**** BLIPMAP FORECASTS
BLIPMAP = Map of Boundary Layer Information Predictions by Dr. John W. (Jack) Glendening, Meteorologist. Boundary Layer Information Prediction MAPs give thermal soaring parameters over a geographic region. They take so many critical factors into consideration that these are the most useful tool for forecasting.
Univiewer is one of the best interfaces to view ajoining regions, RAP & NAM as well as different forecast times.
Links To Example BLIPMAP Regions (follow main link for other regions and a full explaination):
SouthCentral region BLIPMAPS for GA-AR-AL-KY-LA-MO-MS-TN
region BLIPMAPS for FL-GA-NC-SC-VA
**** XC Skies
XC Skies Soaring Forecast Maps & Tools. Interactive soaring forecast maps and tools for virtually every flyable location on planet Earth. Our goal is to provide timely and highly useful soaring forecasts to allow pilots to make better decisions on when and where to fly.
**** Thermal Index (TI) reports
Kevin's Ford's Thermal Report Generator, is based on RAOB sounding and is very useful. A TI of 0 is the max height a thermal will reach, a TI of -3 is an estimate of how high a sailplane can fly. The 12Z sounding is useful for predicting soaring conditions (available as soon as 1245Z-1330Z [7:45EST/8:45EDT - 8:30EST/9:30EDT] and until 2359Z). The 0Z sounding is useful to review the conditions after a day. See Kevin's full instructions for further details. When forecast high is missing, you can input your own # based on another forecast source (TWC...). Choose an upper air station that is upwind of your soaring location, and a surface station that is close enough to have the same forecast high temperature. http://www.soarforecast.com
A few examples:
**** Interactive SkewT soundings
This resouce shows you how the read the vertical profile of the atmosphere, it is a very key point in knowing how the thermals will be generated based on the stacking of layers of air, you can determine where the inversion is and if a small temperature change is significant to changing the thermal heights or not, and if clouds will form etc.
1. Any location, (use 3 letter airport ID such as ffc, lgc or cha, or Lat/Long)
2. Future time, since you are more likely to be soaring at 18Z instead of 12Z,
3. Model source - choose AVN, RUC or ETA etc (base your choice on daily guidance from the local NOAA weather office as to which computer model they feel is most accurate in their Forecast Discussion. Find your Forecast Discussion in this List).
4. Zoom in on the altitudes below 400mb to see the convective area that we usually fly in. Choose the Skew-T Log-P only up to 400 mb
5. You can even Plot 1 time period OR an animated GIF loop, with your choice of number of forecast hours for the animation. This is a good way to see how the sounding will change throughout the day.
NOAA Soaring Forecasts for specific locations
Roab GIF imagesCalled a "RAOB" (Radiosonde Observation), these images show both a diagram of the upper air sounding as well as some lift/instability indexes at the top. Examples:
FFC Peachtree City GA . . . BMX Birmingham Shelby County . . . GSO Greensboro NC . . . BNA Nashville, TN . . .TLH Tallahassee FL ... REV Reno, NV
Source: Real-Time Weather Data: Upper-Air Page
also available: Stuve Thermodynamic Diagrams ... and ... Atmospheric Thermodynamic Diagrams
NOAA Weather Balloon Data
(Surface Temperature - Dewpoint) / 4.4° F . . . 400ft per ° C.
Click on the graph to see a larger version and explanation for Strength of Thermals and the relationship to cloud height and cover.
Unisys' K Index Stability Contour is a contour plot of K index with a contour interval of 4. The KI field shows instability in the atmosphere as it relates to the development of air mass thunderstorms. It is based on the 850 to 500 mb lapse rate plus 850 mb dewpoint minus the 700 mb dewpoint depression. Strong Springtime thunderstorms often require dry air at mid levels to cap the convection. On the other hand, summer air mass thunderstorms need a very moist atmosphere at mid levels to prevent evaporation through entrainment. Where KIs are greater than 35, air mass thunderstorms are likely. the higher the number, the higher the probability. Values less than 10 indicate areas of stable weather where skies are generally clear. (Purdue University) Basically double the KI value to calculate the chance of thunderstorms.
Some of the feedback I have gotten is that the K Index is a more reliable predictor of thunderstorms (which it was invented for) than lift, so your mileage may vary. So this is just one of the many indicators.
The Relative Humidity/Lifted Index (4 panel NAM Forecast) RAP chart depicts two fields:
1 Lifted Index (in white line contours). The LI field shows instability in the atmosphere. where LIs are <0 (also highlighted in a gray shading), thunderstorms are possible. the lower the number, the more unstable the atmosphere is and as a result, the stronger the thunderstorms (and Thermals) could become. Values of -4 or lower indicate areas where severe thunderstorms are possible. Values >10 indicate areas of stable weather where skies are generally clear.
2 Integrated Relative Humidity (in color contours) from 850 to 500 mb The RH field is a good predictor of cloud location and thickness. Areas of RH <60% generally are clear or have partly cloud skies. areas of 60-80% are generally overcast or mostly cloudy. areas greater than 80% are overcast with a high likelihood of precipitation as rh approaches 100%. This can show you if the thermal is likely to be capped by a cloud.
LI > 2 No significant activity 0 < LI < 2 Showers probable, isolated thunderstorms possible -2 < LI < 0 Thunderstorms probable -4 < LI < -2 Severe thunderstorms possible LI < -4 Severe thunderstorms probable, tornadoes possibleLifted Index - is calculated by lifting (frontal, orographic, upper air dynamics, etc.) a parcel of air dry adiabatically while conserving moisture until it reaches saturation. At that point the parcel is lifted moist adiabatically up to 500 mb. The Lifted Index is the ambient air temperature minus the lifted parcel temperature at 500 mb. If the parcel is warmer than the environment (negative L.I.), it has positive buoyancy, and will tend to continue to rise, favoring convection. L.I. values less than -5 C indicate very unstable conditions. A positive L.I. value indicates negative parcel buoyancy, and the parcel will tend to sink. This is representative of stable conditions where convection is unlikely. Increasingly negative numbers correspond to increasing instability and likelihood of severe weather. At times, very high (stable) lifted index values in cold air are indicative of frozen precipitation verses rain during warm advection events. The extreme stability results in cold air "damming", which restricts the advance of warm air at the surface. .. Forecast Product Development Team (FPDT) NOAA
Unisys TT. This is a contour plot of total totals index with a contour interval of 2. The TT field shows instability in the atmosphere based on the lapse rate from 850 to 500 mb plus dewpoint at 850 mb. Where TTs are greater than 45, thunderstorms are possible. The higher the number, the more unstable the atmosphere is and as a result, the stronger the thunderstorms could become. Values of 52 or higher indicate areas where severe thunderstorms are possible. Values < 40 indicate areas of stable weather where skies are generally clear.
for those lucky enough to be close to mountains:
Wave forecasts from Dr Jack:
Plan your own Record & Badge Tasks to be flown at SES.
Comments & Suggestions are welcome gmail Last modified June 4, 2014