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Category: Ensemble Discussion
Permanent link to this article: https://indywx.com/2018/08/01/video-foggy-open-to-august-discussing-rain-chances-ahead/
Jul 28
Time To “Buck The Trend” On The Dry Summer?
Summer has been dry, thus far, for central Indiana. With the last month of meteorological summer on the doorstep, will that continue?
Before we discuss further, let’s check-up on precipitation anomalies at IND (through July 28th).
- June: finished the month 0.26″ below average
- July: 2.69″ below average, month-to-date
- (This comes after a May that featured a 3.63″ deficit).
We have discussed the upcoming shift to a wetter regime that will develop Sunday into the first half of next week. A Saturday evening update continues to point towards increasing rain chances arriving as we rumble into Sunday evening. As expected, this morning’s high resolution NAM was likely a bit too excited on the initial wave of moisture and has come around to a “more realistic” idea in our opinion.
Rain and embedded thunder will likely be rather widespread early Monday, especially across the southern half of the state.
Data continues to point towards the greatest coverage of rainfall arriving Monday night and Tuesday. We still expect a widespread 1″ to 2″ rain for central Indiana before things begin to wind down mid to late week. There will be locally heavier totals.
As we look ahead, we think the balance of the month of August will feature an upper ridge across the western portion of the country that will keep our immediate region in an active northwesterly flow aloft. Perhaps the GEFS is seeing this best at the moment (important to note the model has been consistent with respect to run-to-run updates as of late). This is a wet signal this time of year…
The model has support of a return to wetter times as noted from the latest JMA Weeklies, CFSv2, and European ensemble.
While the cool will relax as we rumble past the first couple days of the month (we’re in the “dog days” after all), I still think the worst of the heat is over for the summer and the headline for August will likely be a situation where we begin to make up for lost time in the precipitation department. That upper ridge centered to our west in the means will likely result in a continuation of rather active times from a precipitation perspective through the month and our idea is that we finish August with above normal precipitation across central Indiana for the first time since April…
Permanent link to this article: https://indywx.com/2018/07/28/time-to-buck-the-trend-on-the-dry-summer/
Jul 22
VIDEO: Closing Out July And Looking Ahead To August…
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Permanent link to this article: https://indywx.com/2018/07/22/video-closing-out-july-and-looking-ahead-to-august/
Jul 07
Looking Ahead…
With the first week of July in the books, we wanted to touch base on what we believe the remainder of the month has in store. In short, there’s no change to our ongoing idea of a transitional period July 10th through 20th followed by a more pronounced shift to cooler temperatures as we wrap up the month: roughly the 21st through 31st.
In some aspects, the transitional period has already begun- just a couple of days earlier than originally expected. Thankfully, the early month heat has subsided, giving way to a couple days of very refreshing conditions. After a slight rebound in humidity to open the work week, a cold front will slip through central Indiana Tuesday. This will offer up the potential of a thundershower followed by a return of the refreshing easterly flow we’re currently enjoying.
Our latest 7-day forecast reflects this slightly cooler air mass and the associated “pull back” in humidity over the midweek stretch.
Heat and humidity will then build again during the late week period ahead of an approaching cold front that will likely offer up more in the way of scattered to numerous storms next weekend. Note the “ups and downs” over the upcoming 7-10 day period. While sustained heat isn’t expected, there will be a few hot days thrown in the mix for good measure as the overall pattern works through its’ transition.
After the upcoming 10-day stretch, we notice the data becoming more aligned in a manner that will pull the worst of the heat, relative to average, west and put the Mid West and Ohio Valley in a position to turn cooler with more authority, as well as more active to close the month. We have to give a hat tip of the cap to the JMA Weeklies for first seeing this a couple of weeks back, and while we weren’t ready to jump on the idea of a sustained trough setting up over the Great Lakes in what will now be the Week 2-3 time period, the model did see the pull back before the majority of other data.
The new GEFS this afternoon sees something similar:
Again, along with the expected cooler shift, the model is painting a wet pattern emerging as we put the wraps on the month of July. With the developing northwest flow aloft, it’s tough to disagree with this overall more active look.
Enjoy this pleasant early-July weather and have a great weekend! Additional updates will arrive here and on our social media outlets throughout the weekend.
Permanent link to this article: https://indywx.com/2018/07/07/looking-ahead-2/
Jun 30
Serious Heat & Humidity Continues In The Week Ahead…
An expansive upper level ridge will keep many across the eastern half of the country very hot and humid over the upcoming week. The worst of this particular heat wave, relative to average, will center itself over the Great Lakes and Northeast.
