Detailed Predictions for: Elk Mountain
Launch Altitude (f): 4000
LZ Altitude (f): 1600
Sounding

Station:

KOAK

Date/Time:

17 FEB 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)
4 AM Sun 30 30 W 7 2579 4000 0 Blue 0
5 AM Sun 29 29 W 7 2579 4000 0 Blue 0
6 AM Sun 29 29 W 7 2579 4000 0 Blue 0
7 AM Sun 30 30 NW 7 2579 4000 0 Blue 0
8 AM Sun 31 31 NW 7 2579 4000 0 Blue 0
9 AM Sun 33 33 NW 7 2579 4000 0 Blue 0
10 AM Sun 36 37 NW 7 3324 4000 0 Blue 0
11 AM Sun 37 38 NW 7 3960 4000 0 Blue 0
12 Noon Sun 38 39 NW 7 4340 4000 0 Blue 1
1 PM Sun 39 40 NW 9 4674 4000 0 White 2
2 PM Sun 40 41 NW 9 4893 4000 0 White 3
3 PM Sun 40 40 NW 9 4674 4000 0 White 2
4 PM Sun 39 39 NW 12 4340 4000 0 Blue 1
5 PM Sun 38 38 NW 12 3960 4000 0 Blue 0
6 PM Sun 35 35 NW 12 2579 4000 0 Blue 0
7 PM Sun 33 33 N 8 2579 4000 0 Blue 0
8 PM Sun 32 32 N 8 2579 4000 0 Blue 0
9 PM Sun 31 31 N 8 2579 4000 0 Blue 0
10 PM Sun 30 30 N 9 2579 4000 0 Blue 0
11 PM Sun 29 29 N 9 2579 4000 0 Blue 0
12 Midnight Mon 29 29 N 9 2579 4000 0 Blue 0
1 AM Mon 28 28 N 10 2579 4000 0 Blue 0
2 AM Mon 28 28 N 10 2579 4000 0 Blue 0
3 AM Mon 27 27 N 10 2579 4000 0 Blue 0
4 AM Mon 27 27 N 8 2579 4000 0 Blue 0
5 AM Mon 26 26 N 8 2579 4000 0 Blue 0
6 AM Mon 26 26 N 8 2579 4000 0 Blue 0
7 AM Mon 27 27 N 8 2579 4000 0 Blue 0
8 AM Mon 30 30 N 8 2579 4000 0 Blue 0
9 AM Mon 33 34 N 8 2579 4000 0 Blue 0
10 AM Mon 37 39 N 9 4340 4000 0 Blue 1
11 AM Mon 41 44 N 9 5536 5536 1536 White 6
12 Noon Mon 44 47 N 9 6177 6177 2177 White 9
1 PM Mon 46 49 N 9 6600 6600 2600 White 11
2 PM Mon 47 49 N 9 6600 6600 2600 White 11
3 PM Mon 47 48 N 9 6388 6388 2388 White 10
4 PM Mon 46 46 N 7 5964 5964 1964 White 8
5 PM Mon 43 43 N 7 5322 4689 689 White 5
6 PM Mon 39 39 N 7 4340 4000 0 Blue 1
7 PM Mon 36 36 N 7 2579 4000 0 Blue 0
8 PM Mon 34 34 N 7 2579 4000 0 Blue 0
9 PM Mon 34 34 N 7 2579 4000 0 Blue 0
10 PM Mon 33 33 NE 8 2579 4000 0 Blue 0
11 PM Mon 32 32 NE 8 2579 4000 0 Blue 0
12 Midnight Tue 32 32 NE 8 2579 4000 0 Blue 0
1 AM Tue 31 31 NE 8 2579 4000 0 Blue 0
2 AM Tue 30 30 NE 8 2579 4000 0 Blue 0
3 AM Tue 30 30 NE 8 2579 4000 0 Blue 0
4 AM Tue 29 29 NE 6 2579 4000 0 Blue 0
5 AM Tue 28 28 NE 6 2579 4000 0 Blue 0
6 AM Tue 28 28 NE 6 2579 4000 0 Blue 0
7 AM Tue 29 29 NE 6 2579 4000 0 Blue 0
8 AM Tue 31 31 NE 6 2579 4000 0 Blue 0
9 AM Tue 35 36 NE 6 2579 4000 0 Blue 0
10 AM Tue 39 41 NW 6 4893 4000 0 White 3
11 AM Tue 42 44 NW 6 5536 5536 1536 White 6
12 Noon Tue 45 48 NW 6 6388 6388 2388 White 10
1 PM Tue 46 49 NW 6 6600 6600 2600 White 11
2 PM Tue 47 49 NW 6 6600 6600 2600 White 11
3 PM Tue 47 48 NW 6 6388 6388 2388 White 10
4 PM Tue 45 45 W 6 5751 5751 1751 White 7
5 PM Tue 43 43 W 6 5322 4689 689 White 5
6 PM Tue 41 41 W 6 4893 4000 0 White 3
7 PM Tue 38 38 W 6 3960 4000 0 Blue 0
8 PM Tue 37 37 W 6 3324 4000 0 Blue 0
9 PM Tue 36 36 W 6 2579 4000 0 Blue 0
10 PM Tue 35 35 NE 5 2579 4000 0 Blue 0
11 PM Tue 34 34 NE 5 2579 4000 0 Blue 0
12 Midnight Wed 33 33 NE 5 2579 4000 0 Blue 0
1 AM Wed 33 33 NE 5 2579 4000 0 Blue 0
