It is emphasized...this soaring forecast information is valid only for the RAOB site area, and frequently will not apply to other areas of the state.
Soaring Forecast
National Weather Service Wichita, Kansas
0735 CDT Thursday, August 17, 2017
This forecast is for Thursday August 17, 2017
:
If the trigger temperature of 79.4 F/26.4 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 294 ft/min (1.5 m/s)
Maximum height of thermals.................. 7019 ft MSL (5481 ft AGL)
Forecast maximum temperature................... 88.0 F/31.6 C
Time of trigger temperature.................... 1100 CDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 5395 ft MSL (3857 ft AGL)
Thermal soaring outlook for Friday 08/18....... Fair
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:49:05 / 20:22:08 CDT
Total possible sunshine........... 13 hr 33 min 3 sec (813 min 3 sec)
Altitude of sun at 13:35:37 CDT... 64.03 degrees
Upper air data from numerical model forecast valid on 08/17/2017 at 0600 CDT
Freezing level.................. 15174 ft MSL (13636 ft AGL)
Convective condensation level... 14237 ft MSL (12699 ft AGL)
Lifted condensation level....... 10740 ft MSL (9202 ft AGL)
Lifted index.................... +4.0
K index......................... -4.5
Height Temperature Wind Wind Spd Lapse Rate ConvectionT Thermal Lift Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft deg C deg F Index fpm m/s
--------------------------------------------------------------------------------
18000 -5.2 22.6 290 14 7 5.7 3.1 45.6 114.0 12.0 M M
17000 -3.5 25.7 295 14 7 5.8 3.2 44.2 111.5 10.9 M M
16000 -1.7 28.9 300 15 8 6.3 3.4 42.9 109.2 9.9 M M
15000 0.2 32.4 305 15 8 6.6 3.6 41.7 107.1 9.0 M M
14000 2.3 36.1 305 15 8 7.2 4.0 40.7 105.3 8.3 M M
13000 4.5 40.1 305 14 7 7.1 3.9 39.9 103.8 7.6 M M
12000 6.5 43.7 310 14 7 6.6 3.6 38.9 102.1 6.8 M M
11000 8.4 47.1 310 12 6 5.1 2.8 37.8 100.0 5.8 M M
10000 10.2 50.4 315 11 6 5.8 3.2 36.0 96.9 4.1 M M
9500 11.0 51.8 315 10 5 5.6 3.1 35.4 95.7 3.4 M M
9000 11.8 53.2 315 10 5 5.4 3.0 34.7 94.4 2.7 M M
8500 12.5 54.5 315 10 5 5.2 2.9 34.0 93.2 2.0 M M
8000 13.3 55.9 315 10 5 5.2 2.8 33.2 91.8 1.3 M M
7500 14.0 57.2 315 9 5 5.0 2.7 32.5 90.5 0.6 M M
7000 14.7 58.5 310 9 5 5.0 2.7 31.7 89.1 -0.1 289 1.5
6500 15.4 59.7 310 9 5 4.2 2.3 30.9 87.7 -0.9 255 1.3
6000 15.9 60.6 305 9 5 2.6 1.5 30.1 86.2 -1.8 223 1.1
5500 16.4 61.5 305 9 5 5.6 3.1 29.1 84.4 -2.9 195 1.0
5000 17.0 62.6 305 9 5 4.4 2.4 28.4 83.1 -3.7 162 0.8
4500 17.4 63.3 310 9 5 3.6 2.0 27.5 81.4 -4.7 133 0.7
