Re: Long Range Thread 16.0

[rb924119]

Based on how tonight's runs have generally gone, I'm fairly inclined to say that we may have ourselves a pretty robust EURO run/suite tonight. Especially with the CMC and UK looking the way they do tonight. Gotta wait and see, unfortunately lmao

[WeatherBob]

I know it’s late , but does anyone have a few model maps to post? Maybe the Ukie depicting the low off the coast, something like that?

[WeatherBob]

RB -  due you really think the GFS is that off?  It kinda has the same idea as the NAM with the precip field and the 850 temp does go below 0 at 84 hours.  It then spits out over .50 QPF from 84 hrs to 96 hrs.  Am I missing something? I don’t think it should be discounted that harshly, that’s all I am saying.

[rb924119]

I know it’s late ,  but does anyone have a few model maps to post? Maybe the Ukie depicting the low off the coast,  something like that?

Unfortunately, this is the last frame, but you can get the idea when you compare it to the GFS and even the NAM lol



Note that the 850's are crashing to below 0°C through the northern tier of PA during and just after this time (within a couple hours after), so the heaviest precipitation rates would occur as snow for at least those regions, if not even further south.

[rb924119]

RB -  due you really think the GFS is that off?  It kinda has the same idea as the NAM with the precip field and the 850 temp does go below 0 at 84 hours.  It then spits out over .50 QPF from 84 hrs to 96 hrs.  Am I missing something?  I don’t think it should be discounted that harshly,  that’s all I am saying.

YES. At least between the surface and mid- and upper levels. Clearly chasing the convection with the surface low where it's depictions at both H5 and H3 DO NOT support that secondary placement/track. As for it's thermal profile, it could still be right, or at least close, but I'm hedging my bets agains that at this time. To me, the consensus of the trends tonight have significantly shifted in my personal favor, and if what I am expecting to end up happening does, you can expect further positive adjustments by the modeling as we continue to near the event.

[WeatherBob]

RB - ok , what you are saying is all the vertical motion depicted on the GFS at 700 mb that runs north to south right along the coast from NNJ to Va at 72 hrs , races east and elongates the upper system by 84 hrs .  The GFS then places the surface low at the eastern end of this 700 mb elongation at 84 hrs, thus chasing the convection and leaving the cut off 500 mb low over the Delmarva.

[WeatherBob]

OOz Euro looks like the GFS but worse from what I can tell. I am just looking at the maps from the Weather Models on this site. Anyone have a different viewpoint?

[rb924119]

No lol well, maybe. It's hard for me to say because I don't have access to H7 omega, but from a purely observational standpoint: Yes. From the meteorological standpoint: No. I can't explain it nearly as well as I would like via text because it would be come much too convoluted. However, watch the evolution of the H5 vorticity; mainly on the energy that seemingly develops rapidly AHEAD OF THE MAIN SOUTHERN STREAM ENERGY. As that specific vorticity develops, watch the evolution of the QPF field at the same time frames and then take note of where your main southern stream energy actually is. You'll notice that the actual energy hangs behind that other stuff, but the heaviest QPF actually sits BENEATH that other stuff. What that other stuff actually is, is the model developing convection, thunderstorms, so deep that they actually feed back on the H7 and H5 maps so much so that they actually create artifact (fake) vorticity that the model them thinks is real and assumes as the main forcing mechanism in the midlevels. However, if you follow that energy, as soon as the convection fades so does that energy, which is why you then see the secondary jump back westward as the model realizes the actual southern stream energy will then be forcing the ascent for its development. Coincidentally, if you look at the jet structure, that artifact energy and surface low that runs out well ahead of the southern stream energy, also runs in an unfavorable region of the jet (pretty much directly beneath it in the front- which is a subsident region. However, the front-right quadrant lines up extremely well with the the H5 positive vorticity advection. This, THAT region is where your ssecondary low SHOULD/WILL develop, which is likely to be over or SSE of the Delmarva. Then, as the northern stream energy, which is more vigorous, phases in, THAT'S when the explosion of the surface low transpires and the thermal profile begins to cool rapidly in response and the rain-snow like crashes southeastward. For a better explanation of this "convective feedback" I discussed much better in the video I did for the blizzard. It's its own thread, so if you want to watch it, it should be fairly easy to find in here. I demonstrate the concept pretty well in there, I think lol if I have time after get back home tomorrow from my parents' I might do a video for this event as well. Not really sure, though, but if I did, I would include another segment about the convective feedback if it is still being shown at that point. Again, still undecided, but hopefully that explanation helps a little, and if you watch the video, that will drive it home haha

[WeatherBob]

RB - you didn’t have to go through all that explanation , especially at this hour, but Thank You! In any event , this is a really complicated system to figure out and definitely is a forecast challenge at the present time.

[rb924119]

Annnnddddddddd the EURO is doing it too lmao hence the ugly look. HOWEVER, the EURO's main show is purely northern stream driven, and that result is damn impressive in it's own right with respect to QPF amounts. If you blended the EURO with the CMC I think you end up with something approximately equal to what the UKMET showed, which is better compared to the NAM. The EURO here made the northern the dominant energy because the southern stream energy was too quick and remained far enough ahead of the northern stream that there was no phase. All the QPF resulted from the rapid tightening and intensification of the northern stream; no southern stream energy was involved. This is interesting to me because the EURO usually holds the southern stream back too long, so this may be something that we need to watch for in future runs. I don't know, though.

[WeatherBob]

RB - just finished the video. It’s like I found God! HaHa! I always kinda understood convective feedback but that video has locked the concept into my brain. Thanks!

[skinsfan1177]

Today's model runs are key to see the extent of snow to the coast. Also we need to keep an eye on the march 7 timeframe as well.

[algae888]

Nice Trends overall on the models last night the Euro has below zero 850s and plus one 925s when the heaviest precipitation Falls in our area it's not far off. If we get the mid in Upper levels below zero Celsius and the low is in the right position we will snow even down to the coast should be fun model runs the next few days

[docstox12]

NWS now has rain snow mix Thursday night into Friday.Says no accumulation but yesterday it was all rain for the event.This is good news!

[jmanley32]

Good lord 06z nam the precip changed to snow and the lp rides along just south li giving absolutely screaming winds if they mix down from 850. 80+ kts at that level and that's sustained. Nam also has closest to a snow solution no?

[billg315]

Yeah the 0z and 6z NAMs continue to want to bring snow to the whole area by daybreak Friday. Surface temps remain above frz in many areas but 850 level crashes below frz overnight and changes it over. If it’s heavy, at night I think it still accumulates, so the surface temps aren’t as big an issue. I think the NAM solution of energy transferring to a low right off the Delmarva and then cold air coming in as it blows up and deepens near LI continues to make sense to me. The gfs keeps pushing the low 500/600 miles offshore - which doesn’t make sense to me (as discussed with rb last night maybe chasing convection). NAM has been more trustworthy of late and makes more sense from my knowledge of how these Miller B type events work. So I’m sticking with it. Question will be how long do we stay in heavy snow (if indeed it goes over) and how quickly does it accumulate. That would make a huge difference in accumulation in this scenario with warm surfaces. Be interesting to see if the NAM sticks to its guns in today’s runs.

[billg315]

It seems because the gfs jumps the secondary low sooo far to the east, the primary stays just as strong over the Great Lakes and never transfers it’s energy completely like the NAM. This keeps the cold air from crashing in behind the secondary (as it does across NJ on the NAM) until both storms pull north of the area and the precip ends. You essentially end up with two equally strong lows several hundred miles apart. I guess it’s possible, but NAM setup makes more sense.

[nutleyblizzard]

It seems because the gfs jumps the secondary low sooo far to the east, the primary stays just as strong over the Great Lakes and never transfers it’s energy completely like the NAM. This keeps the cold air from crashing in behind the secondary (as it does across NJ on the NAM) until both storms pull north of the area and the precip ends. You essentially end up with two equally strong lows several hundred miles apart. I guess it’s possible, but NAM setup makes more sense.

GFS is out to lunch. Euro is not much better as of late. For some reason the past few years the major models are having trouble with the placement and thermal aspects of these complex storm setups; chasing convection, mid levels to warm. Same old song and dance. By no means am I proclaiming a major snowstorm. Its all dependent on how strong the low gets and where the CCB ends up. Very complex situation! Go with the short range models!

[sroc4]

New thread

[sroc4]

I moved the banter into banter Jimmy

[Guest]

I moved the banter into banter Jimmy

Ok. I actually thought I was originally posting in banter. My bad

[amugs]

Saddle up for round 2 peeps - dont sleep on this one next week


EPS good signal here - from PB





GEFS


And then the Archambault Event that will end winter Mondayish time frame
GEFS


And yes the airmass in front of both is normal not 15-20 above normal so cooling down the column of air is quicker. Coast may have issues depending upon teh track as climo this time of year but those details will be worked out as we get closer in time.

[Frank_Wx]

I actually like this event. More cold air to work with and NAO block still in place.

[amugs]

I actually like this event. More cold air to work with and NAO block still in place.

ABSOLUTELY Commander!! I like both to be honest - you know as well as others here Frank that the Archambault events are very interesting and can produce in a big way especially withe barclonic zone with the warm air to teh south and cold air still in place to the north. A NAO and AO in place then a decaying NAO which will offer resistance but all it to have a more NNE projection rather than a ENE.

DING DING - Round 2 and 3 - just like Olympic Boxing!!

[WeatherBob]

Looks like our departing Monster might help in funneling down some low level cold air from eastern Canada down the NE coast. See GFS 925 mb maps.  HUM!

[billg315]

As I said in the previous storm thread - sorry jumped the gun posting about this there, couldn’t help myself :-) - I think there’s a lot to like about this midweek event. Where the low develops, more cold air, duration. Could be another fun one!

[sroc4]

Looks like our departing Monster might help in funneling down some low level cold air from eastern Canada down the NE coast. See GFS 925 mb maps.  HUM!

Exactly!

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