BLOG: Everything You Need To Know About Winter Storm

in

Here's a collection of all the graphics I have shared on social media and on TV today.Temperatures and precipitation, showing timing of transition from rain to freezing rain and sleet to snow: [wpvideo pAt4oCHW]Check out that temperature plunge: Timing and impacts: Computer models' ice accretion forecast. Enough to make things very slick but likely not enough for widespread utility interruptions. What's the difference between sleet and freezing rain? Freezing rain occurs when there is a deep enough warm layer aloft, allowing the precipitation to remain liquid until it hits the ground, where it freezes on contact. Sleet occurs when the warm layer is shallower, meaning there is time for the rain to refreeze into ice pellets. Freezing rain is much more problematic. [wpvideo pGtvoC1I]Bridges and overpasses ice up first because they are exposed to the cold air on all sides. The snow forecast: A Winter Storm Warning will go into effect for the whole area. Wind chills will be rather harsh during the weekend. [wpvideo 7xm4yzUh]

BLOG: Winter Storm To Impact Region Friday-Saturday

in

Good morning! I wanted to share some thoughts on a storm that will impact the region Friday into Saturday....a storm that is very complicated and will likely bring a variety of precipitation types before it departs. It'll be quite a wild ride at the end of the week and into the weekend. Temperatures will soar into the upper 50s Thursday afternoon. High temperature forecast:You know at this time of the year temperatures like that are not likely to stick around for very long. Indeed a fresh batch of pure arctic air will descend into the lower 48 states Thursday into Friday, setting the stage for a battle of the air masses. Storms love to form along temperature gradients like that. An area of low pressure will get organized over the Lower Mississippi Valley Friday morning and then head north. They key to getting the details of the forecast right will be determining when the arctic air wins over the warmer air.Let's walk through what is possible and likely.

LIKELY

  1. Temperatures will start mild Friday and any precipitation that occurs in the morning will be rain.
  2. Temperatures will start falling at some point Friday, but I'm not sure if it's in the morning or later in the day. This has big implications for the TYPE of precipitation that will occur Friday afternoon and evening.
  3. We will likely get snow from this system, but when the changeover to snow occurs and how much snow falls is something we don't have high confidence in right now.

POSSIBLE

  1. The cold air is slower to arrive, thanks to a farther west storm track. This delays a changeover to snow, but opens up the possibility of an extended period of mixed precipitation/ice Friday night.
  2. The cold air overwhelms the warmer air, pushing the storm track east. This would result in a changeover to sleet/freezing rain sooner and also a quicker change to snow by the end of the day Friday.  Our region could be in the bulls eye for heavy snow Friday night and Saturday morning.

On the table:a) A "nuisance" event with some inconveniences for travelers Friday night into Saturday...a period of sleet and/or freezing rain followed by some snow but not a tonb) A major winter storm with a period of icing followed by several inches of wind-driven, heavy snow.I lean toward option "A" but can't rule out option "B" yet. 

MODELING

Both the European and GFS (American) models have a swath of hefty snow with this storm, it's just a matter of where. The European is option "A" described above. The GFS is more option "B".European model (ensemble mean):GFS (ensemble mean): Why do I lean toward the European model idea? For starters, it "wins" over the GFS more often than it loses.  It's been fairly consistent with the idea when above for a few runs now.  It also has the support of  some other modeling, which is a good sign.Let's look at the odds of certain amounts of snow, according to the European.At least 1": About 50-80% for our region.At least 3": Roughly 10-40%.At least 6": Generally 10% or less.The takeaway from this data: A "big" storm of a half foot or more is unlikely for eastern Ohio and western PA but can't be ruled out yet. Don't forget, even if the Euro has the right idea on snow, ice may still be a concern. Overall confidence in the details on this storm is low to medium this morning but will increase over the next 24-36 hours. One thing for sure, the cold air WILL win at some point. It looks very cold for a few days behind the system. Then...a nice thaw later next week.    

BLOG: Christmas Weekend Weather+Long Range Look

in

Happy Saturday! It's the Saturday before Christmas which means the malls will be packed, Rt 224 will be the 9th Circle of Hell and egg nog will taste extra good by the end of the day. It's going to a busy and impactful weekend weather-wise so let's get right to it.

