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Wintry March 05-06th 2019 Wintry Weather

We may not rip fat dendrites in central NC tomorrow morning but I still wouldn't be surprised to see some of the small "dandruff" flake type stuff around in the morning rush to mid morning time period.
 
The RAP seems to be trending wetter as well, each run looks better. Some interesting last minute changes going on today for sure.
 
I would like to note I ran a singular test on the HRRR, GFS, ECMWF, GEFS, and EPS during a large rain event at the beginning of the year and the EPS followed by the GEFS did the best in regards to how much fell in my back yard. The HRRR was extremely skewed by inches within 8 hours of the event and the NAM was under done.

One test isn't enough data to say if the ECMWF/EPS/GEFS combo is always the most accurate, but it will be interesting to tally up what those models show in regards to total precipitation in this weak event versus the hi-res mesoscale guidance.

If I have time, I will summarize the 12z guidance precipitation totals from the whole suite of models for this area since it looks to get heavier precip and see how they perform this time around.
 
why is everyone assuming 10 to 1? Not happening. Asheville NC to Charlotte Metro may see some snow showers in this setup
 
Accumulations will be wet. Some grass may become snow covered while it’s snowing but melt during any breaks or as precip shunts east. Going to be very isolated for anyone to see 1” imo. But I know many would be happy with a light coating of snow under 0.5”. This will not affect the roads anywhere.
 
Mucho credit to the King and his ensemble if this ends up wetter as the 12Z models are suggesting. The King was already starting to see a wetter trend yesterday, which is way earlier than the GFS suite!
 
GaWx said:
Mucho credit to the King and his ensemble if this ends up wetter as the 12Z models are suggesting. The King was already starting to see a wetter trend yesterday, which is way earlier than the GFS suite!
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I think the 12km NAM also deserves credit, it picked up on a wetter solution as early as the 6z run on Sunday.
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snowlover91 said:
I think the 12km NAM also deserves credit, it picked up on a wetter solution as early as the 6z run on Sunday.
View attachment 17306
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Indeed, But oddly enough, the 12Z NAMs are significantly drier than the 6Z versions overall, which is about the only drier 12Z run vs the respective prior run. Let's see what the Euro says in an hour+.
 
This is based off the KCAE airport area. These are not snow totals, just precipitation as a whole using 24 hour accumulation maps.

I am using Tropical Tidbits, as I have no raw data access to the majority of these models. I wanted to use the same method, the only difference is I will be using Weatherbell to get amounts from the Euro to update this post in a little while. Ranges like 0.20 - 0.30 are large differences, but I'm trying to be fair here due to larger gridding of the globals, which in turn won't resolve the miniscule details as well.

I will be updating this post with the GEFS/ECMWF/EPS later on and reposting it.

In summary, so far without Euro data:
The HRRR, 3KM NAM, and CMC are the lightest.
The GFS followed by ICON & FV3 & RGEM are heaviest.

The mean of all the models, so far using the higher tiers of totals noted below comes out to:
0.143 inches of precipitation.

KCAE Precipitation Accumulation:
12z ICON: 0.15 - 0.20
12z GFS: 0.20 - 0.30
12z FV3: 0.15 - 0.20 (has heavier amounts, but shifted to the West versus the GFS's location)
12z CMC: 0.05 or so (heavier precipiotation towards the South)
12z RGEM: 0.15 - 0.20 (the higher end is a tiny blip in Richland county and it has heavier axis South of the GFS and FV3 in the Augusta area)
12z NAM 3KM: 0.01 - 0.05 (random areas of 0.10+ to the South)
12z NAM 12KM: 0.05-0.10 (heavier just to the South with a large area of 0.20 or so)
12z HRRR: 0.05, maybe a tad more. (heavier precipitation to the North and South)
 
Shawn said:
This is based off the KCAE airport area. These are not snow totals, just precipitation as a whole using 24 hour accumulation maps.

I am using Tropical Tidbits, as I have no raw data access to the majority of these models. I wanted to use the same method, the only difference is I will be using Weatherbell to get amounts from the Euro to update this post in a little while. Ranges like 0.20 - 0.30 are large differences, but I'm trying to be fair here due to larger gridding of the globals, which in turn won't resolve the miniscule details as well.

I will be updating this post with the GEFS/ECMWF/EPS later on and reposting it.

In summary, so far without Euro data:
The HRRR, 3KM NAM, and CMC are the lightest.
The GFS followed by ICON & FV3 & RGEM are heaviest.

The mean of all the models, so far using the higher tiers of totals noted below comes out to:
0.143 inches of precipitation.

KCAE Precipitation Accumulation:
12z ICON: 0.15 - 0.20
12z GFS: 0.20 - 0.30
12z FV3: 0.15 - 0.20 (has heavier amounts, but shifted to the West versus the GFS's location)
12z CMC: 0.05 or so (heavier precipiotation towards the South)
12z RGEM: 0.15 - 0.20 (the higher end is a tiny blip in Richland county and it has heavier axis South of the GFS and FV3 in the Augusta area)
12z NAM 3KM: 0.01 - 0.05 (random areas of 0.10+ to the South)
12z NAM 12KM: 0.05-0.10 (heavier just to the South with a large area of 0.20 or so)
12z HRRR: 0.05, maybe a tad more. (heavier precipitation to the North and South)
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Very nice, this will be interesting to see how the 12z runs turn out vs what's modeled. Would you add in the UK and RAP 12z runs as well so we can get a good comparison of all globals vs meso models?
 
If anyone has access to raw model data (the number stuff) from most modeling, I'd like to possibly develop us a tool that will calculate all the data from a certain station ID, compute them together, and come up with a mean of precip/snow in the future.

I think a tool like this could be invaluable to us and we could make much more accurate forecasts for our areas.. I'm thinking NWS use tools that do this already.

I haven't been able to make the tool yet, because I think only accuweather pro allows you to have raw data from the euro and other modeling as a whole. I had asked Ryan Maue to consider adding raw euro output to his modeling site, along with others, but he said most people didn't care for it so it's low priority.
 
snowlover91 said:
Very nice, this will be interesting to see how the 12z runs turn out vs what's modeled. Would you add in the UK, Euro, EPS, GEFS and RAP 12z runs as well so we can get a good comparison of all globals vs meso models?
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I will definitely add the UK as long as someone with the data from weathermodels can post the map/message it to me as I have no access to it. I will go ahead and add the RAP to the list and get the GEFS in a few ready to post for when the EPS comes out.
 
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