GEFS display question

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Jack Settelmaier, modified 4 Years ago.

GEFS display question

Youngling Posts: 67 Join Date: 11/2/12 Recent Posts

Was looking at GEFS output available in the WSUP (was looking for a Snow-related field, but the best I could find was PQPF24), and noticed the squared-off west side of the forecast for the upcoming coastal low's QPF. See image below.

I was curious how you create these visuals? Given that square "back edge" over PA, I'm guessing you are using GEFS grid points, creating "blobs" of them over some radius, and then merging into a contiguous feature with some value-gradation within?

The straightness of how the feature hugs the northern PA border, and then cuts due south over the western 1/3 of PA seemed somewhat odd.

Thanks for any response.

David T Miller, modified 4 Years ago.

RE: GEFS display question

Youngling Posts: 10 Join Date: 11/7/13 Recent Posts

Jack,

These are the bias-corrected GEFS QPF relative frequency grids (PQPF). As this is a worldwide grid, our scripts slice out each region (CONUS, AK, and PACR) and then we warp the data to each region's projection. In CONUS's case, that's Lambert Conformal. We also save the data in GeoTIFF format instead of GRIB as it's just easier for a few reasons. Then Mapserver will color the pixels/grid boxes according to the legend you see in the display. Some of what's displayed may be an artifact of the warping and also not using the fractional part of the data in the GeoTIFF. However, looking at the display of the grid via QGIS and in GRIB format:

Note the pixels are colored every percent and the lightest color here goes from 0 to 11 percent. Still, there still seems to be a relatively straight edge to the west of the higher percent values.

Let us know if you have any other questions.

Dave M

On Tue, Dec 15, 2020 at 12:13 PM Jack Settelmaier <VLab.Notifications@noaa.gov> wro

Was looking at GEFS output available in the WSUP (was looking for a Snow-related field, but the best I could find was PQPF24), and noticed the squared-off west side of the forecast for the upcoming coastal low's QPF. See image below.

I was curious how you create these visuals? Given that square "back edge" over PA, I'm guessing you are using GEFS grid points, creating "blobs" of them over some radius, and then merging into a contiguous feature with some value-gradation within?

The straightness of how the feature hugs the northern PA border, and then cuts due south over the western 1/3 of PA seemed somewhat odd.

Thanks for any response.

--
Jack Settelmaier Whole Story Uncertainty & Probabilities Viewer Virtual Lab Forum http://vlab.noaa.gov/web/wsup/forums/-/message_boards/view_message/12955848 VLab.Notifications@noaa.gov

David T. Miller

Research Associate, Programmer/Analyst

National Weather Service, Meteorological Development Laboratory

Cooperative Institute for Research in the Atmosphere/Colorado State University

1325 East West Highway | Silver Spring, MD 20910 | Phone: 301-427-9454 | Fax: 301-713-9316

David T Miller, modified 4 Years ago.

RE: GEFS display question

Youngling Posts: 10 Join Date: 11/7/13 Recent Posts

Correction, the image from QGIS using the original GRIB file is shaded approximately every 11 percent.

On Tue, Dec 15, 2020 at 1:49 PM David T Miller - NOAA Affiliate <david.t.miller@noaa.gov> wrote:

Jack,

These are the bias-corrected GEFS QPF relative frequency grids (PQPF). As this is a worldwide grid, our scripts slice out each region (CONUS, AK, and PACR) and then we warp the data to each region's projection. In CONUS's case, that's Lambert Conformal. We also save the data in GeoTIFF format instead of GRIB as it's just easier for a few reasons. Then Mapserver will color the pixels/grid boxes according to the legend you see in the display. Some of what's displayed may be an artifact of the warping and also not using the fractional part of the data in the GeoTIFF. However, looking at the display of the grid via QGIS and in GRIB format:

Note the pixels are colored every percent and the lightest color here goes from 0 to 11 percent. Still, there still seems to be a relatively straight edge to the west of the higher percent values.

Let us know if you have any other questions.

Dave M

On Tue, Dec 15, 2020 at 12:13 PM Jack Settelmaier <VLab.Notifications@noaa.gov> wro

Was looking at GEFS output available in the WSUP (was looking for a Snow-related field, but the best I could find was PQPF24), and noticed the squared-off west side of the forecast for the upcoming coastal low's QPF. See image below.

I was curious how you create these visuals? Given that square "back edge" over PA, I'm guessing you are using GEFS grid points, creating "blobs" of them over some radius, and then merging into a contiguous feature with some value-gradation within?

