Things May Get Interesting After All....
The last 3 runs of the NAM and, to a lesser extent, the 12z run of the GFS now display a better potential for some accumulating lake snow by Sunday evening. Following a cold frontal passage around midday Sunday, a tight pressure gradient will produce strong winds and cold advection into the evening. There are some signs the boundary layer winds will back to either SWly or WSWly for much of the evening, with temperatures at 5000'/850mb becoming sufficiently cold to bring about some lake effect. Now that Lk Erie is down to 36 degrees, the lapse rate in temperatures between 850mb and the lake surface has dropped off. Earlier in the season, nature was able to crank some lake effect with an 850mb temp of -7 (C). Now, it needs to be around -9 or -10. However, during Sunday evening some lift will be generated by an upper level low. Of course, it's still too early to determine precise boundary layer wind directions, and the GFS has drier air over us Sunday evening than does the NAM, which can dampen activity considerably.
Winds will eventually veer to a more Wly or WNWly orientation on Christmas Eve, but there will still be some snow showers and limited lake snow, the latter being mainly in Ski Country and the srn tier. It looks dry and seasonable for Christmas.
Winds will eventually veer to a more Wly or WNWly orientation on Christmas Eve, but there will still be some snow showers and limited lake snow, the latter being mainly in Ski Country and the srn tier. It looks dry and seasonable for Christmas.
posted by Don Paul at
1:39 PM
41 Comments:
Thanks again, don.
looks like this will be another one of those systems to watch closely.
Do you see a bit of rain with it?
I really do hope we get some lake snows in buffalo. We hardly see a SW wind in buffalo. We see it once in a blue moon. Most of the lake snow are always in the ski country or southern erie.
Don im just woundering. lets say if it starts in the metro then shifts to the southern tier wolud evry one in between there be affected???
It would be so nice to have a FRESH coat of snow for Christmas day!! So if this LES event does look likely... it wont hit the north towns?? Or is it still too early to tell, and you would like to see more model runs...
Thanks!! -Sean from Getzville
Dear Mr.Don
it's great to hear that snow is possibly coming. however, We have 30 people coming to our house christmas eve. i think i said before we live in the Boston Hills. Would everyhting be okay or is it possible things might get rough. i know it's really early to tell. i just hope things don't get bad for the family.
otherwise let it snow, let it snow
im concerned about the winds during sunday the gfs is forecasting the 850mb winds to be 65 then rapidly increase to 80 so don i think those kinda winds have the magnitude to be potentially strong wind event what do u think don
btw why do storms appear on weekends this month or is it me last weekend we had winter storm and the weekend before it we had another one???????????
Don,
Sounds like your shifting your forecast closer to what the NCEP said yesterday. hmm
What is the probability right now, we could get some lake effect here in the metro on Sunday? 50-60%? Just wondering because its going to be in the upper 40s low 50s sunday morning to afternoon, then drop quickly once the cold front goes through right? Followed by extremely strong winds? or are the winds before the front goes through? Doesnt the winds mess with the Lake Effect? Temperatures at the surface will be close to 32 also, so maybe wet snow? Winds go from SW-WSW to West later on sunday night or monday morning? How many hours of snow for the metro, do you think?
Thanks!
alot of good questions there rich! some that we probably cant answer right now. We wouldnt want don to give you a answer and it end up being wrong come sunday. Lake effect can be VERY tricky.
anonymous--all the Climate Prediction Ctr was doing yesterday and the day before was broad-brushing the Great Lakes, which is of very little value for a smaller specific region. There was no evidence to support that broadbrush outlook until the 00z run last night of the NAM. That's why the Buffalo office and I chose to steer clear of an alarmist outlook in a specific forecast. There are enough chances to issue a false alarm.
Lake effect snow is mainly a meso (small)scale event, the the CPC doesn't deal with the mesoscale much, if at all. Understand?
By the way, anonymous, if you look at the CPC website today, you'll see the heavy snow outlook is gone--just strong winds.
I think that's a better call, because it's entirely unclear whether conditions will favor heavy l.e.s.
hey don paul what about the winds are they strong enough for a high wind warning or any advisories
They might be but, as almost always, it's too early to tell.
Heyy Don, is there a possibility of the air alofe getting colder then expected and we end up seeing heavier lake snow then expected??? Adam-from Hamburg
Mr. Don,
If winds get to "high" isn't that ususally to strong for lake effect. Doesn't the band usually get sheared apart. for example last lake effect event, Warsaw and Olean had the heaviest snow. the winds were 40 to 50 mph. wouldnt 50 to potientally as high as 60 mph winds to strong for lake effect formation? Or if it does form say on a 260 flow wouldn't it be heaviest in Java? Or on a 250 flow would it go to Medina or Rochester?
Just wondering.
marinecore--too much wind does produce too much wind shear in some cases, especially if the airmass is fairly dry. But we have had many lake storms with fairly strong winds, including gusts to over 50 (not sustained winds, though). Still too early this evening to be precise about boundary layer winds.
