WxMan1

I guess this would qualify as banter.. Who else was alive and remembers the Challenger explosion 35 years ago today? I was 15, living in Springfield VA. Aside from the trajedy that day, another indelible memory for me was a Nor'easter that was to never be that weekend for us in the mid Atlantic. Cold and dry, with any development well off the coast. Not sure which model was pummeling our area with heavy snow... NBM perhaps? Imagine if thiis forum was around 30-40 years ago with the state of NWP back then? Lots of broken hearts for sure!

I did a bit of research on the topic a few years back. It was quite an illuminating experience! Miller_Cyclogenesis_Classification_US_Atlantic_Coastal_Region.pdf

Been chatting with the BGM NWS office overnight. They got 5, that's FIVE inches in one hour, midnight to 1 am. The deformation band is pivoting, but Binghamton is right smack in the middle at the pivot point. They'll end up over 30" for sure.

Officially had 0.6" in Crofton before the slopfest, and 0.8" at the NCWCP in College Park. Pretty tight gradient into northern AA with over an inch in Odenton, 2" in Severn. Looking at the CTP obs thread in the PA/NY group makes me want to cry. Getting raked up there, now over a foot in many areas.

And the Bay and Atlantic coastal water SSTs are as warm as they're going to be for the rest of Dec as well as JFM. This is quite "climo" for mid December, at least with the absence of antecedent arctic air going in. For me it evokes the Dec 1992 storm, at least for PA (though not as intense). Also makes one appreciate Dec18, 2009, in how rare of an event that was early in the season. 11/11/87 was just a freak of nature.

A little over 1/2" of snow and sleet here in Crofton, about 3/4 sleet 1/4 snow falling right now. CC says yep..

Yeah, it looks like the delays impacted the HRRR.

Hello all... A note from NCEP Central Ops, as I am just spinning up at work... There's an issue with one of the supercomputers...which is currently causing a delay in the 00Z model production. Certainly the 00Z HRRR and RAP have been delayed, and the NAM will likely be as well. Sorry folks...just passing along what I know..

Outside of the Jan 2016 event, you have to go back to the Feb 2014 Miller A since we last saw a true climo gradient NW-SE. I got around 22" here in northern AA County with the Jan 2016 storm, while areas west of the fall line got 36+. In the Feb 2014 event, I recorded 7" on the front end, 4-5" with the deformation the next day, with rain/drizzle/dry slot in between. Areas west were well over a foot. I'm not expecting much IMBY on the front end -- I'm definitely more intrigued about the deform potential early Thursday. How far south will that CCB band extend, what will the rates be, and how progressive will it be lifting out are the big questions.

That EC low track is a bit too far west for my liking, but with the season relatively early in terms of the warmer Bay and Atlantic shelf water temps, cannot be shocked by this. Warm layer looks to be 850-800mb, though for us in the southern/eastern burbs, the EC track would imply the entire surface layer above freezing. Having said all of this, I'm not sure how the EC gives MBY 8" (Bowie-Crofton). Not enough duration on the front end for a good thump. So, at least for us along and east of I-95, I think we're putting our chips in on the backside CCB. As PSUHoffman said, the backside CCB/deformation axis is such a low percentage occurrence in this region; a football analogy is the fade pass on 3rd and long. However with a system like this this, going all-in (or not) on the backside CCB can make or break a forecast. Timing and thus location of the more rapid deepening and strengthening low-mid layer FGEN will be pivotal. When it happens soon enough for our region, the n-s or nne-ssw deformation banding also leads to a reduction in the westerly or downsloping low-level component -- which is more typical around here as we more often dry out sooner than later. Keeping my expectations low until I see a more definitive trend toward a 12/18/09 setup.

Yeah, you want to talk gradients, PG and AA Counties here in MD are like, hold my beer..

For us along the east end of the beltway, the back end deformation can allow us to cash in when we otherwise wouldn't. Problem is, it's such a low percentage occurrence because of the typically post-low westerly component and downsloping. So we obviously need the timing of a well developed cyclone for us in the eastern burbs to cash in. The bulk of the 10" that fell from that system a couple years ago fell on day 2 with the deformation (6-8").

Many of you have noticed and said this before... It's always coming out of the -NAO min when things can get real interesting..

Round 2 does not disappoint. 5.5" part I 1.5" part II and still coming down heavily! 7.0" total in Crofton

Felt it here in Chester, while in the bathroom (of all places!) Actually felt the first wave, though barely, then soon after the surface wave, which shook the mirror.