Category: Ensemble Discussion

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/

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/

VIDEO: Saturday Morning Thoughts On Late March…

In the midst of trying to keep Bo, our youngest golden doodle, from becoming a tremendous distraction in this morning’s video, here are some thoughts on what lies ahead over…

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/2018/03/10/video-saturday-morning-thoughts-on-late-march/

VIDEO: March Roaring In Like A Lion…

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/2018/03/01/video-march-roaring-in-like-a-lion/

Monday Morning Rambles: Pleasant Open To The Week…

I. High pressure will dominate the early part of the work week, helping to supply plentiful sunshine and seasonably mild temperatures.  We’ll continue to enjoy the much-needed dry theme the weekend ended on!

II. Our next weather maker will arrive midweek and provide a few showers Wednesday (not a huge deal from a precipitation perspective).  However, as a deepening surface low tracks into the Great Lakes Thursday morning, a period of heavier rain and even thunder is possible.  In general, this looks like a 0.50″ to 1.00″ type event.

III. Somewhat cooler air will whip in behind the low, allowing leftover precipitation to end as a couple wet snowflakes across the northern half of the state Friday morning.  The bigger story will be the “bumpy” start to Friday with strong and gusty north winds.

IV. High pressure returns for the weekend and with it will come a return of sunny skies.  Though the mornings will be frosty, afternoon temperatures will “warm” to pleasant levels, especially with the increasingly strong early-March sun angle.

V. Looking ahead, let’s keep a close eye on the second week of March.  Potential is present for a stormy period to emerge under the block.  We note the GEFS and EPS (respective ensembles of the GFS and European models) are in relative agreement on a stormy, cold look during this time frame.  While far too early for specifics, the potential is there for a rather widespread wintry event from the Plains into the Northeast.

Permanent link to this article: https://indywx.com/2018/02/26/monday-morning-rambles-pleasant-open-to-the-week/

Heavy Rain, Thunder, And Colder For The 1st Half Of March…

While “nuisance” type showers are possible through the daytime hours, most of Thursday will provide a break from significant rainfall.  Unfortunately, additional periods of moderate to heavy rain will return as we wrap up the work week and head into the weekend.  In particular, we’re targeting the following for additional heavy rainfall:

  • Overnight Thursday into Friday morning
  • Overnight Friday into Saturday morning
  • Saturday afternoon/ evening

Embedded thunderstorms may target southern Indiana late tonight and Friday morning before more widespread thunderstorms (a couple could become strong) Saturday.  The Storm Prediction Center (SPC) has included the southern half of the state in a “marginal risk” of severe thunderstorms Saturday.

All total, additional rainfall between now and Sunday morning should reach 2″ to 3″ across a widespread portion of the southern half of Indiana with locally heavier amounts.

We’ll finally dry things out as we close the weekend and head into early next week as high pressure settles overhead.

Next week will begin a pattern transition from the unseasonably warm weather we’ve enjoyed as of late to a colder regime for the first half of March.  We note models continue to tank the NAO and AO.

Accordingly, the models are seeing the trough and associated colder than average pattern returning to the eastern half of the country as we rumble through the first half of March.  With such a strong block in place, this can turn into an active pattern for a couple weeks to go along with the cold.  Both the GEFS and EPS agree on the overall look.

While there’s no way to get specific on the individual storm threats that will eventually come with this pattern, the potential is present for a few storms to “bowl” underneath the block through the first 10-15 days of the month.  Each storm will have the capability of delivering wintry precipitation, but this can also be a tricky time of year where most, if not all, ingredients need to come together to create significant wintry events.  In a winter that’s been frustrating to central Indiana snow lovers (frigid, but dry first half and milder, wetter second half), perhaps it would be fitting to get a couple good snow dumps in March (when most are wanting and ready for spring)…

Colder times return for the first half of March.

Permanent link to this article: https://indywx.com/2018/02/22/heavy-rain-thunder-and-colder-for-the-1st-half-of-march/

Bet On The Cold…

During wholesale pattern transitions, operational data will struggle at times, including some wild run-to-run swings.  Earlier this week, the European wanted to put early next week in the lower 50s.  At the same time, the GFS suggested lower single digits.  Precisely, it was a difference of 46° between the two models for a high?!  🙂

We note the teleconnections (in particular, the EPO) are aligning in a manner conducive for widespread cold.

The GEFS might be a bit quick on dropping the arctic hammer, but the consistency of the model is impressive.  Meanwhile, the European (even it’s ensemble data) has been much less consistent and has really been struggling the past couple of winters, overall, as a whole.

While we can argue as to just how cold it’ll get through the early part of February, the overwhelming message is that a prolonged colder than normal pattern will develop during this time period.

Let’s also keep in mind that the initial cold onslaught is coming in the face of the MJO still rumbling through the warm phases.  We note the European is consistently having to correct towards a more “amped up” MJO- swinging into the cold phases as we approach mid-month.  And it’s mid-February that continues to have us concerned for the potential of truly nasty, severe cold.

