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1/28-2/1: Multiple winter storm threats per models


GaWx

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As Moto stated, it is best to look at the 850 line as opposed to the 540mb isohypse.  Keep in mind though, graphics with precip account for the period prior, while the 0C 850mb line is valid for the actual time-stamp.  Thickness and soundings are the best tools for determining dominant type, and how it is trending.

I really appreciate the time, patience, and information you all are showing.

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I really appreciate the time, patience, and information you all are showing.

 

From me experience along with 850 temps; you almost need to check out the 0c on the 2m temp maps.

 

Reason being is you can see storm systems with the 850 north of your area; but a high pressure pushing a shallow layer of cold air close to the surface.  If you have 850 above 0c and then 2m at or below 0c you can get freezing rain.

 

If you have both 2m at or below 0c and 850 at or below 0c; you might be looking at snow.

 

There is no replacement from upper air soundings; and they can be seen in the model center here in both graphical and raw text, or if you can't afford it; twister data or college of dupage weather has them for NAM/GFS type models.

 

On a side note; over time you will learn how models under estimate evaporative cooling sometimes.  That's when the dewpoints are really low and you would want to take a look at 2m wet bulb temperatures in precip situations when temps are already really close.

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From me experience along with 850 temps; you almost need to check out the 0c on the 2m temp maps.

 

Reason being is you can see storm systems with the 850 north of your area; but a high pressure pushing a shallow layer of cold air close to the surface.  If you have 850 above 0c and then 2m at or below 0c you can get freezing rain.

 

If you have both 2m at or below 0c and 850 at or below 0c; you might be looking at snow.

 

There is no replacement from upper air soundings; and they can be seen in the model center here in both graphical and raw text, or if you can't afford it; twister data or college of dupage weather has them for NAM/GFS type models.

 

On a side note; over time you will learn how models under estimate evaporative cooling sometimes.  That's when the dewpoints are really low and you would want to take a look at 2m wet bulb temperatures in precip situations when temps are already really close.

Once again, many thanks for all the help.

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Robert just provided a very extensive update on his site...very well spoken thoughts on next week's potential and what needs to go right for the Southeast US.

 

If there's ever a time to help out a great person who spends a ton of time in forecasting weather, right now is the time to get a subscription to WxSouth.

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Robert's write up is great! Guys... go spend $10 and sign-up. WxSouth.com

Best $10 you'll spend all winter long.

 

Robert just provided a very extensive update on his site...very well spoken thoughts on next week's potential and what needs to go right for the Southeast US.

 

If there's ever a time to help out a great person who spends a ton of time in forecasting weather, right now is the time to get a subscription to WxSouth.

Couldn't agree more!!! Great write up, and like you said He spends a lot of time studying patterns. He's hard to beat for a SE Forecaster! (Not saying there's not more great SE forecasters) :thumbsup:  Many of them post on here!

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From Robert's Facebook page:

 

Just issued a big synoptic discussion to the monthly subscribers. It's full of good meteorology stuff but I break it down to how the weather actually works out. Of course, the Southeast is usually too warm for anything but rain. I'm liking the looks of the big Highs shown on GFS and ECMWF with the next week system . The Polar Vortex lifts out, Ridge closes in Alaska, flow retrogrades up north, flow backs down south, but with plenty of cold air in place and well positioned Arctic Highs....going to get interesting next week IF IF IF the upper level 5H charts verify on the models...I'm not worried about surface since that falls in line later.

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Is this thread about the up coming winterstorms, or a ad pg. banter section would be best

 

The thing is; Robert has been giving us free info for years.  Hell, he still gives tons of free info on his own website and facebook to everyone.  He basically summed up his article on his facebook update and basically said it looks good for a storm.

 

It's being advertised (his site) because it seems like he has an extensive write-up about the intricates of what will or wont or may happen on the real close level for all of us.

 

He's well respected by many in the weather community and he's much better than many other premium services because of the data in his head alone; much less all the modeling he has to go with it.

 

So while it is ad type speak; it's just users supporting a great meteorologist who's been around a very long time and verifies exponentially well.

If you've never read his analysis and or previous postings back on the older boards etc; you should check them out.  You'll learn a lot and notice why people respect him so much.  His thoughts are worth much more than $10 a month for the Southeast.  Especially in the Winter!

 

People like JB etc focus on his clients up North for example.  Think of Robert as the JB of the SE but all around awesome!

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I see your interest is up with this system. Have not seen you around in awhile. You thinking this turns the corner earlier?

 

I've been lurking all winter...just not posting.  I've been spending all my time on my DahlonegaWeather facebook page where I focus 100% on MBY stuff.  LOL

 

I very much think there is still opportunity for a better track for us.  You can see clearly that the EURO for the past 3 12z runs has trended further west with the mean trough position.  Small changes there make big changes at the surface.  Some look at the surface maps and say that the EURO did a massive change but when you look at the 500mb maps the changes are not all that large.  But it makes a huge difference in what happens at the surface.  So just a bit more west with the mean trough and a lot more of us could be in business.  At least I don't think cold air will be the issue like it normally is.

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Fired some more data over to Larry to check out for a post.

 

Guys, I really wish I could show all of you some of this stuff.  It's been an extremely long time since I've seen it..  The Euro is going insane with a monster possibility... OP & more importantly almost all EPS members.  Larry should have a great post in a bit with more details. <3

 

Shawn/Folks,

 As modeled by the 12z Thu Euro and likely by many of the accompanying ensemble members, we'd be looking at an incredible and historic storm for the SE coast. Just looking at my hometown of Savannah, whose wx history I know well, an insane 21 of the 51 members give a snowfall, ~5"+, that exceeds anything since March of 1837! A few even exceed that and give the heaviest since the epic Jan. of 1800 storm!Even the ensemble mean is at ~5.75", which exceeds anything since 1837!!

 

 Now, when I looked at the Euro op., I stated here that I thought that my own provider's clown map in addition to WxBell was strongly overstating snowfall for SAV/CHS with 3.9" at SAV vs. what I thought was really ~1" based on the 0C 850 mb line being inland about 50 miles for much of the precip. As modeled, this would be a pretty serious storm whose  biggest impact at SAV/CHS would appear to not be from S but instead from ZR, which would possibly be the worst in over 90 years at least at SAV ! (No hyperbole there as I checked SAV carefully). So, I'm not trying to downplay this storm's potential at all. However, I am very skeptical of the snowfall being shown on the coast on the Euro and its members. I'm strongly suspecting that it is counting all qpf with two meter temp.'s at or below 32 as snow when a lot of it is actually ZR and IP. So, if true, this would skew areas with a lot of ZR/IP way too high on the clown maps for both the op. run and its ens. members. Further inland like at CAE/RDU/CLT/ATL/GSP, etc., where it would be all snow with 850's below 0C, the clowns are quite possibly not overstated and reflecting "forecasting reality". Even Ryan Maule, himself, in tweet(s) is finding the numerous 12Z Euro member runs showing 6-12" on the coast as hard to believe.

 

 So, I really wish we get to the bottom of this confusion!! Can someone who is on Twitter or has service from WxBell ask Ryan about their clown maps? Why are the amounts so high on the various models?  Also, I'm wondering why my provider's clowns are too high for the 12Z run along the coast. I suspect they're doing the same thing with ZR/IP. I wish we could get some answers. :(

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At least I don't think cold air will be the issue like it normally is.

 

I think that's one of the things that gives a lot of us more confidence than we might normally have  Barring some massive, unforeseen changes, most of us (at least in the interior) will have zero to worry about as far as temperatures, unless you stress between being 18 degrees or 25 degrees while it's snowing! :)

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Shawn/Folks,

 As modeled by the 12z Thu Euro and likely by many of the accompanying ensemble members, we'd be looking at an incredible and historic storm for the SE coast. Just looking at my hometown of Savannah, whose wx history I know well, an insane 21 of the 51 members give a snowfall, ~5"+, that exceeds anything since March of 1837! A few even exceed that and give the heaviest since the epic Jan. of 1800 storm!Even the ensemble mean is at ~5.75", which exceeds anything since 1837!!

 

 Now, when I looked at the Euro op., I stated here that I thought that my own provider's clown map in addition to WxBell was strongly overstating snowfall for SAV/CHS with 3.9" at SAV vs. what I thought was really ~1" based on the 0C 850 mb line being inland about 50 miles for much of the precip. As modeled, this would be a pretty serious storm whose  biggest impact at SAV/CHS would appear to not be from S but instead from ZR, which would possibly be the worst in over 90 years! (No hyperbole there as I checked carefully). So, I'm not trying to downplay this storm's potential at all. However, I am very skeptical of the snowfall being shown on the coast on the Euro and its members. I'm strongly suspecting that it is counting all qpf with two meter temp.'s at or below 32 as snow when a lot of it is actually ZR and IP. So, if true, this would skew areas with a lot of ZR/IP way too high on the clown maps. Further inland like at CAE/RDU/CLT/ATL/GSP, etc., where it would be all snow with 850's below 0C, the clowns are quite possibly not overstated and reflecting "forecasting reality". Even Ryan Maule, himself, in tweet(s) is finding the numerous 12Z Euro member runs showing 6-12" on the coast as hard to believe.