18z gfs does look good for the metro the wind is sw from all night sunday to monday morning but the strong winds may create some bad conditions on sunday night
There's definitely a subtle veering to the west from the southwest during the Sunday overnight period in the 18z GFS. The 00z NAM may hold on to the SWly flow a bit longer. In either case, the airmass dries out late Sunday into Sunday night, so at first glance this doesn't look to be that heavy event in either model--a dry slot will move across WNY late Sunday.
DP,
Good Job mentioning snow for the latter half of the game. The most important point is making sure the travelers get home safely from this home game...
We will be in good hands with MB again this weekend.. You and her are so good--excellent team work...
Don-
Do you think the north towns will see any accumulating LES this weekend?
Hey Don,
Is there a possibility that out ahead of this cold front there could develop a squaw line with damaging straight line winds ?
thanks
There is a chance that this storm could slow down and allow conditions to develop into a major LES event.. But model guidance are suggesting shear...Oh dear Shear always fear shear as shear will smear the lapse rates...
Im hearing high winds, rain... but not much in the way of snow! What is the snow aspect (if any) of this weekend storm?
Don-
What are the chances of Buffalo and its northren suburbs seeing lake effect snow?
I really hope we see some LES here in the north towns this time, we hardly ever see SW winds!!
Ed
Ed,
It's not just wind direction. It is also whether the winds have a connection to the Gulf or whether the winds are from the cut-off low having originated not from GofM but rather from Canada. We can see this in the models looking at the 850 and 500mb plots.. Sometimes the wind directions are not lined up together at all levels then we have shear! Dreaded shear is the dagger to a LES events heart.
Don please correct me if I mistated anything..
We don't have the precise wind vector/direction data yet tonight--we'll start to see it on Friday. Eyeballing the NAM & GFS, my first guess is not much for the northtowns, but Buffalo may be targeted for a few hours--or it may start south of the City in the Buffalo Stowns and settle further south by Monday AM. As I posted earlier, a dry slot crosses WNY behind the cold front. The cold advection doesn't appear to be carrying much that much moisture so that--combined with some shear--will probably hold down accumulations.
Look for a 240 degree boundary layer wind--if any of you have dabbled with numerical output on some websites--for any northtowns lake snow. 250 generally won't do it.
Yea... its never good to hear LES and strong winds in the same sentence... because those winds rip the LES bands appart, or sometimes dont allow them to form! However this is a seldom oppertunity for the north towns to see LES, I would think.
Ed
The 12z run of the NAM will include in its numerical output the likely low level/boundary layer wind direction. Until then, the lower resolution of the GFS (which sometimes doesn't capture backing winds that well) along with a visual check on the 00z NAM panels, doesn't seem to quite favor the Ntowns--but it can't be ruled out.
Don--
With all this rain, and temps nearing 50 degree mark for a day, wouldnt you think all of our snow would melt? (I live in Amherst) If the north towns are not really going to be appart of this LES event (which is pretty much our last chance for snow before xmas), then it will probaly be a greeeeeeen Christmas for the second year in a row :( oh well!
-Jim
just checked some national weather outlooks, and theres light snow forecasted for Monday around 1am with winds at 250 deg (90% chance of precip). The light snow is forecasted to stick around until 1pm with wind directions shifting to 252 deg at 7am (80%chance of precip) and 258by 1pm (70%chance of precip). To me, that looks like we'll see snow in metro area and north towns. Temps are forecasted high of 31 low of 21.
Just another source, but it looks promising for snow.
I'm expecting area creeks to rise due to the combo of 1" water equiv on the tarmac and some rain. Area creeks will rise but don't expect any flooding unless we get more phasing. We need the water to help support the area wells. Looking at mostly a green christmas. Green is in anyway..
Hey...is there one cold night in there to freeze the backyard rink????
lg, Christmas eve highs are around 31. I'm waiting around for Don's outlook but there should be some steady winds with that, so from 12am on to the night, temps will be cold enough to freeze your rink. The rain that comes before it on Sunday may cause some puckering of your ice, though. You're gonna have to get up really early in the morning to groom it.
lakeshadow, I'm curious where you got such precise wind vector information.
YAY SNOW!!!! WAIT NO SNOW FOR LOCKPORT?!? LOVE THE WHITE STUFF PLEASE KEEP US UP DATED.
http://www.wunderground.com/cgi-
bin/findweather/getForecast?query=14225&hourly=1&yday=357
&weekday=Monday
What places are in the most southern of Niagara County?
Don said southwest winds and west south west that means itll set up closer to the southtowns yayyyyyy hammburg gets a wsw wind trust me id know i hope the stay wsw for ever yayyyyyyyyyy i hope buffalo and the southowns see a white christmass yayyyyyyy
what happened?
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