June 2020 archive

Big Heat- With A Twist…

As we get set to open the month of July, there’s increasing confidence in a developing heat wave to the likes we haven’t experienced in a few years. It seems there are other sources and vendors that have tried to “manufacture” heat waves each of the past few summers and we’ve had to play those “doomsday” forecasts down. This is a different scenario this time around, but there’s yet another interesting case study (one that we can take into the late summer, fall, and winter) in front of us that ultimately may have some say as to the longevity of the upcoming heat wave.

Before we get to that, let’s take a look back at some of the more recent stretches of significant heat Indianapolis has had to deal with. In scrolling through the climate logs, it was a bit surprising how the late summer and early fall has featured the most significant heat over the past few years:

Log of consecutive 90° + Days:

I. September 2nd – 8th, 2015 (7 days)

II. July 21st – 25th, 2016 (5 days)

III. September 21st – 26th, 2017 (6 days)

IV. September 2nd – 6th, 2018 (5 days)

V. July 17th – 21st, 2019 (5 days)

This can help paint some perspective around the magnitude and longevity of the upcoming heat wave. We think there’s the potential for 9-10 consecutive days of 90° + beginning Friday, the 2nd. Admittedly, this now appears as if it’ll be a more significant stretch of heat than once believed a couple of weeks ago, but we also believe there will be some rain to help serve as saving grace before the pattern begins to shift after the first week to 10 days of the month. We’ll handle that with our short-term forecast updates in the coming days and weeks (reminder that we’ll be posting right through the holiday, as per usual).

A significant heat wave to the tune of what we haven’t seen in the past several summers will grip the region to open July.

We still believe the ridge axis will shift southwest after the 9th or the 10th and this will open the door for slightly cooler air and much better rain chances (isolated to widely scattered coverage is all we can expect after tomorrow until around the 9th). We’ll have to be on guard for the threat of northwest to southeast riding storm clusters by mid-month, but this will come on the heels of an oppressive and rare hot, humid stretch of weather across central Indiana.

What will be of interest is the impact the MJO may (or may not) have on this heat wave. Today we note there’s rather significant disagreement amongst the models regarding the overall amplitude into mid-July. The GEFS (image 1) is quite energetic while the European (image 2) is less than impressed. For what it’s worth, the GEFS as of late has been performing better in handling the MJO than the European.

Should we, indeed, make it into Phase 2 towards mid-month, we’d be looking at the likelihood of more significant cooling along with wetter conditions, but we stress this is very low confidence from this distance given the difference in the modeling. Stay tuned.

MJO Phase 2 in July argues for a cooler than normal pattern s-central into the OHV and Southeast.

Permanent link to this article: https://indywx.com/2020/06/30/big-heat-with-a-twist/

Heat And Humidity Builds For The Holiday Weekend…

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Monday Evening Video: Tropical Airmass Locks In; More On Our July Outlook…

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Permanent link to this article: https://indywx.com/2020/06/29/monday-evening-video-tropical-airmass-locks-in-more-on-our-july-outlook/

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/2020/06/29/july-2020-outlook-the-heat-is-on/

Weekly #AGwx And #Severe Weather Outlook…

I. Recent wet pattern remains intact.

II. Persistent hot, muggy regime takes us into the holiday weekend.

Temperatures will run above to well-above normal from the Plains into the Great Lakes and Northeast this week. The Rockies and points west can expect unusually chilly conditions.
Wetter than normal conditions are expected across the southwestern OH Valley into the TN Valley this week, along with the northern Rockies and New England.
We forecast 7-day rainfall totals for central IN to fall within the 1.75″ to 2.50″ range with locally heavier amounts.
In this pattern it won’t take much to have one or two storms pulse to severe levels, but widespread severe storms aren’t expected, locally. The biggest concern from any stronger storm that does form will be centered around damaging straight line winds.

