Harris Hill RASP update

As you can see from the attached screenshot, taken this morning (Friday, 13 July), the Saturday forecast is shown - note that though the header says it is a Friday forecast valid on 13 July 1400EDT the forecast period is 42 hours - that is, for the next day, Saturday.

Take RASP for another whirl, if you're looking for additional forecasting tools (http://www.harrishillsoaring.org/rasptable/RASPtable.html).  If you forget the link, go to the web site, click on the webcam section and you'll find a link to not only RASP but some other great weather tools as well.  

Feedback on the accuracy of RASP is appreciated.  We'll need to make a decision at some point whether to continue with it next year or not.

Things I've learned about RASP so far:

1.  It predicts soaring conditions reasonably well.  That is, what are the atmospheric parameters that are important to soaring like thermal strength and height, wind at the surface and boundary layer, etc.

2.  It does a poor job of predicting "interfering" factors like high cirrus.  Therefore, while the parameters are right when the sun is shining, the day won't turn out as RASP predicts if something like a cloud deck interferes.

3.  Times are approximate.  If it says 1400, that might mean 1500 or 1300.  If a model run on a home PC could beat the NWS forecasting computers something would be wrong with the world.  So, use RASP as a guide.

4.  It is better than Dr. Jack.  The higher resolution of the forecasts, even the "lower resolution" 4km forecasts is much more informative than Dr. Jack, subject to number 2, above.

5.  Using it to fly with GPS precision is probably not a good idea.  In the attached screenshot, broad decisions like "thermals look stronger to the East/Southeast" and how long the day will hang together are a good use for it rather than picking a line of flight that traverses the best lift areas.

 

-Tom