Long Range: Cold Pattern Isn’t Going Anywhere Fast…

We’ll save our short-term discussions for the severe and high-impact arctic outbreak on deck and focus our attention in this post to the upcoming several weeks. In short, we don’t expect the cold pattern to break anytime soon. Could there be a day or two of “relaxation?” Yes, but from an overall perspective, confidence is higher than normal on the colder than average pattern continuing through the month of February.

Let’s dig in to the teleconnections:

EPO

NAO

PNA

Given the teleconnections in agreement pointing towards a cold pattern, it shouldn’t come as a surprise that the majority of data is also on the cold train as we flip the page into February:

CFSv2 Weeklies

Weeks 1 & 2

Weeks 3 & 4

JMA Weekly

GEFS

While we aren’t licensed to show the European Weeklies, the new update runs with a cold pattern into early March. This falls in line with the overall consensus of longer range data, backed up by teleconnections.

Though not nearly at the amplitude of a few weeks ago, the MJO (Madden-Julian Oscillation) is forecast to move through Phases 5 and 6 in the coming weeks before going back into the “null” phase.

Phases 5 and 6 this time of year would suggest colder anomalies are more likely around our neck of the woods:

Given the above, we continue to think a colder than average “2nd half” of winter looms for the region. We lean heavily on the NAO, EPO, and AO state(s) this time of year and all would point towards a cold time of things moving forward, overall. The latest European Weeklies are interesting from a couple of fronts- initially very cold and then progressively stormy. The idea here is that we remain quite wintry through February and into early March before this pattern breaks. While we may not see a “repeat” visit of the Vortex, it wouldn’t surprise us to see another major arctic outbreak again this winter (after next week), but that likely comes later, and towards the end of the game before we snap into spring.

Buckle up; we think we have a long way to go this winter…

Bill McMillan January 24, 2019 No Comments AO, Arctic Cold, CFSv2, EPO, Forecast Discussion, Forecast Models, JMA, Long Range Discussion, NAO, PNA, snow, Unseasonably Cool Weather, Weekly Outlook, Winter Storm, Winter thoughts...

Deeper Look Into The Long Range…

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Bill McMillan December 20, 2018 No Comments AO, Arctic Cold, El Niño, Ensemble Discussion, Forecast Discussion, Forecast Models, High-latitude Blocking, JMA, Long Range Discussion, MJO, NAO, PNA, snow, Unseasonably Cool Weather, Unseasonably Warm, Weather Videos

“Pulling The Curtain Back” On The Late December Pattern…

Late December through early January is a critical time period where most folks (even those maybe not normally interested in the weather) are glued in on the forecast. For some, they’re rooting for a white Christmas, while others are preparing for holiday travel to see loved ones. The idea here of a transitional pattern remains and this should promote active weather during the holidays this year.

Understanding things can change with respect to timing from this distance (in some cases 2+ weeks out), these are the dates we’re targeting for storm impacts across central Indiana:

Dec. 20-21
Dec. 24-25
Dec. 27
Dec. 30-31

Before we talk specifics, it’s important to look at some of the pattern drivers. Some of these drivers include teleconnections such as the NAO, AO, PNA, and MJO.

Forecast indices with respect to the AO, NAO, and PNA are expected to be more or less neutral through the late month period. This is what the respective teleconnection “state” would result in the temperature department across the country.

Arctic Oscillation

North Atlantic Oscillation

Pacific North American Pattern

The basis of our late-December forecast is built from the MJO, or Madden-Julian Oscillation. We note the MJO is expected to rumble through Phase 4 before heading into Phase 5 around Christmas. Phase 4 (image 2 below) is a warm phase and correlates well to what the week ahead will provide. However, Phase 5 (image 3 below) is a colder phase and could “up the ante” for the potential of wintry weather around Christmas.

If the MJO amplitude remains, it’ll roll into Phase 6 to close the month and open January. Here’s how that would correlate in the temperature department:

The upcoming week will run milder than normal- lining up perfectly with MJO Phase 4.

The first of our targeted holiday storm systems will come at the tail end of the warm Phase 4 and will likely deliver a wind-whipped rain in here as early as Wednesday night and Thursday morning. However, as the storm pulls northeast along the Ohio River, it’ll deepen on its journey into the eastern Great Lakes region. This will help pull colder air into the region, likely resulting in rain transitioning to snow Friday. Given the path of the storm, this doesn’t favor some sort of prolonged backlash snow event, but it could be enough to result in accumulating snow across eastern Ohio Valley sections and downwind of the snow belt regions of northern IN, OH, and MI.

