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Thread: Thermal Watch Jun 14-17 Fathers Day Wknd

  1. #1
    Join Date
    Jan 2011
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    Thermal Watch Jun 14-17 Fathers Day Wknd

    With sparse opportunity to fly, I'm always thankful when good WX setups align with a weekend I can fly. This coming Fri thru Mon looks very good with strong heating, within a week of the summer solstice, light winds and most important, good moisture (700mb moisture):
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ID:	5219 Fri 4p Click image for larger version. 

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ID:	5220 Sat 4p Click image for larger version. 

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ID:	5221 Sun 4p Click image for larger version. 

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ID:	5222 Mon 4p

    Danny & I plan to fly Saturday. So far, all 4 days look like 500 to 750km days. Will post more as we close in.
    Kemp
    ASH-25 (FNX)

  2. #2
    Join Date
    May 2011
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    Re: Thermal Watch Jun 14-17 Fathers Day Wknd

    I will fly Saturday if the forecast holds

  3. #3
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    Sacramento
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    Re: Thermal Watch Jun 14-17 Fathers Day Wknd

    Thanks for the heads up Kempton. I'm thinking about flying on Sunday.

  4. #4
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    Re: Thermal Watch Jun 14-17 Fathers Day Wknd

    As of Thu morning, the weekend still looks good. As I only fly Saturday, that's what I'm focused on 8^)
    Saturday is of interest to see which is more accurate, Skysight or the WSC RASP, as the 11a cu are very different:
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ID:	5225Sat Jun 15 11a Skysight cu Click image for larger version. 

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ID:	5226Sat Jun 15 11a WSC RASP cu

    Sunday is also looking a bit better as Skysight has more 11a cu:
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    Winds are light both days also.
    BTW, Saturday is forecast to be the coolest (95F) of the next 10 days from today, Thu. Yet the cu bases will be similar to the hotter days. Why? Because of a gentle upper level low:
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ID:	5228 500mb Jun 15 Click image for larger version. 

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ID:	5229 300mb Jun 15, note the widening pressure lines centered on N California.
    Kemp
    ASH-25 (FNX)

  5. #5
    Join Date
    Mar 2011
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    72

    Re: Thermal Watch Jun 14-17 Fathers Day Wknd

    "Saturday is of interest to see which is more accurate, Skysight or the WSC RASP, as the 11a cu are very different:"

    Ah, but just because there are values for "CuPot > 0" doesn't mean the cloud will actually be able to form. From Jack's explanation of each map, specifically, BL Cloud Cover:

    "Note: Since The the "BL Cloud Cover", "Cumulus Potential", and "BL Extensive CloudBase" are based upon fundamentally different model predictions -- respectively the predicted maximum moisture in the BL, the predicted surface moisture, and an explicit cloud-water prediction -- they can yield somewhat differing predictions, e.g. the "Cumulus Potential" can predict puffy cloud formation when the "BL Cloud Cover" is zero or vice versa." [my emphasis added]

    So, if you compare "Cu Cloudbase (CuPot > 0)" with "BL Cloud Cover", I believe the latter shows something quite close to what Skysight is showing. To me, the two maps have to be used together. But, YMMV.

  6. #6
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    Re: Thermal Watch Jun 14-17 Fathers Day Wknd

    But,.... I don't see BL Cloud Cover, nor BL Extensive CloudBase as a chart choice, or is that hidden?
    Kemp
    ASH-25 (FNX)

  7. #7
    Join Date
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    536

    Re: Thermal Watch Jun 14-17 Fathers Day Wknd

    From what I understood from Mathew, skysight cu cloudbase is the same as cu potential >0, and cu depth is the same as cu potential.
    That said, although all the tools, blipmap, rasp, skysight, using the same formula for cloud predictions, the results vary significantly, even between one rasp to another covering the same area as we have in our area. Each area seem to favor one model over the other. For byron and Hollister the NAM is the most accurate for clouds, while rasp and especially skysight are far more pessimistic. For Williams I found the Williams RASP to be the most accurate for clouds location and coverage, as well as timing, but a bit optimistic for bases which are typically a little lower than predicted. For the Great Basin, I found skysight to be the most accurate. If you want the most educated guess, look at all three (or more) and average them, this is what I normally do. Based on this I would say Saturday looks like 10K or so to the trinities (higher over the trinities) with around the horn opportunity.

    Ramy

  8. #8
    Join Date
    Mar 2011
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    Re: Thermal Watch Jun 14-17 Fathers Day Wknd

    Quote Originally Posted by Kempton View Post
    But,.... I don't see BL Cloud Cover, nor BL Extensive CloudBase as a chart choice, or is that hidden?
    The menu item is "Cloud Percent". I don't remember where the name came from. Maybe I should change it to what the map header says?

  9. #9
    Join Date
    Jan 2011
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    536

    Re: Thermal Watch Jun 14-17 Fathers Day Wknd

    OK, TG is planning on flying both Saturday and Sunday with thoughts about Shasta and around the horn to the Sierras.
    Kempton, do you have a task and start time in mind?

    Ramy

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