BLIPMAP USER EXPERIENCE
Flight reports from soaring pilots about their BLIPMAP experiences

These postings are intended to help BLIPMAP users benefit from the experiences of other soaring pilots who are utilizing BLIPMAPs.  The newest reports are at the top.   [DrJack has added words in italics+brackets]


EXPERIENCE SUMMARIES

Hemet, CA - March 13, 2004
[Taking a long tow, if you know where to go]
    BL top and Hcrit in the Hemet area said, at least to me, that soaring in the immediate vicinity of Hemet would be poor.  A few miles east in the Idylwild area however, and running a considerable distance north and south, the prediction was for excellent conditons.  Treating the Blipmap as gospel, I took a long tow east, found strong lift in the areas predicted, flew for 3 1/2 hours between 14,000 and 8,000 feet a total distance of 125 nautical miles.   It is my understanding no one else got away from Hemet.  I fielded several calls from pilots on the ground, asking how I did it, and heard a half dozen calls for relights.  As another Jack said so well, this is as good as it gets.  Thanks  Robert L. Hunter

Williams, CA - Mar 6
[Use of BLIPMAP for finding and flying terrain-generated convergences]
    DrJack Forum posting by Milt Hare: USER GUIDE: BL Upward Motion Max

Phoenix, AZ - Feb 10
[Winter cross-country forecast]
    I just thought you'd like to know that Dr. Jack's Blipmap forecast showed showed unexpectedly good soaring conditions in Arizona on Sunday after the passage of a low.  Although the predictions were viewed with skepticism by quite a few, since the air was completely dead around noon, trigger temperature was reached about 12:30 and thermals began to develop.  A half-dozen of the ASA members launched at 1:00 p.m.and found 4-knot thermals to 3,000 ft AGL. We flew a 75 to 100-mile cross country, finding occasional 5 and 6 knot thermals, the odd one topping at 8,000 ft MSL.    Cross-country in February - not bad!  Most useful, though, the Blipmap forecast was spot on!   Mike Stringfellow   ASW 20

Monticello, IL - Jan 2, 2003
[Here is what I would most like to achieve.]
Dear Dr. Jack,   Your maps have made flying our central Illinois conditions easier, more predicable and FUN.   Regards, Rod Pool

Peoria, AZ - Dec 24, 2002
[Another comparison to another FSS soaring forecast.]
Dr Jack   Thanks to your excellent BLIPMAP forecast I was able to make a nice winter thermal XC flight on X-mas eve.  The FSS Soaring Forecast was predicting poor conditions, but with the passage of a Low Pressure system I had the feeling it was going to be a good day - which the BLIPMAP forecast predicted.  Flight:  from Turf Soaring, Peoria AZ to Wickenburg, AZ and return for 100KM in 1:45  ...   Thanks again for this wonderful forecasting tool!   Tony Smolder
[Note that Tony first used his knowledge that passage of an upper level trough or front often brings good soaring conditions.  Of course not all lows/fronts are created equal so some produce much better/poorer conditions than others - BLIPMAPs provide info on which ones will give the better soaring.]

Big Spring, TX - Aug 2, 2002
[An example of small-scale model noise:   I happened on this case after seeing a report of a "bogus" GSD wind direction forecast at Big Spring, TX during the HG US Open.  The boundary-layer-average wind direction forecast map for that day shows two "bulls eye" patterns near Big Spring (found by extending the East-West TX-NM border further east to the middle of the panhandle region), their size being that of a model grid cell, which are a characteristic of small-scale model noise and indicate untrustworthy results there.  But the surrounding area is noise-free and a human looking at the plotted results above can recognize the model noise and use the brain's pattern recognition ability to infer reasonable forecast winds for Big Spring. This illustrates one advantage of using a wider area forecast rather than just conditions forecast at a single point.]

Hollister, CALIFORNIA - Nov 9, 2002
The best example of a recently created forecasting summary for a specific site that I have found is at http://www.flybasa.org/blipmap.htm and I encourage others who have local forecasting knowledge/experience to create a similar summary for their site so those with less forecasting experience can benefit and get to the field when good soaring is predicted.  What I particularly like about this summary is that (1) it describes specific local BLIPMAP forecasts which have been found to be accurate and most useful but also mentions locally-determined weaknesses, and (2) it discusses the use of NOAA products which can be combined with BLIPMAP forecasts.  In fact, the NOAA products it mentions are those which I use myself:  the Forecast Discussion to get a human interpretation of model results and their anticipated reliability, the Terminal Aerodrome Forecast for its cloud height predictions, and satellite photos for early AM real world observations.  I was particularly impressed that Harry Fox, who flies with the Bay Area Soaring Associates, has described everything perfectly accurately, since I often have quibbles about pilot-written descriptions.  And I was pleasantly surprised to find that it was written for the site I presently fly out of since I had no foreknowledge of it!  [The summary mentions BLIPs and TIPs, which are presently only available for certain CA locations - however, additional BLIPs may be created nation-wide next summer.]

