Widespread Lake Effect/Upslope Snows Expected Later this Week...
Posted Tuesday, 18 December 2012
A closed upper level low will continue to slowly move through southern Canada and upstate New York during the later half of the upcoming week. A deep trough and subsequent northwest flow will allow for the first prolonged lake effect snow event of the year. Widespread upslope snows are also expected across the Appalachians up through the White/Green Mountains. Accumulations will be widespread in the snow belt regions, but generally light to moderate amounts.
Lake Effect Snow Outbreak December 21-23, 2012
A significant winter storm will be tracking through the Midwest and Great Lakes by the middle of this week. This 992mb surface low will track across the Great Lakes and begin to weaken across western New York. A closed upper level low will begin to slowly meander across southern Canada increasing moisture under a northwest flow behind the steep cold front. H85 thermals will fall to a meager -6C, but given that lake temperatures are near 10F above normal, there will be enough of a gradient to spark a widespread lake effect event. The flow for the duration of the event will be around 300-315 degrees with possibly an even more northerly component depending on the track of the ULL. Limited instability will prevent significant banding, but nevertheless with PWATs +0.5SD there will be widespread snow shower activity for several days across the region.
This flow will increase snows across favored upslope and orographic locations from northern West Virginia up through the Laurel Highlands. Favored peaks in Garret County, MD up through Mt. Davis, PA and Laurel Summit, PA may see upwards of 10" of snow during this period. Current model QPF is already at an impressive ~0.5 inches. Across the Chautauqua Ridge in southwestern New York, upslope totals may also approach 10" of snow. This will help lay a fresh snow pack to several ski resorts in the region that are featuring a seasonal snow deficit of nearly two feet to date. As drier air begins to rotate into the region on Saturday, widespread light snow shower activity (with a few enhanced SN bands) will begin to focus into a more cellular nature under diurnal forcing. Mesoscale guidance indicates the development of several stronger bands off of Ontario down through possibly Rochester and Syracuse. UUV and omega growth peak during this period allowing for excellent dendritic growth. Snow ratios during this period may approach 17:1 with snow rates at 1in/hr in some locations. Northern Cayuga County through Onondaga and Madison Counties in New York will see the highest accumulations. During this period upslope snows will increase across northern Vermont in the higher elevations. This will be a multi-day event for this area with amounts approaching two feet above 3000ft by Monday.
Given the length of the fetch and typical northwest flow, a few snow bands may stretch east of the mountains into the central ridge and valley region of Pennsylvania and Poconos. Any accumulations in this area will be isolated and generally around 1-3 inches. A bit of Huron connection may be possible Saturday night during the peak of the lake effect snow event. At this point in the medium range, it is too early to highlight typical bands such as the 322 streamer.
Drier and more stable air will cutoff the cyclonic circulation by early next week with more seasonable temperatures. Winds will also begin to relax.
Regional Radar...
(Courtesy of NOAA)
Regional Advisories...
(Courtesy of NOAA)
Storm Reports...
None.
Storm Impacts...
1. Sustained winds of 20-30mph with gusts approaching 40mph are expected over the region with whiteout conditions possible in snow squalls.
2. Deep moisture field and long fetch will allow snow showers to stretch east of the mountains.
3. Heavy snow accumulations in favored 300 degree snow belts are expected with totals approaching up to 10"
4. First widespread lake effect event of the winter will have greater impacts than normal due to the the infrequency this December.
5. Temperatures and air mass will be marginally cold and generally in the upper 20s to mid 30s for most areas.
Snow Map...
*The heaviest snow accumulations will be confined to the higher elevations and favored northwest flow snow belt regions. The highest accumulations are expected near the Syracuse metro region and across the upslope effect region of the Green Mountains near Stowe in northern Vermont. Heavy accumulations are also likely up through West Virginia and into the Laurel Highlands. Outside the snow belts snow amounts will be more isolated and dependent on the exact location of the bands and showers which are impossible to forecast exactly at this point in time.
Current Great Lakes Water Temperatures...
(Courtesy of NOAA)
Current Lake Erie Wind Direction and Speed...
(Courtesy of NOAA)
Current Lake Erie Water Temperature...
(Courtesy of NOAA)
"Selected City Accumulations"
Erie- 4-6" of snow with higher amounts to the south and east of the city
Meadville, PA- 4-8" of snow
Bradford, PA- 3-6" of snow with higher amounts near Warren County
Butler, PA- 2-4" of snow
Pittsburgh, PA- 1-4" of snow with isolated higher amounts
Latrobe, PA- 1-4" of snow
Indiana, PA- 2-4" of snow
Johnstown, PA- 5-10" of snow with higher amounts possible
Somerset, PA- 4-8" of snow with higher amounts possible
Altoona, PA- 1-4" of snow
Du Bois/Clearfield, PA- 3-6" of snow with locally higher amounts
Philipsburg, PA- 3-5" of snow
State College, PA- 1-3" of snow
Lock Haven, PA- 1-3" of snow
Williamsport, PA- Locally 1-2" of snow
Mt. Pocono, PA- 1-2" of snow
Selinsgrove, PA- Locally 1-2" of snow
Harrisburg, PA- Isolated C-1" of snow
Hagerstown, MD- Isolated C-1" of snow
Cumberland, MD- 1-3" of snow
Frostburg, MD- 2-4" of snow
McHenry, MD- 4-8" of snow
Oakland, MD- 4-9" of snow
Snowshoe, WV- 4-9" of snow
Buffalo, NY- 2-5" of snow with higher amounts to the south and west
Watertown, NY- 3-5" of snow
Syracuse, NY- 6-12" of snow with locally higher amounts
Albany, NY- Locally 1-2" of snow
Ithaca, NY- 1-4" of snow
Binghamton, NY- 1-2" of snow
Saranac Lake, NY- 3-5" of snow
Utica, NY- 5-10" of snow
Burlington, VT- 1-2" of snow. Higher amounts to east approaching 12"
North Conway, NH- 1-4" of snow
"Subject to Change"
Current Northeast Snow Depth and Northeast Wind chills...
(Courtesy of Wunderground)
Model Analysis
The GFS is a low resolution global model that typically does not do well in mesoscale events such as lake effect snow. But forecast QPF maps already suggest widespread high amounts over the Northeast snow belts, which is very impressive at this forecast range. A deep moisture field and long northwest fetch is suggested. The ECMWF is also in full support of this event especially across the upslope regions of northern Vermont where an extended multi-day period of heavy snow is possible. Isolated amounts in this region could reach 24" in some areas above 3000ft. All guidance supports a closed low that will allow for a bit of synoptic influence favoring some lighter snows outside the typical snow belts especially for western Pennsylvania and upstate western New York. These amounts will remain light though with QPF less than .15" for most areas. At this range, the NAM and other high resolution guidance is a bit too far out for their time frame. Latest trends in the GFS/ECMWF are showing a possible increase northerly component which would decrease the widespread activity of the snow showers. At this time it looks like the Buffalo metro area will be spared the worst of the event, while areas towards Rochester and Syracuse will be more favored.
After the Storm
As temperature anomalies approach +6F for the month of December for many climatological reporting stations across the Northeast, many are left asking where is winter. A majority of the cold air is locked well to the northwest of the contiguous United States in northern Canada. Even across areas seeing the next bout of winter weather in the Midwest, H85 thermals never even fall below -10C south of the Canadian border. This is a clear indication that much of the nation is well above normal in the temperature department. A +EPO in correspondance with a -PNA will continue to keep the cold air locked up to the north through the end of the month. A few energy meteorologists have been hinting at winter storm chances post Christmas in the Northeast, but given the latest tropical monsoon forcing indices out of the Indian Ocean and the status quo of the current NAO, it is likely these middle latitude cyclones will continue tracking through the Great Lakes. If any secondary cyclogenesis occurs on the east coast, it will only favor far northern New England with wintry precipitation. Unless we see a dramatic change in ensemble guidance and teleconnections, period through the end of December will be snowless across much of the east. While temperatures will likely average near normal, they will feature an oscillating pattern of unseasonable warmth as lows track to the northwest, and then brief arctic air behind the cold fronts.
After a near record dry November, the polar jet has begun to increase in activity as we continue a stormy pattern with several shortwaves per week. This pattern will continue through early January with precipitation totals averaging above normal for all climatological stations. While the MJO forcing remains meager and few changes in the NAO are expected, there are a few signs that the EPO will shift negative and begin to dump some arctic air farther south. As we also enter the coldest portion of the year, it is likely snow chances will begin to increase by early January. That being said, there are no signs of any abnormally snow periods.
Despite another snowless and record warm start to the meteorological winter, the synoptic pattern is very different than last winter. Whether that is encouraging or not, it is critical for snowlovers that we do not see any development of a PV in Alaska. This would disrupt the potentially favorable Pacific by January and allow increasing upper level heights over the eastern United States. The main idea to take from the long term will be a continued stormy pattern of Great Lakes cutters, while the east coast sees mostly rain in association with frontal passages. Any front end warm air advection winter precipitation will likely be confined to northern New England. If any pattern change does occur, it will likely be post New Years.
Please post storm reports in this blog from across the Northeast during the winter storm and please post location of observation in each report...
This blog is in progress. Check back soon...
Winter Forecast 2012-2013... Link
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Lower Susquehanna Valley Doppler...
(Courtesy of WGAL)
"10mi northeast of Harrisburg 2012-2013 Winter Statistics"
(Snow Stats)
Monthly Total (October)- 0.0in
Monthly Total (November)- 0.8"
Monthly Total (December)- 9.5"
Seasonal Total- 10.3"
Winter Weather Advisories- 4
Winter Storm Warnings- 0
Ice Storm Warnings- 0
Blizzard Warnings- 0
Freezing Rain Advisories- 0
Winter Storm Watches- 0
(Temperature Stats)
Lowest High Temperature- 36.1F
Lowest Low Temperature- 18.5F
Wind Chill Advisories- 0
Wind Chill Warnings- 0
(Snow Storms Stats)
First Trace of Snow - November 24 - Lake Effect Snow Showers
First Measurable Snow - November 27 - 0.8" - Overrunning event
Enhanced Clipper - December 24 - 2.1" - Christmas Eve Snow!
Miller B - December 26 - 3.3" - 0.15" of freezing rain also
Miller B - December 29 - 4.1" - Moderate all snow event
Reader Comments
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29F overnight here in Tinton Falls NJ -- above the forecasting and modeling of 22-25F.
I wonder if there are implications.
As I felt until the meandering lingering low departed that the models weren't able to properly depict the upcoming environment for the Saturday low.
They didn't and we can see while it wasn't too far off it certainly made a difference.
Trended warmer despite a further south low solution and of course lighter precip.
Still seems to be some if ands buts involved in forecast discussions - where is the heavier band - how far north does the warmth get - which could put some folks (Philly into central/southern NJ) in the inch of slush to 4-5 inches of snow - either or - Clusteryouknowwhat of a forecasting problem!
So, stay tuned to those fine details which as we know never come until the onset of an event.
For now it looks like mix or rain at the coasts. Could be a 0" bust to a 2" mess.
Not too far inland could be 2" bust to 4-5" luck of the draw with the expected short lived banding setting up.
Not sure where I'd place this storm but I think the NWS is using the proper approach with this one.. 2-4" widespread, watch where the mix lines set up for more or less in those borderline areas.
Interesting since both the NAM and GFS seemed to be pretty low on their totals.
The NAM especially has recently been a low and warm outlier with these systems.
Perhaps the different low approach as we move into what seems like a more zonal flow...is what the NAM is better at.
Honestly it seemed at first we could be headed for a widespread 4-8" Philly--Boston type event. (going back a few days ago).
Then I saw that the first storm was going to linger and meander on Thursday and knew it'd put a wrench in all of that.
Yet now it seems like the forecasting may be a bit on the lower side of things?
I guess we will see a correction this evening and an uptick in forecasted totals.
Mount Holly had us at 2-4" and just downgraded us to 1-3". I think they saw your map and reconsidered, Blizz! :)
Showing 9" in Chatham,MA.
I know there are some, as Blizz is one, who has the cape as snow and a good deal at that.
There are some that have it as rain or mix, as the NWS does.
Anyone have any thoughts here? Models having problems depicting how the low will intensify and where it turns northward heading towards Nova Scotia?
Looks like Eastern MA is a confusing forecast at this point.
...
The rest of us seem to be holding firm with the widespread 2-4", possibly less in mix prone areas, possibly more in 'heavy banding' areas.
I feel like there is still uncertainty in this storm and nobody really wants to commit lower towards bust or higher into Watch/Warning potentials.... so everyone is just echoing "2-4" and mentioning the mix lines as an out.
*shrug*
New York has seemingly begun to favor heavier totals. 3-4" now.
Taunton MA is holding firm with their totals. Mostly 2-4" as well with some hints 4-5" around 495 to RI region, and rain/mix on the cape.
Interesting to note the NWS seemingly ignores that models show next to nothing for central and southern NJ and have gone with 2-4", 1-2" immediate coast. Models seem to follow I95 as the rain/snow line while NWS has a more west-east snow line in southern NJ with some tapering further inland further south you go.
And by interesting I of course mean frustrating, annoying, and why do we wait until the event is nearly over to be able to properly forecast it?
Something odd to me regarding the tentative nature of this forecast.
Also curious is the widespread mid-30s high temps throughout the regions coupled with all-snow forecasts and calls for 2-4".
I dunno...somethings off...and it all goes back to Mt Holly a couple discussions back alluding to an awful lot of if/ands/thens in regards to potential phasing, when, where, ETC.
Anyone else feel the high bust and high hit potential here? Like it's there so they've simply split the difference? Uniformly office to office?
...dream world.
So far, yeah, and that's odd since their snow maps are absolutely advisory criteria.
Could be a question of timing in terms of precip onset versus when to issue.
But something just seems overly odd with the whole forecast, model runs included.
Perhaps they are being tentative in making it offical waiting until this evening to "be sure". Meaning, maybe they see bust potential here. (They wouldnt hold off if they felt it might be stronger than expected, they'd do the advisories, then upgrade)
Well there you go... rain introduced into forecast for most local areas within the last half hour
So now we understand. Science no longer applies. Steady accumulating snows in mid30s possibly upper 30s. And rain at 12F.
GOT IT!
haha.
I think they're not confident either way yet with the rain/snow lines and are unwilling to commit to either warmer or stronger/colder. Perhaps later this evening the wording will tighten up.
For now it just seems like they are splitting the difference and waiting to see which way to lean as we get closer. Also giving us the out with the whole mention of potential mixing at the coasts - while also giving mention of an interior heavier snow band possibly setting up - somewhere.
Just....seems like averaging out the outlying solutions and splitting the differnce "to be safe".
They need to get it right tonight - for tomorrow morning what we read will coincide with the onset of the system...and at that point..what good is forecasting other than "Yeah, its snowing, so, here's your forecast: Snow!" (LOL)
Confusing forecast indeed. WWA advisories now into southern CT and spread northeastward. The first Winter Storm Warnings that I've seen are list for portions of Indiana and Ohio. Not sure what to make of that.
==========
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
THE APPROACHING SYSTEM IS PROGRESSIVE (THERE ISN`T ANY PHASING AT
MID LEVELS), HAS MODERATE DYNAMICS (THE UPPER JET, Q-VECTOR
CONVERGENCE, DIFFERENTIAL DIVERGENCE, AND TROWAL ARE THERE BUT ARE
NOT TERRIBLY ROBUST), AND MODERATE MESOSCALE FORCING PER LOWER
LEVEL FRONTOGENETIC FIELDS. IT ALSO HAS DECENT LIFT IN THE SNOW
GROWTH REGION WITH A NEAR-ISOTHERMAL THETA E PROFILE AT THAT LEVEL.
ON THE OTHER HAND, IT DOES NOT HAVE ANY COLD HIGH PRESSURE SYSTEM
TO THE NORTH TO TAP, AND THE WINDS IN THE SNOW GROWTH REGION ARE
RATHER ROBUST. CHANGES IN THE LATEST MODEL RUNS GENERALLY TREND A
LITTLE BIT WARMER AND A LITTLE BIT WETTER. ALL OF THIS AND A
DESIRE TO MAINTAIN SOME CONTINUITY ARE FACTORED INTO THIS
PARTICULAR FORECAST, WHICH INCREASES SNOWFALL AMOUNTS A BIT
NORTHWEST AND DECREASES THEM A BIT SOUTHEAST. WE MAINTAIN THE
ADVISORY AS IT WAS. WERE THIS FORECASTER TO BE THE CONFIDENT
TYPE, HE MIGHT HAVE TRIMMED OFF SOME OF THE SOUTHERN EDGE OF THE
ADVISORY. HOWEVER, HE IS WELL AWARE OF THE PERISHABLE NATURE OF
ANY ONE SNOWFALL FORECAST.
WE WENT WITH THE COLDEST STAT GUIDANCE WE COULD FIND ON
TEMPERATURES, BECAUSE THE WARM AIR ADVECTION ABOVE THE SURFACE IS
NOT TERRIBLY STRONG; EVAPORATIONAL AND SOME DYNAMIC COOLING CAN BE
EXPECTED, AND IT WILL BE CLOUDY WITH PRECIPITATION WHEN THE SUN IS
ABOUT AT ITS LOWEST ANGLE OF THE YEAR.
============
In other words...they have low confidence in their temperature forecasts, and thus the rain/snow line, and thus accumulations.
NOT helpful...to anyone.
These aren't forecasts, IMO - they're jokes. So much for my daily entertainment...back to work.
Winter Storm Watch for parts of RI and Mass
Conversation in office must have went something like this
"GFS and NAM and other model guidance points us in 10 different directions but surrounding offices have issues WWx, what shall we do?"
"I dont know bro, it might rain we cant post Warnings yet"
"Screw it.. You want to just post a Watch even though the event is less than 18 hours away?"
" I'm cool with that"
NW Suburbs as in Me? Roseland, NJ
Seems like a rain/snow line is going to set up where one town gets nothing and the adjacent town gets 5". It would seem given the temperatures coming in that a very tight gradient from max amounts to rain-influenced minimum amounts would arise.
Seems we got teased on this one.
Taunton MA really upped their totals. Widespread 6-8".
New York has yet to update..... but I think they will and will up their inland totals to mesh nicely with Mt Holly and Taunton.
Well, I hope the timing of the storm is about what is currently anticipated, as we plan to drive to Eastern MA tomorrow morning, back on Sunday afternoon. If the storm comes too soon that's a problem. Too late and again it will be an issue for us.
We'll be monitoring, that's for sure!
It's been a rough forecast attempt so far...are they zeroing in on it now? Or are we up for more flip flops in models and thus forecasts?
Seems like your difficulties are all about the system wrapping up. Ours further south here in NJ are all about the rain/snow line which they have continued to migrate northward each forecast update.
It really is..and it's presentation more closely mimics the model ensembles that wanted to be colder solutions for the northern middle atlantic. Wonder if there's anything to that or not.
It's really been a strange evolution of forecasting this one.
It's ok with me that NWS doesn't know, and I like that they say they have low confidence so we know they don't know. Much of science is art, and I'd rather it be my meteorologist than my physician.
Here's what Steven DiMartino has to say:
"For the most part the forecast is unchanged for many locations. However, I did bump up totals just away from the coast to 3 to 5 inches because I'm becoming increasingly concerned with the threat for mesoscale lifting properties. There in lies the difference between models like the ECMWF (synoptic) and the more juiced up NAM/HRRR guidance. I think the NAM/HRRR are picking up the mesoscale lifting potential while the GFS/ECMWF are not. Note, all models have the same timing on the phasing, which is a bit earlier than thought this morning, and the same track. The difference is that the mesoscale models are picking up mesoscale features that the synoptic models have a difficult time doing. Still, I think most people see around 2 to 3 inches of snow out of this low pressure system."
Think the folks from NW VT. will have either a cake walk or a knuckle dragger back from down east again. Great photos by the way. P-C ( :-) ) either way its a more interesting time to view the changing winter scene. Kids in so we have been building sand castles and tunnels on the beach. So far its been a beach week.
You will have to forgive, it will extend that far north. I put the map together pretty early this morning and a few pieces of guidance were not in yet showing the snow reaching that far north in New England. You will probably see 2-4in with higher amounts across the mountains.
By the way I forgot to mention, I love your pictures below! Thanks for posting!
Ah, I see. No worries; it's simply good to comprehend.
Turns out my family has decided to cancel our family gathering in MA for tomorrow, as family would be driving in from CT, ME, NH and VT. =Sigh=
I'm glad you like the photos! I have more and may post some as the storm gets going. I just didn't want to be showing all my treasure while others are looking at grass, y'know?
May the whim of the snow gods lead to snow goons for all! :-)
Off blog for the evening :-)
but sure will be checking in tomorrow!
But it has a nice plume of up to 0.5" per hour rates that starts to build quickly near Maryland behind the collapsing dry slot by 11am.
The 00z GFS has that dry slot as well with the best accumulated snowfall over north-central PA by 7pm Saturday.
The 00z NAM has everything placed several miles to the east of the GFS by 7pm Saturday.
All winter weather products were mountain only. Didn't even manage a special weather statement here. The forecast was 34 degrees and rain.
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