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Possible Saturday Night Snows


showmethesnow
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Thought I would separate this from the mid/long range thread. Wouldn't typically start a thread/discussion on what would most likely be a minor event at best but this winter has been so crappy I need to keep in practice not to mention that I am bored silly. So here we are.

 

Now when it comes to any system and precip it is all about generating lift of a parcel of moisture laden air from the lower levels of the atmosphere into the higher levels. So when looking at the possibilities tonight a casual glance at the maps the last day or two would have you scratching your head as to where that lift was coming from. But digging into it somewhat it was interesting to see how that lift was being generated.

Lets start at the lowest levels of the atmosphere where the lift initiates. What we are seeing at the lowest levels of the atmosphere (roughly 800-850 mbs down to the surface) is that we are seeing a weak disturbance running through the region. This is the starting point of where we see a parcel of fairly juicy low level moisture air begin to be lifted. Now that alone would probably not get the job done but what we are seeing above this in the atmosphere does.

925mbdisturbance.gif.fcd87c3cfdee14ed6e4c20d997e487b3.gif

 

 

Now we lose the lift generated by the disturbance roughly around 800-850 mbs so the question becomes, 'Where are we getting the lift for above that?' Well below we have the wind speeds for 850 mbs. What I want you to note is that we have a dead spot of air flow through central MD. But behind that we some fairly robust winds. What is occurring is that these winds that are trailing this dead spot need to go somewhere. ***Think a rock in a stream. The water can't go through the rock nor can it go downwards through the ground so it flows to either side and above it.*** So this is what we are seeing in the higher levels of the atmosphere. We have the air being shunted to both sides but we are also seeing it forced upwards creating lift. Now this lift being created this way is occurring from roughly 850 mbs up to roughly 700 mbs. So as we are see the influence of the lower level disturbance wane we are seeing this take over to provide the lift to above 700 mbs.

windspeedlift.gif.a1e79ef6a3b1c932717af22b09595757.gif

 

Now one last piece and that can be found at 500 mbs. What we are seeing is a strong SWesterly flow setting up in front of our incoming NS energy/trough. This is providing a mechanism to evacuate the lifted air below it. ***Think vacuum cleaner that sucks up air.*** So the air that has been lifted above 700 mbs on the previous examples is now being lifted even farther upward. 

500mbwinds.gif.d983f38a069b95198a2e830bb48d72b4.gif

 

Now we can see the migration of this parcel of air on the sounding below. Now what we are seeing initially is that the lift is in the lower levels of the atmosphere. But looking at the follow up sounding we now see the lift has moved into the midlevels of the atmosphere.

430366409_lowerlevellift.gif.15df8601e739a22fb7a1e67079f417ed.gif

 

1141486223_midlevellift.gif.d02c91216e98b19ab4078a5ddf9b5973.gif

 

There is another thing that could potential be a wild card for some lucky souls. Look at what we are seeing at 850 mbs. Small packets of energy everywhere giving a very localized boost to the lift. We are seeing these packets of energy strewn throughout the lower levels all the way up to 500 mbs. Get some of these to sync up just right and some could experience a very localized strong short lived burst of precip. 

energy.gif.c27f745d2eb0a47ce68f2952374017dc.gif

 

Now at this point I think indications are pretty good that we will see a roughly 6 hour period of precip tonight running through the general MD/S PA region dumping anywhere from .15-.25" of precip. The bigger question is, will it be wet or white? Right now we are looking at a pretty rough sounding for those through the general DC/Balt corridor and I have seen better for those to the north and west. What it will more then likely come down to is elevation, rates and latitude to a point.

So for those that like predictions (won't name names :) ). Here's my preliminary one. 