The pattern, as a whole, appears to be one of transition to close the month and open January and it’s not really until we get to mid-January where we think all of the drivers “align” to create more of a lock and hold cold pattern. With that said, a stormy late December pattern can present problems, even in the midst of relatively mild times. We’ll be here to dissect the storms as they come throughout the holiday season…

Bill McMillan December 16, 2018 No Comments AG Report, AO, Christmas/ Thanksgiving, Forecast Discussion, Forecast Models, GFS, Lake Effect Snow, Long Range Discussion, MJO, NAO, PNA, Rain, snow, Unseasonably Cool Weather, Unseasonably Warm, Weather Classroom, Weather Rambles, Windy

Looking Ahead To The Merry Month Of May…

Folks are growing tired of the cold and snow, and for good reason; it’s mid-April for goodness sakes. As of today, we’re currently ranked as the 5th snowiest spring (March-May) in recorded history, with Indianapolis recording 14.2″ thus far. By the way, we’re only .3″ from moving into the 4th place spot.

With that said, it’s not just April that’s been unusually cold and snowy, but the entire year thus far. As of April 15th, year-to-date CONUS temperatures are running more than 1° below average:

More specific to Indianapolis, here’s the monthly temperature breakdown so far for 2018:

April: 5.7° below normal (MTD)
March: 3.3° below normal
February: 5.6° above normal
January: 3.0° below normal

As we look ahead, there are a couple of key items that we’re monitoring closely to get a better idea as to where this pattern is heading as we rumble into the merry month of May:

NAO- does it show signs of finally flipping to a positive state with any sort of duration?

MJO- does it go into the “wheelhouse” or continue to rumble into the milder phases (5 and 6 this time of year)?

The North Atlantic Oscillation (NAO) is a bit troubling as it shows signs of heading towards a negative phase once again as we open the month of May. This would promote the threat of colder than normal temperatures continuing in early May. With that said, May is the first month of the next several (until winter returns) where the overall influence of the NAO state begins to lessen it’s grip. Unlike from the mid and late winter months into the early spring (Jan through April), mid and late spring, through the fall, isn’t controlled by the NAO. With May being a “transition” month, we’ll favor a colder than average pattern continuing during the early portion of May as the NAO looks to trend negative. As we move towards mid and late month, we won’t rely on the NAO like we have been lately as the said influence “wanes.”

The Madden Julian Oscillation (MJO) is forecast by most data to head towards the “null” phase. The consensus of modeling takes it into the wheelhouse after traversing Phase 3 (present) which is a cold phase. The end result? Unfortunately, we can’t rely on the MJO with any sort of confidence from this distance for the month of May.

Looking at the data itself, the CFSv2 and European Weeklies (just to name a couple) show conflicting ideas. The CFSv2 (courtesy of weatherbell.com) is in the warmer than normal camp for May while the NEW European Weeklies (courtesy of weathermodels.com) suggest the chill lingers throughout the month.

While we have conflicting temperature ideas, both suggest a drier than average month emerging:

At the end of the day, our call on May’s forecast from mid-April would be for an early cooler than average start before flipping towards more of a seasonable to slightly warmer than normal regime. Our idea all along this spring has been that when this pattern flips, the potential is present to jump right to a summery feel. In the face of the new European Weeklies, we still feel this warmer idea mid and late May is on the table. We’re in agreement with the data of a drier than average month.

Bill McMillan April 16, 2018 No Comments AG Report, Arctic Cold, Autumn, CFSv2, European Model, Forecast Discussion, Forecast Models, Long Range Discussion, MJO, Monthly Outlook, NAO, snow, Spring, Summer, Unseasonably Cool Weather, Unseasonably Warm, Weather Rambles

Spring Fling…

An approaching storm system will help pull spring-like air into the region for at least a couple days later this week. Highs will go into the lower 70s Thursday and middle to upper 70s Friday. After a winter that’s certainly overstaying his welcome, that will feel mighty nice!

Highs will zip into the mid and upper 70s Friday!

Unfortunately, the nice spring-like feel won’t last. A cold front will sweep through the state Saturday with showers and thunderstorms late Friday night into the daytime Saturday, followed by a dramatic wind shift and much colder air for the second half of the weekend behind the frontal passage.

As upper level energy moves overhead, mixed rain and snow showers will fall early next week.

Longer term, the negative NAO will continue to lead to prolonged colder than average temperatures. At this point, we think this pattern will run at least through the remainder of April.