Category: GFS

More On This Weekend’s Winter Storm…

As we’ve been discussing, a significant winter storm is developing this weekend.  The set up is one that will feature an arctic cold front sinking south and stalling out across southern and central Indiana Saturday night.  Low pressure will then organize over the Ark-la-tex region and head northeast, tracking into the northern Tennessee Valley Sunday and Sunday night.  The low will move off the southern Mid Atlantic coastline Monday evening.  This will be more of a prolonged event when compared to our last two winter storms as waves of moderate to heavy snow move into central Indiana beginning late Saturday night.

This is an ominous set up for more heavy snow across central Indiana- one that’s notorious for heavy snow events across central Indiana.  We hoisted our initial snowfall forecast Thursday morning and placed central Indiana under the threat for 6-8″.  As of this morning, we’re remaining firm on that idea.  It should be noted that the GFS remains very bullish on heavier totals (and consistent, as well), but it should also be pointed out it’s somewhat of an outlier as of this morning as the GEM and ECMWF are more suppressed with lighter totals.  All of that said, we lean more towards the GFS solution versus the more suppressed Canadian and, to some extent, European forecast model.  Should the other model data begin to trend towards the snowfall idea per the GFS then the initial 6-8″ forecast will have to be adjusted upward.  The storm is just now coming onshore and will be sampled better with model runs later today.

Any way you slice it, a significant and disruptive winter storm is brewing this weekend and could make an absolute mess of your Sunday and Monday.  A shot of bitterly cold air will flow in behind our departing storm early next week.

Our current accumulation idea and storm track can be found below:  We’ll have another update here late tonight and you can keep up-to-date with all of our thoughts on the go on Twitter (@indywx).

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Permanent link to this article: https://indywx.com/2014/02/28/more-on-this-weekends-winter-storm/

Old Man Winter Is Back… (Did He Ever Leave)?

We touch on the potential winter storm brewing in the Sunday-Monday time period in this video.  A significant winter storm is brewing for some and we cover some initial thoughts…

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Permanent link to this article: https://indywx.com/2014/02/24/old-man-winter-is-back-did-he-ever-leave/

Early 0z Runs Trending More Icy Vs. Snowy…

Quick post tonight just to alert you that early model runs off the 0z suite of data suggests less of   a snow threat and more of freezing rain/ sleet…

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Permanent link to this article: https://indywx.com/2014/02/16/early-0z-runs-trending-more-icy-vs-snowy/

Next Week’s Spring Tease Is Just That, A “Tease…”

There’s no doubt we’re looking at a brief pattern change next week that will result in air temperatures that will have many of you craving spring.  That said, the key word in that sentence is “brief” and a colder, more wintry pattern looks to return to wrap up February and head into March.

Before we discuss the return of the cold and potentially wintry regime for late month, let’s focus on the milder conditions.  Data suggests we may be looking at highs zooming all the way into the lower to middle 60s towards the 20th-23rd time period.  The spring tease is likely to come at a cost as the milder southerly breezes likely result in lots of dense fog and areas of drizzle as a deep snowpack remains locked in place.  Flooding concerns may also become a concern next week, especially if we inject moderate to heavy rain into the region.  10-day rainfall numbers do have to make us a little nervous as a blend of model data suggests 1″-1.5″ down between now and the 22nd.  We’ll continue to monitor things.

Finally, it should be noted that while a brief “relaxation” of the seemingly unending winter is on the way, the long term pattern continues to suggest a cold and wintry time of things continues overall.  Next week appears to be an “island of warmth in a sea of cold” type pattern.  Latest ensemble data continues to back this idea up.  That’s not saying we’re going to deal with the type of severe cold we’ve seen over the past several weeks, but instead means we’re going to go back below normal as we get set to wrap up February and head into March.

The latest GFS ensembles show the evolution of things well.  The “double secret probation” European model also shows something similar.

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Note the ridge and associated spring “tease” is replaced with a cold and more wintry looking eastern trough rather quickly.  Circle the 24th on your calendar for the potential of a widespread storm system.  Far too early for details or questions, but the pattern looks to produce some busy times around this point.  Before that we have plenty of weather in front of us to deal with… weekend snow opportunities, foggy/ drizzly weather to accompany the initial surge of milder air next week, and a spring tease by late next week!

Permanent link to this article: https://indywx.com/2014/02/12/next-weeks-spring-tease-is-just-that-a-tease/

Watching The Pattern Turn Active Yet Again…

After a dry period through early to mid week, our weather pattern will begin to turn active yet again as we head into late week and this weekend.  Three of our more trusted mid range computer models handle the individual impulses of energy differently and the snow potential ranges anywhere from nothing more than 1″ to as much as 10″ in the Friday-Tuesday period.  Most likely, we’re looking at something somewhere in the middle.

