Richmond Metro/Hampton Roads Area Discussion

[overcautionisbad]

Ok, noone panic. Let's wait for 0z

[eaglesin2011]

https://www.weather.gov/akq/winter

 

[overcautionisbad]

[Sernest14]

I don’t understand everything showing minimal snow then that shows up on a blend model

[Ephesians2]

2 minutes ago, Sernest14 said:

I don’t understand everything showing minimal snow then that shows up on a blend model

the NBM is unfortunately broken. its ratios are wildly overstated - I know there have been discussions of 15-20:1 ratios, but the ratios the NBM uses at least on the weatherbell maps are like 40:1, 50:1, or even more in some situations

[eaglesin2011]

https://youtu.be/yj0nqFxF7H8

I’ll take it! Lol

& yes I’m being sarcastic 

[Sernest14]

16 minutes ago, Ephesians2 said:

the NBM is unfortunately broken. its ratios are wildly overstated - I know there have been discussions of 15-20:1 ratios, but the ratios the NBM uses at least on the weatherbell maps are like 40:1, 50:1, or even more in some situations

Just ChatGPT’d the map and it basically downgraded everything the nbm shows for this area.  Pretty interesting read.  Asked it what ratios are used and why it shows so high compared to many models tha show 0-1”

[migratingwx]

21 minutes ago, Sernest14 said:

I don’t understand everything showing minimal snow then that shows up on a blend model

17 minutes ago, Ephesians2 said:

the NBM is unfortunately broken. its ratios are wildly overstated - I know there have been discussions of 15-20:1 ratios, but the ratios the NBM uses at least on the weatherbell maps are like 40:1, 50:1, or even more in some situations

The problem is, it lags a cycle or so behind so it's using old data and still catching up. The 00z run should have lower totals around RIC based on trends.

[overcautionisbad]

Yeah something seems off with it

[Ephesians2]

3 minutes ago, migratingwx said:

The problem is, it lags a cycle or so behind so it's using old data and still catching up. The 00z run should have lower totals around RIC based on trends.

For RIC it has 7" of snow on 0.2" precip
But where it is REALLY broken is along the northwest fringe, as you can see there is basically no QPF but the NBM is still showing accumulating snow.

[eaglesin2011]

just say…

[ldub23]

Nam might  be an improvement

[Ephesians2]

5 minutes ago, ldub23 said:

Nam might  be an improvement

Yes, slightly so. Not what we need in Central VA but it is so, so close. 

[eaglesin2011]

let’s go!   Back to 3-6 we go .. lol

[DJnVa]

20 minutes ago, overcautionisbad said:

Yeah something seems off with it

 

DT seemed on board with it...

[wasnow215]

49 minutes ago, overcautionisbad said:

How can a "blend of models" get higher totals than the model that shows the most snow lol. Makes no sense. It's like saying 0+2+0+4+1 divided by 5 equals 5

[ldub23]

2 minutes ago, wasnow215 said:

How can a "blend of models" get higher totals than the model that shows the most snow lol. Makes no sense. It's like saying 0+2+0+4+1 divided by 5 equals 5

Confession. I am the  one who actually puts  out the  NBM with a secret  snow  formula

[ldub23]

NAM  is a huge  improvement. gets  5-6 into SEVA and the  snow  line  has  moved alot NW to the doorstep of RIC

[chris624wx]

[ldub23]

1 minute ago, chris624wx said:

I think it was a miss for SEVA at 18Z

[Kevin Reilly]

3 minutes ago, ldub23 said:

I think it was a miss for SEVA at 18Z

Let the north trend begin with our number one model this year the NAM.  How far north will she go!??

Did the weather channel name this winter storm yet?  

[overcautionisbad]

[Berlin1926]

51 minutes ago, Sernest14 said:

Just ChatGPT’d the map and it basically downgraded everything the nbm shows for this area.  Pretty interesting read.  Asked it what ratios are used and why it shows so high compared to many models tha show 0-1”

I did that too and got scolded on the MA forum.  I asked for an interpretation of the latest NBM.  Interesting response.  Tempered nit cliff diving.h

[Sernest14]

6 minutes ago, Kevin Reilly said:

Let the north trend begin with our number one model this year the NAM.  How far north will she go!??

Did the weather channel name this winter storm yet?  

Needs to happen quick- running out of time

[overcautionisbad]

[overcautionisbad]

4 minutes ago, Berlin1926 said:

I did that too and got scolded on the MA forum.  I asked for an interpretation of the latest NBM.  Interesting response.  Tempered nit cliff diving.h

Yet they lap up AI models like fresh mac n cheese

[Berlin1926]

Chesterfield Co (South of Richmond) – Why 3–4” Could Still Be a High-Impact Event (Model Context)

After digging through the latest guidance I think expectations for those of us south of Richmond (Chesterfield County) need to be framed around impacts, not just raw snowfall totals.

Current model consensus:

NBM (latest cycle): Places Chesterfield solidly in the yellow band, generally ~3–6 inches, with a very tight gradient immediately north toward the blue shading.

GEFS / EPS ensembles: Continue to show a coastal-favored solution, with the mean low track east of Hatteras, but with enough spread that the NW cutoff remains sharp.

Operational GFS / Euro: Both still support a rapidly deepening coastal low, but differ on how far inland the deformation band pivots before pulling east.

WPC probabilities: Suggest moderate-impact potential extending inland to near or just south of Richmond, even where warning-level snowfall probabilities are lower.

What stands out across all guidance is that this is not a benign snowfall setup, even for locations that end up on the lower end of totals.

Even if Chesterfield ends up closer to 3–4 inches, the environment matters:

Strong pressure falls associated with rapid cyclogenesis

Sustained winds 20–25 mph with gusts near 30–35 mph inland

Very cold antecedent air mass

Snow falling during peak wind fields

That combination produces blowing snow, reduced visibility, drifting, and rapid road deterioration — very different from a calm, overnight 3–4” event.

Synoptically, this fits the broader pattern we’ve been tracking:

Strong Arctic high to the north

Deep coastal low developing off the Carolinas

Tight thermal and precipitation gradient

Classic sharp NW cutoff zone

Small track changes still matter, but impact does not scale linearly with accumulation in this setup.

Bottom line for Chesterfield:

I’m not expecting a historic storm here, but I am expecting a high-impact winter weather event, particularly Saturday night into early Sunday, even if totals remain modest.

Interested to hear how others along the I-95 / Route 360 corridor are interpreting the latest NBM, EPS, and GEFS trends — especially given how tight the gradients are.

[Berlin1926]

[Berlin1926]

1 hour ago, eaglesin2011 said:

https://www.weather.gov/akq/winter

 

This seems very plausible.

[ldub23]

ICON  just  jumped NW 8-9 ON southside and snow  on the  doorstep of RIC