bristolri_wx

Isn’t this the third or fourth event with a modeled Norlun of this season? (Monday)

It’s been 800 for many runs now, while 700 and 850 remain below freezing by several degrees.

I feel like this is exactly why this is a now cast kind of storm. You can’t say that the models are totally wrong with things like jackpots and sleet lines, but it’s a very anomalous setup where the models may be “guessing” a little more than usual, and we still see discrepancies 24 hours out…

This page seems to discuss how NWS offices/mets are to create operational snowfall forecasts, and how not to, based on model output: https://vlab.noaa.gov/web/forecast-guide/nwp-snow-accumulation-products

That's a lot of clouds and moisture on their way...

Our AI overlords are not good at weathermaps but very good at weenies.

Yes we need the free liberated maps rather than the governed ones!

What a way to end that 6" storm streak. Ka-boom!!

As some others have posted, we are lucky we are getting this much for a SWFE. Ordinarily they do not perform well in coastal plain, and they often end as rain, not sleet, for those closer to the south coastal areas. I’ve seen as much as 6-8” wash away to nothing or almost nothing at the end in some of the more potent ones. 8-12” with sleet at the end isn’t the end of the world. Canada actually being cold again has been the key this year. We have seen more favorable setups in previous seasons but no cold to tap into and we end up with mostly slop.

It can get a nickname when it actually goes operational. The RRFS A on Pivotal has already been deemed a “failure” by NOAA and will never be used for official forecasts. All the FV3 (of which RRFS is one) based models are going to be replaced, unless I’m misunderstanding what I have read. The next version based on different physics is still considered even more experimental. So maybe the nickname should be “cancelled”? LOL

Look at both and compare. If Kuchera is higher, then expect that there will be higher than 10-1 ratios, but probably not to the extreme that KR is depicting. Then look at QPF and compare the three. CT Rain described other things to look at that are the factor. There isn’t going to be one model generated map that will accurately show snowfall in most forms. It’s why in most cases maps are made by each site/station/service. The NBM may come close as NOAA does have some formulas built into that but it’s not perfect either, as you may have seen from earlier NMB map posts about this storm.

A little worried about the sleet on the mesos now for those of us south and east of 95. NAM 3K and RRFS A look very sleety, HRRR is a bit better. Globals think differently or aren't picking it up...

The 3K looked better at 0z at 54H than 18Z at 60 as well...

This is a good map. Sums it up. Even if there's sleet along the southern areas, it mostly falls after the bulk of the heavy stuff falls. I think the NAM turns down the volume in subsequent runs...

For those who don't mind weather governance.

Well these NAM 3K soundings are not the governing voice of the forecast, so you are free to form your own opinion.

What a sneaky bugger that warm nose at around 800mb! Still snow, but mutha-fooka... (edited for better images)

Call and Raise!

I would agree. I think sleet doesn’t make it past the immediate coastal zones, at least with the way the 700 - 850 layer is being shown now. Ordinarily, you would expect WAA to bring in a little more but this is an anomalous setup with this much arctic air in place to the north of us - that it’s going to be much more difficult for that warm layer to penetrate than usual. It only lasts for about 6 hours anyway before the coastal slides past us and the UL winds switch around. If the hi-res stuff sees something different - that changes the narrative lol.

LOL I reported that because one day I thought my ability to click on a map correctly/accurately was impaired! Took me a few minutes to figure it out.

"not the governing voice"

Why do you bring this up every single time NWS/NOAA is discussed? They are a group of mets like any other, putting out a forecast. Your criticism is valid, but the subtle undertones of your wording are noted.

Oddly the NBM says I'll be getting more than the map or the text forecast.

For those interested in the NBM, this page allows you to pick the parameter on a dashboard page, and it provides you the model blend for that particular hour's model output. It does change depending on how close or far our the forecast range is: https://blend.mdl.nws.noaa.gov/nbm-dashboard