Safe XC Soaring from Byron

1. Safe XC Soaring from Byron Use of Blipmaps as an XC Planning Tool Ramy Yanetz February 2008

2. Byron XC Potential • 300-500km especially during the spring (March-June) and fall. • May require 20-30 miles 6000-7000ft tows when local lift not presents . • 25 miles tow @ 80knots = 30 minutes round trip ($82). • Often strong convergence marked with clouds over the Diablo Range between Mt Hamilton and Mt Oso, persists all day with typical altitude of 6000-8000, occasional 10,000 feet (highest 13,500!). • Easy glide back to Byron or Tracy.

3. 2007 achievements • At least 7 pilots flew long XC flights from Byron • 7 flights north to Williams, 4 in one day! • Pasco Egg captured twice from Williams and twice from Hollister by NCSA pilots and flown back to Byron!

5. 2007 Personal Statistics • 12 XC flights (averaging 250km per flight) • Longest flight 535km • Typical altitude 6000-9000 ft • 60% from local tows • 4 flights north across the delta

6. How to use blipmaps for XC planning • 3 blipmap models available – NAM (was ETA), RUC and RASP • Check NAM (ETA) forecast up to 3 days in advance. Typically optimistic in the longer range, more accurate the prior evening. • Look at the 1PM (21Z) forecasts. • Check the BLTop map (Height of Boundary Layer Top) – this is the most important and accurate parameter. It indicates how high you can get in the best thermals. • Check NAM Cumulus potential and Cumulus Cloudbase. Note cloudbase altitude is only valid if cumulus potential is positive. • On the prior evening check also RASP blipmap for higher resolution. • On the morning of the flight check also RUC. If it strongly disagree with the other models, good old RUC is probably right. If all 3 models predicting a great day – go fly!.

7. How to use blipmaps for XC planning (continue) • Determine best XC route for the day. • If NAM predicts little or no clouds, but shows BLTop of at least 6000ft over the Diablo range, then plan on a long tow to the Diablo range and release near Rel1-3 above 6000ft, and follow the convergence line to the SE • If NAM predicts good cu’s (cu potential > 0) and cloud base of at least 4000ft all the way across the delta then plan to fly north towards Williams • Detrermine best time to launch. Typically no later than noon, and as early as 10AM if the 10AM RASP indicates good lift.

8. NAM Blipmap • http://www.drjack.info/BLIP/ETA/CANV/ • Available up to 3 days in advance • Tendency to be overly optimistic • The shorter the term the more accurate • Best for checking BLTop, cu potential, cloudbase, wind up to 3 days in advance • Easy map to read, best color scale

13. RASP Blipmaps • http://www.norcalsoaring.org/BLIP/BYRON/index.html • Kudos to Dmitry for creating the Byron RASP blipmap! • Available the prior evening and now up to 2 days ahead • Much higher resolution: 3KM and 750m • Can flip between map and sectional for orientation • For top of lift us Hcrit, not BLTop (overly optimistic) • Check wind direction and strength, cloud potential, cloud base, convergence (BL Max Up/Down) and wave parameters • Easier to determine exact area of best lift, convergence and wave, but harder to determine exact altitude due to color scale • Use RASP to determine location and NAM to determine BLTop and cloudbase • Pay special attention to the area of best lift (usually along the Diablo range south of Byron) to plan the best XC route.

22. RUC Blipmap • http://www.drjack.info/BLIP/RUC/CANV/ • Available only in the morning • RUC BLTop Provides the most accurate and reliable top of lift. It is usually accurate within couple of hundred feet (especially the 6 hour forecast, which is usually available after 9:30AM). • Rest of the parameters, especially cloud base, are not as accurate as NAM

23. Preparation • Check Blipmap and other forecast tools such as the NOAA weather discussion • Determine XC potential and route • Download latest waypoints for Byron/Hollister area and Williams area http://soaring.gahsys.com/TP/Hollister/http://soaring.gahsys.com/TP/Williams/ • Study routes using google earth http://soaring.gahsys.com/TP/Hollister/hollstr7.kmz • Study landouts http://www.soaringnet.com/landout_data/hollister/ • Download IGC files from OLC and study with SeeYou

24. Suggested Routes • North across the delta on unstable post frontal days • South along the Diablo range on most spring days

25. Landout options (South) • Livermore (Tower, OK if can’t make it back to Byron) • Meadowlark • San Antonio Valley (in the Diablo Range) - Landing strip and good fields • Tracy • New Jerusalem • Westley (marginal, probably not aero retrievable) • Patterson • Crows Landing (Huge, but access unknown) • Gustine • Los Banos • Panoche

26. North across the Delta • When blipmap indicates good post frontal conditions with cu’s across the delta, a safe and relatively easy task will be a 300km O&R to Williams (with optional landing at Williams to capture the Pasco egg) • No high terrain and tiger country to deal with and plenty of landing strips • Unless clouds indicate otherwise, fly towards Rio Vista first • Typically less or no clouds for 10-20 miles across the delta until Rio Vista so start as high as possible, at least 4000 ft and with glide to Rio Vista.

27. North across the delta (continue) • From Rio Vista head towards the Nut Tree • Avoid Travis airspace, watch for heavy traffic, keep your transponder on and contact Travis as needed • From Rio Vista follow the mountains or foothills towards Williams. • Usually better and stronger lift over the mountains, but no need to go too deep and the valley works as well

28. Crossing the delta back to Byron • On the way back the first area to shut down is the delta, so don’t turn around too late • Typically no lift and often no clouds from Nut Tree area to Rio Vista area • Unless clouds indicate otherwise, or you are very high over the Nut Tree for a final glide to Byron (above 7000ft) do not attempt a straight glide across, as you will most likely encounter stable marine air and strong cross wind • Instead, head towards Rio Vista even if there are no more clouds, and hope for the best. Often the lift starts again near Rio Vista which takes you high enough for a final glide to Byron.

29. Airports Landouts (North) • Rio Vista • Nut Tree • Multiple strips between Vacaville and Williams

30. Suggestions • XC Mentoring in KP or buddy flying in single seaters • Get your silver and gold distance from Byron during spring • Capture the pasco egg from Williams or Hollister