Our first chance of accumulating snow arrives Friday.  Both the European forecast model and Canadian forecast model agree on this, while the latest GFS takes the same energy through the Great Lakes, missing our region entirely.  We feel the GFS may be in error mode here.  While it’s possible the GFS may lead the way (anything is possible this far off), we feel the EC and Canadian have a better handle on things and we’ve based our forecast (post below) off a blend of these two models for Friday, including accumulating snow.

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Our next shot of accumulating snow blows in Saturday.  All three models agree on this, but handle the track of the low, another clipper system, differently.  The Canadian tracks the low south of IND, strengthens it on it’s journey east and results in a full blown snow storm here Saturday.  The GFS and EC remain weaker and track the low across central or northern parts of the state, with much lighter snow amounts here.

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You can find your completed 7-Day forecast in the post below this one.  Finally, there are some signs the pattern may begin to relax and allow a milder brand of air into the region around the 20th.  We caution though that this won’t be a “suddenly it’s spring” pattern, but rather a tease of sorts as longer term signals suggest a wintry regime returns late February into March…

Permanent link to this article: https://indywx.com/2014/02/10/watching-the-pattern-turn-active-yet-again/

More Thoughts On Our Next Winter Storm…

As we continue to draw ever closer to our next significant winter storm, we wanted to provide some of our latest thoughts.  This isn’t a post that will hash out snowfall accumulation ideas or precipitation types, but instead will provide details on our expected track and potential liquid equivalent precipitation amounts.  With so much hype and hoopla around this storm for the past couple weeks, lets just sit back and look at the “bigger” picture, as opposed to trying to sort out details that, quite frankly, are still too early to lay out with any certainty as I write this late Friday night

Here’s our (IndyWx.com) expected track of the low Tuesday afternoon to Wednesday afternoon.  We used a blend of the GFS, European, and Canadian operational model data, as well as the GFS and European ensemble data sets.  We think surface low pressure tracks out of northeastern Mississippi (Tuesday evening) through north-central Kentucky (Wednesday morning), and into Pennsylvania (Wednesday night) before a secondary low forms off the northeast coastline.

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This is an ideal track for a winter storm across central Indiana, but specifics such as strength and depth of the cold air, potential southern convection, and forward motion of the storm will have to be sorted out over the next day, or so.  Early indications are that while this storm will take a “good” track for winter weather lovers here across central Indiana, the speed in which the system will be moving may reduce snow and ice accumulations from what they otherwise could be.  That said…early raw numbers suggest .50″ to .80″ amounts (liquid equivalent) could fall in the Tuesday-Wednesday time frame which is significant.  Case in point, a standard 10:1 ratio that would suggest 5 to 8 inches of snow- assuming the form of precipitation fell as snow through the entire duration.  Again, that is far from a certainty at this point.

Ignoring items such as model snowfall forecasts and precipitation types, just looking at the expected track would suggest central Indiana is very much in the game for a potentially significant and disruptive winter storm Tuesday into Wednesday.  We’ll have to fine tune precise amounts and precipitation types in the next day or two.  Additionally, much colder air (below zero once again at night) may blow into the state behind this storm for mid and late week before we gear up for yet another winter weather maker heading into next weekend.  We still have a long way to go in this pattern…

Permanent link to this article: https://indywx.com/2014/02/02/more-thoughts-on-our-next-winter-storm/

Wintry Mix Issues Late Week/ Weekend

We’re going to enjoy another day of sunshine, but moderating temperatures (finally) will help being outdoors become a little more tolerable (we think we “warm” into the middle 20s today).  That said, another winter weather maker is brewing and will result in an active Friday-Sunday ahead.

A cold front will sink south Thursday night and could result in a little light snow (not a big deal).  As we move into Friday and Saturday, model data handles our sensible weather differently.  Precipitation type will be highly dependent upon exactly where the cold front stalls.  We want to show you the GFS as it depicts the variety of precipitation types. It should be important to note that the GFS, European, and Canadian, though different in their respected solutions this weekend, are close enough to go with a “blend” of all three models for our official forecast.

We think snow overspreads the region Friday morning and could deposit a quick couple inches across the metro area Friday. It’s as we get into Friday night and Saturday that we’ll note another (stronger) wave moving along the front. In response to this wave of low pressure, warmer air (both at the surface and aloft) will push north.  Exactly how far north is still up for debate as a battle will be established with push back being provided from an area of high pressure across the upper Mississippi River Valley. We feel as if south-central Indiana will get in on some mixing issues with sleet and perhaps a cold rain Friday night into Saturday.  Depending on how strong the wave of low pressure is will determine exactly how far north the rain line makes it.  For now, we think Indianapolis and northern suburbs remain in a wintry mix of snow, sleet, and possible freezing rain through the majority of the day Saturday.  That said, we do note this will warrant tight focus in the days ahead as any deviation from the track of the low or strength of the cold high to our north could greatly impact our weekend weather.1

 

 

 

 

 

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Finally, precipitation will begin to taper late Saturday night as the cold high to our north eventually wins out. It’s possible all of central Indiana deals with a quick pop of accumulating snow as precipitation ends Saturday night/ wee morning hours Sunday.

