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Category: Weather Rambles
Permanent link to this article: https://indywx.com/2019/05/21/video-tuesday-evening-rambles/
May 13
“Transition” Is The Name Of The Game…
As we look ahead to late-May and early June, “transition” is the word that comes to mind when describing the overall weather pattern.
We’re going to begin pulling out of this unseasonably chilly pattern late-week and we’ll replace it with a true summer-like regime. Note the differences at 500mb between now and this weekend:
Not only will the 80s return, but oppressive dew points can be expected as well by Friday (65-70 degrees). The sweat factor will be back in full effect!
With that said, there’s reason for concern that the flip to summer may not last.
Not only do we continue to see high-latitude blocking in place, but the MJO is showing signs of rotating into Phase 1 as we inch closer to early-June. That Phase 1 this time of year is a cool one for the eastern portion of the country. Note the tendency for eastern troughiness illustrated in Image 2 below.
Perhaps ensemble data is seeing this cooler transition in the pattern on today’s 12z run:
Bottom line, confidence is high on a summer-like flip as we welcome in the weekend, continuing into early parts of Week 2, but we don’t think it’s a “stick and hold” variety of warmth. There’s growing reason to believe a flip back to cooler conditions looms before we close out the month.
Permanent link to this article: https://indywx.com/2019/05/13/transition-is-the-name-of-the-game/
May 07
Tuesday Afternoon Rambles: Weekend Model Differences; What’s Beyond The Cooler Mid-May Shift?
I. A couple widely scattered light showers have flared up this afternoon, but most central Indiana neighborhoods have enjoyed dry conditions with sunshine and temperatures in the mid-upper 70s. Look for more of the same Wednesday, including filtered sunshine through a good chunk of the day. Warm Air Advection (WAA) will help boost temperatures into the lower 80s for most of the immediate area.
II. Better aerial coverage of showers and thunderstorms will develop late Wednesday night into Thursday night. We believe 3 rounds of showers and storms are possible during this time frame (at least impacting portions of the central Indiana viewing area):
- Late Wednesday night into the predawn Thursday
- Thursday afternoon
- Thursday evening as the cold front sweeps through the state
III. High pressure will build into the region as we close the week. This will lead to improving weather conditions, including increasing sunshine. A very nice close to the work week/ open to the weekend is dialed up! Make those patio plans now!
IV. Modeling differs on the handling of our weekend weather feature(s). The GFS (image 1) maintains the idea of a dry Saturday, followed by showers Sunday as a cold front sweeps through the region. Moisture would be limited with such a solution. The European (image 2), however, is more bullish on a more widespread rain event arriving Saturday PM into Sunday AM. Stay tuned as we work to reach some sort of agreement between the data.
V. After a cooler than normal period of weather through the middle of the month, we’re thinking the coolest anomalies will pull back into the intermountain west and 4-Corners region. Do we foresee any major late-May heat? No, but we should moderate against the norms during the last week to 10 days of the month.
After a drier stretch of weather through the mid-May period, precipitation should return to at least average levels through the late month stretch. Early indications would then suggest wetter than normal times return as we get set to open June…
Permanent link to this article: https://indywx.com/2019/05/07/tuesday-afternoon-rambles-weekend-model-differences-whats-beyond-the-cooler-mid-may-shift/
Apr 04
Pattern Returns To An Active Time Of Things…
One word to describe the mid-April weather pattern? ACTIVE. Tonight’s medium and long range video update dives in further…
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Permanent link to this article: https://indywx.com/2019/04/04/pattern-returns-to-an-active-time-of-things/
Feb 25
Frigid Open To March And Late Month Musings; Reviewing The NEW European Weeklies…
Average temperatures through the 1st (5) days of the month include highs of 46 F and a low of 29 F at Indianapolis. Instead, a frigid pattern will grip the region as we move through early March, including highs that will likely only top out in the lower to middle 20s and lows in the upper single digits to lower 10s as we move through the first week of the month (coldest centered on Sunday through next Wednesday).
Should we get any sort of snow down during the period (still up for debate as of this evening), lows will likely approach 0 F. The best opportunity for accumulating snow over the upcoming week would come Friday night into Saturday, but confidence remains low. Thereafter, we prefer the “suppressed” ideas currently portrayed by modeling as more meaningful winter storm threats impact the lower Ohio/ TN Valley and southern Appalachian region- especially with such an anomalously cold pattern in place.
Speaking of cold, the deep and expansive snowpack across the central and northern Plains won’t allow the late season taste from the arctic to modify as much as it may otherwise. As the frigid air mass settles southeast, below zero wind chill values are a good bet early next week across the northern half of the state. “Tap the breaks” on meteorological winter kicking off March 1st…
With that said, the NAO and AO are expected to remain positive and while initially “trumped” by the significantly negative EPO, this will trend positive by mid-month. These all suggest the cold is limited and that there shouldn’t be any change to the idea that we really begin to feel more spring-like by the middle of March. This is backed up by the continued idea that the MJO rumbles into Phase 4 by mid-March, as well (again argues for warmth).
Sure enough, longer range models show the ridging and associated warmer times ahead:
It should be noted that with the mean trough position taking up shop across the western portion of the country mid-March, not only should we moderate, but we should also see a return of wetter/ stormier times. With the GOM (Gulf of Mexico) running above normal, early season severe weather outbreaks will have to be closely monitored…
The new European Weeklies in this evening also back up the idea of an unseasonably cold 1st half of the month giving way to milder conditions by mid month. The model paints a drier than normal pattern over the Ohio Valley and Mid West over the next couple of weeks before wetter signals return by the middle of March.
