Detailed Predictions for: Lake McClure
Launch Altitude (f): 2000
LZ Altitude (f): 500
Sounding

Station:

KOAK

Date/Time:

17 NOV 2017

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)
4 AM Fri 50 50 NW 9 2313 2000 0 White 0
5 AM Fri 50 50 NW 9 2313 2000 0 White 0
6 AM Fri 49 49 NW 9 663 2000 0 Blue 0
7 AM Fri 49 49 NW 10 663 2000 0 Blue 0
8 AM Fri 51 51 NW 10 2535 2000 0 White 0
9 AM Fri 55 55 NW 10 3402 3241 1241 White 5
10 AM Fri 58 59 NW 10 4260 4260 2260 White 9
11 AM Fri 59 61 NW 10 4694 4694 2694 White 11
12 Noon Fri 61 63 NW 10 5121 5121 3121 White 13
1 PM Fri 62 64 NW 10 5331 5331 3331 White 14
2 PM Fri 62 63 NW 10 5121 5121 3121 White 13
3 PM Fri 61 61 NW 10 4694 4694 2694 White 11
4 PM Fri 60 60 NW 8 4473 4473 2473 White 10
5 PM Fri 56 56 NW 8 3617 3481 1481 White 6
6 PM Fri 51 51 NW 8 2535 2000 0 White 0
7 PM Fri 49 49 N 5 663 2000 0 Blue 0
8 PM Fri 49 49 N 5 663 2000 0 Blue 0
9 PM Fri 48 48 N 5 663 2000 0 Blue 0
10 PM Fri 48 48 NE 3 663 2000 0 Blue 0
11 PM Fri 47 47 NE 3 663 2000 0 Blue 0
12 Midnight Sat 47 47 NE 3 663 2000 0 Blue 0
1 AM Sat 46 46 E 5 663 2000 0 Blue 0
2 AM Sat 46 46 E 5 663 2000 0 Blue 0
3 AM Sat 46 46 E 5 663 2000 0 Blue 0
4 AM Sat 46 46 NE 6 663 2000 0 Blue 0
5 AM Sat 45 45 NE 6 663 2000 0 Blue 0
6 AM Sat 45 45 NE 6 663 2000 0 Blue 0
7 AM Sat 45 45 E 5 663 2000 0 Blue 0
8 AM Sat 48 48 E 5 663 2000 0 Blue 0
9 AM Sat 54 55 E 5 3402 3241 1241 White 5
10 AM Sat 59 60 S 5 4473 4473 2473 White 10
11 AM Sat 61 63 S 5 5121 5121 3121 White 13
12 Noon Sat 63 65 S 5 5541 5541 3541 White 15
1 PM Sat 65 67 SW 6 5960 5960 3960 White 16
2 PM Sat 65 66 SW 6 5751 5751 3751 White 15
3 PM Sat 64 64 SW 6 5331 5331 3331 White 14
4 PM Sat 63 63 NW 3 5121 5121 3121 White 13
5 PM Sat 58 58 NW 3 4046 4046 2046 White 8
6 PM Sat 52 52 NW 3 2754 2000 0 White 2
7 PM Sat 50 50 NE 2 2313 2000 0 White 0
8 PM Sat 49 49 NE 2 663 2000 0 Blue 0
9 PM Sat 49 49 NE 2 663 2000 0 Blue 0
10 PM Sat 48 48 NE 3 663 2000 0 Blue 0
11 PM Sat 47 47 NE 3 663 2000 0 Blue 0
12 Midnight Sun 47 47 NE 3 663 2000 0 Blue 0
1 AM Sun 46 46 NE 3 663 2000 0 Blue 0
2 AM Sun 46 46 NE 3 663 2000 0 Blue 0
3 AM Sun 46 46 NE 3 663 2000 0 Blue 0
4 AM Sun 46 46 E 2 663 2000 0 Blue 0
5 AM Sun 46 46 E 2 663 2000 0 Blue 0
6 AM Sun 45 45 E 2 663 2000 0 Blue 0
7 AM Sun 45 45 E 2 663 2000 0 Blue 0
8 AM Sun 48 48 E 2 663 2000 0 Blue 0
9 AM Sun 54 54 E 2 3187 2999 999 White 4
10 AM Sun 59 60 W 2 4473 4473 2473 White 10
11 AM Sun 61 62 W 2 4911 4911 2911 White 12
12 Noon Sun 63 65 W 2 5541 5541 3541 White 15
1 PM Sun 65 66 W 2 5751 5751 3751 White 15
2 PM Sun 65 66 W 2 5751 5751 3751 White 15
3 PM Sun 64 64 W 2 5331 5331 3331 White 14
4 PM Sun 63 63 N 2 5121 5121 3121 White 13
5 PM Sun 59 59 N 2 4260 4260 2260 White 9
6 PM Sun 54 54 N 2 3187 2999 999 White 4
7 PM Sun 52 52 N 2 2754 2000 0 White 2
8 PM Sun 52 52 N 2 2754 2000 0 White 2
9 PM Sun 51 51 N 2 2535 2000 0 White 0
10 PM Sun 51 51 E 2 2535 2000 0 White 0
11 PM Sun 50 50 E 2 2313 2000 0 White 0
12 Midnight Mon 50 50 E 2 2313 2000 0 White 0
1 AM Mon 49 49 E 2 663 2000 0 Blue 0
2 AM Mon 49 49 E 2 663 2000 0 Blue 0
3 AM Mon 49 49 E 2 663 2000 0 Blue 0
4 AM Mon 49 49 E 3 663 2000 0 Blue 0
5 AM Mon 48 48 E 3 663 2000 0 Blue 0
6 AM Mon 48 48 E 3 663 2000 0 Blue 0
7 AM Mon 48 48 E 3 663 2000 0 Blue 0
8 AM Mon 50 50 E 3 2313 2000 0 White 0
9 AM Mon 54 54 E 3 3187 2999 999 White 4
10 AM Mon 57 57 SE 3 3832 3739 1739 White 7
11 AM Mon 58 58 SE 3 4046 4046 2046 White 8
12 Noon Mon 60 60 SE 3 4473 4473 2473 White 10
1 PM Mon 61 61 SE 3 4694 4694 2694 White 11
2 PM Mon 61 61 SE 3 4694 4694 2694 White 11
3 PM Mon 60 60 SE 3 4473 4473 2473 White 10
4 PM Mon 60 60 E 2 4473 4473 2473 White 10
5 PM Mon 57 57 E 2 3832 3739 1739 White 7
6 PM Mon 53 53 E 2 2971 2000 0 White 3
7 PM Mon 52 52 E 2 2754 2000 0 White 2
8 PM Mon 52 52 E 2 2754 2000 0 White 2
9 PM Mon 51 51 E 2 2535 2000 0 White 0
10 PM Mon 51 51 E 3 2535 2000 0 White 0
11 PM Mon 50 50 E 3 2313 2000 0 White 0
12 Midnight Tue 50 50 E 3 2313 2000 0 White 0
1 AM Tue 49 49 E 3 663 2000 0 Blue 0
2 AM Tue 50 50 E 3 2313 2000 0 White 0
3 AM Tue 50 50 E 3 2313 2000 0 White 0
4 AM Tue 49 49 E 3 663 2000 0 Blue 0
5 AM Tue 49 49 E 3 663 2000 0 Blue 0
6 AM Tue 49 49 E 3 663 2000 0 Blue 0
7 AM Tue 49 49 E 3 663 2000 0 Blue 0
8 AM Tue 52 52 E 3 2754 2000 0 White 2
9 AM Tue 58 58 E 3 4046 4046 2046 White 8
10 AM Tue 63 63 SE 3 5121 5121 3121 White 13
11 AM Tue 65 66 SE 3 5751 5751 3751 White 15
12 Noon Tue 67 68 SE 3 6169 6169 4169 White 17
1 PM Tue 69 69 SE 3 6376 6376 4376 White 18
2 PM Tue 69 69 SE 3 6376 6376 4376 White 18
3 PM Tue 68 68 SE 3 6169 6169 4169 White 17
4 PM Tue 67 67 SE 5 5960 5960 3960 White 16
5 PM Tue 64 64 SE 5 5331 5331 3331 White 14
6 PM Tue 60 60 SE 5 4473 4473 2473 White 10
7 PM Tue 58 58 SE 5 4046 4046 2046 White 8
8 PM Tue 57 57 SE 5 3832 3739 1739 White 7
9 PM Tue 57 57 SE 5 3832 3739 1739 White 7
10 PM Tue 56 56 E 5 3617 3481 1481 White 6
11 PM Tue 56 56 E 5 3617 3481 1481 White 6
12 Midnight Wed 55 55 E 5 3402 3241 1241 White 5
1 AM Wed 55 55 E 5 3402 3241 1241 White 5
2 AM Wed 55 55 E 5 3402 3241 1241 White 5
3 AM Wed 55 55 E 5 3402 3241 1241 White 5
4 AM Wed 55 55 SE 5 3402 3241 1241 White 5
5 AM Wed 54 54 SE 5 3187 2999 999 White 4
6 AM Wed 54 54 SE 5 3187 2999 999 White 4
7 AM Wed 54 54 SE 5 3187 2999 999 White 4
8 AM Wed 57 57 SE 5 3832 3739 1739 White 7
9 AM Wed 62 62 SE 5 4911 4911 2911 White 12
10 AM Wed 66 67 E 2 5960 5960 3960 White 16
11 AM Wed 68 69 E 2 6376 6376 4376 White 18
12 Noon Wed 71 72 E 2 6994 6994 4994 White 21
1 PM Wed 72 73 E 2 7200 7200 5200 White 22
2 PM Wed 72 73 E 2 7200 7200 5200 White 22
3 PM Wed 71 71 E 2 6789 6789 4789 White 20
4 PM Wed 70 70 N 5 6582 6582 4582 White 19
5 PM Wed 65 65 N 5 5541 5541 3541 White 15
6 PM Wed 61 61 N 5 4694 4694 2694 White 11
7 PM Wed 59 59 N 5 4260 4260 2260 White 9
8 PM Wed 58 58 N 5 4046 4046 2046 White 8
9 PM Wed 58 58 N 5 4046 4046 2046 White 8
10 PM Wed 57 57 N 5 3832 3739 1739 White 7
11 PM Wed 56 56 N 5 3617 3481 1481 White 6
12 Midnight Thu 56 56 N 5 3617 3481 1481 White 6
1 AM Thu 55 55 N 5 3402 3241 1241 White 5
2 AM Thu 55 55 N 5 3402 3241 1241 White 5
3 AM Thu 55 55 N 5 3402 3241 1241 White 5

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