Arctic Hammer Drops Down Around Christmas…
While the evolution of how things transpire from a snow perspective are “murky,” at best, confidence continues to run very high on the prospects of a nasty period of bitter air arriving around Christmas.
Before we dig into the cold details, the pattern is one that still screams “trouble” from a wintry perspective in the December 23rd-Christmas Eve period. We posted over the weekend of the PNA-EPO going to battle Christmas weekend, and before the cold overwhelms, a consensus of the data continues to paint an interesting scenario as resistance will be present initially from the southeastern ridge. Modeling will continue to struggle with this evolution over the next few days, but we’re hopeful we’ll begin to gain more clarity by late in the work week. Needless to say, a stripe of impactful wintry precipitation should fall in a southwest-northeast fashion given the pattern, but whether that’s to our northwest, over our region, or off to our southeast is simply impossible to call from this distance. A glance at the individual ensemble members (GEFS shown below) shows this nicely, as well. The European ensemble members also paint a similar picture.
Hang in there as we continue to sort through the data over the next few days. Once confidence increases (for or against an event), you’ll be the first to know! 🙂
Now to the ugly stuff: Bitterly cold air of true arctic origin will be dislodged southeast late week and encompass more of the country by Christmas weekend. Eventually, this arctic air will make it across the Appalachians and reach the East Coast just after Christmas.
Recent operational data (GFS and Canadian included) has suggested a sprawling high in the range of 1050mb+ descending into the eastern slopes of the northern Rockies. Such a regime would be plenty capable of spreading sub-zero temperatures east into the Ohio Valley (with or without snow on the ground). Add in a biting north wind and wind chill values would drop to levels of dangerous and deadly levels if any length of time was spent outdoors. Some of the latest data paints a picture similar to shades of the famous ’13-14 winter (20° to 30° below zero chill factor). If you have travel plans over the Christmas holiday, please plan in advance to have a winter survival kit packed and loaded. It absolutely never hurts to be prepared.
III. A period of brief moderation will come in this pattern early Christmas week, but all eyes continue to focus on the period between December 22nd through December 26th for the potential of impactful weather across our region. For model “worshipers” out there, we suggest paying more attention to overall trends, and a blend of ensemble data, as opposed to specifics associated with operational runs. It’s a “jailbreak” pattern of sorts as true arctic air will be pouring down the Plains while the southeastern ridge tries to fight for a time. The resistance from the southeastern ridge and associated tight thermal gradient should promote a very stormy regime for the interior (Ohio Valley into the interior northeast) as we head into the true holiday/ Christmas stretch. As of now, we favor the idea of multiple waves along the pressing arctic boundary, as opposed to one big storm. Looking back through the records shows some of the heaviest snows at IND have come from similar set-ups. Understanding each set-up is unique, the overall pattern does have to raise an eye brow for potential of wintry weather in, or around, our region as Christmas approaches…
This will keep highs in the middle 20s Tuesday with wind chill values in the single digits and teens most of the day.
This doesn’t last long as the pattern begins to reload as Christmas week approaches. As the evolution to a fresh cold pattern takes place, there’s a window of opportunity present for a more significant wintry system to potentially impact the Ohio Valley into the Mid Atlantic region. Notice the relatively “flat” ridge across the southern tier and associated tight thermal gradient. This look suggests we need to be on guard for the chance of a storm system to ride the thermal gradient in a west-to-east fashion, and has wintry implications for our region. Far too early for specifics; just know the possibility looms of a wintry event, locally, as Christmas week nears.
Speaking of Christmas, it sure appears as if cold will overwhelm the pattern for Christmas, itself, and the overall cold regime doesn’t show signs of letting up (with the exception of potentially a day or two) into the new year.
In coffee shops and my travels around the great state of Indiana, I’ve overheard lots of talk centered on because October has been so warm, another lackluster snow season awaits. Let us remind you that the infamous snow season of ’13-’14 featured a very warm first half of October.
The upcoming 7-10 days will feature more of a transitional period of weather that we’ve come to know and love around these parts. Warmth will spread northeast this weekend ahead of an approaching cold front (around 80° Saturday) before falling temperatures Sunday afternoon behind the frontal passage. The chilliest air so far this season will descend upon the region early next week. That said, the chill won’t hold and another surge of above normal warmth will spread northeast by the latter parts of next week.
It should also be noted that analog data and research also would lean heavily in the cold direction to wrap up October and these findings also favor a chilly November… More on that later! Speaking of later, an updated 7-day will be posted this evening. Make it a great day!