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#11
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Outstanding Soaring: California Mojave, Owens Valley, Western NV- Fri-Sun 08/26-28
On Aug 28, 2:23*pm, Alex wrote:
On Aug 27, 6:19*pm, Mike the Strike wrote: On Aug 26, 4:58*pm, Alex wrote: On Aug 26, 3:04*pm, Ramy wrote: On Aug 26, 8:35*am, WaltWX wrote: Ramy, I agree with your assessment. My focus for the good weather is aimed at the Owens Valley, and Mojave Deserts (south of Bridgeport). *More moisture spreading over entire area on Saturday with cloud bases 15,000-16,000 north of Bishop instead of 17,000msl. Widely scattered TS in the usual hot spots but the cells should be fairly small and short lived. *Sunday, as Alex pointed out below, looks a little drier everywhere... still at least a very good to outstanding day. Walt, Wx On Aug 25, 11:51*pm, Ramy wrote: On Aug 25, 5:45*pm, WaltWX wrote: Take a look Dr Jack... Outstanding soaring weather Fri through Sun. *Lift rates 700-800fpm average... much stronger in those 10 per cent... It's a toss up between Fri and Sunday. *The Mojave Desert, Owens Valley and Western NV show full cu coverage bases 15,500 to 17,500. It appears to be dry enough that only isolated thunderstorms will form in the normal "hot spots". *Early trigger times also. I reviewed Dr Jack this afternoon with a long ago crew of mine, John Halcrow. *For Crystalaire, the pattern on Friday looks as good as I'v ever seen it. *BL (thermal) max heights 17,500msl (of course cloud bases will limit altitudes to a little lower). I'm coming back out Saturday to give my 750 km triangle another try from Inyokern (please... leave me room for an 11:30am takeoff Walt Rogers, WX I don't see the same outstanding conditions when reviewing the NAM blipmap, especially for going north towards Minden. Bases only 15-16K, lots of moisture with potential for overcast and OD and stronger wind to the north. Could still be good but probably not as good as it was the last few days. Ramy- Hide quoted text - - Show quoted text - One little known secret of Dr Jack Blipmap is the "Total Cloud Cover" parameter. This is one of the most reliable parameters I've seen to detect overcast. If there are white areas you are pretty much guarantee that there will be at least some level of overcast. It does not tell if it will be high cirrus or mid level overcast, and how thick it will be, nor if it will be persistent or short lived. But it hardly ever fails to detect that there will be some degree of overcast in the area. It indicated *successfully today pockets of overcast especially in the southern zones of region 11 and 12, and more so tomorrow over the central Sierra. None for Sunday. For those who prefer looking at the RASP, besides the Avenal one, there is one which covers the whole Sierra:http://www.norcalsoaring..org/BLIP/SIERRA/index.html It has 'BL Cloud Cover' but I did not use it enough to confirm if it provides the same as the NAM Total Cloud Cover. Ramy Also on the Dr. Jack RASP sites, if the operator has set up locations for plotting forecast soundings as *Skew-T diagrams, *you can see on the left side of these diagrams black lines corresponding to forecast cloud layers. *These *try to forecast both the heights and thicknesses *of cloud layers. * *These include *cloud layers that are above the "boundary layer" that most of the blipmap diagrams concern themselves with, *such as high cirrus layers. * *If there is also a similar layer marked in green over on the left side representing *"cloud water in g/k", that seems to correspond with the chance of precipitation. * An example of this could be seen today on some of the soundings from the Avenal RASP, such as this one: http://alcald.homelinux.org//RASP/AV...8.curr.1400lst.... Alex Caldwell Rapid Refresh plots have this and more and are a lot more accurate than RUC or NAM based Blipmaps. *It'll be nice when RR goes online and replaces RUC. Mike- Hide quoted text - - Show quoted text - The RASP blipmapshttp://www.drjack.info/RASP/index.html are quite different than the RUC and NAM based blipmaps. I'm not an expert on this stuff, so take this with a grain of salt, but I have been running the RASP on my own for a few years now for our club. There appear to be some misconceptions as to the differences between Dr. Jack's *RASP blipmaps and the orginal Dr. Jack RUC and NAM blipmaps, as well as the