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We stress that this is still a highly changing weather situation and most likely will require some “fine tuning” as we move forward.  This morning we think heaviest snow (potentially approaching half a foot) falls across north-central Indiana, including Kokomo, Marion, and Lafayette.  A wintry mix of all precipitation types will fall south of there, including the Indianapolis metro.  South of I-70, we think rain will be the predominant precipitation type, with only a light accumulation of snow as precipitation ends.

As stated above, stay tuned…

Permanent link to this article: https://indywx.com/2014/01/29/wintry-mix-issues-late-week-weekend/

Big Fight Late Week Into The Weekend….

A major battle is taking shape between two of the more respected mid range forecast models for the late week period, including Super Bowl weekend.  The differences range from yet another wintry weekend, with a couple shots of accumulating snow to one that’s much milder and includes some rain.  Operational guidance today has remained consistent with what each particular model has been saying for the past 24-48 hours, adding further complexity to the upcoming late week period.  Usually we’d give a slight nudge towards the European output (warmer solution), but here in a bit we’ll tell you why we’re really not ready to hedge more towards one particular model over the other at this time frame.  Instead, we want to give it a couple more days and see which model “gives in” to the other.

Let’s dive into the European output first.

We note both models in relative good agreement on Thursday night into Friday as light snow overspreads the region (not a huge deal, but potentially enough to make for a slippery Friday morning commute).

As we move into Saturday the European tracks a developing surface low much further north than the GFS, resulting in a milder solution across central Indiana and a forecast that would produce a rain to snow solution Saturday as cold air quickly pours back into our region, with enough snow, perhaps, to produce a light accumulation Saturday night. However, it’s important to note, most European ensemble members are colder than the operational run and this is something we’ll need to continue to monitor.

As we head into early early next week, the European forecast model remains bullish on a potential major winter storm, with a favorable storm track for heavy amounts of wintry precipitation across central Indiana.  The time we’re eyeing for this next storm falls in the Monday night-Tuesday time period so we have plenty of time to monitor things and iron out the details…

Now, as we look at the GFS forecast model, we note a colder solution from start to finish.  We have to raise an eye brow here as the track record of the GFS in the mid range is one that has been known to be biased too “flat” and too cold in handling similar patterns.  Is that saying the GFS is wrong here?  Absolutely not…nobody knows that at this juncture.  It is saying we have to rely on experience and remember similar patterns of the past, including the way the model “corrected” itself with time as we drew closer to the particular event in most cases…

Nonetheless, similar to the European, the GFS delivers a round of accumulating snow Friday morning, but is flatter (colder) with the initial wave and also leads to quite the overrunning event through the Ohio Valley.  As a matter of fact, we deal with two rounds of accumulating snow…Friday morning into the early afternoon and again Saturday morning, associated with yet another wave of low pressure.

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Of interest, the GFS also sees the potential strong winter storm that could impact our neck of the woods early next week.  Needless to say, the surface map next Tuesday morning would have snow lovers smiling in a big way should this come to fruition…

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While we have many details to iron out late week and on into early next week, the overall weather pattern is one that we remain confident on and the results are cold and stormy (i.e. snowy) over the upcoming 10-14 day period.  As a matter of fact, long range teleconnections suggest we remain colder than normal and stormy through the majority of February. In short, there’s really no let up in sight from the overall cold and wintry time of things Hoosiers have grown oh so accustomed to this winter…

Permanent link to this article: https://indywx.com/2014/01/27/big-fight-late-week-into-the-weekend/

Quick Remark On Sunday.

We have enough to worry ourselves with tonight and again Friday night-Saturday, but many are wondering about what Sunday holds.  The consensus of operational model data today is for a north track Sunday, keeping most of the heavy snowfall across northern Indiana.  That said, is it the correct idea?  We’re not ready to buy the extreme north trend just yet…

While anything is possible, the northward trend in operational runs today has me scratching my head a bit given the overall pattern.  Current thinking here would suggest operational models  “correct” south with time over the next couple days, but time will tell.  The GFS ensembles help illustrate the wide variance with the track of Sunday’s snow storm (below).  While the track of the system is still up for debate, confidence is growing on amounts just north of the low’s track that approach half a foot Sunday.  Much more later!