2 AM Wed 32 32 NE 5 2579 4000 0 Blue 0
3 AM Wed 32 32 NE 5 2579 4000 0 Blue 0
4 AM Wed 31 31 N 6 2579 4000 0 Blue 0
5 AM Wed 31 31 N 6 2579 4000 0 Blue 0
6 AM Wed 31 31 N 6 2579 4000 0 Blue 0
7 AM Wed 31 31 N 6 2579 4000 0 Blue 0
8 AM Wed 33 33 N 6 2579 4000 0 Blue 0
9 AM Wed 35 35 N 6 2579 4000 0 Blue 0
10 AM Wed 37 38 W 9 3960 4000 0 Blue 0
11 AM Wed 40 41 W 9 4893 4000 0 White 3
12 Noon Wed 42 43 W 9 5322 4689 689 White 5
1 PM Wed 43 44 W 9 5536 5536 1536 White 6
2 PM Wed 43 44 W 9 5536 5536 1536 White 6
3 PM Wed 42 42 W 9 5107 4319 319 White 4
4 PM Wed 41 41 NW 14 4893 4000 0 White 3
5 PM Wed 39 39 NW 14 4340 4000 0 Blue 1
6 PM Wed 37 37 NW 14 3324 4000 0 Blue 0
7 PM Wed 36 36 NW 14 2579 4000 0 Blue 0
8 PM Wed 34 34 NW 14 2579 4000 0 Blue 0
9 PM Wed 33 33 NW 14 2579 4000 0 Blue 0
10 PM Wed 33 33 NW 10 2579 4000 0 Blue 0
11 PM Wed 32 32 NW 10 2579 4000 0 Blue 0
12 Midnight Thu 32 32 NW 10 2579 4000 0 Blue 0
1 AM Thu 32 32 NW 10 2579 4000 0 Blue 0
2 AM Thu 31 31 NW 10 2579 4000 0 Blue 0
3 AM Thu 31 31 NW 10 2579 4000 0 Blue 0
4 AM Thu 31 31 NW 10 2579 4000 0 Blue 0
5 AM Thu 30 30 NW 10 2579 4000 0 Blue 0
6 AM Thu 29 29 NW 10 2579 4000 0 Blue 0
7 AM Thu 30 30 NW 10 2579 4000 0 Blue 0
8 AM Thu 32 32 NW 10 2579 4000 0 Blue 0
9 AM Thu 34 34 NW 10 2579 4000 0 Blue 0
10 AM Thu 37 38 N 10 3960 4000 0 Blue 0
11 AM Thu 40 41 N 10 4893 4000 0 White 3
12 Noon Thu 41 43 N 10 5322 4689 689 White 5
1 PM Thu 42 44 N 10 5536 5536 1536 White 6
2 PM Thu 42 43 N 10 5322 4689 689 White 5
3 PM Thu 42 43 N 10 5322 4689 689 White 5
4 PM Thu 41 41 N 13 4893 4000 0 White 3
5 PM Thu 39 39 N 13 4340 4000 0 Blue 1
6 PM Thu 37 37 N 13 3324 4000 0 Blue 0
7 PM Thu 35 35 N 13 2579 4000 0 Blue 0
8 PM Thu 34 34 N 13 2579 4000 0 Blue 0
9 PM Thu 33 33 N 13 2579 4000 0 Blue 0
10 PM Thu 32 32 N 9 2579 4000 0 Blue 0
11 PM Thu 32 32 N 9 2579 4000 0 Blue 0
12 Midnight Fri 32 32 N 9 2579 4000 0 Blue 0
1 AM Fri 31 31 N 9 2579 4000 0 Blue 0
2 AM Fri 31 31 N 9 2579 4000 0 Blue 0
3 AM Fri 30 30 N 9 2579 4000 0 Blue 0
4 AM Fri 29 29 N 8 2579 4000 0 Blue 0
5 AM Fri 28 28 N 8 2579 4000 0 Blue 0
6 AM Fri 28 28 N 8 2579 4000 0 Blue 0
7 AM Fri 29 29 N 8 2579 4000 0 Blue 0
8 AM Fri 32 32 N 8 2579 4000 0 Blue 0
9 AM Fri 35 35 N 8 2579 4000 0 Blue 0
10 AM Fri 39 40 E 5 4674 4000 0 White 2
11 AM Fri 42 43 E 5 5322 4689 689 White 5
12 Noon Fri 45 47 E 5 6177 6177 2177 White 9
1 PM Fri 47 49 E 5 6600 6600 2600 White 11
2 PM Fri 49 50 E 5 6810 6810 2810 White 12
3 PM Fri 49 50 E 5 6810 6810 2810 White 12
4 PM Fri 48 48 W 6 6388 6388 2388 White 10
5 PM Fri 45 45 W 6 5751 5751 1751 White 7
6 PM Fri 41 41 W 6 4893 4000 0 White 3
7 PM Fri 38 38 W 6 3960 4000 0 Blue 0
8 PM Fri 36 36 W 6 2579 4000 0 Blue 0
9 PM Fri 36 36 W 6 2579 4000 0 Blue 0
10 PM Fri 36 36 NW 5 2579 4000 0 Blue 0
11 PM Fri 35 35 NW 5 2579 4000 0 Blue 0
12 Midnight Sat 34 34 NW 5 2579 4000 0 Blue 0
1 AM Sat 33 33 NW 5 2579 4000 0 Blue 0
2 AM Sat 33 33 NW 5 2579 4000 0 Blue 0
3 AM Sat 34 34 NW 5 2579 4000 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