Chrisrotary12

Just a trend I have been noticing, but where I think I am going with this is that as the system traverses the country, we need to prevent it from gaining as little latitude as possible. Back when the HP was modeled in the 1050s, the storm center was exiting the east coast down near the DelMarVa. As the HP has trended weaker, the storm center is able to gain latitude and traverse through SNE. While its likely a cause and Tip can add much more confusing language to explain what I'm thinking, its just something to keep an eye on.

The high pressure dropping into the Dakotas continues to trend weaker. Last 4 ECMWF runs for SFC HP strength at 06z Sunday: 14.00z = 1050 mb 14.12z = 1047 mb 15.00z = 1045 mb 15.12z = 1042 mb

It is incredible how the majority of you find a way argue in favor of a snowier solution at all times.

First thoughts, general paint brush of 2".

Gives me confidence in this "graphic" and discussion i included with my blog post this morning. Where it stays all snow, upwards of 12″ is possible; The areas in red: Potential for upwards of 6″ of snow; Followed by a firm crust of sleet; On top of which significant icing, >0.25″, is possible. The area in green: Potential for plowable snowfall; Followed by a change to sleet & ice; Transitioning to rain for a time. The area in purple: a few inches of snow transitions to rain. All areas likely end as a bit of snow. A couple additional inches are possible.

Real talk for a moment......did Tippy write the long range BOX AFD? Looks colder, stormy. Continued poleward sub-tropical contributions per potential temperature along the dynamic tropopause, lately over the N Pacific where volatility / robust classical storm development has ushered warm air, higher heights N of Alaska, beginning to down- shear N-stream energy over N America, potential vorticity anomalies, deeper tropospheric folds. Pattern maintains within 5-day average H5 height ensemble means out through early February with a deep E CONUS H5 trof, negative H85 temperature anomalies. But other noteworthy signals: 1.) Possible downstream traffic build- up, S Greenland H5 ridging, slowing the upstream pattern at one point or another, 2.) How and if the split 50-10 mb polar vortex plays a role, 3.) A forecast re-emerging MJO, phase 4 to 7 for late January, that climatologicaly would contribute to a warmer E CONUS in part due to potential E propagation of sub-tropical Pacific low- level wind anomalies from a weak +ENSO to the CONUS, and 4.) The EC- control continuing to signal strong -AO / -NAO teleconnections for the start of February. Lots of uncertainty, unknowns. Seemingly there`s greater opportunity for deeper storm development in vicinity of New England given the H5 pattern noted above. But reiterating ... cascading gyres equatorward undergoing perturbations, amplification, interactions yield abundant potential outcomes difficult to nail down with certainty. To put it simply, would not expect deterministic forecast models to coalesce and corroborate upon details more precisely until we are closing in on the system, perhaps not until we see the whites of its eyes. Break down details, forecast thinking in the discussion below. Low confidence forecast starting with Friday. Greater weighting towards EC / ECens. */ Discussion ... Wednesday through Thursday... Sweeping cold front late Wednesday into Wednesday night. Attendant continental-polar airmass, mainly a dry passage but can`t rule out the squeeze of some snow shower / flurry activity across the high terrain of the Berkshires. Cold air advection into Thursday morning as winds turning light under mostly clear conditions. While mainly seasonable Wednesday, colder Thursday with morning lows around the single digits forecast. Thursday night through Friday... Snow chagning to rain. Isentropic upslope along 280-290K surfaces. Precipitable waters up to 0.75 inches. Along an open-wave trof axis, maybe spurring secondary low development if 14.12z GFS is correct, front boundaries sweep through providing ample lift beneath weaker ascent. Anticipating light outcomes, onset snow Thursday night then changing to rain. Onset cold quickly eroding as synoptics do not support cold air drainage / maintenance of Thursday`s Arctic air- mass. Maintaining ice within the column, no precip-type issues, will see snow gradually change over to rain with S winds prevailing, warm air ushered N, change over mainly during daylight hours. Thinking a coating to 2 inches, locally higher over the Berkshires, before it erodes and/or melts away. Potential Friday AM commute impacts. Got to watch trends on the attendant shortwave whether if it becomes amplified or not, invoking a secondary low. If that be the case, could see greater outcomes given stronger ascent through the column. Friday night through Saturday... Canadian high pressure carves S. Conditions clear out. Cold air advection proceeds. Arctic air slips back across the region. Dry. Saturday night through Sunday night... A frontal wave, and with that, inherant challenges in regards to the juxtaposition of weak synoptic fields, thermal gradient, and overall outcomes. Wiggles, perturbations, etc., considerable challenges with the forecast. A consensus, heavily weighted with ensemble means, has the weak low center sweeping W to E Just S-offshore of New England. Hardly a closed low above H85, moist-stream focused within the anti- cyclonic warm conveyor belt. One big Baroclinic Leaf with a SW-NE dividing line at the surface between liquid and frozen precip-types, a likely mix in-between given a weak element of pull back of the conveyor belt motions beneath lower heights associated with the positively-tilted trof axis, a warm-air intrusion up around H8. A shift N, a shift S, the spread among guiance, it`ll be awhile before we can really nail down exact and specific outcomes. Low confidence forecast.

We rain

EPS Mean bumped northwest. Instead of tracking over ACK its now at the canal. (if you attempt to pinpoint the middle of that strung out contour). The bump is really evident in the means snow. 6" snow line went from Block Island to the Pike that run. But of course the important component is that the storm is still there. Slight bump up in QPF too. Edit: that bump might actually be associated with the Friday system.

This.....although does anyone have any good published papers regarding surface freezing layer thickness and freezing rain. Like if the freezing layer is 3000 ft, but the precipitation is falling quick enough, does it have time to freeze again? Or is it's velocity too high to actually form pellets?

Are Euro soundings available anywhere? Free or paid? I really want to see what it looks like. Taking verbatim at hour 148 for KASH: SFC -6 C 925 -5 C 850 5 C 750 -2 C

Anyone know what 12" of snow, plus 4" of sleet and a 1/4" of ice is like to move? Asking for a friend.

Mountains.....they are above 850. Basically the 850 mb pressure level would be below ground.

You can keep it. I'd like to see a 2" ice storm as much as the next person, but as long as the power and heat stay on.

Imagine what's going to happen when Friday delivers more snow than Sunday!

Yup. Will's all over it.

EPS Mean continues to look great for Sunday. But there's still a decent sized cluster (1/3 maybe) of members that track the weak LP over our heads and leave us on the wrong side of the gradient. ECMWF Op taken verbatim is a serious thump (~12") of snow followed by an impressive period of ice/sleet as all of SNE except for Adams, MA cooks at 850.

Excellently said. Also, can we put these in the Weenie Modeling Hall of Fame?

The EPS mean continues to look great, but a lot of the individual members would leave the weenies unsatisfied. Starting to get the sense that the hype for next weekend in here is about to get out of control. Which if it doesn't work out would lead to some beautiful melts.

Is there a website that produces point & click soundings a la College of DuPage & Tropical Tidbits, but for the FV3 GFS?

EPS looked good. Strong signal for next weekend. All that matters.

Seriously. Sick and tired of the MJO. Might as well talk about the QBO & the AMO while we're at it.

We're literally within 3" of each other on the season.

Darn. Will wait patiently then. I was told I was getting 1-3" during a snowy Sunday (this one).

Is there ever a point in which you begin to root for futility? Say February 15 comes and signs point to a warm March. Do you just go "Eh the hell with snow, earlier golf season."

Which weekend? Great, now we have to hear about how we're getting 1-3" on the 17th for a week. Seriously, look what you did. lol