The straightness of how the feature hugs the northern PA border, and then cuts due south over the western 1/3 of PA seemed somewhat odd.

Thanks for any response.

--
Jack Settelmaier Whole Story Uncertainty & Probabilities Viewer Virtual Lab Forum http://vlab.noaa.gov/web/wsup/forums/-/message_boards/view_message/12955848 VLab.Notifications@noaa.gov

--

David T. Miller

Research Associate, Programmer/Analyst

National Weather Service, Meteorological Development Laboratory

Cooperative Institute for Research in the Atmosphere/Colorado State University

1325 East West Highway | Silver Spring, MD 20910 | Phone: 301-427-9454 | Fax: 301-713-9316

David T. Miller

Research Associate, Programmer/Analyst

National Weather Service, Meteorological Development Laboratory

Cooperative Institute for Research in the Atmosphere/Colorado State University

1325 East West Highway | Silver Spring, MD 20910 | Phone: 301-427-9454 | Fax: 301-713-9316

David T Miller, modified 4 Years ago.

RE: GEFS display question

Youngling Posts: 10 Join Date: 11/7/13 Recent Posts

NOTE: In my investigation of the original GRIB data and displaying it separately via QGIS, I discovered the menu selection and display labels for the data was incorrect. These are the 6-hour accumulation relative frequency grids (PQPF06) instead of the 24-hour ones as Jack S's screen capture shows (PQPF24). We have corrected the labels in the WSUP viewer accordingly for all GEFS BC relative frequency precipitation grid displays.

Dave M

On Tue, Dec 15, 2020 at 2:01 PM David T Miller <VLab.Notifications@noaa.gov> wrote:

Correction, the image from QGIS using the original GRIB file is shaded approximately every 11 percent.

On Tue, Dec 15, 2020 at 1:49 PM David T Miller - NOAA Affiliate <david.t.miller@noaa.gov> wrote:

Jack,

These are the bias-corrected GEFS QPF relative frequency grids (PQPF). As this is a worldwide grid, our scripts slice out each region (CONUS, AK, and PACR) and then we warp the data to each region's projection. In CONUS's case, that's Lambert Conformal. We also save the data in GeoTIFF format instead of GRIB as it's just easier for a few reasons. Then Mapserver will color the pixels/grid boxes according to the legend you see in the display. Some of what's displayed may be an artifact of the warping and also not using the fractional part of the data in the GeoTIFF. However, looking at the display of the grid via QGIS and in GRIB format:

Note the pixels are colored every percent and the lightest color here goes from 0 to 11 percent. Still, there still seems to be a relatively straight edge to the west of the higher percent values.

Let us know if you have any other questions.

Dave M

On Tue, Dec 15, 2020 at 12:13 PM Jack Settelmaier <VLab.Notifications@noaa.gov> wro

Was looking at GEFS output available in the WSUP (was looking for a Snow-related field, but the best I could find was PQPF24), and noticed the squared-off west side of the forecast for the upcoming coastal low's QPF. See image below.

I was curious how you create these visuals? Given that square "back edge" over PA, I'm guessing you are using GEFS grid points, creating "blobs" of them over some radius, and then merging into a contiguous feature with some value-gradation within?

The straightness of how the feature hugs the northern PA border, and then cuts due south over the western 1/3 of PA seemed somewhat odd.

Thanks for any response.

--
Jack Settelmaier Whole Story Uncertainty & Probabilities Viewer Virtual Lab Forum http://vlab.noaa.gov/web/wsup/forums/-/message_boards/view_message/12955848 VLab.Notifications@noaa.gov

--

David T. Miller

Research Associate, Programmer/Analyst

National Weather Service, Meteorological Development Laboratory

Cooperative Institute for Research in the Atmosphere/Colorado State University

1325 East West Highway | Silver Spring, MD 20910 | Phone: 301-427-9454 | Fax: 301-713-9316

--

David T. Miller

Research Associate, Programmer/Analyst

National Weather Service, Meteorological Development Laboratory

Cooperative Institute for Research in the Atmosphere/Colorado State University

1325 East West Highway | Silver Spring, MD 20910 | Phone: 301-427-9454 | Fax: 301-713-9316

--
David T Miller Whole Story Uncertainty & Probabilities Viewer Virtual Lab Forum http://vlab.noaa.gov/web/wsup/forums/-/message_boards/view_message/12958043 VLab.Notifications@noaa.gov

David T. Miller

Research Associate, Programmer/Analyst

National Weather Service, Meteorological Development Laboratory

Cooperative Institute for Research in the Atmosphere/Colorado State University

1325 East West Highway | Silver Spring, MD 20910 | Phone: 301-427-9454 | Fax: 301-713-9316

Jack Settelmaier, modified 4 Years ago.

