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

Station:

KOAK

Date/Time:

18 OCT 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 Fri 49 49 NE 7 476 2000 0 Blue 0
6 AM Fri 49 49 NE 5 476 2000 0 Blue 0
7 AM Fri 48 48 NE 5 476 2000 0 Blue 0
8 AM Fri 50 50 NE 3 476 2000 0 Blue 0
9 AM Fri 57 57 SE 3 1784 2000 0 Blue 2
10 AM Fri 62 63 S 5 3195 2459 459 Blue 8
11 AM Fri 65 68 S 6 4036 3399 1399 Blue 13
12 Noon Fri 67 70 SW 5 4972 3610 1610 Blue 15
1 PM Fri 68 71 W 5 5448 3999 1999 Blue 16
2 PM Fri 69 72 W 8 5913 4398 2398 Blue 17
3 PM Fri 70 72 W 6 5913 4398 2398 Blue 17
4 PM Fri 71 72 NW 7 5913 4398 2398 Blue 17
5 PM Fri 70 70 NW 10 4972 3610 1610 Blue 15
6 PM Fri 67 67 NW 6 3625 3293 1293 Blue 12
7 PM Fri 62 62 NW 6 3089 2233 233 Blue 7
8 PM Fri 59 59 NW 8 2241 2000 0 Blue 4
9 PM Fri 56 56 NW 5 1555 2000 0 Blue 1
10 PM Fri 55 55 N 5 1324 2000 0 Blue 0
11 PM Fri 54 54 N 6 476 2000 0 Blue 0
12 Midnight Sat 53 53 N 5 476 2000 0 Blue 0
1 AM Sat 52 52 N 3 476 2000 0 Blue 0
2 AM Sat 52 52 N 6 476 2000 0 Blue 0
3 AM Sat 53 53 N 5 476 2000 0 Blue 0
4 AM Sat 51 51 N 3 476 2000 0 Blue 0
5 AM Sat 51 51 N 5 476 2000 0 Blue 0
6 AM Sat 50 50 N 5 476 2000 0 Blue 0
7 AM Sat 49 49 N 5 476 2000 0 Blue 0
8 AM Sat 51 51 N 5 476 2000 0 Blue 0
9 AM Sat 58 58 NW 3 2013 2000 0 Blue 3
10 AM Sat 64 66 W 6 3512 3188 1188 Blue 11
11 AM Sat 67 70 W 8 4972 3610 1610 Blue 15
12 Noon Sat 69 73 W 8 6364 4908 2908 Blue 18
1 PM Sat 70 74 W 8 6806 5384 3384 Blue 19
2 PM Sat 71 75 W 12 7169 5843 3843 Blue 20
3 PM Sat 72 75 W 12 7169 5843 3843 Blue 20
4 PM Sat 73 74 W 12 6806 5384 3384 Blue 19
5 PM Sat 72 72 NW 15 5913 4398 2398 Blue 17
6 PM Sat 69 69 NW 15 4440 3504 1504 Blue 14
7 PM Sat 64 64 NW 15 3301 2752 752 Blue 9
8 PM Sat 61 61 NW 6 2776 2007 7 Blue 6
9 PM Sat 58 58 NW 6 2013 2000 0 Blue 3
10 PM Sat 57 57 NW 6 1784 2000 0 Blue 2
11 PM Sat 56 56 NW 6 1555 2000 0 Blue 1
12 Midnight Sun 55 55 NW 6 1324 2000 0 Blue 0
1 AM Sun 54 54 NW 6 476 2000 0 Blue 0
2 AM Sun 54 54 N 6 476 2000 0 Blue 0
3 AM Sun 55 55 N 6 1324 2000 0 Blue 0
4 AM Sun 53 53 N 6 476 2000 0 Blue 0
5 AM Sun 53 53 N 6 476 2000 0 Blue 0
6 AM Sun 52 52 N 6 476 2000 0 Blue 0
7 AM Sun 51 51 N 6 476 2000 0 Blue 0
8 AM Sun 53 53 N 5 476 2000 0 Blue 0
9 AM Sun 60 60 N 5 2468 2000 0 Blue 5
10 AM Sun 65 66 N 5 3512 3188 1188 Blue 11
11 AM Sun 68 71 W 7 5448 3999 1999 Blue 16
12 Noon Sun 70 74 W 7 6806 5384 3384 Blue 19
1 PM Sun 71 75 W 7 7169 5843 3843 Blue 20
2 PM Sun 72 76 NW 9 7413 6289 4289 Blue 21
3 PM Sun 73 76 NW 9 7413 6289 4289 Blue 21
4 PM Sun 74 75 NW 9 7169 5843 3843 Blue 20
5 PM Sun 74 74 NW 10 6806 5384 3384 Blue 19
6 PM Sun 71 71 NW 10 5448 3999 1999 Blue 16
7 PM Sun 65 65 NW 10 3406 3083 1083 Blue 10
8 PM Sun 62 62 NW 3 3089 2233 233 Blue 7
9 PM Sun 60 60 NW 3 2468 2000 0 Blue 5
10 PM Sun 59 59 NW 3 2241 2000 0 Blue 4
11 PM Sun 58 58 NE 3 2013 2000 0 Blue 3
12 Midnight Mon 57 57 NE 3 1784 2000 0 Blue 2
1 AM Mon 56 56 NE 3 1555 2000 0 Blue 1
2 AM Mon 56 56 NE 3 1555 2000 0 Blue 1
3 AM Mon 56 56 NE 3 1555 2000 0 Blue 1
4 AM Mon 55 55 NE 3 1324 2000 0 Blue 0