4000 18.0 64.4 315 9 5 4.6 2.5 26.6 79.9 -5.7 102 0.5
3750 18.2 64.8 320 9 5 3.3 1.8 26.2 79.1 -6.1 87 0.4
3500 18.4 65.1 325 9 5 3.2 1.7 25.6 78.1 -6.7 75 0.4
3250 18.6 65.5 330 9 5 4.5 2.4 25.2 77.3 -7.2 61 0.3
3000 18.9 66.0 330 10 5 4.8 2.6 24.8 76.6 -7.7 44 0.2
2750 19.2 66.6 335 10 5 3.9 2.1 24.4 75.9 -8.1 28 0.1
2500 19.3 66.7 335 10 5 1.2 0.7 23.9 75.0 -8.8 17 0.1
2250 19.3 66.7 330 9 5 0.6 0.3 23.2 73.7 -9.6 12 0.1
2000 19.2 66.6 330 9 5 -0.6 -0.3 22.5 72.5 -10.4 7 0.0
1750 18.7 65.7 325 8 4 -11.8 -6.5 21.4 70.5 -11.6 13 0.1
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
08/17/2017 at 0900 CDT | 08/17/2017 at 1200 CDT
|
CAPE... 0.0 LI... +4.7 | CAPE... 0.0 LI... +4.4
CINH... -1.0 K Index... -16.5 | CINH... -0.0 K Index... +1.9
|
Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft
--------------------------------------------------------------------------------
18000 -5.5 22.1 285 17 9 5.9 3.2 | -6.0 21.2 280 17 9 6.2 3.4
17000 -3.8 25.2 285 17 9 5.9 3.2 | -4.1 24.6 285 17 9 6.2 3.4
16000 -1.9 28.6 290 17 9 6.4 3.5 | -2.2 28.0 285 17 9 6.6 3.6
15000 0.1 32.2 295 17 9 6.6 3.6 | -0.1 31.8 290 17 9 6.8 3.7
14000 2.1 35.8 300 16 8 6.8 3.7 | 1.9 35.4 295 16 8 6.5 3.6
13000 4.2 39.6 300 16 8 6.7 3.7 | 3.9 39.0 300 16 8 6.7 3.7
12000 6.2 43.2 305 15 8 6.7 3.7 | 5.9 42.6 300 15 8 6.8 3.7
11000 8.3 46.9 310 13 7 6.7 3.7 | 7.9 46.2 305 14 7 7.0 3.8
10000 10.8 51.4 315 12 6 6.9 3.8 | 10.6 51.1 310 13 7 6.9 3.8
9500 11.8 53.2 315 11 6 6.8 3.8 | 11.6 52.9 315 12 6 6.7 3.7
9000 12.9 55.2 315 11 6 6.8 3.7 | 12.6 54.7 315 12 6 6.7 3.7
8500 13.9 57.0 315 11 6 6.4 3.5 | 13.6 56.5 315 12 6 6.5 3.6
8000 14.8 58.6 315 11 5 6.4 3.5 | 14.6 58.3 320 11 6 6.5 3.6
7500 15.7 60.3 315 10 5 5.0 2.7 | 15.5 59.9 320 11 6 5.4 3.0
7000 16.4 61.5 320 10 5 5.0 2.7 | 16.2 61.2 320 10 5 5.5 3.0
6500 17.1 62.8 320 10 5 3.8 2.1 | 16.8 62.2 325 10 5 3.7 2.0
6000 17.6 63.7 325 10 5 3.3 1.8 | 17.4 63.3 330 9 5 2.9 1.6
5500 18.1 64.6 330 10 5 3.9 2.1 | 17.6 63.7 335 8 4 2.8 1.5
5000 18.6 65.5 335 10 5 2.8 1.5 | 17.8 64.0 340 7 4 4.2 2.3
4500 18.9 66.0 340 10 5 3.0 1.7 | 18.7 65.7 335 6 3 8.5 4.7
4000 19.2 66.6 340 9 5 3.6 2.0 | 19.9 67.8 335 5 3 10.3 5.6
3750 19.3 66.7 340 9 5 2.7 1.5 | 20.7 69.3 335 5 3 9.3 5.1
3500 19.3 66.7 340 9 5 2.8 1.5 | 21.4 70.5 335 5 3 9.7 5.3
3250 19.5 67.1 340 9 5 3.8 2.1 | 22.1 71.8 335 5 3 10.5 5.8
3000 19.6 67.3 340 9 4 4.1 2.2 | 22.9 73.2 335 5 3 10.3 5.6
2750 19.8 67.6 335 8 4 5.6 3.1 | 23.6 74.5 335 5 2 10.3 5.6
2500 20.2 68.4 335 8 4 7.5 4.1 | 24.4 75.9 335 5 2 10.8 5.9
2250 20.7 69.3 330 7 4 7.1 3.9 | 25.2 77.4 335 4 2 10.2 5.6
