January-Like Cold Inbound Next Week; What Awaits Thereafter?

“Normals” for January includes highs in the middle 30s and lows in the upper 10s to lower 20s across central Indiana. Early to middle parts of next week are forecast to feature highs in the upper 20s to around 30 and lows in the middle 10s. Yes, these temperatures will challenge records as a truly impressive arctic invasion claims next week’s weather headlines.

A lot of this has to do with the sea surface temperature (SST) configuration across the northern Pacific. We’ve been focusing in on the warmer anomalies across the north and northeastern Pacific and tendency for this to drive a persistent ridge across NW NA since late summer. That persistent NW NA ridge leads to a persistent trough downstream and the associated cold pattern we’re now looking at. As our Winter Outlook suggests, we think this overall pattern repeats itself throughout the majority of the months ahead.

As we look more “immediate term,” what do teleconnections and the MJO tell us about the overall pattern moving past the middle of November? Well, to start, the highly amplified MJO is forecast to roll into Phase 7 around mid-month. This suggests the colder than normal pattern persists.

The EPO is forecast to remain negative while the PNA remains positive into and through the mid month period. Both argue for continued cold.

To no surprise, the latest long range data continues to drill unseasonably cold air south into our portion of the country and a large majority of the eastern portion of the Lower 48 in the Weeks 2-3 time period. Snow opportunities will undoubtedly follow with this kind of pattern.

Buckle up…

Bill McMillan November 5, 2019 No Comments Arctic Cold, Autumn, Client, EPO, European Model, Forecast Discussion, Forecast Models, Long Range Discussion, MJO, PNA, Record Cold, snow, SST Discussion, Unseasonably Cool Weather, Winter Outlook

Pattern Evolution Through Late October…

The teleconnections are aligning in a manner that favors a colder than average period of weather by late-October standards. Note the PNA trend positive while the EPO heads negative. The AO and NAO also follow suit.

The sum of all of the above should feature a predominant western ridge for late month with a persistent eastern trough- at times deeper than others.

Add in the fact that the MJO is anticipated to swing into Phase 2 and this further serves to increase confidence in the colder shift.

The models are focusing in on the colder close to the month and though specifics will continue to vary from run-to-run, the primary message that we want to convey is to expect a colder than average 2nd half of the month with an active storm track. As pops of more “winter-like” air get involved behind one or two of the late month storms, pre-Halloween flakes may fly across a portion of the Ohio Valley.

Given the pattern progression and anticipated teleconnection states, we think it’s wise to ensure the kiddos have a warm Halloween costume this year!

Bill McMillan October 17, 2019 No Comments AO, Autumn, Client, Ensemble Discussion, EPO, European Model, Forecast Discussion, Forecast Models, Halloween, Harvest19, Long Range Discussion, MJO, NAO, PNA, Rain, snow, Unseasonably Cool Weather

Taste Of Winter Before Month’s End?

A cold front will whip through central Indiana Tuesday evening. Showers will accompany the frontal passage, but we still don’t anticipate much in the way of significant moisture across central Indiana. Heavier rainfall totals in excess of 0.50″ will likely fall across drought-stricken areas downstate.

Colder and blustery conditions will be with us Wednesday and Thursday, including wind chills in the upper 20s at times Wednesday morning.

A moderating trend will get underway this weekend as a gusty southwesterly breeze takes hold on the backside of retreating high pressure. This will lead to a couple of days of above normal warmth early next week (not quite done with the 70s just yet).

We’ll continue to monitor for a wet and stormy time of things Monday PM into Tuesday. The severe threat is to be determined and will require fine tuning as we push ahead over the next several days.

Once this area of low pressure and associated cold front blow through, colder air will arrive on gusty northwest winds by the middle to latter portions of next week.

This will set the tone for a rather significant colder shift as we get set to put a bow on the month of October. A secondary and more significant trough will descend into the region just after Day 10. With a developing negative EPO, positive PNA, and MJO heading for Phase 2, it’s time to start “beating the cold drum” a bit harder. In fact, latest 500mb charts would indicate there’s the potential of at least a little wintry mischief present to go along with the colder shift.

This should at least kick up the lake effect snow guns for the first time this season, and we’ll have to monitor things for the possibility of “backside” energy digging south at the base of the trough that would present the possibility of a little early season snow across parts of the Ohio Valley region as Halloween week nears…

Times, they are, indeed, ‘a changing…

Bill McMillan October 14, 2019 No Comments Autumn, Client, EPO, Forecast Discussion, Forecast Models, Halloween, Lake Effect Snow, Long Range Discussion, MJO, PNA, Rain, Severe Weather, snow, T-storms, Unseasonably Cool Weather, Unseasonably Warm, Windy

VIDEO: Frosty Midweek; Colder And Active Stretch Of Weather For Late October?

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Bill McMillan October 14, 2019 No Comments Autumn, Client, EPO, First Freeze, First frost, Forecast Discussion, Forecast Models, Harvest19, PNA, Rain, Unseasonably Cool Weather, Weather Videos, Windy

Cool 6-10 Day Period Ahead, But Then What?

A strong cold front will sweep through the area tomorrow and help usher in the coolest air so far this autumn. This will set the tone, combined with the recurving WPAC typhoon, for a chilly upcoming 6-10 day period, but what lies beyond this period later in the month?

Recurving Super Typhoon Hagibis will promote reinforcing chill across our area next week.

We turn to a couple of our more trusted teleconnections for advice.

Note the PNA “bobbing” up and down through the medium range period, with more of a negative look around the 20th. This argues for a milder stretch of weather around that time. (Further out, we’ll keep close eyes on the PNA to see if a more consistent positive signal develops as we inch closer to November).

The EPO pops strongly positive mid month which, too, argues for milder times, locally. That said, similar to the PNA above, the EPO is trending towards a scenario that would present colder times as we rumble towards November. We’ll monitor for consistency.

To no surprise, given the two primary teleconnection drivers above (remember these can change as the seasons evolve), we see the pattern set to turn milder just beyond Day 10. Note the strong agreement between the European, Canadian, and GFS ensemble data below.