Extreme Cold, Snow & Sleet: SECS 1/24 - 1/26

[weatherpruf]

16 minutes ago, RU848789 said:

Great point.  Here's the NAM GIF for the last 36 hours with essentially nada in LR.  

they don't have the ocean nearby, so perhaps that matters

[EastonSN+]

9 minutes ago, donsutherland1 said:

I was living in Washington, DC at the time and don't recall that storm. You might be referring to January 26, 1994, but I'm not completely sure.

There were a few storms over the 80s as well where we had an arctic airmass in place and quickly changed to sleet. Have not seen something like this since the early 90s.

[eduggs]

1 minute ago, wilton_wx said:

Yes, we should definitley note this and not be afriad to pump the brakes. At the same time however, the NAM completely shit the bed on precipitation type, not totals. It showed nothing for little rock, AFB reported just under 6" with NW parts of the city reproting 6"+.

As I mentioned earlier, the NAM doesn't forecast snow. It forecasts QPF and temperature across multiple vertical levels. Other organizations have developed algorithms to translate that data into accumulated snowfall. And in marginal cases where a warm nose is very close to freezing (like Little Rock this morning), it's possible those algorithms incorrectly count snow as sleet. When QPF is significant, this graphical error can add up quickly. In these cases, the fault lies with the algorithms, not the model itself. We would need this morning's sounding from Little Rock airport to try to diagnose any model errors. But based on the NAM forecast sounding from the past 4 runs at Little Rock, I suspect this was the case. Unfortunately the NAM is not showing a marginal sounding for NYC tomorrow afternoon. But NWNJ and the LHV could benefit from a similar clown map error.

[EastonSN+]

Updated Upton map.

[Winterweatherlover]

3 minutes ago, weatherpruf said:

they don't have the ocean nearby, so perhaps that matters

Not in this case since it has nothing to do with surface temps in either location, although as Eduggs just outlined their may be noticeable differences in how far off the NAM soundings are to snow in our area vs in Little Rock.

[Winterweatherlover]

Just now, EastonSN+ said:

Updated Upton map.

still very bullish 

[EastonSN+]

Just now, Winterweatherlover said:

still very bullish 

I have noticed that they tend to air on the side of caution and lean towards the worst case. Better to prepare people for the worst and bust high than the other way around.

[nycsnow]

[nycsnow]

Euro AI is more snow than 6z

[wthrmn654]

39 minutes ago, donsutherland1 said:

For reference, here's the map though 1/26 0z. Typically, if one reduces the amounts by a category at this lead time, it's estimate is pretty good. As snow will continue to fall in parts of the Hudson Valley after 0z, it's current listing of 12"-15" there is reasonable. I think there will be some 18" amounts there.

That has me in the 12-15 range along with north shore of Long Island. 

[eduggs]

I'll be watching obs from VA late tonight with interest. The NAM/RRFS bring sleet rapidly through S and C VA overnight while the colder models (RGEM/HRRR/RAP) keep it snow. That should give us a good heads up regarding how quickly we are likely to mix or change over on Sunday.

[SACRUS]

12 minutes ago, North and West said:

Checking in at halftime of my older son’s game; what is the storm actually doing at this moment versus what the models have shown? Thanks.

I’ll hang up and listen.


.

[nycsnow]

[NEG NAO]

19 minutes ago, donsutherland1 said:

I was living in Washington, DC at the time and don't recall that storm. You might be referring to January 26, 1994, but I'm not completely sure.

Snow storm, January 25-26, 1994 - Storm Summary

[Jt17]

Pretty much mostly snow just like Ukie.. makes ya wonder.


.

[jm1220]

1 minute ago, nycsnow said:

Euro AI is more snow than 6z

Well-it either scores a coup here or falls flat on its face. It’s supposed to build better results with experience-not sure how much it has with setups like these. It did pretty well with the Dec storms. 

[donsutherland1]

1 minute ago, NEG NAO said:

Snow storm, January 25-26, 1994 - Storm Summary

So, it wasn't that storm. I am not sure what storm was involved.

[nycsnow]

2 minutes ago, jm1220 said:

Well-it either scores a coup here or falls flat on its face. It’s supposed to build better results with experience-not sure how much it has with setups like these. It did pretty well with the Dec storms. 

It’s in the camp of the hi res (minus nam) and Ukie for sure 

[NEG NAO]

1 minute ago, donsutherland1 said:

So, it wasn't that storm. I am not sure what storm was involved.

I am not even sure what you guys were discussing since there are so many people posting all at once

[SACRUS]

 

1/24 12z ECM

 

[EastonSN+]

4 minutes ago, NEG NAO said:

Snow storm, January 25-26, 1994 - Storm Summary

It may have been 93. I was pushing karts at a supermarket called stew Leonards and was absolutely frozen in the morning. 

[Brasiluvsnow]

20 minutes ago, North and West said:

Checking in at halftime of my older son’s game; what is the storm actually doing at this moment versus what the models have shown? Thanks.

I’ll hang up and listen.


.

people have posted that THE NAM had Little Rock getting nada when in reality they already have 6 inches,,,,,,now back to the game

[wthrmn654]

11 minutes ago, EastonSN+ said:

Updated Upton map.

Should use the more accurate version of there forecast then pinpoint amounts.  This looks like a good snow forecast map. 

[Winterweatherlover]

8 minutes ago, EastonSN+ said:

I have noticed that they tend to air on the side of caution and lean towards the worst case. Better to prepare people for the worst and bust high than the other way around.

True I realize most peoples worst case scenario is the opposite of this forums worst case scenario.

[EastonSN+]

1 minute ago, wthrmn654 said:

Should use the more accurate version of there forecast then pinpoint amounts.  This looks like a good snow forecast map. 

Still means they are going for 12 in CPK, but yeah for surrounding areas.

[donsutherland1]

2 minutes ago, NEG NAO said:

I am not even sure what you guys were discussing since there are so many people posting all at once

Here was the initial inquiry: 

 

[Prue11]

Just now, EastonSN+ said:

I don't get why they put the highest amounts on their pinpoint 

To amp people up lol

[NYER72]

1 minute ago, jm1220 said:

Well-it either scores a coup here or falls flat on its face. It’s supposed to build better results with experience-not sure how much it has with setups like these. It did pretty well with the Dec storms. 

so question from a lurker.  What is the difference between how the AI models adapt over time versus established? is it more pattern recognition versus manual calibration??

[weathermedic]

Bernie Rayno with a nice explanation on things

https://x.com/AccuRayno/status/2015106637212659787?ref_src=twsrc^tfw|twcamp^tweetembed|twterm^2015106637212659787|twgr^c7b51d61c8a3e5047944a1f086a006052f31bce0|twcon^s1_c10&ref_url=https%3A%2F%2Fpublish.twitter.com%2F%3Furl%3Dhttps%3A%2F%2Ftwitter.com%2FAccuRayno%2Fstatus%2F2015106637212659787

[Brasiluvsnow]

21 minutes ago, North and West said:

Checking in at halftime of my older son’s game; what is the storm actually doing at this moment versus what the models have shown? Thanks.

I’ll hang up and listen.


.

I will try this again,,,,,,people posting that THE NAM had Little Rock getting nothing a=nd right now Little Rock has 6 inches,,,,now back to the kids game