2000 21.1 70.0 330 7 3 9.9 5.4 | 26.0 78.8 335 4 2 12.7 7.0
1750 22.1 71.8 330 6 3 18.8 10.3 | 27.2 81.0 335 4 2 21.4 11.8
08/17/2017 at 1500 CDT | 08/17/2017 at 1800 CDT
|
CAPE... 0.0 LI... +3.2 | CAPE... 0.0 LI... +2.0
CINH... -0.0 K Index... +15.4 | CINH... 0.0 K Index... +21.7
|
Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft
--------------------------------------------------------------------------------
18000 -6.0 21.2 280 17 9 5.6 3.1 | -6.4 20.5 285 17 9 6.2 3.4
17000 -4.3 24.3 285 16 8 6.1 3.3 | -4.4 24.1 285 16 8 6.8 3.7
16000 -2.5 27.5 285 15 8 6.4 3.5 | -2.4 27.7 290 15 8 7.2 3.9
15000 -0.6 30.9 285 15 8 6.5 3.6 | -0.3 31.5 290 14 7 6.9 3.8
14000 1.4 34.5 290 15 8 6.8 3.7 | 1.6 34.9 290 13 7 6.8 3.7
13000 3.4 38.1 290 14 7 6.9 3.8 | 3.6 38.5 290 13 6 6.5 3.6
12000 5.5 41.9 295 14 7 7.6 4.2 | 5.5 41.9 295 12 6 7.2 3.9
11000 7.8 46.0 305 13 7 7.6 4.2 | 7.6 45.7 295 11 6 8.2 4.5
10000 10.6 51.1 310 12 6 7.7 4.2 | 10.6 51.1 300 10 5 8.1 4.5
9500 11.8 53.2 310 12 6 7.3 4.0 | 11.8 53.2 305 10 5 7.6 4.2
9000 12.9 55.2 315 11 6 7.3 4.0 | 12.9 55.2 310 9 5 7.4 4.1
8500 13.9 57.0 315 11 6 5.3 2.9 | 14.0 57.2 310 8 4 6.6 3.6
8000 14.6 58.3 320 10 5 4.9 2.7 | 15.0 59.0 315 7 4 6.6 3.6
7500 15.3 59.5 325 8 4 4.9 2.7 | 15.9 60.6 320 6 3 5.1 2.8
7000 15.9 60.6 325 7 4 5.0 2.7 | 16.7 62.1 320 5 2 5.2 2.8
6500 16.6 61.9 330 6 3 5.8 3.2 | 17.5 63.5 320 3 2 6.0 3.3
6000 17.3 63.1 330 4 2 5.9 3.2 | 18.2 64.8 315 1 1 5.5 3.0
5500 18.5 65.3 330 4 2 10.2 5.6 | 19.3 66.7 305 1 0 10.1 5.5
5000 19.8 67.6 330 3 2 9.4 5.2 | 20.6 69.1 000 0 0 9.0 4.9
4500 21.2 70.2 330 3 1 10.3 5.6 | 22.0 71.6 180 1 0 10.1 5.5
4000 22.8 73.0 335 3 1 10.2 5.6 | 23.5 74.3 170 1 0 10.3 5.7
3750 23.5 74.3 335 3 1 9.7 5.3 | 24.3 75.7 165 1 0 9.5 5.2
3500 24.2 75.6 335 3 1 9.7 5.3 | 25.0 77.0 165 1 0 9.4 5.2
3250 24.9 76.8 335 2 1 9.6 5.3 | 25.7 78.3 165 1 1 9.6 5.3
3000 25.7 78.3 335 2 1 10.0 5.5 | 26.4 79.5 165 1 1 9.8 5.4
2750 26.4 79.5 335 2 1 10.5 5.8 | 27.1 80.8 160 1 1 10.1 5.5
2500 27.2 81.0 335 2 1 10.7 5.9 | 27.9 82.2 160 1 1 10.1 5.5
2250 28.0 82.4 335 2 1 10.3 5.7 | 28.6 83.5 160 1 1 10.2 5.6
2000 28.8 83.8 335 2 1 11.5 6.3 | 29.4 84.9 160 1 1 9.8 5.4
1750 29.8 85.6 335 2 1 17.2 9.4 | 30.0 86.0 160 1 1 9.5 5.2
________________________________________________________________________________
This product is issued twice per day, once by approximately 0630 CST/0730 CDT
(1330 UTC) and again by approximately 1830 CST/1930 CDT (0130 UTC). It is not
continuously monitored nor updated after its initial issuance.
