April 2021 Discussion

[ORH_wxman]

12 minutes ago, codfishsnowman said:

Is there a reasonable shot at some wet snow or ip mixing with the rain in Death Valley? Just enough to say last frozen of the season was 4/14-15

 

Yeah I think there's a great chance for most people to at least see flakes....the column gets pretty cold as the ULL meanders slowly east so at the very least, I think most will see some snow showers/flurries/pellets/graupel on Friday evening-night/early Saturday if they miss out on the heavy stuff Thursday night/Friday.

[MJO812]

27 minutes ago, ORH_wxman said:

NAM is likely on crack....I'd prob lean C-3" over interior elevations with 6"+ confined to high spots of Berkshires/S VT and Monads. Then another max up in Phin's area to W ME.

Phin has been waiting for this since January

Congrats.  April is his new January  

[PhineasC]

Just now, MJO812 said:

Phin has been waiting for this since January

Congrats.  April is his new January  

I’m in FL dude 

[MJO812]

Just now, PhineasC said:

I’m in FL dude 

Sorry 

[Ginx snewx]

Was looking up snowiest 3 day periods in April after the 15th. Hfd would only need 3 inches, Boston 5. Of course everyone else cashed on the 87 bomb but after that there is not much over 5 inches even in Worcester. Odds against a NAM outcome are tremendous.  Likely a Berks Monads NNE snowstorm 

[PhineasC]

I wouldn’t be getting overly excited even if I was up there. Seen enough football pulls this season to just wait and see instead of getting invested. 

[ORH_wxman]

6 minutes ago, Typhoon Tip said:

Short memories with the NAM ... ?  Lest we forget that it hammered everyone east of the Hudson for multiple runs back in Feb, when other guidance like the UKMET was pancaked and out to sea with cirrus streaks.   That set up did not hammer the regions.

Big phantom event way too far NW - I warned the NAM does this with NW bias/amplitude beyond 48 hours back then, too ... Inevitably, it left the devoted suckers sitting alone in the cafe staring at the door, wondering if she'll show ...

Seeking pros: This is different pattern-wise, however.  The flow is slower around this thing, ..the wave-lengths smaller... It's a more self-determining/mechanically conserved "dynamics" storm - drilling down from above also has its deterministic headaches.  The baroclinic canvas is almost non-existent in the lower troposphere at event entry, but a crucial feed of cold air ( NAM ) injects at critical timing, as the 500 mb passes underneath SNE. This induces frontogenics ..probably 850 to 600 mb range...  which the NAM uses to materialize UVM ... So, upward vertical motion hydrostatically causes downward heights, and that machinery drills its way down - drawing the freezing level with it.  For snow ...obviously first to the elevations ...then that looks bit like flashing over to parachutes. I can't throw that behavior away in and of itself, because I've seen that happen in early May.

It may be worth it to note, these top-->down events tend not to need 32 to snow below... When height falls take place and freezing level sags deeply under the UVM regions.. the cat-paw temp is probably 40 F believe it or not. Flip to slush blats is 37.6 or something, and it's all snow at 35/36 F after dark.

I must admit, it's been pretty anchored across the last 5 consecutive cycles in the NAM, with less variance than any other guidance across that span of runs.  Wild speculation but maybe the slower field and shorter wave lengths, and more mechanics not already blown open at the planetary scale but conserving inward to the 'self-centered' low ( haha)... maybe this sort of circumstance et al is just more the NAM's wheelhouse. 

Euro was yeah ...a tad better at 500mb ...if by attitude alone.  Problem is.. obviously this situation being spring marginal incarnate ... has very low tolerances for whether it's cat paws or actual aggregates.

NAM is definitely digging for oil on the upper low...it really stretches it SE and then slides it right under LI as it deepens whereas the other guidance is bringing it over CT or so...maybe the south coast. There has been a slight shift in the global guidance toward the NAM in the past 12 hours...we've seen the more elongated H5 look on those runs that the NAM first advertised. But that trend obviously has to continue to reach the grid-collapsing solution the NAM is spitting out for several cycles in a row. The other guidance is nibbling a bit rather than biting on the NAM solution.

