Detailed Predictions for: Marshall
Launch Lat, Long, Altitude (f): 34.2099918919, -117.302860125, 4040
LZ Altitude (f): 1700
Sounding

Station:

KNKX

Date/Time:

18 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 Tue 57 55 S 2 3 4306 4234 194 Blue 3
1 AM Tue 57 55 S 3 3 4306 4234 194 Blue 3
2 AM Tue 57 55 SSE 3 3 4306 4234 194 Blue 3
3 AM Tue 57 55 SSE 2 2 4306 4234 194 Blue 3
4 AM Tue 57 55 SSE 1 1 4306 4234 194 Blue 3
5 AM Tue 58 56 SSE 0 0 4330 4258 218 Blue 4
6 AM Tue 61 59 S 1 1 4402 4330 290 Blue 7
7 AM Tue 64 62 SW 1 1 4546 4402 362 Blue 10
8 AM Tue 67 66 W 1 2 5265 4804 764 Blue 14
9 AM Tue 70 71 W 3 3 7296 5518 1478 Blue 19
10 AM Tue 74 78 W 4 5 9271 8396 4356 Blue 26
11 AM Tue 78 83 W 5 6 12213 9800 5760 White 31
12 Noon Tue 80 87 W 6 7 13032 13032 8992 White 35
1 PM Tue 81 88 W 7 8 13236 13236 9196 White 36
2 PM Tue 83 89 W 8 9 13440 13440 9400 White 37
3 PM Tue 82 86 WSW 7 8 12828 12828 8788 White 34
4 PM Tue 80 82 WSW 6 7 11251 9497 5457 Blue 30
5 PM Tue 79 79 WSW 5 6 9546 8674 4634 Blue 27
6 PM Tue 76 75 WSW 4 5 8435 7551 3511 Blue 23
7 PM Tue 73 71 SW 3 4 7296 5518 1478 Blue 19
8 PM Tue 71 69 SW 2 3 5682 5260 1220 Blue 17
9 PM Tue 69 67 SSW 2 3 5386 5019 979 Blue 15
10 PM Tue 68 66 S 2 3 5265 4804 764 Blue 14
11 PM Tue 66 64 SSE 2 2 5022 4450 410 Blue 12
12 Midnight Wed 64 62 S 2 3 4546 4402 362 Blue 10
1 AM Wed 63 61 S 2 3 4450 4378 338 Blue 9
2 AM Wed 62 60 S 2 3 4426 4354 314 Blue 8
3 AM Wed 62 60 S 2 3 4426 4354 314 Blue 8
4 AM Wed 62 60 SSE 2 2 4426 4354 314 Blue 8
5 AM Wed 62 60 SSE 2 2 4426 4354 314 Blue 8
6 AM Wed 64 62 S 3 3 4546 4402 362 Blue 10
7 AM Wed 65 63 SSW 3 4 4820 4426 386 Blue 11
8 AM Wed 67 66 SSW 4 5 5265 4804 764 Blue 14
9 AM Wed 69 70 SSW 5 6 5839 5381 1341 Blue 18
10 AM Wed 72 75 SW 6 7 8435 7551 3511 Blue 23
11 AM Wed 74 79 SW 7 8 9546 8674 4634 Blue 27
12 Noon Wed 76 82 SW 7 8 11251 9497 5457 Blue 30
1 PM Wed 77 84 SW 7 8 12418 10122 6082 White 32
2 PM Wed 79 85 WSW 7 8 12623 10984 6944 White 33
3 PM Wed 78 82 WSW 7 8 11251 9497 5457 Blue 30
4 PM Wed 77 79 SW 7 8 9546 8674 4634 Blue 27
5 PM Wed 76 76 SW 7 8 8716 7835 3795 Blue 24
6 PM Wed 75 73 SW 6 7 7870 5830 1790 Blue 21
7 PM Wed 74 72 SSW 5 6 7584 5674 1634 Blue 20
8 PM Wed 72 70 SSW 4 5 5839 5381 1341 Blue 18
9 PM Wed 71 69 S 4 5 5682 5260 1220 Blue 17
10 PM Wed 70 68 S 5 6 5525 5139 1099 Blue 16
11 PM Wed 69 67 S 5 6 5386 5019 979 Blue 15
12 Midnight Thu 64 62 SSE 6 6 4546 4402 362 Blue 10
1 AM Thu 59 57 SSE 6 6 4354 4282 242 Blue 5
2 AM Thu 54 52 SSE 6 7 4234 4040 0 Blue 0
3 AM Thu 54 52 SSE 6 7 4234 4040 0 Blue 0
4 AM Thu 54 52 SSE 6 7 4234 4040 0 Blue 0
5 AM Thu 54 52 SSE 6 7 4234 4040 0 Blue 0
6 AM Thu 55 53 S 6 8 4258 4082 42 Blue 1
7 AM Thu 56 54 S 6 8 4282 4160 120 Blue 2
8 AM Thu 58 58 S 7 8 4378 4306 266 Blue 6
9 AM Thu 59 60 S 7 8 4426 4354 314 Blue 8
10 AM Thu 60 63 S 8 9 4820 4426 386 Blue 11
11 AM Thu 62 67 S 9 10 5386 5019 979 Blue 15
12 Noon Thu 66 72 SSW 9 11 7584 5674 1634 Blue 20
1 PM Thu 69 75 SSW 10 12 8435 7551 3511 Blue 23
2 PM Thu 73 78 SSW 11 13 9271 8396 4356 Blue 26
3 PM Thu 72 76 SSW 11 13 8716 7835 3795 Blue 24
4 PM Thu 70 72 SSW 11 13 7584 5674 1634 Blue 20
5 PM Thu 69 69 SSW 11 13 5682 5260 1220 Blue 17
6 PM Thu 67 65 SSW 10 11 5144 4544 504 Blue 13
7 PM Thu 65 63 SSW 8 10 4820 4426 386 Blue 11
8 PM Thu 63 61 S 7 8 4450 4378 338 Blue 9
9 PM Thu 61 59 S 7 8 4402 4330 290 Blue 7
10 PM Thu 59 57 SSE 7 8 4354 4282 242 Blue 5
11 PM Thu 56 54 SSE 6 8 4282 4160 120 Blue 2

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