MillvilleWx

I've been out of the loop the last few days. Been unbelievably busy. Just got a chance to look a bit further. It's certainly a minor event we're looking at here. A majority will see 1-3" but a few spots could reach the 4" mark if things break right. Hi-res guidance has a weak area of 850mb frontogen basically running up the 95 corridor which should be a positive for areas along and NW of the fall line. Temps will be slowly improving through the overnight into the AM, but the modest rates and lack of strong forcing will keep ratios at a solid 8-10:1 with perhaps some slightly higher in the best bands. NBM currently has a wide area of 2" for most with some 3" readings along Parrs Ridge and the higher terrain running along the M/D up to NW of Philly. 18z HRRR was crazy bullish on snow potential surprisingly, so curious to see if it's off its rocker. HRDPS (Yeah I know it sucks) has been somewhat consistent on a 40 mile wide band in CMD that bisects MoCo/HoCo/Balt Co. I'd watch that area and places 20-30 miles either side. Enjoy the snow y'all! Final call: Widespread 1-3" with lolli of 4" over portions of NMD and along Parrs Ridge possibly

Ninas give me an ulcer. Since I've only lived at 40N or south, they have been mostly pain for me. I am less enthused going into the season with them, but I still watch to see if something can surprise.

Right now the timing is still decent with the CAA pre-storm. The PBL improves on approach, which should keep the event either as straight snow, or a touch of rain before changing to snow. The ground temps will cool as snowfall chills the surface with elevated surfaces and grassy areas first to go. It's a standard event, and with it being overnight Sat into Sunday AM, impacts should be pretty low. More of a stats padder by the looks of it. I haven't dug too deep into the event since I've been working and have projects I've been working on for a spring conference, but from what I've seen, its a borderline event with WWA potential for portions of the sub. I don't foresee this changing to something more significant. Missing a prominent southern stream influence to get it to more SECS territory.

This is a drive-by post telling you, "La Ninas in the Mid Atlantic suck." There's several variables necessary for us to get solid storms in the sub-forum in a northern stream dominant setup. Small shifts in amplitude and longitudinal structure of the mean trough can mean whether we get a decent hit or it scurries to the north/south. That said, the GFS was a broader look, but it still managed to get snow into the area with a solid snowfall for Rt 50 on south. A sharper trough should help areas to the north. Time will tell if this trend continues, but the setup is far from dead. I would just temper expectations for places north of I-70 for this one. Further south you are, the better the chances are at the moment.

@WxUSAF The good ole Moco/HoCo deathband

Feb 2013 in Mass was #3 overall on my storms list if you included storms outside the area. It was very close to #2, but the factor of that storm confirming me being a meteorologist supersedes it. Still, it's the best true blizzard I remember outside Feb 9-10, 2010.

1. Feb 5-6th, 2010 (The lead up and the eventual storm was incredible. 32.5" of snow) 2. Feb 12-13th, 2006 (Snowfall rate of 4.5"/hr from 2-3am that morning. Was the storm that full confirmed my commitment to becoming a meteorologist. 20" in 8 hrs.) 3. Jan 2016 (33.5" at work in Germantown; 36" at my apartment in Maugansville near Hagerstown) 4. Feb 9-10th, 2010 (I will never see my neighborhood look that way after that storm and predecessor ever again. 52" base in the backyard. Drifts over 9' high. A Jeb walk to remember that afternoon the 10th) 5. Jan 2000 (I will never forget my dad waking me up because Paul Kocin came on the Weather Channel and mentioned the change to the WSW. Truly one of the most memorable weather experiences of my life) Honorable mentions: Jan 2011 and PDII (Was sick or injured for both so couldn't fully enjoy them); Dec 2009; Dec 2013 overperformer (Ravens/Vikings snow game I attended)

Been out all day. Haven’t looked at anything until the last 15 min since I got home. It was pretty toasty on 70 and down 27 from Mt Airy to Laytonsville area. I will say there was some cooler air out in NE MD where I drove down. Regardless, cold front will move through overnight for the northern half of the sub. Temps will crash pretty quick post front with below freezing by 9am over the northern tier leading some ice accretion. Elevated areas will of course be better for ice formation, but the surface will cool quickly and road conditions will deteriorate the back half of the event. NAM Nest and NSSL WRF are both pretty good agreement with ice potential. FRAM estimates over the northern tier are anywhere from 0.05 to 0.25 depending on model. Mappyland is probably the best spot for ice given the setup. A place like Shrewsbury will certainly be the target for ice. I’d avoid I-83 north of Monkton today if traveling. I still think a light ice is possible for those areas like Damascus/Monkton/Reisterstown with areas along I-70, east of Woodbine a very borderline call. WWA is probably great call right now for the situation. If things break perfect, Hereford zone in Balt Co could get a warning, but that might be a stretch. Either way, cold is coming, so get the jackets ready. I have one more full day here, so I’ll enjoy my precip since it’s hard on come by in West TX. Night y’all!

Interesting upstream trend showing a lot of areas a touch colder than orginiallly forecast for the time being, but the warm nose is more pronounced to the south (Shocker, I know). I still like a climo based event for ice with the northern tier getting the brunt of the ZR risk. Mt PSU will be glazed over like a Krispy Kreme Friday but DC will only be able to see ice if they get a Dunkin Iced Mocha. Areas with sneaky ice potential are spots like Damascus/Clarksburg/Mt Airy/Monkton/Jarretsville.