That "elongated" upper air look not only produces a colder profile, but it also prolongs the very heavy precip with that deep layer E flow and CCB....kind of a double whammy. If we lose that, then it's probably just a relatively forgettable system outside of the novelty of "last flakes of the season"....another 36 hours of spring misery in the vault that already holds hundreds in our lifetime. Exception would prob be the monadnocks into S VT and N Berkshires.

[Chrisrotary12]

21 hours ago, Chrisrotary12 said:

I wonder if we see a correction that direction in the coming days (at least a little bit). I feel like we are right in the window of modeling guidance where it over corrects on wrapping up these coastal lows. You know the period of "OMG it's going to stall and loop south of ACK".

Then when the actual event happens its always more progressive and never actually stalls or loops.

Almost there!

Note: for sensible purposes, not currently expecting accumulations outside of elevation. Flakes yes for most places though.

[Lava Rock]

56 minutes ago, MaineJayhawk said:

Not like Hubby to go conservative like this

you and me might score a few inches

[Typhoon Tip]

23 minutes ago, ORH_wxman said:

NAM is definitely digging for oil on the upper low...it really stretches it SE and then slides it right under LI as it deepens whereas the other guidance is bringing it over CT or so...maybe the south coast. There has been a slight shift in the global guidance toward the NAM in the past 12 hours...we've seen the more elongated H5 look on those runs that the NAM first advertised. But that trend obviously has to continue to reach the grid-collapsing solution the NAM is spitting out for several cycles in a row. The other guidance is nibbling a bit rather than biting on the NAM solution.

That "elongated" upper air look not only produces a colder profile, but it also prolongs the very heavy precip with that deep layer E flow and CCB....kind of a double whammy. If we lose that, then it's probably just a relatively forgettable system outside of the novelty of "last flakes of the season"....another 36 hours of spring misery in the vault that already holds hundreds in our lifetime. Exception would prob be the monadnocks into S VT and N Berkshires.

I like behaviors to 'make sense' ...or at least suggest plausible explanation if reasons for behavior cannot be coherently evinced.  Heh...

I mean, the NAM's run variance between 12z yesterday and now ...really, I don't know which run I'm looking at if just boxing east of Utica, N of Jersey and S of Brian.  That region is, other than very minor irrelevances, the same run across 5 cycles.   How is that possible ?  It's almost like the low already exists over Nantucket in the virtual sense - like a slot for a cog, and it wants to find it's nesting point.   ...heh, symbolism but you know what mean... But seriously, go to TT and put the 32km NAM on hour 54 (06z run this recent), and click the Prev. Run button 5 times:  same result inside of nuance and noise. 

Operational philosophy:  That's weird in itself. Lol.  What to do?   ...I guess I'm hinting that "maybe" ( ouch) this could be a weird situation where the other models are missing some sort of dynamical feed-back and how that integrates and forces deep layer morphology.   In general, there are events in history where the NAM did well... however rare that may be the case - ugh. But of those, I do distinctly recall this sort of stalwart stubborn continuity leading.  Back in February ... it didn't have that... It was repositioning features run to run, and then for 3 -cycles it feigned continuity and went amped/NW between 60 and 84 hours...only to pull the rug out < 54. But that was a fun 18 hours of model-cinema, no doubt!

This 12z run ...can't wait to see if it hits for 6th consecutive run, ...not just the 6th run, ...but as though it is just duplicating intervals like that.

I guess for the purpose of being very concise:  this is using the "behavior" of the NAM as a possible deterministic tool - but I would only suggest so because said behavior being what it is.