Frederick, MARYLAND - Oct 24, 2002
[A season-end report comparing BLIPMAPs to actual conditions.  Now that the summer soaring season is over, I encourage other pilots to send a report summarizing BLIPMAP performance, both successes and weaknesses, at their site.]
Dr Jack   On the 10 or so days that I have flown where there has been BM forecasting, I have been very impressed by the overall accuracy.  I'd estimate that the BMs are running in the vicinity of 85-90% accurate or better.  Especially impressive is the consistently good call on the height of thermals.  The BMs are considerably better than the IAD (Dulles AP) thermal index-based soaring forecast, which has a f/c accuracy down in the 50% range at best.  The TI soaring forecast is so unreliable that years ago I stopped regularly looking at it.   Bill Whelan

Minden, NEVADA - Sept 16, 2002
[I don't generally post individual cases, but everyone is intrigued by head-to-head comparisons and I later received additional reports for Truckee and a wider area around Minden indicating agreement with this comparison.  So here is a comparison to the Reno NWS's "Soaring Forecast", which is based solely on the AM Reno RAOB.]
Dr Jack   Yesterday your blipmap was calling Minden 12 to 13 K with 700 fpm of updraft.  Reno soaring forecast said [over] 18K with 1.5 K of up!!  Talk about disparity!!!  Unfortunately the blipmap was right and I struggled around the Carson Valley and over the Pinenuts never getting much over 11 K.  bumper [John Morgan]
[The site-specific BLIP forecast for Minden gave mid-day maxima for Hcrit, BLtop, and W* of 10800 ft, 12792 ft, and 622 fpm.  I should note that the Reno Soaring Forecast will _never_ predict a soaring height above 18kft - the NWS, in its wisdom, artificially truncates its "maximum altitude" forecasts at the FAA's 18kft airspace limit.  The un-truncated thermal height would have been much above 18kft.  My TIP forecast for Minden uses a methodology similar to the Reno soaring forecast for it's AM forecast and gave Hcrit & BLtop of 20833 & 23785 ft - but the TIP also includes a PM forecast based on model soundings, which indicated a PM change of -7260 ft as an alert that the AM sounding forecast was a big over-prediction.  The bottom line is that this exemplifies a PM model forecast being more correct than an observed AM RAOB due to atmospheric changes after the observation time.] 

Indianapolis, INDIANA - August 7, 2002
[An example of how the model can fill in gaps between the isolated RAOB locations, often allowing better forecasts than can be obtained from a non-local RAOB.]
Dr.Jack   I have been using your BLIPMAP product all season and have been constantly comparing to Kevin Ford's Soaring Forecast.  Sometimes when I have been unable to fly, I have checked the BLIPMAP and then discussed it with some others who did.  BLIPMAP has been consistently more accurate than [non-local] RAOB based forecasts.  Central Indiana Soaring Society is based at Indianapolis- Terry (TYQ).  The closest RAOB sites are Lincoln, IL and Wilmington, OH.  With the prevailing wind from the SW, neither is really great.  Wilmington data is often not available as well.  BLIPMAP has not only given us a better quality product, but a more reliable one as well.   Jeff Melin, 8C

Tucson, ARIZONA - June 17, 2002
[Here's an interesting thought on using BL Depth instead of BL Top for race tasking]
Dr. Jack,  Thanks again for the Blipmaps.  We use them for tasking the ASA [Arizona Soaring Association] racing series.  BTW we tend to use updraft velocity and BL Depth.  That eliminates the need to subtract ground elevation.  Depth tells us what our operating band will be, and that in turn tells us how fast and how far we can go.  (It also tells us if we can safely fly over remote areas.).  If one flies where the average terrain is of similar elevation over the entire task area, then the msl maps will work about as well (they essentially are depth maps).  But, we have an area up north and east were terrain averages 5,000 msl (some large areas of 6,000 agl).  To the west and south it averages less then 2,000 (some large areas of 1,000 agl).  So, the height maps are misleading unless one subtracts the terrain elevation.  Why would we do that manually when it's readily available in the depth maps?  I'm puzzled about why pilots would want to use height maps.   Alan Reeter
[DrJack uses the "BL Top" maps because they correlate with what he is used to seeing on the altimeter and he knows what MSL altitudes are useful at different locations - and he suspects other pilots operate similarly  Also, the MSL height is most useful when flying in higher elevations where, in extremis, one will escape to a valley having airports at much lower MSL elevations, even though the BL depth may be small there (as when flying in the mts at the edge of California's Central Valley).  BL depth maps can be especially useful when choosing which direction to fly if average surface elevations vary greatly in those different directions.  Users must decide for themselves which maps best suit their individual circumstances.]