Permanent link to this article: https://indywx.com/2019/02/25/frigid-open-to-march-and-late-month-musings-reviewing-the-new-european-weeklies/
Feb 13
Disruption In The Force Or Just Noise?
Our longstanding call has been for the period of early to mid-February to feature a “transitional” pattern before locking into one last cold, stormy period for the winter during the 2/18 through 3/10 time frame. The reasoning behind this idea has been stated multiple times in previous updates.
However, there’s no denying that today’s 12z ensemble update (both from the GEFS and EPS) has rattled us a bit with that idea. The GEFS and EPS are in very good agreement at 500mb:
This is in the face of Phases 8 and 1 from an MJO perspective:
Furthermore, the sudden negative “jolt” in the SOI (Southern Oscillation Index) also favors a significant period of cold, stormy weather, locally:
Please understand this isn’t us changing our ongoing forecast that’s out there, but instead making sure we’re presenting a 100% transparent idea from two of the most highly respected ensemble products out there (that have been generating a lot of attention today with this output). We prefer to give it another few days before altering our medium and longer term forecast to see if any sort of consistency can develop.
At the end of the day, this may be a situation where the resistance from the SE ridge puts up enough of a fight to lead to a lack of “suppression” from the hyperactive storm track currently in place, and instead continuing the busy storm track into the TN and Ohio Valley regions as cold air presses.
Rest assured, you’ll be the first to know if a wholesale medium to long range forecast change is required here. Stay tuned.
Permanent link to this article: https://indywx.com/2019/02/13/disruption-in-the-force-or-just-noise/
Jan 25
Accumulating Snow Impacts Central Indiana Saturday…
Light snow is flying across central Indiana this evening, but “light” is the key word here. For most, a dusting is all we’ll muster with this initial wave of energy.
As we move into the first half of the weekend, a more vigorous disturbance will track across the region. We’ll notice snow breaking out across southwest Indiana around lunchtime before the area of snow grows in overall coverage and intensity through the afternoon into the evening hours.
With a cold surface and temperatures in the mid to upper 20s as the snow falls, expect slick roadways across the region Saturday afternoon into the evening. While winds aren’t expected to be particularly strong, the “open country” may experience a few issues with blowing and drifting snow due to the dry, powdery nature.
Most of central Indiana, including Indianapolis, can anticipate 1″ to 2″ of snow with this event Saturday, but there will likely be a couple of 2″+ reports. Snow will diminish from southwest to northeast after midnight.
Attention will then shift to additional snow and severe cold early next week… More on that in the AM.
Permanent link to this article: https://indywx.com/2019/01/25/accumulating-snow-impacts-central-indiana-saturday/
Dec 25
Looking at the Holiday Week and Ahead to January…
Tomorrow will be a rather uneventful weather day across central Indiana, but things will begin to change as we head into Thursday.
An area of low pressure will track out of the central Plains into the Great Lakes by Friday. The end result will be increasing coverage of showers Thursday afternoon and perhaps even a rumble of thunder Thursday evening.
Most of the concentrated rain should come to an end around dark Thursday. By that time we forecast a general 1/2″ to 1″ to fall in area rain gauges.
More seasonable air will blow in here behind the storm system and we’ll have to keep an eye on energy “attacking” from behind over the weekend. With colder weather in place, snow is possible next weekend.
Looking ahead, a combination of ingredients appears to be coming together to create a rather significant transition in the pattern as we head into January. Note the developing positive PNA…
This will result in more sustained below normal temperatures making a return early January to our neck of the woods…
Additionally, it also appears an active storm track will continue. While impossible to say this far in advance, prospects for above average snowfall (average is 8.6″) appear likely through the month of January.
Permanent link to this article: https://indywx.com/2018/12/25/looking-at-the-holiday-week-and-ahead-to-january/
Dec 16
“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…
Permanent link to this article: https://indywx.com/2018/12/16/pulling-the-curtain-back-on-the-late-december-pattern/
Dec 12
Stormy Pattern Ahead For The Heart Of The Holiday Season?
A “relaxation” of the well below normal cold is on the way.
While this will support a 5-10 day period of temperatures of 5° to 10° above average (milder overnight lows, and a few days with highs at or above 50° are a good bet during the period, as well), the stage is already being set in motion for a return of colder conditions around the Christmas holiday. While admittedly, transitional periods can be “finicky,” there’s support from other pattern drivers behind a wintry return between the 12.22 and 12.24 time period. Furthermore, data suggests that there will be plenty of storminess to boot.
For those that love to review the operational model data as it rolls in (in some cases, up to 4 times per day), expect wild swings as the data begins to “hone in.” Despite some of that model fluctuation, we expect the pattern to look something like this around Christmas.
We expect the mean ridge position to set up shop over the Pacific northwest. This will result in a warmer than average regime across the west. At the same time, the trough will be pushing back into the east. As the cold air settles back in, we expect a rather active time of things during the period. This certainly doesn’t mean we’re talking snow storms, but it does appear likely that at least one or two systems of interest loom. We’ll have to deal with the challenges that will come from one or both as time draws closer.
While a “transitional” pattern appears likely around Christmas, there are growing concerns of a return of sustained cold as we get into the new year.
Permanent link to this article: https://indywx.com/2018/12/12/stormy-pattern-ahead-for-the-heart-of-the-holiday-season/