Category: Monthly Outlook

Oct 01

October 2020 Outlook…

Average temperatures for the month of October fall from 71° and 50° on the 1st to 60° and 41° by Halloween. Indianapolis averages 3.12″ of rain this month and 0.40″ of snow.

We expect the MJO to remain in Phase 5 for the better part of the first half of the month. This, in conjunction with the positive PNA and negative EPO, will help drive the early cool pattern into the East. Note how that begins to change next week (the PNA goes negative and the EPO goes positive). This will likely erode a lot of the cool air and slowly, but surely allow warmer temperatures to penetrate east into the Ohio Valley beyond the 10th (give or take a day).

Note how the upper pattern follows suit:

Days 1-5
Day 5-10
Days 10-15

The end result should be an unusually chilly start to the month that moderates towards mid and late month. Based on the MJO movement, there’s the potential of chill making a comeback just before Halloween (and into November), but this is a lower confidence call at this point. We’ll keep an eye on that as we move through the next few weeks. From a precipitation perspective, another very dry month is ahead. We’ll end up wetter than September, but still several weeks away from truly changing the precipitation pattern up from a holistic standpoint.

Here’s our official October Outlook. For central Indiana in particular, we expect an average to slightly above average temperature month (less than 1° above average) with well below normal rainfall.


Permanent link to this article: https://indywx.com/october-2020-outlook/

Jul 29

August Outlook: Does The Refreshing Start Run The Duration?

Average August temperatures in Indianapolis feature highs falling from 84° to begin the month to 83° by months end, while average lows drop from 65° to 62°. We average 3.13″ of rain for the month as a whole.

There’s been a lot of chatter recently from local weather sources around how recent Augusts have run cooler than normal. Simply put, that’s not the case. Looking back to 2015, we’re running a clip of “every other year” running cooler than normal, locally.

As we look at August 2020 and the last month of meteorological summer, there are reasons to buy stock into cooler prospects, especially through the 1st half of the month. While there will likely be a rebound late month, it may not be enough to tip the scale towards the warmer side of normal.

Note the recent trends of the CFSv2. While never overly warm for our particular region, the model is expanding the cool for the month and pressing the relative warmth to the coasts.

Interestingly, the model is also developing a more consistent wet look.

The latest European Weeklies have a similar (but not identical) look:

The JMA is in the same boat, as well:

A positive PNA is anticipated to rule through the majority of the month:

The wild card, as is always the case this time of year, will be the tropics. There’s reason to buy into the idea (outlined in previous discussions and videos) that the “heart” of the season will be hyperactive and that begins during the month of August. Obviously, it’s impossible to talk landfall/ inland impacts, but those with interests to the GOM (Gulf of Mexico) and East Coast should closely monitor the tropics through the month, and for that matter, into the fall months.

Officially, we expect a much wetter than normal month across central Indiana along with average temperatures. The cooler than normal 1st half of the month will likely be met with moderation (compared to normal and in the means) late month to balance things out close to average. Our official August forecast is below.

Permanent link to this article: https://indywx.com/august-outlook-does-the-refreshing-start-run-the-duration/

Jul 19

More Thoughts On August…

The last month of meteorological summer is on our doorstep and while we’re still several days from having our finalized forecast built, here are some early ideas on where the pattern is going for August. First, let’s start with some modeling:

European

The Euro features the ‘mean’ ridge axis across the inner-mountain West with a northwesterly flow aloft into the Ohio Valley and eastern Lakes. Given the 500mb pattern, one would think the model would have the heat and wet areas shifted west to better correlate with the ridge placement, but that’s not the case. One item of note is that the model may be seeing tropical influences with the wet area across the Southeast and Mid Atlantic.

JMA

The JMA is similar with the handling of the 500mb pattern, but better aligns the temperature and precipitation pattern with this look at the upper levels. Brunt of the heat (relative to normal) is across the West with a wet Southeast and Ohio Valley.