Hollister, CALIFORNIA - May 18, 2002
[A long-term verification of thermal predictions over local mountains from a very active cross-country LS-4 pilot.]
After using BLIPMAP and BLIP for almost a year I am happy to confirm that it's accuracy is indeed truly amazing.  My observations are based mostly on the boundary layer top prediction for the Panoche-Avenal shear [convergence] line.  I believe the boundary layer top is the most reliable and most informative indicator of how good the day is going to be.  I know many pilots talk about thermal strength, but personally I don't think it says anything about how good the day is... I can get in the shear line consistently as high as the boundary layer top prediction (NOT the Hcrit!) give or take few hundred feet.  I am using both BLIPMAP to see the whole picture, and BLIP for the Panoche and Hernandez area (it is not very accurate for the Hollister area though, probably due to marine influence).  I actually make my decision to fly or not based on it.   Ramy Yanetz
[This is an example of empirical BLIPMAP "calibration", determing by experience that over these local mountains (for which the smoothed model terrain height is much lower than the heights of small-scale peaks not resolved by the model, and where a convergence line is often created by marine vs inland valley air mass contrasts) the actual maximum thermalling heights agree best with the BL top prediction (whereas over flat terrain the Hcrit predictor is more likely to be the correct choice)  For those unfamiliar with this region, the importance of these forecasts is that Panoche flights require a long aero-tow followed by a glide to reach thermals which are beyond the marine influence, which often limits thermal strengths near the airport itself.  Strong Panoche thermals will allow extended flights and a final climb to a height sufficient to glide back to the airport - but if the thermal tops are not high enough then one must land in a local field and get a retreive.  Ramy Yanetz is the person who first explored this new soaring area, which now allows longer flights out of Hollister than had previously been thought possible.]

Arlington, WASHINGTON - May 10, 2002
[The following is not a pilot report per se, but is included because it indicates that better soaring weather awareness can increase the number of non-weekend soaring flights, which is nice to hear.]
Over the last 6 weeks or so since our Western WA folks have been paying attention to the TIP and BLIP, we've been able to go soaring at least once and sometimes twice on weekdays.  On Wednesday, some folks in club ships were getting to 6,100 feet and some in private ships went into the mountains and got to 7,000 feet.  And, we're going again today.  This also is helping to improve our club finances!   Dennis Eckert

Owl Canyon, COLORADO - May 10, 2002
[It's nice to get a report about the B/S (Buoyancy/Shear) factor - determination of values which represent "workable" and "unworkable" thermals must be made empirically, through actual flight experience, and also depend upon pilot and plane capability.]
The area of Northern Colorado around Owl Canyon has a lot of boundary shear... the boundary layer wind speed is often more than 30 Kts. in the spring.  Most of the time the forecast B/S is between 5 and 10. Good pilots are able to climb in rough thermals as long as the B/S ratio is more than 5.  I have yet to fly on a day when the B/S ratio is more than 10 or less than 4 so I can't say if that would indicate that shear is a problem.   Bill Daniels

[The reports below were posted prior to Apr 18, when it was discovered that the height plotting routine was producing plots which underreported heights by 500-1000ft, so the height predictions given below have been increased by 500ft to provide a more correct comparison between actual model predictions and achieved heights.]

Arlington, WASHINGTON - Apr. 2002
[Nice to get a report including a convergence prediction-vs-observation comparison]
Soaring in Western Washington is pretty iffy due to the stable marine air so we mostly have a training operation at Arlington airport north of Seattle.  Forecasters were talking about the Puget Sound Convergence Zone becoming active and since the most common location of the PSCZ is just south of Arlington, I wasn't inclined to head for the airport because the convergence area brings low clouds and showers.  Dr. Jack's BLIPMAP, however, looked really favorable as it was forecasting the BL at 4500-5500K feet, thermals of 4-5 knots and, most interesting to me -- predicting the convergence area well south of the area.  Sure, enough the convergence zone moved south of the airport early in the morning and stayed over the City of Seattle.  Most of our club pilots are based in Seattle so they stayed home.  Cloudbase was 4,200 to 4,700 and average lift was about 4 knots with vario peaks around 6-7 knots.  We had a nice one-hour flight in an L-13 and private ships flew longer.  Also interesting was the BLIPMAP showing a fairly narrow north-south band of better lift.  The private-ship folks reported the north-south band was really working well so they pretty much stayed out of the mountains.  Great job, Jack!   Dennis Eckert
[Dennis has been studying soaring weather in the NW for many years, as might be apparent from the details in his report.]

