RE: SPC Outlooks

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James Deberry, modified 7 Years ago.

SPC Outlooks

Youngling Posts: 4 Join Date: 5/25/17 Recent Posts

Howdy,

I'm new to Forecast Builder (FB), so this is a pretty basic question:

SPC Outlooks, e.g. "SWODY2", are valid from 12Z to 12Z on any given day. However, when I run FB to incorporate, say a marginal risk on two 12-hr WX blocks in GFE (12Z-00Z and 00Z-12Z), FB separates the 12-15Z period with no severe mentioned, leaving a

15Z-00Z block and a 00Z-12Z block with the severe mentioned. Why does FB separate out that 12Z-15Z period with no severe convection mentioned?

Thanks,

Jim DeBerry

WFO Midland/Odessa, Texas

Edward Townsend, modified 7 Years ago.

RE: SPC Outlooks

Youngling Posts: 11 Join Date: 8/18/13 Recent Posts

Hey Jim,

It sounds like this involves Probability of Severe (PotSevere), correct? If so, the PoT_Severe procedure that runs with ForecastBuilder will only put severe mention (T+) if the user-selected minimum SPC Convective Outlook risk category and the SREF PotSevere threshold are both met. As such, maybe the SREF PotSevere threshold at that time period is the issue and may need to be lowered to meet your needs.

To make sure you are running the latest version of ForecastBuilder, is this the GUI you see after selecting to populate PotSevere?

Regards,

Ed T

Ed Townsend

NOAA/NWS North Platte, Nebraska

On Wed, Apr 18, 2018 at 1:58 PM, VLab Notifications <VLab.Notifications@noaa.gov> wrote:

Howdy,

I'm new to Forecast Builder (FB), so this is a pretty basic question:

SPC Outlooks, e.g. "SWODY2", are valid from 12Z to 12Z on any given day. However, when I run FB to incorporate, say a marginal risk on two 12-hr WX blocks in GFE (12Z-00Z and 00Z-12Z), FB separates the 12-15Z period with no severe mentioned, leaving a

15Z-00Z block and a 00Z-12Z block with the severe mentioned. Why does FB separate out that 12Z-15Z period with no severe convection mentioned?

Thanks,

Jim DeBerry

WFO Midland/Odessa, Texas

--
Virtual Lab Message Boards https://vlab.noaa.gov/web/cr-soo/forecast-builder-forum/-/message_boards/view_message/3774895 VLab.Notifications@noaa.gov http://vlab.noaa.gov

James Deberry, modified 7 Years ago.

RE: SPC Outlooks

Youngling Posts: 4 Join Date: 5/25/17 Recent Posts

Ed T,

Thanks for the response. I set the "Threshold for SREF ProbSevere" to "0", so that those probabilities would not factor in (only SPC SWODY2 would). FB still separates out the 12-15Z time period. I have tried this on several occasions, and FB always separates out the 12-15Z time period and will not insert severe there. Never the 15-18Z, 21-24Z, etc.

Since I begin with two 12-hr WX grids (12-00Z and 00-12Z) with non-severe thunder, and SPC SWODY2 is valid from 12-12Z, then when I run FB, I should get two 12-hr WX grids (12-00Z and 00-12Z) with severe thunder. Instead, I get one 12-15Z WX grid with non-severe thunder, one 15-00Z WX grid with severe thunder, and one 00-12Z WX grid with severe thunder. Again, the SREF probability slider is set to "0", so it should play no part.

Thanks,

Jim

Nicholas Langlieb, modified 7 Years ago.

RE: SPC Outlooks

Youngling Posts: 5 Join Date: 1/20/15 Recent Posts

Hi Jim,

The Pot_Severe procedure (called by ForecastBuilder) is creating PoTSevere grids in 3 hour blocks. It looks like the SPC convective elements are not storing at 12Z-12Z in GFE, rather 7 AM LST - 7AM LST. When you create the PoTSevere it is probably using the previous days SPC convective elements for your 12Z to 15Z period.

I have started a trouble ticket for this issue on the NIC.

T+ will be assigned to the Wx grid wherever PoTSevere >= 30%. Until this issue is resolved, if you need to get T+ in the 12Z to 15Z period, you could manually assign an area of 30% to the PotSevere grid.

Thank you for pointing this issue out!

-Nick

James Deberry, modified 7 Years ago.

RE: SPC Outlooks

Youngling Posts: 4 Join Date: 5/25/17 Recent Posts

Nick,

Thanks so much for the response. That makes sense. I could have just dragged the 15-00Z block back to 12Z, but I wanted to know why it was doing that.

Thanks Again,

Jim