[MaineJayhawk]

3 minutes ago, Lava Rock said:

you and me might score a few inches

I'm only at like 400' so it'll be a bit tougher.  I'll consider it a W if there's an inch.  I'll prob drive to NH Sat morning to grab some photos

[dryslot]

1 minute ago, MaineJayhawk said:

I'm only at like 400' so it'll be a bit tougher.  I'll consider it a W if there's an inch.  I'll prob drive to NH Sat morning to grab some photos

Won't even be worthy of taking the shovel back out.

[HIPPYVALLEY]

6 minutes ago, dryslot said:

Won't even be worthy of taking the shovel back out.

I wouldn’t get a shovel out for anything under 6” at this point.  It will be gone in a few hours.

[dryslot]

Just now, HIPPYVALLEY said:

I wouldn’t get a shovel out for anything under 6” at this point.  It will be gone in a few hours.

Nope, GYX has 2-3" here and i'm expecting maybe half of that if anything at all.

[CoastalWx]

Regardless of low positions etc,  I noticed a lot of the "snow" depiction on ptype is generated by lift below 700mb and temps warmer than -10C. I feel like that would be tough to do much more than whiten the mulch beds at times. I think you really need to be in the big QPF/firehose for dynamic flippage to snow where the lift is deep, and DGZ is saturated. Otherwise, I can't see a whole lot of stickage where the lift is shallow. There might be one exception. Some models generate a narrow band on the W and SW side of the low when it wraps up. Probably just a massively tilted back bent warm front. Perhaps some areas removed from the main firehose forcing could get some accumulation in that spot? 

[Typhoon Tip]

I keep thinking of this ... It's funny that this was a whopper teleconnection flagged by the GEFs some 14 days ago actually.. I remember posting several repeating iterations ( to deliver a point that I still don't know if anyone actually acknowledged despite my harangue  LOL..), that there was a 'monster mid month signal.' Probably the reticence to do so centers around the unfortunate caveat also discussed re that mid April thing ... uh yeah.  By then, nearing mid August sun power ...

I had let it go but here we are...  It's just hard to keep on things when for one, you stop caring.. .but, we are putting up 78 F days off and on waiting for some signal to materialize...when the other side is even more warmer climate as inevitable. It's not really conducive to giving a shit -

Ever think of that - ?  whilst we offset acceptance and sorrow stage of the winter death psychology,  with a couple of blips on the EKG, we do so under the equivalence of August 24th sun.  

Imagine a blue bomb in discussion on any August 22nd?  

I've seen it be 96.4 F on August 24th and that was a cold bust because it was 22.5 C at 850 ..but of course cirrus plumes timed which is usually how the true cutting edge big heat fails in New England. ... Anyway, it's tough to argue seasonal lag when we make legitimate comparisons, huh -

[moneypitmike]

24 minutes ago, MaineJayhawk said:

I'm only at like 400' so it'll be a bit tougher.  I'll consider it a W if there's an inch.  I'll prob drive to NH Sat morning to grab some photos

Had you been living in Portland for a while?  I recall reports from you from there.  

[MaineJayhawk]

Just now, moneypitmike said:

Had you been living in Portland for a while?  I recall reports from you from there.  

Yup, we moved full-time to our lavish country estate last summer.   

[Typhoon Tip]

26 minutes ago, CoastalWx said:

Regardless of low positions etc,  I noticed a lot of the "snow" depiction on ptype is generated by lift below 700mb and temps warmer than -10C. I feel like that would be tough to do much more than whiten the mulch beds at times. I think you really need to be in the big QPF/firehose for dynamic flippage to snow where the lift is deep, and DGZ is saturated. Otherwise, I can't see a whole lot of stickage where the lift is shallow. There might be one exception. Some models generate a narrow band on the W and SW side of the low when it wraps up. Probably just a massively tilted back bent warm front. Perhaps some areas removed from the main firehose forcing could get some accumulation in that spot? 

Yeah, I wonder where the NAM is situating it's UVM core(s) with respect to thermal profiling.