Probably looking at mostly rain through the cities with snow mixing in with the heavier bursts. Just N and W of the cities I can see a mulch covering. And for the farther NW crew who also enjoy some elevation I can see a legit coating to an inch. Now those in the general jackpot areas are to be favored of course. I will throw one thing out there as well. I can see the possibility of a there being a very localized jackpot or two of 1-2 maybe even 3 inches if the stars align and we see some syncing with the different packets of energy within the atmosphere. And again those jackpots would more then likely favor those that enjoy some good elevation (won't name names errr... PSU :) ) . Now the above prediction is still somewhat fluid. I really want to see what the 12Z suite shows as far as total precip and soundings. I have a hunch that we may see this precip juice up even more during those runs which will have an impact on the temp profile in the lower levels of the atmosphere.

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5 minutes ago, showmethesnow said:

Bah Humbug!!! For you I predict 38 degree rain. And mud. Can't forget the mud. ;)

Got plenty of that!

And 38 and showers sounds about right for us lowlanders.

Looking at the EURO, it looks like things come together for a decent duration of good lift over DE and esp southern NJ. Don't think temps will cooperate though.

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There was one other thing I wanted to mention though I wouldn't expect it to be a big deal. Keep an eye out for the possibility of a squall or two (rain/snow) running through the region (favored more to the PA line) early Sunday morning as the NS energy comes pushing through. And once again Sunday afternoon/evening as we see even more NS energy diving down the backside of the trough. The mesos are showing some indications of this but may very well be underplaying it somewhat.

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48 minutes ago, C.A.P.E. said:

Not sure about rates. Will have to fall heavily for a decent duration to overcome LL temps, and ofc the warm, soggy soil. :D

Actually I think we might do half decent with rates. If the models are correct. I mentioned above that this would be a 6 hour event but it is probably more like a 4 hour event. So If some of us actually do get .2-.25'" inches of precip in that time that is some half decent rates. Now whether that is good enough to overcome the warmth 900mb to the surface is another story. Now if we can see the models juice up little more...

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34 minutes ago, showmethesnow said:

There was one other thing I wanted to mention though I wouldn't expect it to be a big deal. Keep an eye out for the possibility of a squall or two (rain/snow) running through the region (favored more to the PA line) early Sunday morning as the NS energy comes pushing through. And once again Sunday afternoon/evening as we see even more NS energy diving down the backside of the trough. The mesos are showing some indications of this but may very well be underplaying it somewhat.

 

6 minutes ago, losetoa6 said:

Overnight/ and tomorrow am might be our best shot... with ns energy.  Temps look better to cooperate.  Nams look real warm this afternoon and early evening. 

Was actually talking for tomorrow afternoon with the NS energy and that probably has the best temp profile of the 3 periods.

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Know this gets over played a lot and I will probably come off as a :weenie: using rule #326 from the Weenie Handbook but I think cloud cover may play a factor for tonight. We won't have much of a benefit from evaporational cooling as the lower levels are fairly moist and the wet bulbs are above freezing. So any degree or two we can shave off in the lower levels to the surface from limiting solar radiation (heavier cloud cover) could go a long way. Right now I myself am seeing fairly thick overcast and am hoping it stays that way for the duration of the day.

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2 hours ago, showmethesnow said:

Know this gets over played a lot and I will probably come off as a :weenie: using rule #326 from the Weenie Handbook but I think cloud cover may play a factor for tonight. We won't have much of a benefit from evaporational cooling as the lower levels are fairly moist and the wet bulbs are above freezing. So any degree or two we can shave off in the lower levels to the surface from limiting solar radiation (heavier cloud cover) could go a long way. Right now I myself am seeing fairly thick overcast and am hoping it stays that way for the duration of the day.

A persistent light rain is keeping temperatures down here.  Currently 36°. Forecast high for this afternoon is 43.

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3 hours ago, showmethesnow said:

Know this gets over played a lot and I will probably come off as a :weenie: using rule #326 from the Weenie Handbook but I think cloud cover may play a factor for tonight. We won't have much of a benefit from evaporational cooling as the lower levels are fairly moist and the wet bulbs are above freezing. So any degree or two we can shave off in the lower levels to the surface from limiting solar radiation (heavier cloud cover) could go a long way. Right now I myself am seeing fairly thick overcast and am hoping it stays that way for the duration of the day.

I’m still hanging out around 32 here. 