The information contained herein is based on rawinsonde observation and/or
numerical weather prediction model data taken at the Wichita Gliderport at
North Latitude: 37 deg 45 min 48.420 sec
West Longitude: 97 deg 10 min 41.220 sec
Elevation: 1380 feet (420 meters)
and may not be representative of other locations around the Wichita area. Note
that some elevations in numerical weather prediction models differ from actual
station elevations, which can lead to data which appear to be below ground.
Erroneous data such as these should not be used.
The content and format of this report as well as the issuance times are subject
to change without prior notice. Comments and suggestions are welcome and should
be directed to one of the addresses or phone numbers shown at the bottom of this
page. To expedite a response to comments, be sure to mention your interest in
the soaring forecast.
DEFINITIONS:
CAPE (Convective Available Potential Energy) - An integrated measure of the
energy available for convective development, also known as the positive
area on a thermodynamic diagram. Units are Joules per kilogram. Larger
values are indicative of greater instability and the possibility of
stronger convective activity, including thunderstorms. Values around or
greater than 1000 suggest the possibility of severe weather should
convective activity develop.
CIN (Convective Inhibition) - An integrated measure of the amount of energy
needed to initiate convective activity, also known as the negative area on
a thermodynamic diagram. Units are Joules per kilogram. The more negative
this number, the more energy is required to initiate convection. This
inhibitive energy can be overcome through surface heating, cooling aloft,
lifting mechanisms (orographic, frontal, gravity waves, etc.)
Convective Condensation Level - The height to which an air parcel possessing the
average saturation mixing ratio in the lowest 4000 feet of the airmass,
if heated sufficiently from below, will rise dry adiabatically until it
just becomes saturated. It estimates the base of cumulus clouds that are
produced by surface heating only.
Convection Temperature (ConvectionT) - The surface temperature required to make
the airmass dry adiabatic up to the given level. It can be considered a
"trigger temperature" for that level.
Freezing Level - The height where the temperature is zero degrees Celsius.
Height of Stable Layer - The height (between 12,000 and 18,000 feet above
mean sea level) where the smallest lapse rate exists. The location and
existence of this feature is important in the generation of mountain
waves.
K Index - A measure of stability which combines the temperature difference
between approximately 5,000 and 18,000 feet above the surface, the amount
of moisture at approximately 5,000 feet above the surface, and a measure
of the dryness at approximately 10,000 feet above the surface. Larger
positive numbers indicate more instability and a greater likelihood of
thunderstorm development. One interpretation of K index values regarding
soaring in the western United States is given in WMO Technical Note 158
and is reproduced in the following table:
below -10 no or weak thermals
-10 to 5 dry thermals or 1/8 cumulus with moderate thermals
5 to 15 good soaring conditions
15 to 20 good soaring conditions with occasional showers
20 to 30 excellent soaring conditions, but increasing
probability of showers and thunderstorms
above 30 more than 60 percent probability of thunderstorms
Lapse Rate - The change with height of the temperature. Negative values indicate
inversions.