More specific to central Indiana, daily highs in the lower to middle 90s and overnight lows in the lower to middle 70s will continue into late next week. For the most part, this is a dry pattern, as well, BUT there will be a few exceptions.
The first of such arrives Sunday evening into Sunday night with the potential of a line of showers and thunderstorms rumbling into the state. We note high resolution models weaken this line of storms as it arrives into central Indiana (likely after dark Sunday), but we’ll keep an eye on things. As things stand now, the western half of the state stands the greatest risk of getting meaningful rain Sunday evening.
Thereafter, additional isolated to widely scattered storm coverage is possible- primarily during the afternoon and evening hours, but more than not will remain rain-free. 7-day precipitation totals check in this morning in the 0.25″ to 0.75″ range.
In the longer range, we should begin to see a transition to “less hot” 🙂 conditions next weekend followed by a more significant pattern change for the second half of July as the upper level ridge retrogrades west, centering itself over the Rocky Mountain region.
Not only will this likely lead to a cooler second half of July, but should also offer up an increasingly active and wetter northwesterly flow for our immediate region.
Permanent link to this article: https://indywx.com/2018/06/30/serious-heat-humidity-continues-in-the-week-ahead/
May 29
Light At The End Of The Tunnel From The Recent Dry Regime?
In our JMA Weekly recap from last week, we noted the model was transitioning towards a wetter pattern for early and mid June.
It’s encouraging to see the latest ensemble data from the American GFS and European (courtesy of TropicalTidbits.com) support this idea, as well.
In addition to a wetter pattern, we would also want to pay attention to the potential of a gusty storm complex or two riding southeast around the hot dome off to our southwest.
After an unusually dry May (- 3.44″ as of this post), Alberto’s remnant moisture will help us, at the very least, cut into the rainfall deficit tomorrow. Longer term, it sure is nice to see the medium range guidance in agreement on a wetter time of things. As we’re all aware, this is a crucial time to determine the overall long-standing summer pattern. Dry ground and early warmth can easily “feedback” on itself, and it’s easy to understand some of the concern, particularly AG-related over the past few weeks. With that said, it’s certainly not too late to try and at least ease some of the worry a bit.
When we look at the MJO, we note the amplitude and it’s forecast to swing through the wetter phases, at least locally, (4,5,6) through the month of June:
In closing, the JMA Weeklies led the charge in the idea of more active times returning in June, and the combination of GFS and European ensemble data suggests they had merit. With the added bonus of having the MJO on our side, it’ll be hard to avoid a change of the guard towards an overall wetter pattern in the weeks ahead. Perhaps Alberto’s remnant moisture is only the beginning…
Permanent link to this article: https://indywx.com/2018/05/29/light-at-the-end-of-the-tunnel-from-the-recent-dry-regime/
May 21
Storms Rumble In This Evening; Warm Open To Meteorological Summer…
A stalled frontal boundary remains draped across the Ohio Valley this morning. We note ongoing showers across northern Indiana and Illinois, along with considerable cloudiness in association with the front. Also of interest is the disturbed weather off the FL peninsula this morning. Models differ on the evolution of things, but both the GFS and European model suggest we may have a tropical depression or weak tropical storm on our hands by the Memorial Day weekend. Is it more of a threat to the central Gulf Coast region, such as the European implies, or more of a Carolina event? It’s simply too early to know, but it’ll be fun to watch things play out this week.
Back here on the home front, a quiet start to our Monday will turn stormy at times this evening as the front nears. We think best coverage of showers and thunderstorms will come between 5p and 10p. There will be some winners and losers when it comes to rainfall amounts by midnight. Some can expect over an inch in the stronger storms while others may only see a tenth of an inch, or so. Something that must be taken into forecasts moving forward is the tendency of most model data (high resolution and global data alike) to “over forecast” rainfall amounts as of late. Also of note is for the potential of a couple of strong to severe storms to develop this evening. We always have to be wary of fronts draped across central Indiana as they’ve been known to help tornadic activity spin up. We’ve lost count of how many slight risk days with warm fronts nearby that turn busy… If you’re planning to be outdoors this evening, please have a means of receiving the latest watches and potential warnings that may be issued.
High pressure will build in for the midweek period and supply plentiful sunshine along with continued warmer than average conditions. Overnight lows will fall into the upper 50s (couple of degrees above average) with the drier air mass in place, but afternoon highs will continue to climb into the lower and middle 80s (around 10 degrees above average).