relationship of the RASP to the new Rapid Refresh. I apologize in advance to Dr. Jack, *if anything I'm saying below is bogus. The RASP blipmaps (as opposed to the original Dr. Jack RUC and NAM blipmaps), use use a "WRF" computer model (version 2) *which is *the same model the Rapid Refresh is using, except Rapid Refresh is using a newer version, WRF version 3.2+ . *Some people running the RASPs are switching over to the WRF version 3 also. The RASPs in the US are generally "initialized" using ETA (NAM) "grib files". In Europe the GFS model is generally used for initialization. * But from there on, *the atmospheric physics calculations are done based on the WRF model, not NAM or RUC. Dr. Jack has also used the RUC *instead of ETA or NAM to initialize the *WRF model in some experiments he has done. *Basically, what Dr. Jack did with the RASP is to take the WRF model, and have it output the various blipmap "parameters" he developed that are of particular interest to soaring pilots, *plotting them using suite of *plotting programs called "NCL". * The advantage of the RASP over the original RUC and NAM blipmaps is whatever improvement the WRF model offers, plus the much higher resolution - generally 4km for starters, and on up from there, as opposed to 20km with the original blipmaps. This allows much more detailed computer modeling, *with the finer overall grid resolution, and much more detail with respect *to the effects of local terrain, including terrain heights, terrain contours, terrain compostition and soil types, seasonal variations in albedo etc. *The big disadvantage of the RASP is that it requires tremendous computing resources to plot this level of detail over the whole U.S. or the globe, and until recently, this would bring *even the *government's *computers to their knees. *Hence, you see volunteers running RASPs for small local areas of interest on their own. *The new Rapid Refresh appears to be able to overcome that limitation by being able to run a 3km resolution WRF model for the whole US, also including things like radar data that were not available before. The parameters the Rapid Refresh group are publishing are interesting, and many are already useful to glider pilots, but they don't have the same type of soaring centric information available that Dr. Jack developed, such as his "Cu Cloudbase where Cu potential is 0" and the many others we've come to know and enjoy from his work. *An obvious possible future project might be to take the new Rapid Refresh system and get the type of output we've gotten from the blipmap soaring parameters. *I suspect the RapidRefresh team won't do this for us on their own, unless maybe they have a fanatic soaring pilot on their programming staff! Alex Caldwell Central California Soaring Club Avenal, CA, USA Alex: Thanks for your comprehensive explanation. I have only recently had the opportunity to compare the operational models with RASP model output for southern Arizona (Dave Leonard is running it for us on his server). I had been using RR1 skew-T plots for over a year now and have found them generally much more accurate than any of the previous models. More recently, I have been looking at all the RR output fields and find them very useful. The more rapid cycle has enabled me to keep up with changes when the other models lag behind. My observations have been that the RASP output is very comparable to RR (know I know why!) and nearly always better than any of the other models. NAM has been generally best here, but RUC sometimes is better, but neither is as good as the RASP output. It certainly is very nice to have the soaring parameters. The main problem I have with the RASP is the same as the original Dr. Jack's output - the abysmal maps. I am looking forward to RR going operational and getting someone to produce nice interactive maps from the output. I wish I had more software skills, but it's way beyond me! Mike |
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Outstanding Soaring: California Mojave, Owens Valley, Western NV- Fri-Sun 08/26-28
Alex,
