590 0 Blue 0
4 AM Thu 51 51 S 4 9 4488 4590 0 Blue 0
5 AM Thu 50 50 S 4 9 4488 4590 0 Blue 0
6 AM Thu 54 54 S 3 6 4488 4590 0 Blue 0
7 AM Thu 58 58 SSW 2 4 4488 4590 0 Blue 0
8 AM Thu 63 64 SW 1 1 4488 4590 0 Blue 0
9 AM Thu 66 69 WSW 2 3 6154 4945 355 Blue 3
10 AM Thu 69 73 W 4 4 9216 7278 2688 Blue 7
11 AM Thu 73 79 W 5 6 12940 10290 5700 Blue 13
12 Noon Thu 74 81 W 7 8 14316 11990 7400 Blue 15
1 PM Thu 75 82 W 8 10 14918 12741 8151 Blue 16
2 PM Thu 76 83 WSW 10 12 15269 13444 8854 Blue 17
3 PM Thu 75 81 WSW 10 12 14316 11990 7400 Blue 15
4 PM Thu 74 78 WSW 10 12 12183 9524 4934 Blue 12
5 PM Thu 74 76 WSW 10 12 10466 9193 4603 Blue 10
6 PM Thu 72 73 WSW 8 11 9216 7278 2688 Blue 7
7 PM Thu 70 70 SW 6 11 7383 5569 979 Blue 4
8 PM Thu 68 68 SW 5 10 5867 4590 0 Blue 2
9 PM Thu 67 67 SSW 4 9 5578 4590 0 Blue 1
10 PM Thu 66 66 S 3 7 5286 4590 0 Blue 0
11 PM Thu 65 65 SSE 2 6 4488 4590 0 Blue 0
12 Midnight Fri 60 60 SSE 2 6 4488 4590 0 Blue 0
1 AM Fri 55 55 SSE 3 6 4488 4590 0 Blue 0
2 AM Fri 51 51 SSE 3 6 4488 4590 0 Blue 0
3 AM Fri 50 50 SSE 3 6 4488 4590 0 Blue 0
4 AM Fri 50 50 SE 3 6 4488 4590 0 Blue 0
5 AM Fri 49 49 SE 3 6 4488 4590 0 Blue 0
6 AM Fri 53 53 ESE 2 5 4488 4590 0 Blue 0
7 AM Fri 56 56 E 2 3 4488 4590 0 Blue 0
8 AM Fri 59 59 ENE 2 2 4488 4590 0 Blue 0
9 AM Fri 63 64 SSE 3 3 4488 4590 0 Blue 0
10 AM Fri 66 69 WSW 4 4 6154 4945 355 Blue 3
11 AM Fri 69 75 NNW 4 5 9652 8659 4069 Blue 9
12 Noon Fri 71 78 NNW 5 6 12183 9524 4934 Blue 12
1 PM Fri 73 80 NW 6 7 13648 11179 6589 Blue 14
2 PM Fri 75 82 NW 7 8 14918 12741 8151 Blue 16
3 PM Fri 74 79 WNW 7 8 12940 10290 5700 Blue 13
4 PM Fri 73 77 WNW 7 8 11365 9304 4714 Blue 11
5 PM Fri 73 75 W 8 9 9652 8659 4069 Blue 9
6 PM Fri 71 71 S 7 8 8308 5855 1265 Blue 5
7 PM Fri 68 68 E 6 8 5867 4590 0 Blue 2
8 PM Fri 66 66 N 5 8 5286 4590 0 Blue 0
9 PM Fri 64 64 NE 3 6 4488 4590 0 Blue 0
10 PM Fri 63 63 E 2 3 4488 4590 0 Blue 0
11 PM Fri 62 62 SSE 0 1 4488 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 or WeatherAPI.com website.  Puddle temperatures can exceed this temperature. 

Puddle Temp: This estimate is based on the High Temp and the National Weather Service or WeatherAPI.com 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 or WeatherAPI.com website.

Wind Gust: This estimate is taken from the National Weather Service or WeatherAPI.com 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