JamieOber Posted January 11, 2012 Share Posted January 11, 2012 I am not sure why no one is mentioning temperatures for the ULL event. Sure lower and upper level heights crash, but the boundary layer is near 40F when QPF moves into the region with the squall line. Temperatures fall, but it likely starts as rain. It is not as if temperatures are in the 20s with heavy snow for the entire portion of the ULL event. Therefore accumulations will be limited especially east into the Susquehanna Valley where guidance indicates primarily rain before ending as a bit of snow. western and central pa should be ok temp wise but with dew point temperatures running in the 40s to upper 30s around harrisburg and east tomorrow night it will not be as easy as heavy rate to get it cold enough fast enough to be more than mostly rain here That's probably true there, although I've experienced a couple of arctic frontal passages when I lived in York where it was 40 to start and the temp plunged so fast that only the very beginning was rain. That makes it even worse for travelers due to flash freezing. I am not sure what the exact setups were for those, however. Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 Here is a temp comparison of the 6z NAM and actual 10am temperatures this morning: Observations are a bit cooler than forecasted, but with the amount of sunshine out right now, I expect all areas to be above freezing before the precip moves in this afternoon. I expect everyone to have only rain tonight. The ULL feature is going to be tough to nail down as it is a small and delicate feature. I have to agree with the temperatures being an issue in the first half or more of precipitation. But it could transform into a blinding snowfall pretty quickly. One thing is for sure, it will definitely feel like the dead of winter on Friday and Saturday! If the temps were under forecasted now, sure can be then too. Maybe it won't get as warm and then we can cool off quicker. Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 Going along with that temp thing it is 34 here and a 29 dew point. According the the NWS it should be 41. Also the clouds have moved in here. Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 850's dropped below freezing again Link to comment Share on other sites More sharing options...
djr5001 Posted January 11, 2012 Share Posted January 11, 2012 Here is a temp comparison of the 6z NAM and actual 10am temperatures this morning: Observations are a bit cooler than forecasted, but with the amount of sunshine out right now, I expect all areas to be above freezing before the precip moves in this afternoon. I expect everyone to have only rain tonight. The ULL feature is going to be tough to nail down as it is a small and delicate feature. I have to agree with the temperatures being an issue in the first half or more of precipitation. But it could transform into a blinding snowfall pretty quickly. One thing is for sure, it will definitely feel like the dead of winter on Friday and Saturday! models/MOS almost always bust high on temps around here overnight when skies are clear and winds calm/near calm just like they do (edit: meaning bust low in summer) during summer with similar conditions during the day... just want to point that out so there is not an assumption that models being off with overnight temps last night/this morning means modeled temps for tonight and tomorrow night into friday are too warm... Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 models/MOS almost always bust high on temps around here overnight when skies are clear and winds calm/near calm just like they do during summer with similar conditions during the day... just want to point that out so there is not an assumption that models being off with overnight temps last night/this morning means modeled temps for tonight and tomorrow night into friday are too warm... Sure it does. My temp is currently 6 degrees off. Makes a huge difference. Also 850's have dropped below freezing again which is not modeled. Link to comment Share on other sites More sharing options...
Jmister Posted January 11, 2012 Share Posted January 11, 2012 850's dropped below freezing again Be cautious about that…there is supposedly a layer of above-freezing air above 850mb. 12z NAM Skew-t for 10am today: Link to comment Share on other sites More sharing options...
sauss06 Posted January 11, 2012 Share Posted January 11, 2012 That's probably true there, although I've experienced a couple of arctic frontal passages when I lived in York where it was 40 to start and the temp plunged so fast that only the very beginning was rain. That makes it even worse for travelers due to flash freezing. I am not sure what the exact setups were for those, however. Yeah and many HS Wrestling Matches and B-Ball games tomorrow evening.... I agree with the arctic frontal passages, i too have seen that many time where i live in the North East corner of Cumberland County. Where it is to be all rain, or start as rain, then bam, surprise, surprise! the ground is white. I think last January, maybe around the 11th we had a couple inches, was to start as rain and change overnight, but actually only rained for a short time before temps dropped. Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 Be cautious about that…there is supposedly a layer of above-freezing air above 850mb. 12z NAM Skew-t for 10am today: Could cool as precip starts. It is getting pretty close here. Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted January 11, 2012 Share Posted January 11, 2012 Probably won't get any accumulation here, but might have a few chances next week with the GFS showing 2 snowfall events blanketing the state, one on the 15th and one on the 18th. Link to comment Share on other sites More sharing options...
canderson Posted January 11, 2012 Share Posted January 11, 2012 Looks like we start off '12 were '11 left off with the wind. At times i think there is a Turbine in my back yard... I got all my facia fixed last Friday. Makes sense a storm will come through a week later to mock the nails. Link to comment Share on other sites More sharing options...
sauss06 Posted January 11, 2012 Share Posted January 11, 2012 I got all my facia fixed last Friday. Makes sense a storm will come through a week later to mock the nails. Sorry, but i kinda chuckled when i made my original post, thinking of your and my damge from wind this year. Thinking, here we blowwwwwwwwwww again!. Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 That is one wicked vort. I think squalls are going to flying everywhere. Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 982 over NY? Winds even stronger this run. Link to comment Share on other sites More sharing options...
Blizzard92 Posted January 11, 2012 Share Posted January 11, 2012 Up in the lower 40s here in Harrisburg currently. While yes a flash freeze is certainly possible, given the low QPF totals for the arctic frontal/ULL event, it is likely some of it is wasted on rainfall. Therefore the advisory criteria snows are more likely towards western Pennsylvania and central Pennsylvania. Here from Franklin County on eastward in the LSV, it is likely more just rain changing to snow with a coating of snow. The NAM and GFS soundings show little snow accumulation actually for much of the valley. I think people are getting their hopes up and need to be a bit more realistic in this situation. 12z GFS keeps the best lift and dynamics well out of the LSV to our northwest. Link to comment Share on other sites More sharing options...
sauss06 Posted January 11, 2012 Share Posted January 11, 2012 Up in the lower 40s here in Harrisburg currently. While yes a flash freeze is certainly possible, given the low QPF totals for the arctic frontal/ULL event, it is likely some of it is wasted on rainfall. Therefore the advisory criteria snows are more likely towards western Pennsylvania and central Pennsylvania. Here from Franklin County on eastward in the LSV, it is likely more just rain changing to snow with a coating of snow. The NAM and GFS soundings show little snow accumulation actually for much of the valley. I think people are getting their hopes up and need to be a bit more realistic in this situation. 12z GFS keeps the best lift and dynamics well out of the LSV to our northwest. I honestly look for a coating at best where i'm at. I'm paying closer attention to the wind. Link to comment Share on other sites More sharing options...
Santa Clause Posted January 11, 2012 Share Posted January 11, 2012 I've been through these before, and anyone expecting more than an inch or so will be disappointed...just take what you get. Link to comment Share on other sites More sharing options...
Blizzard92 Posted January 11, 2012 Share Posted January 11, 2012 I've been through these before, and anyone expecting more than an inch or so will be disappointed...just take what you get. Exactly, if I were in the Laurels or north central mountains I would be excited, but east of the Alleghany plateau, there is no reason to be. It is a typical arctic January front accompanied by a few squalls and gusty winds; nothing earth shattering or unusual. The clipper is what I would be a tad more excited. Vort looks pretty strong and favorable track could spread many areas a nice light fluffy snow. I would like to see a bit more model support though. Link to comment Share on other sites More sharing options...
Jmister Posted January 11, 2012 Share Posted January 11, 2012 11am (16z) temperatures. All areas are above freezing. Link to comment Share on other sites More sharing options...
Blizzard92 Posted January 11, 2012 Share Posted January 11, 2012 12z GFS washes out the weekend clipper tracking the vort well south of the Mason-Dixon line. Downsloping kills it east of the mountains with little QPF and all south of the PA/MD boder. Link to comment Share on other sites More sharing options...
JamieOber Posted January 11, 2012 Share Posted January 11, 2012 I've been through these before, and anyone expecting more than an inch or so will be disappointed...just take what you get. Exactly, if I were in the Laurels or north central mountains I would be excited, but east of the Alleghany plateau, there is no reason to be. It is a typical arctic January front accompanied by a few squalls and gusty winds; nothing earth shattering or unusual. The clipper is what I would be a tad more excited. Vort looks pretty strong and favorable track could spread many areas a nice light fluffy snow. I would like to see a bit more model support though. For here, I am thinking what we got in the last cold spell, 1-3, is what we get, including post frontal squalls. IMBY I measured 2.5. Nothing to get super excited about but these can make for cool scenes when the wind is whipping. Link to comment Share on other sites More sharing options...
Blizzard92 Posted January 11, 2012 Share Posted January 11, 2012 For here, I am thinking what we got in the last cold spell, 1-3, is what we get, including post frontal squalls. IMBY I measured 2.5. Nothing to get super excited about but these can make for cool scenes when the wind is whipping. That sounds about right. You should head up to Black Moshannon State Park; they probably will receive a healthy 4-8in of snow with whiteout conditions. Link to comment Share on other sites More sharing options...
JamieOber Posted January 11, 2012 Share Posted January 11, 2012 That sounds about right. You should head up to Black Moshannon State Park; they probably will receive a healthy 4-8in of snow with whiteout conditions. Yeah, I live right in Port Matilda and have gone up 322 toward Philipsburg, and it's interesting how much more snow just 4-5 miles away gets with the elevation. Often I've driven from home with a few inches to up there and there's 6-10 or so, and then drive to State College and there's under an inch. Black Moshannon's beautiful after snow. Link to comment Share on other sites More sharing options...
Santa Clause Posted January 11, 2012 Share Posted January 11, 2012 I'm thinking a coating here maybe...everyone got way too frenzied last night(including myself) and now looking at it, looks like a normal windy day with snowshowers. Clearfield and Potter counties might have advisories. Link to comment Share on other sites More sharing options...
Blizzard92 Posted January 11, 2012 Share Posted January 11, 2012 I'm thinking a coating here maybe...everyone got way too frenzied last night(including myself) and now looking at it, looks like a normal windy day with snowshowers. Clearfield and Potter counties might have advisories. Winter weather advisories probably for Bedford, Blair, Clearfield, Potter, Elk, Cameron, Tioga, northern Centre, northern Clinton, and northern Lycoming. Warnings for Somerset, Cambria, Warren, and McKean. Snow accumulations rapidly drop off below the Alleghany Plateau with little to no accumulation in the middle and lower Susquehanna Valley. Winds are advisory criteria, but nothing unusual for after a January cold front. Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 I've been through these before, and anyone expecting more than an inch or so will be disappointed...just take what you get. Last time something this strong like this happened I got 2". So we shall see. Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 Winds up to 25 KTS(29mph) sustained this run in southern PA. 29-31 (34-37mph) KTS in Mountains around JST and Somerset Link to comment Share on other sites More sharing options...
Santa Clause Posted January 11, 2012 Share Posted January 11, 2012 I agree blizzard. IPT and MDT to HGR see light to no accums, UNV sees a little over an inch, but NW of there it goes up a ton. To me if you're east of a Coudersport to UNV sw to Johnstown line don't expect much. Link to comment Share on other sites More sharing options...
EasternUSWX Posted January 11, 2012 Share Posted January 11, 2012 I agree blizzard. IPT and MDT to HGR see light to no accums, UNV sees a little over an inch, but NW of there it goes up a ton. To me if you're east of a Coudersport to UNV sw to Johnstown line don't expect much. You know I got .3" from a system much weaker then this last week right? Link to comment Share on other sites More sharing options...
Blizzard92 Posted January 11, 2012 Share Posted January 11, 2012 You know I got .3" from a system much weaker then this last week right? 0.3in? That would fall under little to no accumulation. An inch or under is probably a safer call. These are tricky forecasts and playing it a bit conservative for accumulation is a much safer forecast. And if you get more, then you can be pleasantly surprised. Link to comment Share on other sites More sharing options...
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