You are right about RASP and the valuable visualization of soaring parameters Dr Jack has given it (and BLIPMAP). If we could get timely access to the high resolution model data and visualize it with the soaring parameter point of view, this would be an alternative to running RASP on smaller systems. You are right on all your comments regarding RASP and how it relates to the big NWS NCEP models... except for one point. The Rapid Refresh model (RR) has been running experimentally for two or three years and is scheduled to replacee the RUC in November 2011. However, it is only 13km resolution. Another model, the High Resolution Rapid Refresh (HRRR - phonetically sounds like "her") is basically the same as the RR but runs on a 3km grid hourly. It is initialized by the RR. To be continued... Walt Rogers, WX |
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Outstanding Soaring: California Mojave, Owens Valley, Western NV- Fri-Sun 08/26-28
On Aug 30, 10:58*am, WaltWX wrote:
Alex, You are right about RASP and the valuable visualization of soaring parameters Dr Jack has given it (and BLIPMAP). If we could get timely access to the high resolution model data and visualize it with the soaring parameter point of view, this would be an alternative to running RASP on smaller systems. You are right on all your comments regarding RASP and how it relates to the big NWS NCEP models... except for one point. *The Rapid Refresh model (RR) has been running experimentally for two or three years and is scheduled to replacee the RUC in November 2011. However, it is only 13km resolution. Another model, the High Resolution Rapid Refresh (HRRR - phonetically sounds like "her") is basically the same as the RR but runs on a 3km grid hourly. It is initialized by the RR. To be continued... Walt Rogers, WX Thanks Walt. Your presentation on this topic for the 2010 SSA Convention was/is really great. In case anyone has not seen it and wants to read more about it, Walt's presentation on "Soaring Forecasts in the NexGen Era" is he http://www.ssa.org/files/member/NWS_SSA_Show.pdf |
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Outstanding Soaring: California Mojave, Owens Valley, Western NV- Fri-Sun 08/26-28
On Aug 30, 1:07*pm, Alex wrote:
On Aug 30, 10:58*am, WaltWX wrote: Alex, You are right about RASP and the valuable visualization of soaring parameters Dr Jack has given it (and BLIPMAP). If we could get timely access to the high resolution model data and visualize it with the soaring parameter point of view, this would be an alternative to running RASP on smaller systems. You are right on all your comments regarding RASP and how it relates to the big NWS NCEP models... except for one point. *The Rapid Refresh model (RR) has been running experimentally for two or three years and is scheduled to replacee the RUC in November 2011. However, it is only 13km resolution. Another model, the High Resolution Rapid Refresh (HRRR - phonetically sounds like "her") is basically the same as the RR but runs on a 3km grid hourly. It is initialized by the RR. To be continued... Walt Rogers, WX Thanks Walt. Your presentation on this topic for the 2010 SSA Convention was/is really great. *In case anyone has not seen it and *wants to read more about it, Walt's presentation on "Soaring Forecasts in the NexGen Era" is he http://www.ssa.org/files/member/NWS_SSA_Show.pdf- Hide quoted text - - Show quoted text - And I stand corrected. Walt forecast was right on at least for Sat and Sun with OLC showing 800-900+ km flights out of Inyokern. The NAM Total Cloud Cover I mentioned earlier was correct also but wasn't as much of a factor as I expected. Glad I didn't listen to myself and went flying anyway :-) Ramy |
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Outstanding Soaring: California Mojave, Owens Valley, Western NV- Fri-Sun 08/26-28
The main problem I have with the RASP is the same as the original Dr. Jack's output - the abysmal maps. *I am looking forward to RR going operational and getting someone to produce nice interactive maps from the output. *I wish I had more software skills, but it's way beyond me! Mike- Hide quoted text - - Show quoted text - Regarding the Maps, several RASP operators are coming up with some quite nice user interfaces for the RASP using Google Maps. They have made this code available to others, so maybe this could also eventually be applied to the HRRR as well. Check out the UK RASP by Paul Scorer: http://rasp.inn.leedsmet.ac.uk/RASPt...SPtableGM.html and the Central Italy RASP by Andrea Barcellona: http://www.ilpulcino.org/meteo/blipmaps Alex Caldwell |
#16
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Outstanding Soaring: California Mojave, Owens Valley, WesternNV - Fri-Sun 08/26-28