As for snow, it’ll come in this pattern.  Again, don’t get caught up in the operational output, but understand that the pattern over the upcoming 7-10 days favors numerous fast-moving snow systems.  While most of these will be light, we’ll have to keep a close eye on things as the potential exists for one of these waves to spin up a moderate event.

As we look ahead to Week 2, the potential is there for a more widespread significant phased interior threat prior to the dumping of the bitterly cold air for mid-month.

As it is, both the GEFS and EPS “mean” paint a bullish signal for piling snow up over the next couple weeks…

Permanent link to this article: https://indywx.com/2018/01/30/bet-on-the-cold/

VIDEO: Cooler For Midweek; Discussing Christmas Snow…

You must be logged in to view this content. Click Here to become a member of IndyWX.com for full access.  Already a member of IndyWx.com All-Access?  Log-in here.

Permanent link to this article: https://indywx.com/2017/12/19/video-cooler-for-midweek-discussing-christmas-snow/

Arctic Hammer Drops Down Around Christmas…

While the evolution of how things transpire from a snow perspective are “murky,” at best, confidence continues to run very high on the prospects of a nasty period of bitter air arriving around Christmas.

Before we dig into the cold details, the pattern is one that still screams “trouble” from a wintry perspective in the December 23rd-Christmas Eve period.  We posted over the weekend of the PNA-EPO going to battle Christmas weekend, and before the cold overwhelms, a consensus of the data continues to paint an interesting scenario as resistance will be present initially from the southeastern ridge. Modeling will continue to struggle with this evolution over the next few days, but we’re hopeful we’ll begin to gain more clarity by late in the work week.  Needless to say, a stripe of impactful wintry precipitation should fall in a southwest-northeast fashion given the pattern, but whether that’s to our northwest, over our region, or off to our southeast is simply impossible to call from this distance.  A glance at the individual ensemble members (GEFS shown below) shows this nicely, as well.  The European ensemble members also paint a similar picture.

Hang in there as we continue to sort through the data over the next few days.  Once confidence increases (for or against an event), you’ll be the first to know! 🙂

Now to the ugly stuff:  Bitterly cold air of true arctic origin will be dislodged southeast late week and encompass more of the country by Christmas weekend.  Eventually, this arctic air will make it across the Appalachians and reach the East Coast just after Christmas.

Recent operational data (GFS and Canadian included) has suggested a sprawling high in the range of 1050mb+ descending into the eastern slopes of the northern Rockies.  Such a regime would be plenty capable of spreading sub-zero temperatures east into the Ohio Valley (with or without snow on the ground).  Add in a biting north wind and wind chill values would drop to levels of dangerous and deadly levels if any length of time was spent outdoors.  Some of the latest data paints a picture similar to shades of the famous ’13-14 winter (20° to 30° below zero chill factor).  If you have travel plans over the Christmas holiday, please plan in advance to have a winter survival kit packed and loaded.  It absolutely never hurts to be prepared.

Permanent link to this article: https://indywx.com/2017/12/18/arctic-hammer-drops-down-around-christmas/

Tuesday Evening Rambles: Wintry Weather And More Christmas Week Chatter…

I.) The pattern we’re currently dealing with is one that presents multiple challenges in the near term.  East-central and northeastern portions of the state have gotten in on the snow act today, but, so far, most of central Indiana has missed out on the snowy goods. With such a fast-paced northwest flow, we have to remain on guard for potential “surprises” in this pattern.  Perhaps the HRRR is beginning to pick up on this.  Latest runs want to deliver a “pop” of snow Wednesday morning, associated with “warm” air advection (WAA).  We’ll monitor tonight.

9a forecast radar Wednesday

II.  The northwest flow will continue to provide disturbances plenty capable of producing periods of snow again Wednesday evening through the end of the week.  Are these monster storms?  Hardly, but they can “suddenly” become sufficient enough to create travel problems given the pattern.  For those who live across the northern half of the state, plan to keep close tabs to local forecasts if you have travel plans through the end of the week.

III.  A period of brief moderation will come in this pattern early Christmas week, but all eyes continue to focus on the period between December 22nd through December 26th for the potential of impactful weather across our region.  For model “worshipers” out there, we suggest paying more attention to overall trends, and a blend of ensemble data, as opposed to specifics associated with operational runs.  It’s a “jailbreak” pattern of sorts as true arctic air will be pouring down the Plains while the southeastern ridge tries to fight for a time.  The resistance from the southeastern ridge and associated tight thermal gradient should promote a very stormy regime for the interior (Ohio Valley into the interior northeast) as we head into the true holiday/ Christmas stretch.  As of now, we favor the idea of multiple waves along the pressing arctic boundary, as opposed to one big storm.  Looking back through the records shows some of the heaviest snows at IND have come from similar set-ups.  Understanding each set-up is unique, the overall pattern does have to raise an eye brow for potential of wintry weather in, or around, our region as Christmas approaches…

Permanent link to this article: https://indywx.com/2017/12/12/tuesday-evening-rambles-wintry-weather-and-more-christmas-week-chatter/

IndyWx.com