Page 1 of 2 12 LastLast
Results 1 to 10 of 17

Thread: Flyable Wave on Monday

  1. #1
    Join Date
    Jan 2011
    Location
    Schleicher ASW-24
    Posts
    2,148

    Flyable Wave on Monday

    Nice "Standing Mountain Wave Lift" for you to fly your glider in, and climb as high as you dare to climb. But it'll be cold, as is usually expected in the wave lift. Your flight path to the north may be limited by clouds, and the path to the south will be an abrupt drop off of lift, but you will be able to travel on a north south line.

    Even if you don't come out to fly, have your cameras ready to capture some nice looking wave clouds.
    The Low pressure system (as mentioned in an earlier post, a few days ago) will in fact arrive on schedule - maybe even 12 hours earlier than previously fcst'd.

    The images below are all from the GFSx model for 4 PM on Monday, 2/18/13.
    This posting was made on Thurs - 2/14 at 8:30 AM.

    Very dry air preceding the change in pressure.
    High RH (Relative Humidity) as the pressure drops and the winds begin.
    The direction of the wind is good for wave for the entire length of the Mendos and the coastal ranges.

    The strength of the winds at lower altitudes are not extreme, and increasing nicely up through 18,000 ft

    FYI: the approximate height of each chart shown below:


    • 850 mb = 5,000 ft
    • 700 mb = 10,000
    • 500 mb = 18,000
    • RH-SW = Relative Humidity - Showalter (850-500mb)

    See NOTE at bottom of page for link to updates.


    The 850 mb
    Colors are temps - light blue is freezing (32f, 0c)
    geostrophic wind is parallel to the white lines
    see definition at - http://en.wikipedia.org/wiki/Geostrophic_wind

    Name:  mon-2-18-4pm-850.png
Views: 97
Size:  17.5 KB


    The 700 mb
    The same value system as 850 - showing temps and winds
    The more the pressure changes (lines closer together) then the stronger the wind.

    Name:  mon-2-18-4pm-700.png
Views: 91
Size:  21.3 KB


    The 500 mb
    The chart color depicts the AVort
    See terms defined at http://www.theweatherprediction.com/habyhints/194/
    see more info about vorticity defined at.. http://www.theweatherprediction.com/charts/500/basics/
    "Vorticity" is used loosely by most forecasters and they often place more emphasis on the vertical component of the "Vort" than anything else.
    AVort is not my focus here, but ths chart is showing the strength and direction of the winds.


    Name:  mon-2-18-4pm-500.png
Views: 95
Size:  26.7 KB


    The RH-SW
    pink is dry, blue is wet
    see good info at http://www.theweatherprediction.com/habyhints/113/

    the white lines are the showalter index - heavy white every ten units.
    see info http://www.theweatherprediction.com/habyhints/113/
    8 and above - it's relatively stable air on a convective day.

    Name:  mon-2-18-4pm-rh-sw.png
Views: 89
Size:  15.3 KB

    Go to the VSA wx page to see the links to all wx resources that I routinely use.

    NOTE: Starting on Saturday night, you will be able to use the NAM model (runs twice a day and after each run it goes into the next 48 hours).
    Use this link on Saturday to see what the models are predicting for the layout of the pressure pattern (and therefore the winds) at 10,000 ft, 48 hours into the future:
    ---- http://weather.unisys.com/nam/nam.ph...700&inv=0&t=48
    ----
    Last edited by Peter Kelly; 02-14-2013 at 11:50 AM. Reason: provide more info
    Peter Kelly

  2. #2
    Join Date
    Jan 2011
    Location
    Schleicher ASW-24
    Posts
    2,148

    Re: Flyable Wave on Monday

    This is Thursday night, and if you are interested in learning how to predict wave/ and/or watch how it develops, this is a good test case to study.

    Look at the 3.5 day and the 4 day charts

    http://weather.unisys.com/gfs/gfs.ph...region=us&t=3e

    etc,

    but tomorrow you'll need to look at the 3 day and the 3.5 day, etc.

    The low is fcst'd to move in fast.
    Calm in the morning, and then blowing strong over the hills by sunset.
    No moisture in the AM, but high RH by sunset, etc.

    very interesting stuff

    If the fcst continues to predict a dry calm start to the day on Monday, and lots of wave by sunset, then I'll probably fly.

    We flew wave on presidents day some ten years ago as I recall, but on that occasion, we drove to the airport in the rain and then we had a good flight after we got to WSC.