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56 minutes ago, psuhoffman said:

I’m still hanging out around 32 here. 

That's pretty amazing considering we saw the sun pop weakly out here for an hour, hour and a half around noon and temps jumped up to 45-46. A thicker cloud cover rolled in about an hour or so ago and we have dropped back down to 43 at this time. Can't get over the differences we quite often see between both our places considering our geographical closeness to each other. Just goes to show how important elevation (I am sitting at just under 600 feet here and I am thinking you are 1100? So 500 feet?) can play into ones snow chances.

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3 minutes ago, showmethesnow said:

That's pretty amazing considering we saw the sun pop weakly out here for an hour, hour and a half around noon and temps jumped up to 45-46. A thicker cloud cover rolled in about an hour or so ago and we have dropped back down to 43 at this time. Can't get over the differences we quite often see between both our places considering our geographical closeness to each other. Just goes to show how important elevation (I am sitting at just under 600 feet here and I am thinking you are 1100? So 500 feet?) can play into ones snow chances.

Station said it was up to 35 after a few mins of sun before I left a while ago. It was hanging out at 32-33 all morning. And sometimes I see a 5 degree difference between here and the valley.

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Just now, psuhoffman said:

Station said it was up to 35 after a few mins of sun before I left a while ago. It was hanging out at 32-33 all morning. And sometimes I see a 5 degree difference between here and the valley.

I was sitting at roughly 38 degrees at around 11 shortly before the sun made an appearance. So a 7 degree jump in roughly an hour and a half. 

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Latest NAMs are in. 12K is coming in with a drier solution whereas the 3K is wetter. Also seeing a shifting south of the main strip of precip on both. As I said in my morning post latitude would play a part in this as well and this shifting south is taking out somewhat the more favorable locations to see any meaningful snow (N and W of the cities) out of the equation. This is due to a combination of lower elevations on average to the south as well as the more favorable soundings being farther north. All that said I do think with what is generally depicted that there would be a good chance some would see snow mixed in with some of the heavier rates especially with those that have a little elevation. 

Now we have seen the shifting back and forth on placement and precip over the last day when the models first began picking this up so I am not so sure I would buy whole heartedly in to what the NAMs are currently throwing out at this time.  This might be a case of looking at radar and temps as it is moving in to get an idea of what to actually expect.

As far as my prediction above...

Probably looking at mostly rain through the cities with snow mixing in with the heavier bursts. Just N and W of the cities I can see a mulch covering. And for the farther NW crew who also enjoy some elevation I can see a legit coating to an inch. Now those in the general jackpot areas are to be favored of course. I will throw one thing out there as well. I can see the possibility of a there being a very localized jackpot or two of 1-2 maybe even 3 inches if the stars align and we see some syncing with the different packets of energy within the atmosphere. And again those jackpots would more then likely favor those that enjoy some good elevation...

Maybe (probably) I am being foolish but I will stick to it despite what has been a general degradation I am now seeing on the NAMs since the 00Z suite. There are several reasons for this but it is mostly because I am stubborn and hard headed (my wife can verify this) and I hate flip flopping like a fish on my calls after every run. And more importantly I checked my Ouiga Board and it says snow. If I bust hard then so be it.

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Glancing over things and I will call it now. Bust on my part for this evening. Precip moved in several hours sooner then projected so we didn't get the benefit of the additional cooling we would have seen in the lower levels with a later start. Kind of thinking that may have not made much of a difference anyway. Still looks possible for a late night squall or two with the NS drop which would favor around the PA line. Nams are starting to really pick up on the idea of a squall line pushing through the region in the early afternoon as we see a secondary drop of NS energy down the backside of the trough.

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I chased to Canaan Valley early Sunday.  28 degrees when I arrived with a few inches of snow on the ground mostly from an overnight storm (it started on Saturday as rain there too).  Spent the day snow shoeing and XC skiing; however, by mid afternoon there were muddy spots on the White Grass trails

I think I heard about 5 seconds worth of pingers on the north side of the Beltway Sunday morning a bit after 6

 

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