Forecast Period: 06.28.20 through 07.05.20

A stationary frontal boundary will remain draped across the region until Tuesday night before getting a slight “nudge” off to the southwest Wednesday. The warm and humid pattern in place today will remain locked into the area straight through the holiday weekend (with a small break in humidity midweek). Periods of hefty thunderstorms can be expected- most numerous during the afternoon and evening hours. With such high moisture content in the air, locally heavy rainfall is expected at times. This “rinse and repeat” forecast will begin to change up by the holiday weekend as ridging builds overhead. While this won’t help us with the heat or humidity, this will reduce rain chances. Instead of scattered to numerous coverage, we’ll be talking about isolated coverage for the holiday weekend, itself. Most will stay dry. By this time frame, we’ll monitor the goings on to our south as a cut off low keeps the TN Valley into the Southeast region unsettled with more widespread storm coverage for the holiday weekend.

Permanent link to this article: https://indywx.com/2020/06/28/weekly-agwx-and-severe-weather-outlook-11/

VIDEO: Humidity Is Back Along With Periods Of Storms…

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Permanent link to this article: https://indywx.com/2020/06/27/video-humidity-is-back-along-with-periods-of-storms/

Soupy Airmass Returns; Looking Ahead To Independence Day…

It’s still pleasant this morning across central Indiana, but that will begin to change by afternoon as heat and humidity increase in rather significant fashion. This tropical airmass will remain intact into early parts of the week and will help fuel hefty storms at times. The culprit? A warm front will lift northeast through the state over the next 12-24 hours, allowing a moist southwesterly flow to take control. A cold front will approach northern portions of the Ohio Valley tonight and Saturday before stalling out. This front will serve as a focal point for strong to severe storms mostly north of Indianapolis tonight. Eventually this front will slowly sink south before potentially even clearing the area, which would allow slightly cooler and much less humid air into central Indiana by midweek.

As we time out rain and storm chances, the first opportunity of scattered showers and storms will arrive late morning into this afternoon as the warm front begins to lift north. These will be of the “splash and dash” variety, but will be capable of brief heavy rain.

More widespread storms, including the possibility of a few strong-severe cells (damaging wind being of greatest concern) will target northern IN tonight- closer to the cold front.

These northern IN overnight storms should diminish before making it into Indianapolis.

With a warm and soupy airmass locked into place along with a trigger mechanism nearby with our frontal system, it’s a safe bet to expect scattered to numerous storms through the weekend and into Monday. During this time, overall coverage of storms should be greatest during the afternoon and evening, but even nighttime storms are possible. With precipitable water values approaching 2″ at times, any shower or storm will be capable of producing torrential rainfall in a short period of time.

As we move into early week, the front will get shoved southwest and drier air will try and intrude from the northeast. This may serve as a focus point for more widespread storms across central and western parts of the state early week. Eventually that drier air will win out across the entire area and should lead to a more pleasant feel along with eliminating rain chances by Wednesday into Thursday. Before we get to that point, widespread rainfall totals of 1.5″ to 2″ can be expected between now and Tuesday afternoon with locally heavier totals.

Drier air should arrive for midweek as a “backdoor” cold front presses southwest.

Looking Ahead: Things still look quite toasty around these parts for the Independence Day weekend, itself, as an expanding ridge builds overhead. Additionally, that same front that will be off to our west midweek will likely move back northeast by next weekend and help fuel a smattering of t-storm coverage during the afternoon and evening hours. Our call for the Independence Day weekend at this point is for hot, humid conditions (highs in the lower 90s and lows in the lower to middle 70s) and plenty of dry time with widely scattered afternoon/ evening storm potential. These shouldn’t last terribly long for any one area.

Permanent link to this article: https://indywx.com/2020/06/26/soupy-airmass-returns-looking-ahead-to-independence-day/

VIDEO: Long Range Update Through The Remainder Of Summer And Early Hint At Fall…

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Permanent link to this article: https://indywx.com/2020/06/25/video-long-range-update-through-the-remainder-of-summer-and-early-hint-at-fall/

VIDEO: Replacing The Pleasant Airmass With Increased Humidity And Periods Of Heavy Rain This Weekend And Into Early Next Week…

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Permanent link to this article: https://indywx.com/2020/06/24/video-replacing-the-pleasant-airmass-with-increased-humidity-and-periods-of-heavy-rain-this-weekend-and-into-early-next-week/

VIDEO: Turning Less Humid; More On Weekend Storms And The Early July Pattern…

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Permanent link to this article: https://indywx.com/2020/06/23/video-turning-less-humid-more-on-weekend-storms-and-the-early-july-pattern/

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