Crucially,  UVM specifics like that?  absolutely. 

In fact, this technically starts off as an amorphously defined southerly flow/conveyor, that pivots/'backs' around to the E ..like taking 12 to 18 hours to do that pivot.  Once it does, that's when these ptypes start going blue blobbed out there over the elevation spines...   ...blah blah the low ( NAM ) then dynamically assists its own cold profile and throws a parachute party. I mean ...folks need to realize ... if the cold profile of NAM worked out, it's a cotton ball snow storm where it does go over. You might hear them thump on the car tops if you turned the engine off ...heh.  The old farmer's adage about the big snow flakes mean a change to rain ...fails in this case, because if you go to those big aggies ...that means you were not handed an address for the popular people party ...only to arrive there and find that the party was in fact somewhere else. 

[Ginx snewx]

Nam not giving up the faith in CT

[weatherwiz]

5 minutes ago, Ginx snewx said:

Nam not giving up the faith in CT

the NAM is not budging...kinda would have thought it would maybe head in the other direction with this run but nope. If GFS inches closer to the NAM with the 12z run (which the past few GFS/euro runs have) well...this is quite interesting. The challenge is conveying this lol

[ORH_wxman]

NAM def did move a little bit...less stretched at H5 and a little NW. Another couple ticks like that and it will be in better agreement with the other guidance.

 

Still destroys agood chunk of interior SNE verbatim, but there was a definite tick there.

[STILL N OF PIKE]

2 minutes ago, ORH_wxman said:

NAM def did move a little bit...less stretched at H5 and a little NW. Another couple ticks like that and it will be in better agreement with the other guidance.

 

Still destroys agood chunk of interior SNE verbatim, but there was a definite tick there.

Yup. Good call . It blinked slightly 

[dendrite]

3 minutes ago, ORH_wxman said:

NAM def did move a little bit...less stretched at H5 and a little NW. Another couple ticks like that and it will be in better agreement with the other guidance.

 

Still destroys agood chunk of interior SNE verbatim, but there was a definite tick there.

Bigger shift on the 3k.

[dryslot]

12z Nam, Looked like it was a few ticks NW at the surface from 06z.

06z

12z

[WinterWolf]

7 minutes ago, weatherwiz said:

the NAM is not budging...kinda would have thought it would maybe head in the other direction with this run but nope. If GFS inches closer to the NAM with the 12z run (which the past few GFS/euro runs have) well...this is quite interesting. The challenge is conveying this lol

It won’t take much to convey if the 12z suite continues towards the NAM.  If there is caving towards the NAM idea, it’s game on for most.  Still Hard to take it seriously...but with this run continuing the crushing...it gets a lil harder to blow it off each cycle. And if the other majors continue/or move towards it...then oh boy. 

[ORH_wxman]

2 minutes ago, dendrite said:

Bigger shift on the 3k.

Yeah the 850 low on the 3km is over like PVD now on the 12z run while at 06z it was over MVY.

[Damage In Tolland]

20 minutes ago, Ginx snewx said:

Nam not giving up the faith in CT

 

[radarman]

2 minutes ago, dendrite said:

Bigger shift on the 3k.

yeah, that 3km would take the lowlands out of the game

[weatherwiz]

1 minute ago, WinterWolf said:

It won’t take much to convey if the 12z suite continues towards the NAM.  If there is caving towards the NAM idea, it’s game on for most.  Still Hard to take it seriously...but with this run continuing the crushing...it gets a lil harder to blow it off each cycle. And if the other majors continue/or move towards it...then oh boy. 

This kinda of reminds me of a setup that I think was kinda similar and not really that long ago...maybe March? The NAM was pretty insistent that H5 would drop to our south while the globals were like right over us...ultimately the globals won. I guess we just need some reason to believe that H5 will become more elongated and pop to our south. I think at least the NW hills could get pounded pretty good. Majority of us still probably see some wintry precip given how cold low-levels are.