Category: Weather 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/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/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/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/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/disruption-in-the-force-or-just-noise/