RE: GEFS display question

Youngling Posts: 67 Join Date: 11/2/12 Recent Posts

Thanks for the details David.

On Tue, Dec 15, 2020 at 2:28 PM David T Miller <VLab.Notifications@noaa.gov> wrote:

NOTE: In my investigation of the original GRIB data and displaying it separately via QGIS, I discovered the menu selection and display labels for the data was incorrect. These are the 6-hour accumulation relative frequency grids (PQPF06) instead of the 24-hour ones as Jack S's screen capture shows (PQPF24). We have corrected the labels in the WSUP viewer accordingly for all GEFS BC relative frequency precipitation grid displays.

Dave M

On Tue, Dec 15, 2020 at 2:01 PM David T Miller <VLab.Notifications@noaa.gov> wrote:

Correction, the image from QGIS using the original GRIB file is shaded approximately every 11 percent.

On Tue, Dec 15, 2020 at 1:49 PM David T Miller - NOAA Affiliate <david.t.miller@noaa.gov> wrote:

Jack,

These are the bias-corrected GEFS QPF relative frequency grids (PQPF). As this is a worldwide grid, our scripts slice out each region (CONUS, AK, and PACR) and then we warp the data to each region's projection. In CONUS's case, that's Lambert Conformal. We also save the data in GeoTIFF format instead of GRIB as it's just easier for a few reasons. Then Mapserver will color the pixels/grid boxes according to the legend you see in the display. Some of what's displayed may be an artifact of the warping and also not using the fractional part of the data in the GeoTIFF. However, looking at the display of the grid via QGIS and in GRIB format:

Note the pixels are colored every percent and the lightest color here goes from 0 to 11 percent. Still, there still seems to be a relatively straight edge to the west of the higher percent values.

Let us know if you have any other questions.

Dave M

On Tue, Dec 15, 2020 at 12:13 PM Jack Settelmaier <VLab.Notifications@noaa.gov> wro

Was looking at GEFS output available in the WSUP (was looking for a Snow-related field, but the best I could find was PQPF24), and noticed the squared-off west side of the forecast for the upcoming coastal low's QPF. See image below.

I was curious how you create these visuals? Given that square "back edge" over PA, I'm guessing you are using GEFS grid points, creating "blobs" of them over some radius, and then merging into a contiguous feature with some value-gradation within?

The straightness of how the feature hugs the northern PA border, and then cuts due south over the western 1/3 of PA seemed somewhat odd.

Thanks for any response.

--
Jack Settelmaier Whole Story Uncertainty & Probabilities Viewer Virtual Lab Forum http://vlab.noaa.gov/web/wsup/forums/-/message_boards/view_message/12955848 VLab.Notifications@noaa.gov

--

David T. Miller

Research Associate, Programmer/Analyst

National Weather Service, Meteorological Development Laboratory

Cooperative Institute for Research in the Atmosphere/Colorado State University

1325 East West Highway | Silver Spring, MD 20910 | Phone: 301-427-9454 | Fax: 301-713-9316

--

David T. Miller

Research Associate, Programmer/Analyst

National Weather Service, Meteorological Development Laboratory

Cooperative Institute for Research in the Atmosphere/Colorado State University

1325 East West Highway | Silver Spring, MD 20910 | Phone: 301-427-9454 | Fax: 301-713-9316

--
David T Miller Whole Story Uncertainty & Probabilities Viewer Virtual Lab Forum http://vlab.noaa.gov/web/wsup/forums/-/message_boards/view_message/12958043 VLab.Notifications@noaa.gov

--

David T. Miller

Research Associate, Programmer/Analyst

National Weather Service, Meteorological Development Laboratory

Cooperative Institute for Research in the Atmosphere/Colorado State University

1325 East West Highway | Silver Spring, MD 20910 | Phone: 301-427-9454 | Fax: 301-713-9316

--
David T Miller Whole Story Uncertainty & Probabilities Viewer Virtual Lab Forum http://vlab.noaa.gov/web/wsup/forums/-/message_boards/view_message/12959794 VLab.Notifications@noaa.gov

Jack Settelmaier

Digital Techniques Meteorologist

NOAA/NWS, Southern Region HQ

Fort Worth, TX

Work: 682 703 3685

Cell: 817 966 0386

Virtual Office (most core work hours): https://meet.google.com/ujm-ajkv-rhk

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