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PotFrost Tool issue and suggestion

JM
Joseph Moore, modified 8 Years ago.

PotFrost Tool issue and suggestion

Youngling Posts: 72 Join Date: 11/1/13 Recent Posts

Issue/Problem: When running the new PoTFrost tool recently rolled out, the tool does NOT update grids as expected if the tool was ran the previous shift. For other non-wx precip type tools, if I check the box, the tool is ran over the entire time range selected (since I always run FB in time-range-selected), which will update every time within the time range. However, running PoTFrost tonight, I noticed old grids from the previous shifts were NOT touched, leaving a mix of new and old grids. This is not what I expected. I expect the entire time range to be updated - in this case, if the previous forecast had frost but my new forecast does not meet the threshold, I would want the grid to either be deleted or replaced with all zeroes.

Suggestion: I don't see an way to manually run the new PoTFrost tool outside the FB process. I asked back in January if all the separate PoWT tools would be maintained for us PoWT veterans to manually run the tools when needed and never saw a response. If possible, I would like to suggest adding a separate smart tool to run the new "Kentucky" method frost tool.

 

JM
Joseph Moore, modified 8 Years ago.

RE: PotFrost Tool issue and suggestion

Youngling Posts: 72 Join Date: 11/1/13 Recent Posts
One more thing: I've had instances of frost and showers with the new tool. While there is a sky check in the "Kentucky" frost method, for cases where sky cover is 31-69, there is a possibility for frost to be included, especially since dew point depressions may be small (especially in the fall and spring seasons) when precip is possible. Is it scientifically sound to have patchy frost/chance of showers? I honestly don't have enough forecast/observation experience to have a strong opinion either way, but I thought I'd bring this up to the team to consider.
CG
Charles Greif, modified 8 Years ago.

RE: PotFrost Tool issue and suggestion

Youngling Posts: 27 Join Date: 9/10/15 Recent Posts

Joe, both your suggestions are reasonable and I think can be accommodated. I will check with Andy Just on making these adjustments.

Thanks for the thoughts on how to improve ForecastBuilder!

Chuck Greif

AJ
Andy Just, modified 8 Years ago.

RE: PotFrost Tool issue and suggestion (Answer)

Youngling Posts: 89 Join Date: 6/2/15 Recent Posts

Joe,

  Yeah I'll include for PotFrost to delete grids over the time range. Will need to do the same with the new BlowingSnow. Honestly, it does make me wonder if I should get rid of the option of deleting all the non-precipitating types grids and just include deletion automatically within each tool selection.

  The trick probably with the PotFrost and PoP would be the uncertainty. I.e. if it doesn't rain, then frost would occur. 

  I've also been trying to keep the PoWT tools updated and available.

  Update - actually I do have the delete in the tools for other non-precipitating types, including the new BlowingSnow update. I just didn't have it in the PotFrost.  So that will be fixed.

JM
Joseph Moore, modified 8 Years ago.

RE: PotFrost Tool issue and suggestion

Youngling Posts: 72 Join Date: 11/1/13 Recent Posts

Regarding deleting the old grids: Perfect! Yeah in my experience I would expect the tool to delete all previous grids for the selected time range when I choose to run the tool, so that change would make sense. Glad it sounds like it's an easy fix!

Regarding the POP/Frost: Yeah I can maybe see some cases where you have a slight chance of showers, but if showers don't happen there could be frost. I think the cases are far and few between, though. Locally we have "clear skies" as part of our frost advisory/freeze warning criteria, and the NPW directive at least suggests clear skies be a requirement. I know the Kentucky Frost flowchart (attached from our previous discussions for others to see) only gives a minor penalty for "scattered" clouds (which is coded as <= 69 sky cover), but in my mind anything more than say, 30%, seems like it would prevent strong enough radiational cooling to form frost. I realize sky cover is a tiny part of the dew check, and thus it isn't much of a factor if sky cover is <= 69%, but maybe that threshold should be lowered? This isn't a critical issue, of course, so maybe after the growing season ends the team can gather feedback to evaluate and possibly make changes to this code.

And finally regarding the separate PoWT tools: On behalf of those of us who have been with ya on the PoWT bandwagon for many years, we really appreciate having the tools available outside the FB procedure! Thank you!