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
Follow my 24hr forecasts on Twitter... Link and Facebook... Link.
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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All winter weather products were mountain only. Didn't even manage a special weather statement here. The forecast was 34 degrees and rain.
Many days ago when the forecast discussion first mentioned this storm the possibility of two pieces of energy, one south, one north, was brought up.
Seems like that's exactly what we have here.
A lack of any phasing at all between the two.
Does this destroy all the forecasts? Does piece one move out to sea and piece two meanders eastward bringing light snows 1-2" through NJ-NYC?
What we have on radar no longer appears to match the forecasting.
Whatever happens this morning and early afternoon it sure isn't what they expected and thus forecasted.
Yet we have all watched since day one this system change on the model runs and also in forecasting...dramatically at times.
So, well, whatever.
Morning.
I've got 32F here. Has been steady at that since 10PM.
A little 'save our rears' type wording this morning in the discussion.
THE DRY AIR IS
GRADUALLY LOSING GROUND AND THE SURFACE IS MOISTENING AS DEW POINTS
IN SOME AREAS HAVE BEEN INCHING UP A LITTLE DURING THE PAST SEVERAL
HOURS. WE WILL MAKE SOME ADJUSTMENTS TO THE POPS AND HOURLY
TEMPERATURES AND DEW POINTS, BUT OVERALL THINGS SEEM TO BE ON TRACK.
THE 06Z GFS/NAM SHOW MORE OF A DRY SLOT OR QPF MINIMUM MOVING NEARLY
RIGHT UP THE INTERSTATE 95 CORRIDOR, AND RADAR TRENDS SO FAR ARE
SHOWING THIS AS THERE IS LITTLE TO OUR SOUTHWEST. WE THINK THIS WILL
FILL IN SOME AS THE UPPER-LEVEL TROUGH MOVES CLOSER AND LARGE SCALE
ASCENT INCREASES. FORECAST SNOWFALL AMOUNTS OVERALL ESPECIALLY ALONG
INTERSTATE 95 MAY BE ON THE HIGH SIDE, BUT FOR NOW WE MADE NO
CHANGES WITH THIS UPDATE.
===
Just admit you clusterfubared it instead of trying to make it seem like you were close. I mean, they admitted yesterday they didnt have a handle on the details and several days prior that there was a lot if then shoulds with the system. Then this morning's forecaster seems to be typing with a blushed face and sweaty palms with a bruised ego.
Odd, really... especially since they continuously ignored models showing no snow accumulations in NJ...when they've been caught model watching often and not forecasting.
This time they tried to forecast while ignoring the models and well.. LOL!!!
Good call. Very well shown on this product:
SSEC Image Loop
Select the GOES-12 Water Vapor Enhancement.
Look at Illinois and Missouri to get acquainted with how the color scale depicts the cold you speak of. Then look at our area.
Clear as day.
Warm piece headed off the coast. Cold piece coming in from the west.
None of this seems to echo the forecast discussions.
IN APPEARANCE one would be inclined to consider the warm piece heading off the coast as of no consiquence and only focus on the Ohio-PA disturbance which appears cold and moving due east.
As if we were in for 1-2" of dry snow showers.
*big shrug*
If and WHEREVER the coastal low forms and takes over would we not already be well on the cold side of things...and just watch the low wind up and pull more cold down?
Just like last night...something..well, nothing...seems to match here. (forecasts, models, imagery) all on separate pages it seems.
Good luck, everyone! And congratulations on your 40th anniversay, Listener. :)
Come on snow!
Come on snow!
9:30am, 23.2F, Light Snow
Dry slot just closed in a few minutes ago. Coating of accumulation so far. I'm going against the NWS and expecting 2" here rather than the 3"-5"
There's quite a bit of snow here in da Burgh this morning. We had about 3" on the ground left over from the previous storm. This storm has brought us reports of 2 to 3 additional inches so far according to the mets. We are expecting another 2" before it's over. Currently light fine snow falling. I need a gas snow blower. My electric one doesn't do a whole lot.
Ollie the aussie is thrilled with his winter playground of fresh white. He refused to come in when I called him.
Graupel is a type of snow.
11z HRRR, 6am to 9pm today
6z GFS, 1am Saturday to 1am Sunday
6z NAM, 1am Saturday to 1am Sunday
Nothing else falling from the sky.
But we have gone up to 39F.
Tinton Falls, NJ, and we're inland where we usually get snow if the coast is borderline or rain. Not this time.
We'll see what happens when the whole mess pulls out later today if we get a couple of inches of the back side.
No telling given the high bust factor of the modeling and forecasting for this particular region.
Probably, LT, maybe even cooler up on that hill.
We warmed rapidly this morning.
And I doubt this precip coming in is the column cooling kind either.
Rain it is...and we see what happens later. Nothing special it appears.
Interesting is yesterday's forecast discussion they said they were going several degrees cooler than the coldest guidance they could find. They gave no reasoning, just said they were, they did, and it's now 5-8 degrees warmer than they forecast.
Models said warm, no snow, for me... and they went against it and heavily at that. Told us they would.
And...it's warm and wet.
Would be nice to know why they went that way. I am guessing they thought the models were wrong in the phasing timing. Seems they were right all along.
12:00pm, 24.9F, Light Snow, 1.5"
PhillySnow ~ Thanks for the well wishes! :-) It was our 40th of engagement. 40th wedding anniversary is exactly one and a half years afterward.
PengSnow ~ Thanks, but I believe it was OriginalLT who commented about the dry slot filling in. So glad it is!!
Blizz ~ Thanks for being here and helping us all watch this storm unfold realtime! I'm thinking that after this one passes through we may need a new thread, as this one is getting nice and heavy. :-)
Sorry Listener by mistake, i was kind of sleepy this early am.
Now its time to enjoy the powder, as always be safe in your travels.
How is the storm verifying with predictions so far Blizz?
The storm looked very poor last night and this morning, but filled in nicely as the coastal low developed. I think my snow map will verify quite well, although will be low for parts of southern New England and the southern tier counties of New York State.
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