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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Good luck, everyone! And have a very Happy Holiday.
Merry Christmas to one and all.
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE PITTSBURGH PA
425 PM EST MON DEC 24 2012
OHZ039>041-048>050-PAZ007>009-013>016-020>023-073 -WVZ001-250530-
/O.NEW.KPBZ.WS.A.0006.121226T0300Z-121227T1100Z/
TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON- JEFFERSON OH-
MERCER-VENANGO-FOREST-LAWRENCE-BUTLER-CLARION-JEF FERSON PA-BEAVER-
ALLEGHENY-ARMSTRONG-INDIANA-WESTMORELAND-HANCOCK-
INCLUDING THE CITIES OF...NEW PHILADELPHIA...DOVER...
UHRICHSVILLE...CARROLLTON...EAST LIVERPOOL...SALEM...COLUMBIANA...
EAST PALESTINE...WELLSVILLE...CALCUTTA...COSHOCTON...CA DIZ...
HOPEDALE...STEUBENVILLE...SHARON...HERMITAGE...GR OVE CITY...
GREENVILLE...FARRELL...OIL CITY...FRANKLIN...SUGARCREEK...
TIONESTA...NEW CASTLE...ELLWOOD CITY...BUTLER...ZELIENOPLE...
CLARION...PUNXSUTAWNEY...BROOKVILLE...REYNOLDSVIL LE...BROCKWAY...
ALIQUIPPA...BEAVER FALLS...AMBRIDGE...MONACA...BEAVER...
PITTSBURGH METRO AREA...KITTANNING...FORD CITY...LEECHBURG...
FREEPORT...APOLLO...INDIANA...GREENSBURG...NEW KENSINGTON...
JEANNETTE...LATROBE...MONESSEN...WEIRTON
425 PM EST MON DEC 24 2012
...WINTER STORM WATCH IN EFFECT FROM TUESDAY EVENING THROUGH LATE
WEDNESDAY NIGHT...
THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A WINTER
STORM WATCH...WHICH IS IN EFFECT FROM TUESDAY EVENING THROUGH
LATE WEDNESDAY NIGHT.
* HAZARD TYPES...HEAVY SNOW.
* ACCUMULATIONS...THE POTENTIAL FOR AT LEAST 6 INCHES OF SNOW.
* TIMING...LIGHT SNOW WILL BEGIN LATE TUESDAY NIGHT. SNOW
INTENSITY WILL INCREASE DURING THE DAY ON WEDNESDAY BEFORE
TAPERING OFF WEDNESDAY NIGHT.
Maybe a slushy dusting on the grass tonight.
Heavy rain and wind on the way for part 2. Could be somewhat interesting NW NJ, and interior SE NY and CT depending on how the low tracks and winds up.
Pretty strong onshore fetch for us down here at the coastlines. Something pretty dramatic would have to happen to get us in the heavy snow.
Catskills could see quite the storm tho. Both NAM and GFS slam em 12-15".
Weekend a better shot for all? Seems to be some hints about that. Let's see how the big one Wed pulls out first.
Amazing how the models showed NOTHING since the beginning of December and look we have a White Christmas. I don't recall any snow on Christmas Eve in my lifetime which spans since the 60's. Not to mention very little Christmas snow.
Any chance of the storm moving 100 miles south? haha
Lt back to your earlier post, I did a little better than I expected actually, thanks!
Looks like the lake effect theme this year is elements...
See, I find this acceptable because it's just a pet name for the storm in hindsight and is only used at the office; plus they don't use actual 'names'. TWC tries to push their names on the mass media...
1. Timing. When do you think the snow will wind down in the Laurel highlands and P-burgh area? Before dark on Wednesday? Or will it continue into the night or thru the night on Wednesday night?
2. Winds. I am also concerned about blowing and drifting, making it hard for the plows to clear the roads and keep them clear.
3. Accumulation. Your posts yesterday showed a big chunk of my route in the heavy snow area. Does that still stand? Accuweather (i know, consider the source!) is saying 3-6 for Pittsburgh, but if a foot is possible/likely, that is a much bigger deal.
4. Lake effect snow in the aftermath of the main storm. This concern is triggered by the idea of driving along the shore of Erie in northern Ohio.
I would be grateful for your insights, or those of the other weather geeks on the blog.
Thanks!
My Opinion and Forcasts---It looks as though snow will start at sunrise in Pittsburgh, going through akron, cleveland and sandusky on RT 76-80 you will run into blizzard conditons---I would not recommend leaving until Thursday.
Here is a map I made for tomorrow. Tell me what ya think!
Naturally I get nervous this time of year as a home visit nurse. I have a daily client that must be seen. It will be interesting to see what develops here in the Pittsburgh area. Will we get the warmer solution? Or will we get the heavy snow projected by the GFS. Stay tuned.
Enjoy your Christmas dinners, your families and a peaceful night to one and all.
Yeah, it would be crazy to try the trip on Wednesday. I am just wondering if things will settle down enough by Thursday for the major highways to be tolerable.
Thx,
Doom
The locals are saying we will see 10" to 18" beginning 7pm Weds and ending 7am Friday. We'll see!
Meanwhile, I have some snow photos, taken on our Christmas Day drive to and from our son's house near Mount Abraham, in Vermont.
Camel's Hump
Waterfall
Smooth River
Redpolls
I am so jealous.
We are still stuck in a very stark model forecast contrast for the upcoming storm. This is one of the more difficult forecasts in the last few winters. Currently the ECWMF favors a colder outlook and has been very consistent over the last few days. The NAM is nearly +4C warmer for H85 thermals and also very consistent in its approach. But the NAM seems to be having some initiation problems with 850mb temperatures already.
Current surface conditions indicate a weak high over New York and a possible low transfer to the coast already off the southeast. A steady northeast wind is being reported for many locations and will help to lock in the cold air east of the mountains. Also temperatures last night fell lower than expected for many locations in addition with the wet bulb temperatures. Often in these situations the mid level warm layer moves in faster than expected, but low level cold air stays locked in much larger.
The hardest forecast will be the amount of snow. I would take a mean between the GFS/ECWMF expected snowfall with accumulations of 4in or more possible as far south as the Mason-Dixon line in some areas. But if the mid level warm layer is more prominent, significant sleet accumulations are possible. I also expected temperatures to remain below freezing along and north of the PA turnpike for the majority of the event. This will cause a significant ice event in some areas. Presently I would bring the NWS warnings down one layer of counties and the advisories also down one layer of counties. It will be interesting to see what happens as the day progresses.
Here 10mi northeast of Harrisburg I am at 27F with a dew point of 23F. I also have a steady light wind out of the east-northeast. There is a bit of snow still on the ground in the shaded spots from the other night. I think we are going to have a tough time seeing just plain rain and that it will likely wait until a majority of the precipitation is over. We will see though; this is a tough forecast and due to the it falling near Christmas I have not had the time to fully analyze it.
Blizz- I assume the forecast for the coastal areas is going to be mostly rain, is that right?
Also, we have another storm coming in a couple days... I can't believe how quiet this blog is, Christmas or not... I hope everyone had a very Merry Christmas!
I see there are 2 more storms coming after this one. wow. Amazing how 2 weeks ago you were saying the Christmas season is not looking good and look at it now.
edit now 25/25
Yep, most likely rain for coastal areas although a brief period of wintry precipitation is possible for the onset.
CTP NWS advisories also do not make sense. The latest one for York/Lancaster says 3-5in, while the one for the next tier counties north says 2-4in. Completely backwards?
EDIT: I see they have since fixed the confusion.
TheRasberryPatch- Lol, I know. I am very surprised how this week unfolded at least from a perspective two weeks ago. In fact it is likely we end up with above normal snowfall for the month of December here in Harrisburg by the end of the month haha
Enjoy the snow, all who get it!
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