Coastal Bend Soaker (FV3) - Home - EMC Model Evaluation Group

This past week, areas along the Texas Gulf Coast received up to 20" of rainfall.

Throughout the week, I've been gathering images from MDL's NBM Viewer to review performance of that forecast guidance, on shorter time scales, but to close out the week, I wanted to a) refer to those NBM VLab Forum posts, but b) also show some FV3 forecasts prior to the event.

Here are the 3 (feel free to rate them! :)) posts I made there (you may have to Join that community to review).

1) https://vlab.noaa.gov/group/national-blend-of-models/discussions-forums-/-/message_boards/message/4278068

2) https://vlab.noaa.gov/group/national-blend-of-models/discussions-forums-/-/message_boards/message/4298448

3) https://vlab.noaa.gov/group/national-blend-of-models/discussions-forums-/-/message_boards/message/4306587

So, in the above posts, I was looking at 72-hr QPF forecasts from various forecast systems (NDFD, NBM v3.0 and 3.1, WPC, and GMOS) with end times at 00Z and 12Z Wed Jun 20th.  So, forecasts ~72 hours in advance.

Below, I'm going to show images comparing the GFS and FV3, from select forecast hours (yes, I'm cherry-picking; but feel free to review the forecast hours of your choice using this link), BUT in these FV3 images, we can only look at 24-hr rainfall accumulations, despite the interface labeling them as Total Precipitation, which had me thinking they were Run Accumulation images.  But at least they are the same end time of 00Z, Wed Jun 20.

First, I thought I'd show the first  forecast hour (=216) to show that there would be heavy rainfall totals along the TX coast.  The GFS, here, outperformed the FV3, by showing a >5" area right about over Shiner, TX.  Granted, the peak rainfall areas in Texas with this event, ending at this forecast time were not in that location, the models were suggesting a heavy rain event.

Next, let's jump to forecast hour=096 , at which time the FV3 showed two distinct fingers of greater than 2" rainfall, whereas the GFS showed >1.5" area along a broad swath of coast.  It's arguable which is better here.

Next, forecast hour=084, at which time the GFS again showed a >5" area (these are 24-hr rainfall forecasts) around Shiner, TX, whereas the FV3 correctly showed the heaviest swath of rain would be in a band that stretch north/south across Beaumont, TX where some of the highest rainfall totals were observed (along with amounts around WFOs CRP and BRO).  Both good forecast guidance 84hours in advance of the event.

Lastly, at forecast hour=060, the superiority of the FV3 (for this cherry-picked snapshot in time) is evident as it nailed the swath of heavy rain that occurred near Beaumont, TX near the LA border.  The FV3 was capable of showing an area of 8-10" of rainfall right near where amounts near that amount fell, with even more than 10" observed if one adds in adjacent time periods.

And, just to show the observed amounts, here is a view of the 24-hr totals ending at 00Z, Wed Jun 20th, as pulled from the MRMS viewer: