12/25/2005 SNOW: GREAT LAKES / NORTHEAST

[Robert Dewey]

I'm still thinking there is a slight chance for a heavy snow event across portions of the Great Lakes tomorrow. Models are STILL showing QPF in excess of an inch, much of which falls in a 6-8 hour period of very intense omega. Since all of the models show the same thing, and the radar echoes and IR cloud tops are blossoming, I don't think models are doing all that bad in the QPF department.

Snow growth actually looks very good with the best omega and RH values centered at -22C... CSI and even CI is present (and quite strong) along the axis of the TROWAL, again - within the best omega, RH, and temp range.

The big question is precipitation type. I still don't think it's clear cut... The 7PM obs showed snow at Hillsdale, and mixed precipitation at Port Huron (maybe errors?) - and this is the WARMEST the profile will be for the next +36 hours. In fact, ACARS data for 00Z shows only a very slim warm layer across areas of south central MI (near Hillsdale). If the atmosphere can support snow within moderate precipitation rates, what will happen tomorrow during a period of very heavy precipitation rates? I would think dynamic cooling (NOT evaporational cooling) would allow for all snow. There is still a good 2.5 inches of snow on the ground here with 0.75 inches of water equivalent... That will be pretty hard to melt with temps remaining in the mid 30's (34F right now).

I really think this is a go big or go home event... If precipitation rates don't materialize - things will be rain. If heavy precipitation does occur, it would probably be in the form of snowfall. Just how much snow would depend on where the axis of heaviest QPF sets up, how much QPF, and whether or not dynamic cooling can overcome the SFC to 1KFT AGL warm layer.

Here are a few case studies in which dynamic cooling caught forecasters off guard:

http://www.crh.noaa.gov/lmk/soo/sclimo/evt...t_jan171994.php
http://www.srh.noaa.gov/topics/attach/html...ml/ssd98-10.htm

 

[Robert Dewey]

DTX noted that the NAM is generally 1-4C too warm... And ACARS data would support this. Strong lift comes through tomorrow between 15Z and 00Z (eastern sections of MI) with good conditional instability present. This would support high precipitation rates, and with the temps already being so close to 0C, things could go isothermally 0C through about 850MB - supporting a rather quick changeover to snow.

DTX said they will be upping the totals by several inches (already at 1-3 inches, I'm guessing they will go with 3-5 inches). That looks reasonable at the moment, but precip rates / changover will have to be watched closely...

It's also interesting to note the system is stronger / slower this go around than the 12Z models. That would generate strong lift over a longer period, supporting a heavier snowfall.

Another very good case study from SPC: http://www.spc.noaa.gov/publications/goss/kaingoss.pdf

 

[rdale]

I picked up maybe 1-1.5" tops just north of Toledo. My CWA picked up 1/2" or less, looks like NWS call for up to 5" may have been a little overboard ;>

 

[nickgrillo]

I picked up about 0.25" inches of new snowfall last night at the most... Which has since completely melted (in addition to some of the previous snow). You can see plenty of grass... I'm glad to see we didn't have a "white" Christmas :twisted:

 

[Darin Brunin]

I picked up maybe 1-1.5" tops just north of Toledo. My CWA picked up 1/2" or less, looks like NWS call for up to 5" may have been a little overboard ;>

Why do you constantly criticize the National Weather Service? I'm curious to know what the reasoning for your weekly bashing is.

 

[rdale]

It's called "verifying" - not criticizing. The snow forecasts have been downright AWFUL so far this winter, and it makes my job much more difficult when I have to go on air all the time and say "you will hear of accumulations up to 12 inches or more over the next day, but we'll get little more than flurries." Made worse because much of my competition spits those numbers out too.

I don't think ignoring an awful (but widely disseminated) forecast is a good thing for me to do. And I don't go on-air and say "NWS are idiots, here's the real forecast" but I can't just pretend they aren't putting those insane numbers out into the datastream.

It's one thing if they said 4" and I said 3", but they called for up to 5" on Christmas Day which would require calling in the plows on overtime and create some massive travel troubles versus calling for flurries to an inch.

- Rob

 

[Robert Dewey]

Yeah... I was one of the ones thinking 3 to 5 inches. Didn't get any accumulation here in reality. I guess I was more in a wishcast mode...

I really thought that precipitation rates were going to be heavier... After seeing the 12Z DTX sounding, I was pretty sure that we would be looking at a quick change over to snow (the sounding was isothermal at 1C through about 850MB). Well, that layer never did cool and the precipitation stayed mostly rain up until about 00Z.

I wasn't too worried about snow not being able to accumulate on top of the snow which was already on the ground, but obviously accumulations on the pavement would have been a bit hard. It seems like I'm the only one that still has snow on the ground... I take it that places like LAN and over by Nick don't have any snow?

 

[Darin Brunin]

It's called "verifying" - not criticizing. The snow forecasts have been downright AWFUL so far this winter, and it makes my job much more difficult when I have to go on air all the time and say "you will hear of accumulations up to 12 inches or more over the next day, but we'll get little more than flurries." Made worse because much of my competition spits those numbers out too.

I don't think ignoring an awful (but widely disseminated) forecast is a good thing for me to do. And I don't go on-air and say "NWS are idiots, here's the real forecast" but I can't just pretend they aren't putting those insane numbers out into the datastream.

It's one thing if they said 4" and I said 3", but they called for up to 5" on Christmas Day which would require calling in the plows on overtime and create some massive travel troubles versus calling for flurries to an inch.

- Rob

I know what verifying a forecast is and that was nothing but smart assed criticism on your first post. What's the problem with doing your own forecasting? If you REALLY thought that there was going to be only a quarter of an inch of snow you would have used your own knowledge of forecasting to atleast back down the forecast a couple of inches. If not you aren't doing your job or using your met. degree IMO. After all, you yourself say that your local forecast office has been "AWFUL" at forecasting winter storms this year. That should only point you in the direction of relying on your own forecasts more. Also, what I pointed out in my first post was in reference to more than a couple of months and a few snow storms.

 

[rdale]

"If you REALLY thought that there was going to be only a quarter of an inch of snow you would have used your own knowledge of forecasting to atleast back down the forecast a couple of inches."

I did, and that's what I put out. However when a majority of the radio stations in town pull the rip-n-read, that means a large number of people would have been under the impression we are going to get 5" of snow. So my options are as follows:

1) Forecast my dusting to an inch, telling people that higher numbers are being put out there but I see no reason for them

or

2) Forecast my dusting to an inch, ignoring the 5" forecast.

or

3) Modifying my forecast to 5".

#3 is never an option. #2 means that the viewers will be confused, because they have two completely different forecasts and no way of determining which one to have confidence in.

So I choose option #1. And I've had to do it a lot lately. Not sure why, if it's the grids or if it's CYA syndrome or what.

"That should only point you in the direction of relying on your own forecasts more."

Not sure what you are assuming here - I never go with someone else's forecast. I make my own.

- Rob

 

[HAltschule]

Darin:

I agree with Rob in that his post was merely an innocent post saying that the NWS may have been a little overboard. That's what we do on other posts too. When there is a bust, we talk about it. Now, having been in the TV biz for 7 years, I can tell you that Rob is right on with what he is saying. When the NWS or other TV stations issue forecasts, everyone assumes it was yours too. They lump us all together. So if/when someone goes with a highly deviated forecast, it is the TV Mets who take all the heat. And usually we have to explain to others what happened because they thought the forecast was from the TV broadcast even though it may have been an NWS forecast that was read on the radio by some Joe Shmo.

Anyway, I believe Rob's post was not meant to start any wars or arguments but simply to discuss a busted forecast. Now you have some insight into the wonderful world of TV life too. There's a reason we refer to some viewers out there as Joe and Betty Beercan...because that describes how clueless some people really are.

 

[Darin Brunin]

When I replied to his post in the first place I wasn't even referring to whether Rob was right in how he forecasted snowfall amounts. I ended up going out on a tangent when he replied to my initial post.

My first rule of forecasting is to not brag about a more accurate forecast than your competition because the next time around it could be them having the upper hand.

If he was truly verifying a forecast he would have given reasoning to back up his own forecast and why it verified rather than posting a one liner to deem himself more superior than the GRR NWSFO. And like I stated in my first post, I see a common reoccurrence of this and was wondering what grudge he has against The National Weather Service in the first place. In my opinion it seems to run a lot deeper than just the NWS making his life miserable by their "AWFUL" forecasts.

Sure, you guys do have more experience than me in broadcast meteorology. That doesn't mean I don't have any idea of what goes on. I interned at a TV station last semester and do have a little bit of experience in the field so I am not "clueless" by any means.

it makes my job much more difficult when I have to go on air all the time and say "you will hear of accumulations up to 12 inches or more over the next day, but we'll get little more than flurries."

I took that as Rob being influenced by the NWS to spit out numbers that were different than his own forecast told him. I understand why this would occur and be a burden to any TV met. But if others are influencing you then it is not solely your own final on air forecast to your viewers.

 

[rdale]

"I see a common reoccurrence of this"

I think that tells you something about either the quality of the NWS forecasts or the deterministic way they are delivered... I.E. "snow up to 5 inches" versus "it looks like we'll just see a dusting, there is a small chance that if the snowfall rates are high enough we can get 5 inches." Text / grid forecasts aren't being used for that, and I don't know if they could be.

"what grudge he has against The National Weather Service in the first place."

I get along great with my local offices. But "offices" don't make forecasts, "people" make forecasts within those offices. And I don't hold a grudge against someone just because they put out bad forecasts. There is no "grudge" that comes out on TV. I think I clearly explained why I was not going with accum's in the first thread on this subject, so my one-liner post-event should have covered it. I didn't drag it out here or on-air, just said that I wouldn't worry about the high numbers being put out by other forecasting sources.

"I took that as Rob being influenced by the NWS to spit out numbers that were different than his own forecast told him."

Absolutely not.

- Rob

 

[Robert Dewey]

Don't worry Rob... There are a couple more events coming up that will provide plenty of grief between forecasters :lol:

I don't see any snow with this upcoming system in the next 36-48 hours... And my eyes are currently on the 84HR period. The NAM, GFS, and UKMET all show some degree of phasing, or perhaps a low riding along a quasistationary boundary. The 18Z NAM and 12Z UKMET show the most phasing, while the 18Z GFS isn't as agressive. The New Years Eve system looks like it will have some colder air to work with (not exactly arctic) compared to the past few systems...

What I can't believe is DTX stating that the first system holds some snow potential while the second wave "doesn't show as much boundary layer cooling".

If things look the same or better over the next few runs... I'll probably start up a new thread.