A highly amplified MJO through Phase 5 will lead to a mean trough across the west with a persistent ridge over the east coast over the next couple of weeks. Week 2 ensemble data correlates almost perfectly with the Phase 5 analog composite (albeit a bit colder in the west).
JAN MJO Phase 5 analog composite
Days 12-16 ensemble data
The end result will be a very active storm track across our portion of the country, sustained cold from the Plains and points west, and sustained warmth along the eastern seaboard. In between, we’ll remain in a transitional time of things with shots of warmth and cold (very “back and forth” regime, locally).
Precipitation will run well above average through 1/20, including periods of heavy rain with storm systems that track through the area.
At times, we’ll need to monitor “waves” that move up along pressing boundaries into the eastern ridge. As cold periodically tries to push, it could present wintry challenges for portions of the Ohio Valley. Our first potential issue with this may present itself late next week.
We’ll have to stay tuned to see if the MJO rumbles into the colder phases or circles back through the warm phases late month. As mentioned last night, it’s also worth keeping tabs on potential Scandinavian ridging down the road.
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Dry air continues to “eat away” at the advancement of precipitation northward this afternoon. It now appears as if we’ll escape rain-free through the evening hours, with steadier rain lifting north into central Indiana towards 10p to 11p.
Heaviest totals still look like they’ll fall across southeastern Indiana (amounts up to 1″ possible) with lighter amounts of .20″ to .40″ across the more immediate area.
Most of the daytime Friday will feature a lack of significant rain, but there could be some drizzle and spotty light shower activity around at times.
It’s as we get into Saturday morning that we need to monitor the track of vigorous upper level energy moving southeast out of the northern Plains and into the lower Ohio Valley. In response to this, an expanding area of snow and/ or mixed precipitation should initially develop across Iowa before building into Indiana prior to sunrise. These systems are admittedly tricky and can spawn surprises and we’ll keep close eyes on things over the next 24-36 hours. As things stand now, I would place the best chances of accumulating snow from Iowa, northern IL, northern IN, and into northern OH with this system, but please stay tuned.
The next weather maker, locally, will likely be responsible for another opportunity of snow Tuesday into Wednesday.
In a way it’s ironic we’re looking at back-to-back opportunities of sticking snow in what’s a warmer than average pattern. This, of course, is on the heels of December’s above average snowfall month. Central Indiana snowlovers know all too well that frigid patterns can be bone dry around these parts…
Longer range hinges squarely on the shoulders of the MJO. Things are highly amplified and will result in one of two scenarios- swinging out of the warm phases and into the traditionally cold phases for mid-winter after mid-month, or circle back through Phase 5. If it’s the latter, anomalous warmth would continue across the east while significant cold takes up shop across the west. In January, Phase 5 is the last thing eastern fans of winter want to see.
As it is, I continue to believe the favorable northeast Pacific will have the final say on this winter with a more favorable regime developing during the 2nd half of January that would pull the cold into the region in more sustained fashion (next 10-14 days will feature transitional cold along with the stormy pattern).
The latest European Weeklies may be starting to see this as the relative warmth in Week 2 gives way to colder times Week 3.
MJO Phase 5 is set to dominate the Week 2 timeframe.
New Weeks 3-4 shows a colder pattern developing.
A very active pattern is set to remain intact over the next 2-3 weeks and even in the warm patterns, snow and wintry mix events can prove to be a headache this time of year.
Both the GEFS and EPS show the EPO moving from a strongly positive phase now (also argues for the warmer than overall pattern in the immediate-medium term) towards neutral to negative after mid-month. We’ve been noticing the tendency both models have had trying to drive the negative EPO too quickly (recall only a few days ago the models wanted to develop the negative EPO around the 12th or 13th).
Rest assured, our eyes will be glued to the MJO and EPO through the 2nd half of the month. Time will tell if the highly anticipated favorable warm northeast Pacific SSTs will begin to do the trick…
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