    An EDIT...
    P.S. I just saw a posting - Kempton is fcsting wave for the Soaring NV readers. follow those alerts by being on the distribution list (subscribing) for this email address...
    info@soaringnv.com
    pk
    Peter Kelly

  3. #3
    Join Date
    Jan 2011
    Location
    Schleicher ASW-24
    Posts
    2,148

    Re: Flyable Wave on Monday

    Update Saturday at 6:30 pm

    Title is still good - "Flyable Wave on Monday"

    we'll need to wait another hour or two before the RASP confirms it all, but the GFS models look good.

    The 48 hour model is for 5 AM and the 60 hour is for 5 PM on Monday.

    I'll put the RH-Showalter for 5 AM first.

    then the upper air charts all for 5 PM ...
    850 - 5,000 ft
    700 - 10,000 ft
    500 - 18,000 ft

    You can see that both the direction and strength are both good for wave.

    Not much moisture in the AM, but it'll be clouding up during the day or in the evening.
    ....
    Sorry about the delay - I started this post at 6:15 / finishing up an hour later.
    ....
    I'll give you those charts I mentioned above, then I'll look at the RASP.

    Name:  rh-show-48 hr mon am.png
Views: 166
Size:  31.8 KB

    these next three are for 5 PM monday (as of tonights fcst)

    The 850 mb chart

    Name:  850-60 hr fcst.png
Views: 172
Size:  30.0 KB

    The 700 mb

    Name:  700-60 hrr fcst.png
Views: 167
Size:  50.2 KB


    The 500 mb

    Name:  500-60hr-fcst.png
Views: 170
Size:  46.1 KB
    Last edited by Peter Kelly; 02-16-2013 at 11:03 PM.
    Peter Kelly

  4. #4
    Join Date
    Jan 2011
    Location
    Schleicher ASW-24
    Posts
    2,148

    Re: Flyable Wave on Monday

    I have signed up for a tow on Monday.
    I see Luke - SD and Rick- flying the 27 both on the schedule.

    I'm surprised there's not a crowd of pilots on the schedule for tomorrow - Monday, considering it is a holiday (Presidents Day) and the forecast is so favorable.
    Peter Kelly

  5. #5
    Join Date
    Jan 2011
    Location
    Lafayette
    Posts
    119

    Re: Flyable Wave on Monday

    Thanks PK for the update, though I'm waiting to see the model predictions in the morning. My current reading is a so-so day on Monday,
    so perhaps you can tell me why my reading of the model calculations is more pessimistic than yours - I have a couple of questions......

    How are you interpreting the 100% cloud cover predicted by the NAM - as good for wave since thermal activity will be marginal?
    Also, the RASP wave prediction is on the low side - do you think the RASP calculations will show improvmant in the updates tonight and tomorrow?

  6. #6
    Join Date
    Jan 2011
    Location
    Schleicher ASW-24
    Posts
    2,148

    Re: Flyable Wave on Monday

    Quote Originally Posted by M.Guerin View Post
    Thanks PK for the update, though I'm waiting to see the model predictions in the morning. My current reading is a so-so day on Monday,
    so perhaps you can tell me why my reading of the model calculations is more pessimistic than yours - I have a couple of questions......

    How are you interpreting the 100% cloud cover predicted by the NAM - as good for wave since thermal activity will be marginal?
    Also, the RASP wave prediction is on the low side - do you think the RASP calculations will show improvmant in the updates tonight and tomorrow?
    Hi Marianne,

    I can't tell what your readings are (other than more pessimistic than me) and which models you are using, but it is worth a discussion in the hangar sometime. But after tomorrow it is all history anyway. I just see the parameters for good wave in all of the charts I have displayed here on this thread... but they were all GFS charts, not NAM charts... but we'll see how it all plays out.

    It would be helpful if you paste the chart up here when you say the NAM is predicting 100% cloud cover - to show me where you got that info. I am guessing that you are referring to the BLIP that is using the NAM for tomorrow at 21z.
    It might have been that way on an earlier graphic, but the current BLIP- using the NAM for tomorrow at 21z shows clouds over WSC at 21% and increasing to 100% as you get more than 30 miles north or south of WSC
    I'll show you that one now...
    Click image for larger version. 

Name:	totcloudpct.curr.21z.png 
Views:	213 
Size:	34.4 KB 
ID:	828

    Totally overcast would be fine with me for tomorrow. I only care about the clouds below 18,000 and where they are located.