5 AM Mon 55 55 NE 5 1324 2000 0 Blue 0
6 AM Mon 54 54 NE 5 476 2000 0 Blue 0
7 AM Mon 53 53 NE 5 476 2000 0 Blue 0
8 AM Mon 55 55 NE 3 1324 2000 0 Blue 0
9 AM Mon 63 63 NE 3 3195 2459 459 Blue 8
10 AM Mon 69 71 NE 3 5448 3999 1999 Blue 16
11 AM Mon 72 75 SW 5 7169 5843 3843 Blue 20
12 Noon Mon 75 79 SW 5 8137 7363 5363 Blue 24
1 PM Mon 76 80 SW 5 8376 7604 5604 Blue 25
2 PM Mon 77 81 SW 5 8615 7843 5843 Blue 26
3 PM Mon 78 81 SW 5 8615 7843 5843 Blue 26
4 PM Mon 79 80 SW 5 8376 7604 5604 Blue 25
5 PM Mon 78 78 W 5 7897 7121 5121 Blue 23
6 PM Mon 75 75 W 5 7169 5843 3843 Blue 20
7 PM Mon 69 69 W 5 4440 3504 1504 Blue 14
8 PM Mon 66 66 NE 2 3512 3188 1188 Blue 11
9 PM Mon 63 63 NE 2 3195 2459 459 Blue 8
10 PM Mon 62 62 NE 2 3089 2233 233 Blue 7
11 PM Mon 61 61 NE 3 2776 2007 7 Blue 6
12 Midnight Tue 59 59 NE 3 2241 2000 0 Blue 4
1 AM Tue 58 58 NE 3 2013 2000 0 Blue 3
2 AM Tue 58 58 NE 5 2013 2000 0 Blue 3
3 AM Tue 59 59 NE 5 2241 2000 0 Blue 4
4 AM Tue 57 57 NE 5 1784 2000 0 Blue 2
5 AM Tue 57 57 NE 5 1784 2000 0 Blue 2
6 AM Tue 56 56 NE 5 1555 2000 0 Blue 1
7 AM Tue 55 55 NE 5 1324 2000 0 Blue 0
8 AM Tue 57 57 NE 3 1784 2000 0 Blue 2
9 AM Tue 66 66 NE 3 3512 3188 1188 Blue 11
10 AM Tue 73 75 NE 3 7169 5843 3843 Blue 20
11 AM Tue 77 80 SW 5 8376 7604 5604 Blue 25
12 Noon Tue 79 83 SW 5 9074 8319 6319 Blue 28
1 PM Tue 81 85 SW 5 9907 8781 6781 Blue 30
2 PM Tue 82 86 W 5 10500 8992 6992 Blue 31
3 PM Tue 83 86 W 5 10500 8992 6992 Blue 31
4 PM Tue 84 85 W 5 9907 8781 6781 Blue 30
5 PM Tue 83 83 W 6 9074 8319 6319 Blue 28
6 PM Tue 80 80 W 6 8376 7604 5604 Blue 25
7 PM Tue 72 72 W 6 5913 4398 2398 Blue 17
8 PM Tue 69 69 NW 2 4440 3504 1504 Blue 14
9 PM Tue 66 66 NW 2 3512 3188 1188 Blue 11
10 PM Tue 64 64 NW 2 3301 2752 752 Blue 9
11 PM Tue 62 62 N 3 3089 2233 233 Blue 7
12 Midnight Wed 61 61 N 3 2776 2007 7 Blue 6
1 AM Wed 60 60 N 3 2468 2000 0 Blue 5
2 AM Wed 59 59 NE 5 2241 2000 0 Blue 4
3 AM Wed 61 61 NE 5 2776 2007 7 Blue 6
4 AM Wed 58 58 NE 5 2013 2000 0 Blue 3
5 AM Wed 58 58 NE 5 2013 2000 0 Blue 3
6 AM Wed 57 57 NE 5 1784 2000 0 Blue 2
7 AM Wed 56 56 NE 5 1555 2000 0 Blue 1
8 AM Wed 58 58 NE 3 2013 2000 0 Blue 3
9 AM Wed 67 67 NE 3 3625 3293 1293 Blue 12
10 AM Wed 72 74 NE 3 6806 5384 3384 Blue 19
11 AM Wed 76 79 SW 5 8137 7363 5363 Blue 24
12 Noon Wed 79 83 SW 5 9074 8319 6319 Blue 28
1 PM Wed 80 84 SW 5 9425 8556 6556 Blue 29
2 PM Wed 81 85 W 6 9907 8781 6781 Blue 30
3 PM Wed 82 85 W 6 9907 8781 6781 Blue 30
4 PM Wed 83 84 W 6 9425 8556 6556 Blue 29
5 PM Wed 82 82 W 6 8835 8082 6082 Blue 27
6 PM Wed 79 79 W 6 8137 7363 5363 Blue 24
7 PM Wed 71 71 W 6 5448 3999 1999 Blue 16
8 PM Wed 68 68 N 2 4036 3399 1399 Blue 13
9 PM Wed 65 65 N 2 3406 3083 1083 Blue 10
10 PM Wed 64 64 N 2 3301 2752 752 Blue 9
11 PM Wed 62 62 NE 3 3089 2233 233 Blue 7
12 Midnight Thu 61 61 NE 3 2776 2007 7 Blue 6
1 AM Thu 60 60 NE 3 2468 2000 0 Blue 5
2 AM Thu 59 59 NE 5 2241 2000 0 Blue 4
3 AM Thu 60 60 NE 5 2468 2000 0 Blue 5
4 AM Thu 58 58 NE 5 2013 2000 0 Blue 3

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