CFSv2

While a bit chaotic with the precipitation idea, the CFSv2 seems to be locking the warmer anomalies into the Central and East for August.

As has been the case, the MJO will likely have a big say in the August pattern (and continuing into the fall and winter). Despite modeled attempts in the past to swing things into Phases 4-7, we’ve been stuck in the 8,1,2, and 3 cycles over the past several months, and in Phases 1-2 over the past 40 days.

The EPO and PNA are in warm phases and this looks to continue overall into early August.

The early lean with our August forecast will feature a large area of above normal temperatures, including across the Ohio Valley (slightly so), along with near average precipitation. We’ll continue to look through the data and present our official August Outlook week after next.

Permanent link to this article: https://indywx.com/more-thoughts-on-august/

Jun 29

July 2020 Outlook: The Heat Is On…

As we head into “halftime” of meteorological summer, there’s good reason to believe the hottest stretch of weather for a big chunk of the country awaits. So far this summer, Indianapolis has only hit the 90° mark a total of (3) times. If our idea is correct, that number will go much, much higher in the month ahead.

A highly amplified pattern will take up residence for the majority of the month which is certainly unusual for this time of year. Anomalous cold will set up shop out West while heat bakes the Plains into the Ohio Valley, Great Lakes, and Northeast. Given the ingredients in place, there’s reason to believe this kind of pattern will “repeat” itself throughout a good chunk of the month. At least locally, we think this will be a rather humid heat, with timely rains throughout the month. Some of this rain will likely come from “ridge riding” storm clusters that ride the periphery of the ridge that will retrograde west from time to time during the pattern transition.

Modeling, overall, is in good agreement with the upper pattern.

Our official July Outlook is below. Officially for central Indiana, we’re forecasting temperatures to run 1° to 2° above normal with near to slightly above normal rainfall (1″ give or take either direction). Greatest concerns for drier conditions will reside through the southern and central Plains into the Great Lakes region.

Permanent link to this article: https://indywx.com/july-2020-outlook-the-heat-is-on/

May 31

June 2020 Outlook: “Transient” Is The Word…

The first month of meteorological summer is here and right on cue, we’re expecting a significantly warmer pattern to emerge. Does that set the tone for the month as a whole? In the words of Lee Corso: “not so fast my friend.”

After a refreshing weekend the first week of June, overall, is expected to be dominated by a MUCH warmer and more humid pattern. This is courtesy of an upper level ridge building east over the region (in response to the MJO moving into Phase 1, along with a strongly positive EPO).

Deeper into the month, it’ll be tough to hold onto this warm, humid regime as the EPO trends negative and the MJO shows signs of rumbling into Phase 2. In the month of June, Phase 2 delivers cooler than normal temperatures into our portion of the country, along with a good chunk of the East.

Sure enough, the latest European computer model is seeing this cooler trend developing by Week 2:

Given the longer range data, there’s reason to believe the cooler than normal temperatures will also be transient (similar to the warmth to open the month). Overall, drier than normal conditions are expected through the first month of meteorological summer. We’ll have to keep close tabs on where the drier pattern sets up as this can “feedback” on itself the deeper into summer we go.

Given the MJO and EPO forecasts, there’s reason to buy into a “transient” pattern that June should dish out. After a drier than normal 1st half of the month, precipitation should average out close to normal by month’s end. The one exception to this will have to do where remnant tropical moisture tracks inland in the Week 2 time period. From this distance, there are 2 camps pertaining to the potential track of soon-to-be Cristobal: TX/ LA coastline or FL panhandle. The next 7-10 days will be interesting. We’d recommend getting used to an ever-changing temperature pattern in the upcoming 3-4 weeks that should balance out close to average for our neck of the woods by month’s end.

Our official June Outlook looks like this:

Permanent link to this article: https://indywx.com/june-2020-outlook-transient-is-the-word/