Category: High-latitude Blocking

Friday will dawn dry, but the mid and high level cloud canopy will be a sign of things to come. These clouds will lower and thicken through the day and eventually give way to a wintry mix by evening. While there may initially be a period of snow (especially north of Indianapolis), the majority of the “overrunning” precipitation should fall as a mixture of sleet and freezing rain. In and around Indianapolis and points north, a light “glaze” of ice is possible Friday evening of up to .10″ (after the possibility of a coating of snow).

Dry air will likely have to be overcome at first, but a burst of snow is possible into the city around 5p to 6p before the transition over to the sleet and freezing rain mixture. Eventually, the icy mixture will transition to a cold rain prior to sunrise Saturday.

MUCH colder air will pour into the state Saturday evening with temperatures falling into the 10s prior to midnight Sunday morning and wind chills into the single digits.

As we look longer term, we don’t see any reason to alter our ongoing thoughts of a colder pattern taking hold, overall, over the upcoming 10-14 day period (and likely into the first half of Feb.). We’ve covered our reasoning in previous posts (Phase 7 of the MJO, positive PNA, neutral EPO, etc.). What’s interesting to note is the rather stark difference in the handling of the EPO between the negative GEFS and positive EPS. The likely end result will be somewhere in between; hence our neutral EPO forecast. At the end of the day, it’s really not the EPO, PNA, or NAO that will drive the mean pattern, but the MJO. And with that said, Phase 7 of the MJO features a cold, stormy look.

The high latitude blocking screams for an active storm track across our neck of the woods (as does the slightly positive PNA and neutral EPO). Sure enough, the latest modeling is going towards this stormy look (active southern stream) in the medium to long range period.

A great mentor once taught me to always be leery of ridges over Hudson Bay in the winter time. Time and time again, this pattern setup results in fairly widespread winter storm events through the Lower 48 and we think there is increased potential in this sometime during the Jan. 25-31 time period. While there’s no way to be specific, just keep a mental note in the back of your mind for this threat.

In closing, a review of the latest JMA Weeklies shows a significantly different pattern than what we’ve grown accustomed to as of late taking up residence through the bulk of the upcoming 3-4 weeks. Given the above, it would be tough to argue this look…

Fresh video update will hit in the AM with new thoughts around tomorrow evening’s winter weather maker.