Good news this morning for all of the Race Day and Memorial Day weekend activities is that forecast models are backing off (seeing a common theme?) on the magnitude and overall coverage of showers and thunderstorms associated with our next system. While we’ll maintain widely scattered thunderstorms in our Saturday-Monday forecast, much more of the time period will be free of any rain and storm activity.
Longer term, thoughts are shifting towards the open to meteorological summer (where is this year going?!). The GFS ensemble suggests the overall warm pattern remains intact as we open a new season with widespread warmth expected through the first few days of the June.
Permanent link to this article: https://indywx.com/2018/05/21/storms-rumble-in-this-evening-warm-open-to-meteorological-summer/
May 18
More Unsettled Weekend Ahead And Closing Out May…
An upper level low pressure system will track northeast today into tonight, and as it does, look for more numerous showers and embedded thunder to develop. Some localized heavier downpours are a good bet this evening across central Indiana.
Otherwise, look for considerable cloudiness and highs topping out in the lower 70s today.
While we’ll have to contend with a few showers Saturday, overall, the day should be drier compared to today and what lies ahead Sunday. Speaking of Sunday, we’re monitoring the potential of a couple of storms reaching strong to severe levels to close the weekend. The Storm Prediction Center includes central portions of the state in a “marginal” risk of severe with their update Friday morning. It wouldn’t surprise us if a portion of the marginal risk is upgraded to a “slight” risk in future updates. We’ll fine tune storm timing over the next 24 hours.
As we look ahead to the end of May, there really aren’t any significant changes to the overall warmer than normal theme we’ve enjoyed so far this month. Longer range guidance off of the European ensemble continues to support broad scale upper ridging across the Mid West and Ohio Valley and a corresponding warmer than average regime. From a precipitation perspective, the next couple of weeks do look more active compared to the dry start to the month. Case in point, the balance of the upcoming week will be dominated by a stalled frontal boundary. While we’ll have to fine tune exactly where the front stalls, daily chances of showers and thunderstorms (scattered fashion) can be expected.
Permanent link to this article: https://indywx.com/2018/05/18/more-unsettled-weekend-ahead-and-closing-out-may/
May 16
Wednesday Morning Rambles…
1.) A narrow, but persistent band of downpours continues to fall just south of the metro this morning. Places from Martinsville to Trafalgar and Shelbyville are enjoying needed rain this morning.
2.) Overall, a drier air mass will build into central Indiana today and Thursday (cooler, too) before moisture returns to close the week. Scattered showers and embedded thunder are more likely Friday and again late Sunday into Monday.
3.) Looking ahead, we notice a more active pattern is presented off the overnight GEFS model. The heat ridge backs west and sets up a busy “ring of fire” pattern with a northwest flow aloft across our region. We have a ways to go before developing consistency and overall confidence, but this is at least an encouraging sign. The end result, should this come to fruition, would be a significantly wetter open to June.
Permanent link to this article: https://indywx.com/2018/05/16/wednesday-morning-rambles-8/
May 07
Quick Evening Notes: Warm Pattern Grabs The Headlines In The Longer Range…
As we look over the 12z long range guidance, we see a common theme: warmer (dare I say “hotter”) than average. Additionally, most data paints a drier than normal trend Days 10-20, as well.
The GEFS shows eastern ridging gaining control during the period which favors a warmer than normal pattern. Consensus of other data is similar in the upper levels.
At the surface, all three major global models agree on warmth in the long range period, including the GEFS, EPS, and CFSv2:
Guidance suggests below average precipitation during the period. With broad scale ridging in place, we agree on a drier theme compared to normal. While trying to put our finger on the flip from the prolonged cold to warmer was difficult to nail down from March and April, May always looked like a drier than average month from several weeks out. (One note is the potential of active times across the Great Lakes region as “sudden summer” gains steam to the south and stubborn chill refuses to let go to our north. The gradient would promote heavier than normal precipitation relative to average).
Given the agreement in the data, along with some additional pattern drivers, we continue to believe the medium to longer term period (including mid and late May) will feature an overall warmer than average pattern along with drier than normal conditions.
More on the short-term in the morning, including what will be a summer-like feel by late week.
Permanent link to this article: https://indywx.com/2018/05/07/quick-evening-notes-warm-pattern-grabs-the-headlines-in-the-longer-range/