On Wed, 31 Aug 2011 09:22:58 -0700, Alex wrote:
Check out the UK RASP by Paul Scorer: http://rasp.inn.leedsmet.ac.uk/RASPt...SPtableGM.html Personally, I prefer the older RASPtable, http://rasp.inn.leedsmet.ac.uk/RASPtable.html The map may be smaller than RASPtableGM and have no identified points apart from the places where soundings are available, but the coloured overlays are much brighter and easier to read. IMO this outweighs all else. My problem with RASPtableGM is simply that the colours are so delicately pastel that they disappear into the maze of towns and motorways on the map and so become needlessly difficult to read. The Central Italian RASP maintained by Andrea Barcellona is much better: I could easily live with that. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
#17
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Outstanding Soaring: California Mojave, Owens Valley, Western NV- Fri-Sun 08/26-28
On Aug 31, 9:22*am, Alex wrote:
The main problem I have with the RASP is the same as the original Dr. Jack's output - the abysmal maps. *I am looking forward to RR going operational and getting someone to produce nice interactive maps from the output. *I wish I had more software skills, but it's way beyond me! Mike- Hide quoted text - - Show quoted text - Regarding the Maps, several *RASP operators are coming up with some quite nice user interfaces for the RASP using Google Maps. *They have made this code available to others, so maybe this could also eventually be applied to the HRRR as well. Check out the UK RASP by Paul Scorer: http://rasp.inn.leedsmet.ac.uk/RASPt...SPtableGM.html and the Central Italy RASP by Andrea Barcellona: http://www.ilpulcino.org/meteo/blipmaps Alex Caldwell This is great, especially the Italian one. I would love to have such maps for the NAM blipmap as well. I still find the NAM to be the most accurate model, and it is available up to 3 days out. Ramy |
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Outstanding Soaring: California Mojave, Owens Valley, Western NV- Labor Day Weekend
On Aug 26, 8:01*am, Alex wrote:
On Aug 25, 5:45*pm, WaltWX wrote: Take a look Dr Jack... Outstanding soaring weather Fri through Sun. *Lift rates 700-800fpm average... much stronger in those 10 per cent... It's a toss up between Fri and Sunday. *The Mojave Desert, Owens Valley and Western NV show full cu coverage bases 15,500 to 17,500. It appears to be dry enough that only isolated thunderstorms will form in the normal "hot spots". *Early trigger times also. I reviewed Dr Jack this afternoon with a long ago crew of mine, John Halcrow. *For Crystalaire, the pattern on Friday looks as good as I've ever seen it. *BL (thermal) max heights 17,500msl (of course cloud bases will limit altitudes to a little lower). I'm coming back out Saturday to give my 750 km triangle another try from Inyokern (please... leave me room for an 11:30am takeoff Walt Rogers, WX Walt, I ran a 4KM resolution RASP last night for AVENAL that goes 2 days out. It is centered on AVENAL, but covers the high desert area around Edwards and the S. Sierra and Owens Valley up to N. of Mono Lake. If I'm interpreting it right (which is highly open to question), it's saying Friday and Saturday, there should be good cumulus in the desert area in Region 12, *but it should *be drying out in Region 12 by *Sunday. *On Sunday, the better cumulus will be more up North in Region 11. *On Friday, there may be some higher level overcast from subtropical moisture coming in from the SW with some chance of OD along the coast range near Castle Peak and New Cuyama and over the S. part of the Sierras. The higher level overcast shows up on the Skew-T sounding forecasts on the RASP, *but not on the regular blipmaps. *This should be gone on Saturday and Sunday. *Would be interested in what you think about it. Also any pilot reports after the weekend is over would be interesting to hear to correlate with the forecast. http://alcald.homelinux.org/RASP/AVE...RASPtable.html Alex Caldwell Central Calif. Soaring Club Avenal, CA, USA- Hide quoted text - - Show quoted text - Well the forecast for this labor day weekend looks epic for the Sierras, much better than last weekend. High base cu along the whole length of the sierra on Saturday and accross the Great Basin as well on Sunday. Monday should be similar. |
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