TODAY

It's a rainy morning and colder air is on the march. Temperatures will continue to fall today and rain will change to wet snow by midday. The snow will be largely non-impactful. You may have to brush wet snow off your windshield and decks/patio furniture can get covered but I am not expecting too many issues on paved surfaces as the snow will be falling during the daylight hours into air that is around 32-33 degrees.Tonight will be quiet with lows in the mid 20s.

CHRISTMAS EVE (DAYLIGHT HOURS)

If you are doing some last-minute traveling or shopping on Sunday, we expect no weather-related issues through the first half of the day. But snow will push back into parts of the Valley during the afternoon. 3pm simulated radar: At first, the snow won't be much of a problem on most roads as temperatures will be near or a little above freezing. But after sunset as temperatures drop and the snow becomes more intense, slick conditions will become likely. 9pm: The snow will continue to fall steadily through about 1-3am, then will taper to flurries/snow showers. A look at the timing of the weather impacts today through Monday morning (clock times at the top of each graphic) 

CHRISTMAS DAY

As you can see in the graphic above, the snow will be less problematic by Monday morning and the day as a whole will be cold and quiet with not much more than some morning flurries ("mood snow"!) How much snow will be on the ground Christmas morning? An average of 1-3" so we are expecting a WHITE CHRISTMAS, officially.  Keep in mind that the bulk of the accumulation will occur before midnight Monday morning. For the actual calendar day December 25th, here's the list of snowiest Christmases since 1934 in Youngstown:  

SORRY KOMARA JEWELERS SHOPPERS, WE AREN'T GETTING 4" ON CHRISTMAS DAY.

LONG RANGE

This  might be the coldest stretch of the whole Winter coming up from Christmas into the first week of 2018. 

 THANKS FOR READING! I WISH YOU AND YOURS A MERRY CHRISTMAS!

 

BLOG: December 18th White Christmas Update

in

I'm on vacation this week but I can't NOT look at the weather! I thought I'd do a quick post with an update on our chances for a "white" Christmas this year.The snow pack reached a maximum of about 6-7 inches in parts of the Valley a few days ago but it has been receding since, thanks to milder temperatures and a little rain. Animation of the snow cover across the region over the last 2 weeks:The snow will continue to vanish this week with temperatures like this: So the chances of the OLD snow still being on the ground come Christmas morning are looking slim. To get a White Christmas, we will need NEW snow. Will we get any?

MOST LIKELY WEATHER DECEMBER 23RD THROUGH 25TH

A cold front will cross the region Friday night into Saturday, bringing rain (and also balmy temperatures ahead of it). Here's a snapshot of the placement of precipitation Saturday morning, according to the European model: The key to predicting our weather for the rest of the weekend and into Christmas is:  what happens to that front? 1) Does it keep sweeping east and unlock the doors to colder air, or 2) does it stall not far to our east....with waves of moisture coming northward out of the Deep South, keeping the coldest air to the west and making for a wet, not white Christmas Eve and perhaps Christmas Day?I lean toward idea #2 right now. Why? That's the solution favored by the "operational" European model and it has decent to good support from it's "ensembles", which leads to increased confidence.The average of all 51 members of the European ensemble model has little snow on the ground Christmas morning: With the "control" run showing even less: Basically the idea is that it's more likely to rain than snow Sunday night into Christmas morning.Meanwhile, the US counterpart to the European model, the "GFS", sweeps the front east over the weekend and the arctic air is allowed to drop anchor across the region. Check out the temperature difference Christmas Day between the European and GFS.European: GFS: By the way, look at those ridiculously cold temperature over the Upper Midwest. Ouch!Although the GFS is quite a bit colder, it does NOT bring much hope for a snow "storm" at Christmas. The best we could hope for would be some lake-effect. A couple of the GFS ensemble's "members" are interesting looking but they are the exception.   Based on all this, I have lowered our White Christmas chances to 25%. Keep in mind we are still a week out and confidence in any forecast (and particularly one involving a wobbly front in the winter) this far out isn't high. Rely on human forecasters to give you the real story and not national weather apps that are usually based on ONE model.