Memphis, TENNESSEE - Apr. 2002
[Another report sent to the Memphis Soaring Society illustrates the importance of timing, particularly for cloud behavior - if the clouds had not cleared the forecast would have been a bust.  Predicting cloud behavior is difficult, so DrJack is feeling lucky in this case.]
The day started out looking very grim.  Heavy cloud cover and it looked like rain all morning at FCY.  Dr. Jim Hendrix beat Charlie to the gliderport with his glider.  He wasn't going to make the same mistake he made last Saturday.  He had read the BLIPmap with its prediction of 4500 ft thermals and 500fpm. thermal strengths.  Dr. Jim kept looking at the leaden sky and started packing up his glider.  He almost left but some blue sky appeared in the South West. Some more of the regulars started to show up and the sky started to clear.  Bryan took off with the Puch and Charlie followed him in the L-13.  They reported lift and the sky looked better and better with some cu's starting to form.  Jim finally got airborne about 1:45 P.M.  He didn't return until 6 P.M. Robert Williams took off in the 1-26,  I got into the LegalEagle, and Bob Moore left in the Super Blanik.  Dr. Frank DeBianca took off later in the Russia. Bill Lawrence had 8 tows.  Most flights were for more than an hour with the experienced pilots averaging 3 hour flights.   Monroe S. David
     Dr.Jack    Pilot Reports
Upward Velocity    500 fpm    400-500 fpm lift
BL Top    4500 ft    4500 ft high for the day - Jim H.
Critical Height    3500-4500 ft    That was where most of us thermalled
BL Wind    10 kt SW    About right

Memphis, TENNESSEE - Apr. 2002
[This report of a bad forecast, and the significance of the height variability prediction, is provided to balance out the highly successful reports from the same site given below.  From a report sent to the Memphis Soaring Society mailinglist]
Both Dr. Jack and the soaring forecast out of Little Rock had the day classified as a no-soaring day, but for the record:
    Dr.Jack   Pilot Reports
Upward Velocity   200 fpm   800 fpm
BL Top   1500 ft   4000 ft
Height Variability   3500 ft   nice fudge factor Dr. Jack!
BL Wind   5 kt SSW   OK
Monroe S. David
[Note that the predicted height variability was large, 2-3 times larger than for the same site on other days, indicating that the forecast is very sensitive to any error in the surface temperature prediction.  This day's forecast illustrates why this parameter is provided:  it helps assess the reliability of a day's predictions.  So this day's forecasts should have been viewed with more suspicion than usual, and indeed they proved to be well off the mark.]

Memphis, TENNESSEE - Apr. 2002
[Are there weather cynics everywhere?  From a report sent to the Memphis Soaring Society mailinglist]
Got up this morning, turned the clocks forward one hour, and sat down at the iMac to find out what Dr. Jack is forecasting for today's soaring at FCY.  It looked to me like the forecast was:   Updraft Velocity 400-600 fpm   Boundary Layer Top - 4500 to 5500 ft   Critical Height 3500 to 4500 ft   Height Variability +/- 1500 ft   Boundary Layer wind speed - 5-10 kt out of the South East.   Discussed this forecast at the SawMill Restaurant at 9:00 AM while wolfing down an Arkansas breakfast.  A lot of weather cynics around the table. ... It looked a little grim for Dr. Jack early in the afternoon, as there were several sled rides.  However about 2 P.M. the fleet launched and didn't come back.  We had 26 tows.  Pilots encountered lift velocity of 400-to 500 fpm.  The highest altitude was 4920 ft by Trent Whitehead in the Grob.  The average altitude was 3500 to 3800 ft  The wind speed at altitude was 5-10 mph.  however, the wind was out of the northeast to east, instead of the predicted southeast!!!   Close enough for horseshoes and hand grenades !!!  Dr. Jack is 4 out of 4 in my book.   Monroe S. David
[DrJack is occasionally a weather skeptic, but never a cynic.]