Lifted Condensation Level - The height to which an air parcel possessing the
average dew point in the lowest 4000 feet of the airmass and the forecast
maximum temperature must be lifted dry adiabatically to attain saturation.
Lifted Index (LI) - The difference between the environmental temperature at a
level approximately 18,000 feet above the surface and the temperature of
an air parcel lifted dry adiabatically from the surface to its lifted
condensation level and then pseudoadiabatically thereafter to this same
level. The parcel's initial temperature is the forecast maximum
temperature and its dew point is the average dew point in the lowest 4000
feet of the airmass. Negative values are indicative of instability with
positive values showing stable conditions.
Lift Rate - An experimental estimate of the strength of thermals. It is
computed the same way as the maximum rate of lift but uses the actual
level rather than the maximum height of thermals in the calculation.
Also, none of the empirical adjustments based on cloudiness and K-index
are applied to these calculations.
Maximum Height of Thermals - The height where the dry adiabat through the
forecast maximum temperature intersects the environmental temperature.
Maximum Rate of Lift - An estimate of the maximum strength of thermals. It
is computed from an empirical formula which combines the expected maximum
height of thermals with the difference in the environmental temperatures
between the maximum height of thermals and the temperature 4,000 feet
above the ground. After this computation, further empirical adjustments
are made based on the value of the K-index and the amount and opacity of
middle and high level cloudiness expected between the time of trigger
temperature and the time of overdevelopment.
Middle/High Clouds - The amount and opacity of middle (altostratus, altocumulus)
or high (cirrus, cirrostratus, cirrocumulus) clouds. Broken means that
between 60% and 90% of the sky is covered by the cloud, with overcast
conditions occurring when more than 90% of the sky is covered by the cloud.
Thin implies that the clouds are predominantly transparent, meaning that
some sunlight is reaching the ground, in contrast to opaque which suggests
that little sunlight is reaching the ground.
Potential Height of Wave - The minimum of the following two heights:
1. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind direction changes by 30 degrees or more
2. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind speed no longer increases with height
PVA/NVA - Positive vorticity advection (PVA)/negative vorticity advection (NVA)
on the 500 millibar isobaric surface (approximately 18,000 feet above mean
sea level). Weak PVA has been shown to assist in mountain wave soaring.
Soaring Window - The time between the time the trigger temperature is reached
and the time of overdevelopment.
Thermal Index - The difference between the environmental temperature and the
temperature at a particular level determined by following the dry adiabat
through the forecast maximum temperature up to that level. Negative values
are indicative of thermal lift.
Thermal Soaring Index - An adjective rating (for sailplanes) based on the
computed maximum rate of lift, and the wind speed and middle and high
cloud cover expected during the soaring window (the time of the trigger
temperature and the time of overdevelopment) according to the following:
Maximum rate of lift Adjective Rating
>= 800 fpm Excellent
>= 400 and < 800 fpm Good
>= 200 and < 400 fpm Fair
< 200 fpm Poor
Time of Overdevelopment - The time one or more of the following phenomena,
which essentially shut off thermal lift, is expected to occur:
1. formation of broken to overcast convective cloud cover
2. formation of scattered to numerous downbursts
3. initiation of widespread precipitation
Time of Trigger Temperature - The time the surface temperature is expected to
reach the trigger temperature.
Trigger Temperature - The surface temperature required to make the first 4000
feet of the atmosphere dry adiabatic.
Wave Soaring Index - An empirical, adjective rating (for sailplanes) which
attempts to combine a variety of phenomena important in mountain wave
soaring into a single index number. Objective points are assigned to
these phenomena: wind speed and direction at 14,000 ft MSL, the static
stability in the 12,000-18,000 ft MSL layer, the wind speed gradient above
the stable layer, jet stream location and frontal and upper trough
movements.
051515
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