 

 So, I really wish we get to the bottom of this confusion!! Can someone who is on Twitter or has service from WxBell ask Ryan about their clown maps? Why are the amounts so high on the various models?  Also, I'm wondering why my provider's clowns are too high for the 12Z run along the coast. I suspect they're doing the same thing with ZR/IP. I wish we could get some answers. :(

 

I've tried to ask on Twitter; no response a while back.

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Shawn/Folks,

 As modeled by the 12z Thu Euro and likely by many of the accompanying ensemble members, we'd be looking at an incredible and historic storm for the SE coast. Just looking at my hometown of Savannah, whose wx history I know well, an insane 21 of the 51 members give a snowfall, ~5"+, that exceeds anything since March of 1837! A few even exceed that and give the heaviest since the epic Jan. of 1800 storm!Even the ensemble mean is at ~5.75", which exceeds anything since 1837!!

 

 Now, when I looked at the Euro op., I stated here that I thought that my own provider's clown map in addition to WxBell was strongly overstating snowfall for SAV/CHS with 3.9" at SAV vs. what I thought was really ~1" based on the 0C 850 mb line being inland about 50 miles for much of the precip. As modeled, this would be a pretty serious storm whose  biggest impact at SAV/CHS would appear to not be from S but instead from ZR, which would possibly be the worst in over 90 years! (No hyperbole there as I checked carefully). So, I'm not trying to downplay this storm's potential at all. However, I am very skeptical of the snowfall being shown on the coast on the Euro and its members. I'm strongly suspecting that it is counting all qpf with two meter temp.'s at or below 32 as snow when a lot of it is actually ZR and IP. So, if true, this would skew areas with a lot of ZR/IP way too high on the clown maps. Further inland like at CAE/RDU/CLT/ATL/GSP, etc., where it would be all snow with 850's below 0C, the clowns are quite possibly not overstated and reflecting "forecasting reality". Even Ryan Maule, himself, in tweet(s) is finding the numerous 12Z Euro member runs showing 6-12" on the coast as hard to believe.

 

 So, I really wish we get to the bottom of this confusion!! Can someone who is on Twitter or has service from WxBell ask Ryan about their clown maps? Why are the amounts so high on the various models?  Also, I'm wondering why my provider's clowns are too high for the 12Z run along the coast. I suspect they're doing the same thing with ZR/IP. I wish we could get some answers. :(

 

Just toss out all the snow depth maps and look at QPF and temp profiles to make an educated calculation for snow estimates.  It's always difficult to make an accurate snow depth calculation. So many variables.

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Just toss out all the snow depth maps and look at QPF and temp profiles to make an educated calculation for snow estimates.  It's always difficult to make an accurate snow depth calculation. So many variables.

 

SAV looks like 850's are right on the edge per the Euro. Would have to think at worse it would be sleet. CHS would maybe be ZR. With you though hard to make any type of accurate guess. 

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If what has been said here occurs, the impacts for eastern SC would be crippling. Back in '10, that snow fell on a Friday night/Saturday morning, so the impacts were lessened. This would be a mid-week storm.

If what could happen happens and ZR comes first in Charleston, then it sounds more like Feb. 1973 ...

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SAV looks like 850's are right on the edge per the Euro. Would have to think at worse it would be sleet. CHS would maybe be ZR. With you though hard to make any type of accurate guess. 

 

Burger,

 The 850 0C line doesn't come back to near SAV until just before 12Z on 1/29 or at ~144 hours. By that time, a whopping ~0.55" of qpf has already fallen. Hardly any of that would be snow since it normally doesn't snow when 850's are warmer than 0C as you know. They are as high as +4 C and the 0C 850 line is ~50 miles inland from Savannah during much of the precip. I checked with a second source of model data and it confirmed this. That leaves only ~0.05" of qpf to fall once 850's have fallen to 0C or colder! So, this looks to me like ~0.55" of a ZR/IP combo followed by ~1/2 " of snow. There's no way SAV is anywhere near 3.9" as modeled! Now if it has the 850 line too far inland vs. what actually would occur, that would be different. Regardless, the model shouldn't think it is snowing if the 850's are in the +1 to +4 range.

 

 Any opinions?

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