0.000000000000000002 fathoms

North of Harrisburg, I have no idea what to expect. There is a Central PA forum that has many members from there. They’ve been following this event for days. A great meteorologist is there as well. @MAG5035is awesome and should have a good feel. I’ve been on vacation back here in MD, so I’ve been tracking for my personal needs and for my home area.

12z GFS FRAM Ice Accretion 12z NAM Nest FRAM Ice Accretion

GFS continues to hold firm on the cold push. The NAM Nest was still a pretty solid ice event for areas north of a line of GAI-Savage-Annapolis. A more significant ice event is increasingly likely over areas north of I-70, especially once you get towards Central Frederick/Carroll/Baltimore/Harford counties. Temps will be borderline south of I-70 for areas below 500’. Above 500’ 27-30° will be possible with light/mod precip still in the area. CAA will still be occurring through the AM, so that benefits the icing setup with the FRAM numbers getting more substantial through the AM as a result. I think WSW criteria ice is possible for the northern tier, but a forecast around 0.1-0.2” is probably a good start. Glaze to 0.1 is probably solid starting point south of there. Regardless, local impacts to travel will be likely. Roads will get icy through the day and remain that way thru Saturday AM. It’s not going to be an all timer at first glance, but still not half bad. DC area will likely miss a majority of the ice.

I think for the DC crew, it’s a non event on the latest guidance. I know you live in western HoCo. I wouldn’t be pulling the plug in your hood. Parrs Ridge area down to northern MoCo could still be a mess. I think the areas north of I-70 are in the best shape for ice. Climo winning again

It's definitely got the low level cold now. The interest will be timing and rate of precip. Light precip with falling temps would create some serious skating on the roads potential. Hell, Bob could skate around Rockville with this setup.

Now I know what I'm getting for dinner. Thanks!

I know. I know. Not until Connecticut Ave caves

So ummmmmm, this is legit a more serious situation brewing on the ECMWF for Friday. This is the trend loop for Ice Estimations with FRAM dynamics. This would be a memorable event if this would verify

The lighter precip being shown via the GFS for Friday would certainly be a worse case scenario for ice. Light precip accretes very efficiently as you limit the latent heat processes involved with ice generation. As we get closer to the event, using modeled output that has the FRAM will have a better idea on expectations for ice potential. Accumulated Freezing Rain output is not total ice formation. It's basically a ptype accumulation of precipitation that would fall as freezing rain. The actual amount of ice accretion would need incrementally more formulation to infer potential for ice. Given the lighter precip field, that would yield more significant results considering the physical process. As for the major difference in temperatures in the short term, WRF NSSL is also agreeing with the NAM 3km with the temperature profile in question for tomorrow. I'm curious to see any adjustments between those two models in the next 24-36 hrs. Low level cold can be tough to erode, but I think a case of climo will come into play. A sharp delineation will likely occur with a setup of this nature. 30s to near 40 over the northern tier but 50s into the DC area would not be a shock at all. I don't have any concrete forecast at the moment, but I would expect areas north of I-70 will have a rough day on Friday with ice accretion, ending as some sleet and a touch of snow. I am bearish with snow prospects. Edit: When talking about the temperatures in the final few sentences in the second paragraph, I was referring to Thursday high temperatures. I should've specified. NBM 25th percentile temperature forecast agrees with my assumption. 38-42 over the northern tier, mid 40s for I-70 down through northern half of MoCo/HoCo/southern half of Baltimore Co, 50s over Rt 50 on south.

It would take some time for the surface to drop for the ability to accrete, but the cold advertised wouldn’t take long. The airmass leading in is mild, but it kind of scales back overnight and then the hammer drops on Friday AM. Seen it go from 55 to 30 in Midland and ice started forming in a few hrs after precip started. IF the temps being shown materialized, we wouldn’t be waiting too long for things to ice up. DC might cuz of UHI effects, but burbs would switch. Flash freeze could occur as well once the temp dips below 26.

Also, for anyone reading my last post, I don’t explcitly think this is a slam dunk. I will say the ingredients are there for an ice event for the sub. I’m actually curious to see the NAM 3km as it gets closer. It does well with these air masses. Not so much the precip, but I want to see how it handles the temps.

This has icy mess written all over it. This arctic shot is no joke. As @Bob Chill alluded to earlier, the backing off of the WAR has been huge for these successive runs of the GFS. Considering the magnitude of the cold being modeled, you gotta think it’ll have the opportunity to cause some serious concerns once the airmass gets here. I think GFS might be a tad fast with the cold considering the density of the expected airmass, but it’ll hit like a hammer and any precip in the area will eventually cause issues. For any in here, take a look at CIPS Historical Analogs around 2pm today to see the latest updates using the current 12z guidance. Could open some light on expectations considering the environment both aloft and at the surface. Great tool.

So ummmmm, this seems like something I’m gonna have to track eh? This has textbook ice storm for a large swath of the country written all over it. Keep an eye on the progress on the layer between 925-850mb. That layer will be important for designating sleet or ZR for a good chunk of the area. I’ll be here for it…maybe.

Ballin! Right around my 10-15" forecast for the coast. Enjoy the winter scene today!