Weekend Video Update…
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Times Are Changing, Or Are They?
January-to-date is running milder than normal across the region- to the tune of 3.3 degrees (F). This is after a frigid open to the month, as you recall.
The second week of the month warmed significantly and continues, overall, for the next week.
The mid-January warmth is attributed to a roaring PAC jet which is currently helping flood the country with temperatures much more like spring than the dead of winter. We continue to forecast 60+ this weekend across central IN.
Winter lovers, have no fear as changes appear to be in the offing as we go through the last few days of January and head into February. The winter so far has featured conflicting signals that continue to try and compete with one another to take hold of the pattern. Can we get these drivers to align in a way that would pull a more persistent trough into the east for the second half of the winter and, ultimately, set-up a sustained cold pattern helping make up for lost time in the snowfall department? Time will tell, but we do note the following late month:
- (+) PNA pattern
- Sudden stratospheric warming event
- High latitude blocking
All are encouraging for a shift back towards a wintry regime. As always, the devil is in the details and we’re skeptical as to the longevity of these signals. “Cautiously optimistic” would be the way to sum up our current feel longer-term into the month of February, but we’re not as bullish on lock and hold cold, wintry conditions at this time as what you may hear from some of our national compadres. Understanding that various drivers can have a different impact mid and late winter as opposed to early is one thing. It’s also important to note that long term modeling has been abysmal as of late and we want to tread through the next couple of weeks with caution to see whether or not the cold drivers can finally take hold.
Needless to say, at least through late month, one can see the significant changes take place at 500mb.
Thursday:
This Weekend:
Next Thursday:
Next Weekend:
The pattern begins in the short-term with a look that will power anomalous warmth through the weekend, along with renewed rain chances Thursday night into Friday (another 1″+ for most), but begins to shift next week towards the colder look. The 2nd (weekend) storm system will be significant and poses a severe risk to the southeast region. Modeling has backed away on the heavy rain threat Sunday, but showers will be around early next week along with very windy conditions (40+ MPH gusts). Blocking is forcing the low south. By the time we get to next weekend, the pattern has done a 180 and in a position to drill unseasonably cold air back into the central and eastern portions of the country.
As far as storms go later in the period, it’s far too early to discuss specifics, but the pattern seems to be one that will promote the chance to get into the act on high-ratio producing clippers. It’s the first time we can say that this year. Time will tell…
Shift Back To A Cold Pattern Awaits; What About Winter Storm Potential?
December-to-date is running colder than normal (to the tune of 2.2 degrees at IND), but the past (7) days has seen a flip in the frigid 1st half of the month.
The “relaxation” is temporary. Modeling continues to advertise the recent “thaw” will give way to increasingly bitter times as we get deeper into the New Year. By New Year’s Day we note the positive heights continuing to establish themselves across Alaska and Greenland (cold and stormy signal). We also note the southeast ridge present, though to a lesser degree than over the past week.
By Day (10), the cold pattern is well established over the Lower 48. This is a coast-to-coast cold signal (heart of the cold centered over the west and central) depicted by the European ensemble, along with other modeling.
Teleconnections support a cold pattern returning.
The agreement amongst teleconnections is nice to see and ups confidence in the overall direction of where this pattern is heading in regards to colder than average times looming. The negative PNA correlates nicely with the SE ridge that continues to make itself heard from time to time over the next few weeks. It should also be noted that the phases of the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) become more of a factor for mid and late winter.
As far as storminess goes, we’ll have to handle those as they come. The overall pattern screams towards the idea of an active Ohio Valley to interior Northeast storm track as we move forward (continuing deeper into mid and late winter, as well). That doesn’t mean one or two storms won’t bypass our local region to the south, due to strong, cold high pressure north, but the mean storm track should put areas through the Ohio Valley in the “sweet spot” from a snow perspective throughout the majority of January, and the rest of winter, for that matter. Depending on the position and strength of the Greenland Block will have a lot to say about things. Needless to say, storms cutting NW into the central Lakes should be few and far between after the New Year. Speaking of storms, we have to continue to keep an eye on the second half of next week. At the time of this discussion, the threat is still beyond the 7-day period, but circle late next week and weekend for the potential of wintry “mischief.”
12.23.16 Ensemble Discussion On The 6-10 Day…
*A fresh 7-day will be updated late tonight or early Christmas Eve.*
Modeling continues to suggest a colder return looms as we close out 2016 and open 2017. We’ve discussed the implications of a negative EPO and it certainly appears as if, at least initially, the negative EPO will do the “dirty work” to drive a colder regime in the 6-10 day period.
We note ensemble data is suggesting high latitude blocking tries to develop towards Day 10. Recall this was the missing ingredient in the bitterly cold blasts of air that occurred during the first few weeks of December. Both the GEFS and EPS agree on the increasingly blocky look to the pattern by Day 10. This would help drive a cold, stormy pattern by early January. Instead of storms cutting, we would see more suppression. With a “stubborn” southeast ridge, things could get interesting across the Ohio Valley from a wintry perspective….
We don’t want to jump the gun, but it the positives can “hook up” over the pole, we stand the chance of locking into a rather lengthy cold, snowy regime as we rumble deeper into the heart of winter.
Given the look, it’s no surprise we see the 12z teleconnections want to continue the trend of a negative look to the NAO and AO in the medium to longer term.
Summary: A rather mild regime remains as we rumble through Christmas before trending more seasonable next week. From a wintry perspective we need to continue to keep an eye on the period around New Year’s Eve/ Day. Confidence continues to increase on the potential of a return of arctic air come early January.
Changeable Weather Christmas To New Years…
It’s hard to believe we’re only a few days from Christmas! Through the 22nd, Indianapolis is running a whopping 6 degrees below average. Cold rules across the Lower 48, month-to-date.
This is, of course, is in stark contrast to December 2015.
As we move forward, an active pattern awaits between now and the end of the year. This comes after a few days to catch our breath, including moderating temperatures leading up to Christmas.
An initial wave of moisture will lift northeast and result in a rather gloomy day Friday with increasing rain chances Friday afternoon and evening. Initially, precipitation won’t make it to the ground, but we should saturate the column enough that rain reaches the ground for most of central IN by evening. Showers continue Friday night into the wee morning hours Christmas Eve. (If traveling towards Chicago, a wintry mix and snow will be a good bet Friday PM).
Christmas Eve will feature overcast skies with areas of fog and drizzle, but the majority of the concentrated rain should fall south of the region. Santa’s ride into central IN should be uneventful, weather-wise.
Christmas Day will start off with temperatures in the mid to upper 30s along with cloudy conditions and an increasingly gusty breeze that will shift out of the southeast to the south Christmas night. Shower chances will be present by the evening before giving way to more widespread showers and embedded thunder overnight into Monday morning. Temperatures will be stuck in the 40s most of the daytime Christmas before rising into the upper 50s predawn Monday.
Temperatures will fall through the day Monday and we should run much closer to seasonable temperatures next week. A couple of additional storm systems will have to be monitored for rain and snow prospects the middle of next week and again around New Year’s Eve/ Day. Initially, we’ll be rather mild, but there may be more in the way of cold air readily available to make the storm system around New Years “more interesting” from a wintry perspective.
Longer term, we have to wonder if the negative EPO isn’t about to take control just past the New Year. More and more data is coming around to the idea that the arctic hounds may (yet again) be on the attack early January… Time will tell and we’ll continue to keep a close eye on things.
