What Goes Wrong???  
Under Construction.... So you've worked out this great forecast, then reality strikes...
Here is a incomplete list of...
  excuses for why that great lift did not materialize 
    like you planned, maybe even for the better:
Learn more:
Surface Heating              
Obscuring of Sunlight, haze in the atmosphere, cirrus or other high clouds, humidity, smoke, pollution, mountain shadows for morning or afternoon. High resolution 1km/pixel satellite images. Animations show progression/movement.
GEOS High Resolution Satellite images
Geostationary Satellite Server

Western US
Slow to heat day - often due to the sun's energy being used to burn off dew or moisture on the surface. Rain or wet ground. Snow cover reflects the sunlight. Fog/low cloudcover to burn off.  
Overdevelopment - too many cu build and block off the sun OvercastDevelopment Potential
OvercastDevelopment Cloudbase (BL CL)
CAPE blipmap CAPE Unisys CAPE
K index, Lifted Index
Terrain influences, terrain that faces into the sun, or stays in shadows, or terrain height as many thermal related dynamics are AGL related rather than MSL.  
Blue or Cu - the key question on how confident you can fly

COMPOSITE: Cumulus Cloudbase for Cu Potential > 0
COMPOSITE: OvercastDevelopment Cloudbase for OD Potential > 0
Cumulus Potential
Cumulus Cloudbase (Sfc. LCL)
soundings: Thermal Index
Interactive SkewT soundings

Surface Wind too light to kick off thermals, or wind too strong tearing apart thermals. Buoyancy/Shear Ratio (B/S)
BL Convergence BL Convergence
Wind Shear in the Boundary Layer Wind Shear in the Boundary Layer
Wave suppression, wave above will enhance and suppress thermals in different zones. In 2006 the Cordele regionals day 1 was supressed by wave action, and Cordele GA is in the coastal plains well away from mountains, and it was mid-May not winter.  
Stable sea breeze moves in under your courseline and kills the lift.  
Cloud cover at night traps in the day's heat, causing a stronger inversion to cap the lift.  
Building of high or low pressure.  
  soundings: Thermal Index
Interactive SkewT soundings
Forecast Model 
Fronts in different position/timing than the computer model expects at time of flight. Current Frontal Analysis Plot
Current Regional Surface Map
Virga or false rainfall/precipitation reflection on radar. The false readings on radar could cause computer models to assume the ground is wetter. look at webcams to see if it is really raining, check local sources Georgia Webcams
Missing/obsolete/incorrect data in the computer forecast model.

Check forecast from several models AVN/ETA/RUC etc
Thermal Height Variability

Forecast high temperature wrong. Sometimes the lift strength is very sensitive to 1 or 2° F changes, depending on the curve of the temperature profile. Forecasts are of limited accuracy for the exact high temperature for many reasons. Check forecast from several models AVN/ETA/RUC etc
Daylight savings time, suntime not matching what you have on your watch. Each fall and spring you may need to recalibrate your expected timing to the new time setting. Similar things can happen when flying at extreme ends of timezones such as Marfa Texas at the far western end of Central Time Zone.  

If Thermals do not trigger then often the higher wind speed airmass can just fly over the terrain. When thermals are active the upper and lower airmasses are "connected" allowing the higher speed upper level winds drag the surface level airmass along with it. soundings: Thermal Index
Interactive SkewT soundings


The right stacking of stable and instable layers does not exist. soundings: Thermal Index
Interactive SkewT soundings
Position of the jet steam National Jet Stream Chart
Jet Stream Position

Unisys NAM 300 mb Plot
Jet Stream Analyses & Forecasts at 300 mb
Moisture moves in and creates a layer that you cannot climb up through or more dangerously down through if it develops suddenly. soundings:
Interactive SkewT soundings
Other links:            
Weather Archives 
Can I obtain old BLIPMAP forcasts ? Two archive viewers are available: (1) NAM+RUC Archive Viewer can plot both NAM and RUC model archives, (2) RUC Archive Viewer with IGC overlay can plot only RUC model archives has the ability to overlay them with an IGC file trace. [from Dr Jack].
Daily Forecast Map (National) from NCEP (2001 - to present)
Daily Surface Map w/ Fronts & Isobars from NCEP (2002 - to present)
Satellite Images: California Regional Weather Server - San Francisco State University
Weather Archives - Data and Maps
Observed Weather data DAILY CLIMATE REPORT - issued daily: Detailed daily weather statistics (usually for yesterday), including temperature, precipitation, degree days, wind, humidity, sunrise/sunset, and record temperature data for the following day. Precipitation data includes both calendar year and water year totals, percent of normal values, and comparisons to normal. This product is available for up to 2 months.GA, Middle AL North AL Middle TN Eastern TN
METARS (observations) for past 48 hours Courtesy Texas A&M
past weather information NOAA
Near-Surface Forecast Verification Statistics for Operational NCEP models: 2004-present Explaination
U.S. Climate at a Glance
Other tools to build comparisons between 
forecasts and reality.
HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility. It allows you to download a World Wide Web site from the Internet to a local directory, building recursively all directories, getting HTML, images, and other files from the server to your computer.
BMapper is a program that overlays BLIP data (http://www.drjack.net/), onto any geographic projection raster map (BMP format) with known coordinates. The program comes with background maps similar to the above map. Additionally, BMapper allows screen capture of the background map from other programs you may own such as SeeYou and Delorme.
Forecast Verification - Issues, Methods and FAQ

This has just begun, help me complete the incomplete list...
contact: read carefully