Memphis, TENNESSEE - Apr. 2002
[A successful forecast - from a report sent to the Memphis Soaring Society mailinglist]
Dr. Jack's BLIPMAP called for a boundary layer of 4500 ft, a critical height of 3500 ft, and an upward velocity of 400 fpm.  No Way! ...  Launched and punched off at 3000'.  My vario is going off like an alarm clock with thermals of 4 to 6 fpm.  I get up to 3800 ft and start bouncing around between 3200 ft and 3700 ft . Soon my hour is over, and I radio back to FCY to see if anyone wants the Grob.  Are you kidding!  They are lined up like sharks.  For the first time since Uvalde last summer, I have to pull spoilers to get back to FCY.  For the day, we had nine tows, with the highest being 4,000 ft by Dick Cadieux in the Grob.  It was a hell of a day, and Dr. Jack proved himself again.  OK Dr. Jack, give us a good forecast for this Saturday. We want to fly in Arkansas!!  Monroe S. David

Forrest City, ARKANSAS - Mar. 2002
[The first non-California report]
Dr. Jack,   I have used your SouthCentral Blipmap for the past two weeks in flying my 1-26 with the Memphis Soaring Society at Forrest City, Arkansas.  I find it to be very helpful and the predictions have been very accurate. when when the BL Top is under 2500 ft and updrafts of 200 fpm.  I want to test the full range - get the BL Top up to 8000 ft, the updraft velocity up to 600 fpm and the BL wind speed down to 10 kts over east Arkansas on a week-end and I will. Thanks and keep up the good work.  Monroe S. David, LegalEagle 275
[DrJack sez that Monroe needs to come out to Nevada!]

Hollister, CALIFORNIA - Mar. 2002
[A report verifying a prediction of small-scale height differences]
Thanks again to Dr. Jack.  His blipmap yesterday was right on the money again.  I was surprised to see that the max altitude forecast for Hernandez area was significantly higher than Panoche - usually it is only a couple of thousand feet higher, but today there was a difference of 4000 ft.  Yet while we struggled at 5K-6K all the way to Hernandez, there we found a shear line marked with high base cu's and got up to 10.5K.  Ramy Yanetz
[While it is gratifying that such small-scale forecasted differences can be correct, users should not expect that to always be the case.  BTW, Ramy flies an LS4 sailplane]

Williams, CALIFORNIA - Mar. 2002
Milt Hare has written about his extensive first year experiences using BLIPMAP in his posting to rec.aviation.soaring.

Los Angeles, CALIFORNIA - Feb. 2002
[A long-term verification from a hang-glider pilot]
Hello Dr. Jack   Crestline hang glider pilot Dan DeWeese here.  Have used the top of lift page for about 6 months now.  Great work.  With the GSD [sounding] page I have been able to nail almost every great soaring day this winter.  Thanks again for your contributions to the greatest sport on earth!!  Dan

Los Angeles, CALIFORNIA - Aug. 2001
[How a hang-glider pilot utilizes BLIPMAPs with other weather predictions]
Hi Dr. Jack,
As for how I use the blipmaps -- I primarily use them to pick the best place to launch my hangglider from. Secondarily, I use it for advice on which direction to fly, but primarily it helps me choose which site I think has the most potential for a given day. For a regular weekend day out soaring, I do not mind driving up to approx. 100 miles to get to the best site. The thermal height and velocity pages are my primary interest for this, but I am also watching the boundary layer convergence map, as Lake Elsinore is known for fantastic convergences. I will be comparing your maps against my actual experiences when I can, especially regarding the 'Elsinore Shear'.
I don't know if this info is useful to you, but here is a quick rundown of the other weather resources I use. I start by checking the NWS forecasts for the local mountains, usually LA, Ventura, and San Bernardino counties. Sometimes I also check Santa Barbara and San Diego counties as well. Then I read the NWS Area Forecast Discussion memos put out by both LA/Oxnard and the San Diego offices. Sometimes I also check the Owens Valley forecast, and the Las Vegas office area forecast discussion, if I am looking at heading up to the Owens. I will check the BLIPMAPS either just before, or just after I do this. Then I will also check the southern california winds and temperatures aloft forecast. I will also check the 700 MB AVN model forecast map on Unisys. Finally, I also will look at the 'forecast soundings' provided by the NOAA Forecast Systems Laboratory. Sometimes, I will have pretty much figured out where to fly just from the Blipmaps and the NWS Area Forecast Discussions (and forecasts). Other times, I use all the data I can get to make the best choice.
The Blipmaps are the one piece of weather data that is designed for soaring use, so it fits my needs the best of all my resources. But of course, I am still trying to compare real world results to the forecast data, so for that and other reasons, I feel compelled to gather as much info as I can.
Thanks, Mike Miller


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