    I don't think we can discuss this cloud parameter here on the forum ... too much to explain... and I suspect you meant other things than what I am interpreting from this statement of yours ...

    "...good for wave since thermal activity will be marginal? "

    We want thermal activity to be marginal - that is, we want stable air, in order to have the best wave.

    My main focus is wind direction and strength, and I do look for stable air.
    Peter Kelly

  7. #7
    Join Date
    Jan 2011
    Location
    Schleicher ASW-24
    Posts
    2,148

    Re: Flyable Wave on Monday

    What we really need are a few inversion is the sounding to speed up the air at lower levels, but we don't have too much in the way of inversions.
    Looks like very mild wave below 12,000
    Peter Kelly

  8. #8
    Join Date
    Jan 2011
    Location
    Schleicher ASW-24
    Posts
    2,148

    Re: Flyable Wave on Monday

    The Day - Monday 9 AM
    Well no inversions.
    Pressure differential could be greater north to south , but it's good enough.
    Direction is still good, just that the strength of the wind is weak dure to the lack of pressure gradient.
    Clouds don't look to be a factor - yet.
    Stability could be higher - looks like a showwalter of about 6 to 8.
    Air is remaining dry most of the day
    Good wave at 3PM to 5 PM
    nice line of lift from diamond M down into Capay Valley
    getting into the higher stuff - above 10,000 will be the challenge.
    I'll tow off about 1 PM or so.
    Click image for larger version. 

Name:	press700.curr.1600lst.d2.png 
Views:	206 
Size:	28.4 KB 
ID:	829


    Click image for larger version. 

Name:	boxwmax.curr.1600lst.d2.png 
Views:	210 
Size:	21.0 KB 
ID:	830
    Peter Kelly

  9. #9
    Join Date
    Jan 2011
    Posts
    645

    Re: Flyable Wave on Monday

    Please let us know how it turned out. I was following the discussion closely as I considered flying as well and was also expecting classic pre frontal wave but RASP indicates lift strength of around 50cm/sec (100 ft/min) which, when after subtracting glider sink rate, gives you zero sink at best. I usually look for at least 100 cm/sec for usable wave.


    Ramy

  10. #10
    Join Date
    Jan 2011
    Location
    Lafayette
    Posts
    119

    Re: Flyable Wave on Monday

    Quote Originally Posted by Peter Kelly View Post
    Hi Marianne,... but we'll see how it all plays out. .....
    Totally overcast would be fine with me for tomorrow. I only care about the clouds below 18,000 and where they are located.

    .......
    We want thermal activity to be marginal - that is, we want stable air, in order to have the best wave.

    My main focus is wind direction and strength, and I do look for stable air.
    From your discussion, I understand now that you were really only interested in wave in this posting, not in soaring in thermals.

    From a previous thread, either Ramy or Pete "98" mentioned the importance of looking at cloud cover as a reality check on optimistic BlipMap predictions.
    The Cloud base for today (Monday) looked decent, but the cloud cover was 100% nearly everywhere, so it looked to me like a marginal day from the soaring
    in thermals perspective. That doesn't seem complicated - though I'm certain there are subtleties I'm missing.

    Like Ramy mentioned, the wave looked on the weak side (for this pilot, anyway) as did the convergence in the RASP - but evidently several other folks, including yourself,
    saw something positive I missed in the predictions.

    I'm on the "No meeting model" (vs. the calendar model) - if I don't have a work meeting, WSC is open, and the conditions look good, I'm flying. I did my taxes today.
    I'll be interested in how the day worked out to see what I missed in my interpretations of the BlipMap and the RASP.

Similar Threads

  1. Monday Morning Wave
    By Pete (98) in forum News & Discussion
    Replies: 0
    Last Post: 03-08-2021, 09:19 PM
  2. West Wave Monday!!!
    By Ben Mayes in forum News & Discussion
    Replies: 1
    Last Post: 02-25-2021, 10:28 AM
  3. Mountain Wave flying on Monday 10/28
    By Peter Kelly in forum News & Discussion
    Replies: 20
    Last Post: 10-31-2019, 01:43 PM
  4. Monday is looking flyable... a different monday
    By Peter Kelly in forum News & Discussion
    Replies: 4
    Last Post: 07-18-2017, 09:18 AM
  5. Monday is looking flyable, mendo cu markets, EOM...
    By Darryl Ramm in forum News & Discussion
    Replies: 2
    Last Post: 07-10-2017, 03:23 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •