BLOG: A Review of Winter, Preview of Spring

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Meteorological Winter (December, January, February) is FINALLY in the books. The opening 8 weeks of 2015 were pretty amazing, I have to say. Cold and snow galore!It's easy to forget how mild and snow-free December was.As far as the numbers, here's the final tally: statsA couple of things to note. Precipitation was almost exactly average, even though snowfall was well above average. The departure from average in the temperature department was heavily, heavily influenced by February's departure of 14 (FOURTEEN!) degrees.Here's how this Winter compares to previous one: coldestwintersNotice that we have had 2 "top" 10 coldest Winters in a row. Much like the cold period from 1976-1979.How did the numbers stack up against our Winter forecast, issued at the end of October? Our forecast was for Winter to be about 3 degrees below average. tempforecastThe forecast would have been almost perfect had February even be "crazy" cold instead of CRAZY cold. Here's the temperature departure map for the whole country: djfOverall, not a bad forecast!What about March and Spring?If you are hoping for a super warm Spring, you are likely out of luck. Many of the same atmospheric drivers from Winter will still be present this Spring. That said, we are NOT expecting the crazy departures from average that we had over the Winter.In the short term, we WILL see a pattern change over the next couple of weeks that will finally bring some warmth into the region. Watch the pattern shift from this week to the middle of the month: mar5mar13That's more like it! The ridge that has camped out over the West Coast all Winter will finally migrate east and allow above-temperatures to take hold. Check out the GFS outlook: imageControlWow. Might as well say 90!That said, March OVERALL may end up being  below average if the latest climate models are to be believed. cfsLast Spring we saw that the colder and icier-than-average Great Lakes do have an impact on our Spring weather. That will be the case again this year. Air masses will get refrigerated as they cross over the lakes. modis1Thanks for reading!Eric

BLOG: Ice Threat Tuesday

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After another weekend snow storm, today we will be in between systems. Tuesday, another storm will rip through the East, but this one will be different. This one will bring WARMER air with it! Good news, right? Well, kinda.The bad news: the air a few thousand feet above our heads will warm at a much faster rate than the air at the ground. A setup for sleet and freezing rain.TIMING: This will NOT be a problem for the morning rush. Precipitation will push in around 10am-11am on average. The threat for wintry precipitation will past until mid afternoon, maybe 3-4pm.Here's the simulated radar at 1pm: 1pmPretty colors, but not pretty weather.SOME METEOROLOGY: How do we know that this will be sleet and freezing rain? One of the most valuable tools in a meteorologist's toolbelt is a "Skew-T" diagram, otherwise known as a "sounding". This gives us a snapshot of the entire column of air above our heads at a certain time. In these diagrams, we live at the bottom of the graph, at the Earth's surface. The top of the diagram is essentially the level at which planes fly. The green and red lines represent the temperature and dewpoint, respectively as you go up in the atmosphere.I have highlighted the freezing line.Notice as the precipitation arrives around midday, there is a small layer of above-freezing air. It's at around 5-6,000 feet. namipThis is a sleet sounding. A reminder of what the different types of precipitation are and how they are formed: 998809_10201188958473876_1604180183_n As the warm layer gets deeper, we should see a change to freezing rain: nam By late afternoon the surface temperature will finally rise above freezing. Now the atmosphere is above freezing from the ground up to 10,000 feet so we'll just have rain. namrain Simulated radar at 8pm: tuenight So will this be enough ice to cause a lot of problems? It might be. We are probably looking at around 0.10" or so of ice accumulation and that can make everything very slick. iceaccumimpacts Rain will fall for much of Tuesday night. While rain amounts will likely be under an inch....we will have to watch for street and highway flooding. Many storm drains are clogged with snow right now.Thanks for reading!Eric

BLOG: A Little Snow and Then More? Plus More Harsh Cold

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The weather pattern has "relaxed" some as we head into midweek. Sure, it is cold but at least it is not the brutal as it has been.BUT, the Deep Freeze will get an encore performance before the pattern changes at the start of March. More on that in a moment.Thursday will bring some light snow into the region. Despite being just one day out, the various computer models all handle this minor system somewhat differently. Some give us basically no snow and some suggest a few inches is possible. I don't think it will be much, and our current forecast of a coating to an inch or two seems fine. Here's the SREF (Short Range Ensemble) model, which has a fairly wide range of accumulations (each represented by a line): srefThe mean, or average is about 1.8" , although that mean is getting pulled up by the big "outlier" that gives 5.5". Overall, the SREF generally jives with our forecast.Beyond the nuisance snow, our attention turns back to the harsh cold. A fresh arctic air mass will invade one more time. Thursday morning's wind chills will likely end up around 5 to 10 below.  chillsthursBut the REAL cold comes Friday into Saturday morning. Check out Friday morning's wind chills: chillsfriLikely in the -10 to -20 range, which means some school adjustments seem likely.Actual temperatures will plummet under a strong dome of high pressure Friday night. With a clear sky, "radiational cooling" will be maximized. (Radiational cooling is the process of the "heat" from the day radiating back into space, causing the air temperature near the ground to cool)Radiational CoolingTemperatures Saturday morning will probably be similar to the readings we have seen during our coldest mornings this season. -20 or so in the coldest spots! lowssatThe cold will quickly ease by Sunday. BUT (always a BUT at this time of the year) any warming will probably be accompanied by some snow. Models are trending toward a decent snow for the region sometime Sunday into Sunday night. Here's this morning's GFS: gfssuneveNotice the rain snow line near I-70. That may get close to us at some point. It's far too early to have any confidence in those kinds of details. A shovel-able snow is becoming more likely, but stay tuned. The European model odds of more than 3" are looking pretty good right now: europrobI will have more on the outlook for March and for the Spring season later this week. Long range climate models are pointing toward a near or somewhat below average March. After the coldest February ON RECORD, a slightly below average March would be great! marchThanks for reading!Eric  

BLOG+VIDEO: Breaking Down The Weekend Storm

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http://youtu.be/4qaO3Xo2cQ0 The video in this blog post has some details on the cold and wind chills over the next 24 hours. Let's talk about the weekend storm. It seems like we are in a pattern where we have a winter storm every weekend....I blame Mike Joyce; him leaving angered the Weather Gods, haha.This will not be a huge, blockbuster storm but will be an inconvenience.TIMING: By Saturday morning, light snow will have pushed into the viewing area. 7amThe snow will continue at varying intensity for much of the day. Some of the time it will be light. Other times it will fall at a good clip, especially in the afternoon. 4pm: 4pmThe precipitation will taper off overnight with most of the accumulating snow finished by midnight at the latest. 1amMODELSThe computer models we use to help us with the forecast are generally in pretty good agreement at this stage of the game when it comes to the timing of the system. The track is not "set in stone" by any means as there are some differences found on the various models.Current average among this set of models is about 3" of snow at the YNG airport. The European models is not included in this average; it has about 4". modelsIMPACTSTravel will be impacted all day, especially in the afternoon. travelCumulative accumulations by 7am: Around 1/2"-1"Cumulative accumulations by noon: 1-2.5"Cumulative accumulations by 10pm: 3-5" FORECAST We think the most likely accumulation is 3-5", based on the current models and other factors. RANGESWHAT CAN GO WRONG? 1) The lower end of the forecast is more likely if mixed precipitation or even rain gets involved Saturday evening. This looked more likely yesterday; we have to be on guard for a last-minute adjustment in the modeling back to this idea. Best chance for sleet and/or rain will be around and south of Rt 30.The lower end could also be more likely if the snow is very light all morning with little accumulation.2) The high end of the range or even a bit more could happen if some heavy banding sets up in the afternoon and there is no mixing with sleet/rain.