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Permanent link to this article: https://indywx.com/2014/01/22/quick-remark-on-sunday/

Historic Snow Season Keeps Rolling Along…

The winter of 2013-2014 is off to a rip-roaring start and, as we’ve discussed in previous posts, the mid to long range data suggests we remain locked in an exceptionally cold and snowy pattern.  Officially, as of this evening, the Indianapolis National Weather Service has posted some impressive stats (the full report can be found here), including:

  • Through Jan. 21st, the 24.4″ of snow ranks as the 3rd snowiest January on record.
  • Through Jan. 21st, the season-to-date snowfall of 33.2″ ranks as the 2nd highest on record in the period Dec. 1st through Jan. 21st.
  • Through Jan. 21st, the season-to-date snowfall of 33.2″ ranks as the 8th snowiest on record for an entire winter season.

As we look ahead to the upcoming 7-10 day period, we note a continuation of arctic reinforcements- each which will be plenty capable of adding to the snowfall total.  Additionally, our cold air mass will only grow even more severe and bitter over time, including multiple days during the aforementioned period where central Indiana will go below zero.  Finally, there have been many questions concerning a potential big storm centered on early February.  I’m not sure where this rumor started, but it’s far too early to say with any sort of confidence any specifics around a possible big winter storm early February.  That said, as we’ll get into briefly below, the pattern does appear to be aligning itself in a way where a widespread winter storm is possible somewhere across the eastern half of the country.

Okay, okay, back to the near term…  Let’s start with tomorrow!  After a cold and dry start to the day, our next arctic front will blow into the region during the evening.  Arctic fronts are notorious for having bursts of heavy snow rates in a scattered fashion and this appears to be the case as the next arctic front moves through Wednesday evening.  We bracket the hours of 5p-8p for the possibility of heavy snow bursts racing through central Indiana.  While these won’t last long, they’ll likely be intense- capable of depositing a quick 1″-2″ of new snow on a gusty northwest wind within 30-60 minutes.  White-out conditions and extremely heavy snowfall rates will accompany the heavier bursts of snow.  Latest high-resolution model data shows the heavy snow bursts accompanying the arctic front tomorrow evening:

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Thursday will be mostly dry and frigid, but all eyes will then begin to turn to our next significant winter event Friday into Saturday.  The pressure gradient between high pressure across the Mississippi River Valley and the next approaching arctic front (and associated low pressure) will really being to kick up the wind across our region Friday.  We’re afraid we deal with another round of severe blowing and drifting snow Friday, especially Friday afternoon and night.  Areas most suspect to drifting and blowing snow will be central Indiana’s open country and may not be too different from the problems our region dealt with Sunday into Monday morning from blowing and drifting.

As we approach Friday night into Saturday, snow will overspread the region and will likely accumulate to the tune of a “few inches” during this time period.  Strong winds will remain, shifting from the west to the northwest and eventually north.  Open country will remain the prime place for continued severe blowing and drifting problems.

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Just as soon as Saturday’s snow systems exits stage right, we turn our attention to potentially another significant snow maker for the second half of the weekend.  Latest model data remains consistent on moving another potent clipper system into our region Sunday, including the GFS and Canadian forecast models.  We still have time to fine tune the precise track of the storm, but just north of the low’s track an additional 3-5″ type snow is possible Sunday.  Note the GFS and Euro in relative agreement on the track of the low, with the Canadian currently a touch further north. We’ll fine tune in the days ahead…  Experience with similar patterns from the past suggests central Indiana should brace for more accumulating snow Sunday.

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As for the brutal cold, we note multiple pushes of fresh arctic air behind each snow maker.  We currently target Thursday morning, Friday morning, Tuesday morning, next Wednesday morning, and next Friday morning as having the most likely shot at dipping below zero. The “coldest of the cold” likely means Tuesday morning takes the crown, with lows potentially dipping into the double-digit below zero range for central Indiana.  The European forecast model (below) even shows sub-zero temperatures making it as far south as the southern Appalachians.

As we look even longer term, there have been many questions centered on the potential of a big winter storm for early February.  Before we go any further, we want to stress it’s far too early to make any claim of certainty to the above.  That said, there are items we can pick up on to a least “raise an eyebrow” that something of significance may be brewing… Do we mean for anyone to take that verbatim and to the bank?  Absolutely not.

The European Weeklies suggest we need to keep an eye on the first week of February.  They show a potential phasing of the jet (where the northern and southern streams of the jet stream phase together- often times resulting in a big storm)… That said, we want to again stress this is far too early to be discussing with any sort of certainty.  Heh, the next week will keep us busy enough!

Keep the shovel handy!  Snow removal companies, thank you for your service and hard work…hopefully you have plenty of coffee on hand!

Permanent link to this article: https://indywx.com/2014/01/21/historic-snow-season-keeps-rolling-along/

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