I.) The pattern we’re currently dealing with is one that presents multiple challenges in the near term. East-central and northeastern portions of the state have gotten in on the snow act today, but, so far, most of central Indiana has missed out on the snowy goods. With such a fast-paced northwest flow, we have to remain on guard for potential “surprises” in this pattern. Perhaps the HRRR is beginning to pick up on this. Latest runs want to deliver a “pop” of snow Wednesday morning, associated with “warm” air advection (WAA). We’ll monitor tonight.
9a forecast radar Wednesday
II. The northwest flow will continue to provide disturbances plenty capable of producing periods of snow again Wednesday evening through the end of the week. Are these monster storms? Hardly, but they can “suddenly” become sufficient enough to create travel problems given the pattern. For those who live across the northern half of the state, plan to keep close tabs to local forecasts if you have travel plans through the end of the week.
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…
What makes seasonal forecasting so challenging (and fun :-)) are the multiple features that can impact a forecast. We’ve talked about the importance of ENSO (various types of Nino and Nina events) in past updates, as well as low solar and QBO. All of these moving parts and pieces are coming together in a manner that seems to be favoring more of a cold, wintry regime, locally, this year. Is that us saying another blockbuster 2013-2014 winter awaits? Absolutely not (there are other differences noted above with the SST configuration). However, it is suggesting that this winter will be absolutely nothing like the past couple…
This will be enough to send temperatures into the 85° to 90° range by the early to middle of next week. To shed some perspective on that, our averages for early October include low temperatures in the upper 40s and highs in the upper 60s. For at least a couple of days next week, overnight lows will be much closer to where our afternoon highs should be this time of year.
As of now, we think the cold front will pass Friday evening and set-up another pleasant weekend with seasonable temperatures. The stretch of gorgeous August weekends’ appears to roll along.