MillvilleWx

NAM has more a look comparable to 12z. 18z was more amped. This was not as intense, but very similar to 12z. Will still get the job done, but a bit SE of 18z imo

This!! And they can sneak up out of no where too as long as you have a lot of little shortwaves rippling in the flow. Squalls and ice are my two biggest things to look out for during major cold outbreaks.

I personally am not a fan of SREF's outside an envelope of potential max and min and that's about it. A lot of times, it guides the 5th and 95th percentiles, so you have a clue as to what is the most extreme result. Hi-res is so prone to minute shifts in guidance that SREF's can exacerbate and/or waver from run to run, so they really are only prudent inside 48 hrs, at least imo. HREF is the newest ensemble blend of hi-res guidance and it does a better job overall and can pick out trends, but it realllllllly struggles with ULL's and intense baroclinicity. It did pick out the potential for the banding in Binghamton with the mega bomb up there, so it's not all for naught. I think there will be more investment in hi-res ensembles down the pike, but we have a major step in Fv3 integration the next 3-4 years, so it's probably more of a side project. Someone who works directly with NWP will have more info on that.

The frame work for the cold spell is there, but just has to evolve. We were several days out from any cold a week ago, but now it's inside 5 days for the polar plunge to begin taking shape. There's a lot of consistency on guidance with the result of cold but 5 days ago was not. There was a lot of scenarios for positioning of the PV and the lobes of vorticity rotating down out of Canada. Now we have less variation for the evolution within a 5 day envelope. The teleconnection pattern screams major cold as well with increasing heights over the pole to open the door for cross-polar flow into NA. Once the cold comes in, there's nothing really going to stop it from spilling. It's all about timing the flood gates at this point.

I know everyone here is very interested in mainly the snow chances for the extended, but I cannot understate how insane this cold signature is for the entire CONUS on guidance right now. This would rival some of the top cold outbreaks of all time. Even the ensembles are hinting at some historic level cold over the country. There will be lots of squall potential in this setup too with that Valentines Day period that @Eskimo Joe brought up above my post as the most aggressive time frame for it. Globals will not see that squall potential until it's within short range either. Bundle up

These are some of my favorite types of events when they materialize. They are quick hitting, but they come in like a banshee and can just dump for 6-10 hrs and scoot on out. I was looking at PWAT Anomalies for the time frame and they jump to 140-180%, or ~1 StDev above normal for the entire area. Classic for a solid high level advisory to WSW type event. Nothing over the top, but above the premise for a lower end event. Keep the 5H progression tilting negative and it'll be a very white Sunday for everyone.

I just peeked over my shoulder to see if John is watching me or something. Eerie timing man on this post right before what I just posted

It's pretty subtle on the 5H plot, but you can see it a little better on the 2PVU panels where there is a bit of a "fanning" signature on the lead side of the shortwave trough as it pivots through the Tennessee valley. The amplifying 250mb trough with jet core strengthening to the north is also a classic sign of diffluence developing under the right entrance region of the jet. Hope this helps!

It is now in my phone under: National Restaurants to Visit. I have it organized by state and everything. Thank you!

Do you ship to TX? Asking for a me

Have you ever just wanted to eat a baguette in driving snow?

Well well well, looks like we have ourselves a nice little event on the horizon. As we've seen the model corrections back to the NW have been due to backing from the extreme cold scenarios that place the baroclinic zone further to the south, as well as the amplification of the southern wave that descends from the Rockies down into the south-central plains to the Tennessee Valley. A couple of things to point out so far with current model progs. The first thing I wanted to touch on is how the trough behavior has been important in getting the precip field further to the NW and why there is still a bit more room for further westward expansion. Below is a gif of the 5H vort panels off the 18z GFS which now has the precip field well to the NW of where we were this time yesterday. Notice the vort as it swings east of the Mississippi begins to take on a more neutral position with a slight negative tilt by the end of the gif as it enters VA. This is important as this places the best diffluent signature further to the north and east ahead of the amplifying wave. In turn, this promotes better mid-level lifting mechanisms to come further NW as the trough pivots east of a longitude of Nashville/Indianapolis. Here's a look at the GFS 700mb frontogenic forcing for Sat night into Sunday morning. Notice the expansion of the lift further NW with SE to NW progression of the mid-level frontogen placement. This will allow for an expansion of the precip field, imo, to be a bit more pronounced to the NW, and maintains a strong lifting signature for Central MD over to the western portion of the eastern shore. This is why the GFS now has the max precip field bisecting the I-95 corridor to about 50 miles on either side. It will be important to maintain the current wave amplification in order to capitalize not just the precip field expansion, but promotion of the best forcing to the NW. The NAM is fairly aggressive with the 7H frontogen as well. In fact, it's incredibly robust and should favor a period of 1-2"/hr rates within the northern periphery of the frontogen placement. Again, this is due to the negatively tilted trough axis as it pivots to the east. Check it out below: Here's the trough axis during the prime time period of the incoming precip field.... The area in the box ahead is a strong diffluent signature that provide the sufficient lift ahead of the pivoting trough, leading to not only precip expansion, but also better lift to generate mesoscale banding structures with persistence as they trek to the north and northeast. One thing I haven't shown is a strengthening 25H jet signature to the northeast that amplifies and places the region right within the right entrance region of the jet. This is why the precip blossoms so quickly on the QPF side of guidance. As long as we continue to keep the current 5H presentation, I think the stars will align for a progressive event, but will have thumping potential given the current lift progged. Lowest boundary layer is the primary concern at the moment, but a marginal setup overnight can absolutely score. I think a general 3-6" with max of 10" somewhere is well within reason considering the trends. A slight tick colder and we'd really be in business.

Looks like they hadn't updated the grids yet as it's drastically different now. Sometimes they are caught up in dissecting runs and then get to the grids late. Our GFE system for the public grids takes time to fenagle with to make it look like you want to forecast. I love you too, man

Tighten the bulb

I was about to say. Your last post aged like milk. Pathetic performance last 23 min and change .

She was a bit buzzkilled from the duration of the sleet (I told her it was inevitable) but she couldn't believe how long and quick it was accumulating. She couldn't believe how much fell when she finally measured it haha

I was watching radar for my sister north of Royersford today and while she was getting absolutely blasted with sleet, I noticed you guys were getting clocked with snow. That mix line was stationary for hours and she was just getting pounded with ice pellets. She had 5.1 of pure sleet. She's over 11" now for snow/sleet storm total. She's gonna need some Tylenol tomorrow shoveling that cement lol Great storm for you guys in here!

The 3N Royersford in MoCo PA is my sister. I've been reporting them to Mount Holly via Twitter

My sister lives in central MoCo PA in Royersford. She's been measuring when I ask her. She had 4.5" with the WAA, 5.1" of sleet that compacted everything to 6.1", then had another 4.1" of snow on top of that by 7 PM and still snowing. I told her to get the Alieve ready lol

Remember when I had you at my 3 way inflection point?

The LES machine is very likely to crank in a week. I can see one of those 60-80"+ events on the horizon and I might be being conservative given the projected delta-T. Both lakes are still very mild and Erie is wide open.

But is it snowing?

Here's what I mentioned in the MA Forum not too long ago I think a genera; 3-6" is likely with a max of 9" possible out by Hanover to @Cashtown_Coop area if things break right. A nice day out there.

Howdy y'all. Hopefully everyone enjoying the snow today. I've been following quietly to see how y'all have doing. Glad to see double digits for most in here. Looks like the area out by @Cashtown_Coop hood is getting slammed constantly. Might be able to reach that 18-20" mark at this rate. Rooting for you guys