Category: Arctic Cold

Jan 04

Cold Is Something To Behold!

With all of the talk about the snow and near-blizzard conditions Sunday (rightfully so), we wanted to make sure we discussed the pending arctic outbreak and record-smashing temperatures ahead early next week.

(As a side note, our going snowfall accumulation ideas remain unchanged with a band of 9-12″ of snow from Indianapolis and points north with less amounts south of Indy where mixing issues will keep accumulations in the 5-9″ range).

As our winter storm moves northeast into the Great Lakes Sunday night, it’ll help slug a huge piece of arctic air south to the likes not seen around these parts since 1994.  We’re talking about dangerous, life threatening, cold Sunday night through Wednesday morning.  With a deep snow pack on the ground left behind by our memorable winter storm, the stage will be set for actual temperatures to most likely drop even lower than guidance currently suggests.

We think actual air temperatures fall below zero as early as 12a-3a Monday, per latest guidance.  (Wind chill values will fall below zero shortly after dark Sunday).

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Let’s take a look at high temperatures Monday.  Frigid and dangerous temperature conditions continue into mid week…

Daytime Highs Monday will range from 7 to 12 BELOW zero (that’s not a typo).

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Additionally, wind chill values will plummet to levels that can quickly lead to frost bite of any exposed skin.  We think wind chill values range as low as 50 degrees below zero Monday.  At 30 degrees below zero, exposed skin can freeze within 30 minutes.  At 40 degrees below zero, exposed skin can freeze within 10 minutes, and at 50 degrees below zero, exposed skin can freeze in under 5 minutes.  Here’s a look at forecast wind chill values:

plotter

Needless to say, please remain indoors and hunker down the next couple days if at all possible.  Weather conditions will be downright dangerous to be outdoors and you risk putting yourself in harms way, as well as first responders, should you venture out of your home.  Getting stuck in a snow bank in any sort of weather conditions is dangerous, but when you factor in this type of cold, major problems can, and will, quickly develop.

Permanent link to this article: https://indywx.com/2014/01/04/cold-is-something-to-behold/

Jan 04

Serious Winter Storm Takes Aim On Indiana

We awake this morning to most of the data very consistent with what we’ve been passing along to you over the past few days…a very serious winter storm is taking aim on Indiana and will result in a combination of significant weather events that ultimately may end up being something we’ll remember for quite some time…

Quick Bullet Points:

  • Snow develops early Saturday morning
  • Heaviest snow falls between 10a-5p
  • Wind increases through the day Sunday and gusts in excess of 30 MPH leading to white outs and severe blowing and drifting
  • Temperatures crash to 10-14 below zero Monday morning with wind chill values of 40 to 50 below zero.
  • Widespread snowfall of 5-9″ is likely across central Indiana, with a heavier band of 9-12″ including Indianapolis and running along and just north of the I-70 corridor on the south side north to include Vermillion to Adams counties on the north side.

This is a hazardous and severe winter weather event that will likely lead to road closures from the heavy snow and wind, as well as extremely dangerous conditions to spend anytime outdoors Sunday into early next week due to the cold.  The bitter wind chills will be capable of frostbite in less than 30 minutes to any exposed skin.

Latest model data shows consistency in precipitation amounts, or QPF. We’re showing you the GFS, Canadian, and European models below.  Please note that the numbers and maps below don’t show snowfall amounts, but show precipitation totals.  Bring in a 12-15:1 snowfall ratio with these numbers and you get the snowfall discussed above.  We’re leaning heavily on a Canadian/ European model blend as the GFS has been more erratic.

gfs_total_precip_east_9cmc_total_precip_east_10ecmwf_tprecip_indy_10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Much more later this evening!

Permanent link to this article: https://indywx.com/2014/01/04/serious-winter-storm-takes-aim-on-indiana/

Jan 02

Rare And Potentially Crippling Winter Storm Brewing…

Fresh on the heels of a significant winter storm that impacted central Indiana Wednesday night-Thursday, we’re eyeing our next winter storm and, quite frankly, it could be a memorable one.

We continue to keep a close eye on the pending winter storm Sunday and remain impressed with what we see.  A severe winter storm is brewing and may require blizzard watches and warnings before all is said and done as a combination of heavy snow, strong winds, and severe blowing and drifting promises to make travel difficult, if not impossible, for some areas Sunday.

Setting the stage:

A powerful arctic boundary will drift south towards Indiana Saturday night and Sunday morning.  As this takes place, low pressure will track off the lee of the Rockies and move east, northeast.  Model data continues to suggest this area of low pressure taps into some Gulf of Mexico moisture and really begins to deepen (strengthen) as it tracks into the central/ eastern Ohio Valley Sunday.  To the northwest of the low’s track, a deep blanket of fresh snow will fall.  As the winter storm departs, the coldest air since 1994 will pour into the region on a gusty northwest wind.  Temperatures will reach record territory, and downright dangerous levels, by Monday and Tuesday.

Last night we mentioned a couple of things going “for” and “against” a major winter storm here in central Indiana.  While there’s no doubt going to be a sharp “cut off” of heavy snow with this storm, this “cut off zone” is most likely well north and west of central Indiana.  Additionally, the impressive thermal gradient between the brutal arctic air mass to the north and the warmer air (relatively speaking) to the south and east will only add fuel to a deepening storm moving northeast into the Ohio Valley.  Finally, with arctic air pouring into the region, the “fluff effect” will be in full-go mode, meaning the northwest flank of the heavy precipitation is likely to have snow ratios of 15:1 as compared to the “normal” 10:1 ratio.  This will be very important to watch as the system develops and will most likely be the spot (far too early to pinpoint at this juncture) where snowfall amounts in excess of one foot will fall.

All of our medium range model data is in agreement on central Indiana receiving quite the blow from Old Man Winter Sunday.  Here’s a look at the latest GFS, European, and Canadian forecast models, valid Sunday afternoon:

GFS1EC1CMC1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

As you can see, there’s excellent agreement and this leads to a rather high confidence idea on a high-impact and rather rare severe winter storm set to impact Indiana.  Can we tell you with certainty exactly where the 12″+ band of snow will lie across the state?  Not at this time.  That said, we suggest preparing now for a rare and potentially crippling winter storm Sunday.  The combination of heavy snow, strong winds, historic cold, and severe blowing and drifting will make for an extremely dangerous situation Sunday, continuing into early next week.  Temperatures by Tuesday morning will approach 20 degrees below zero, with wind chill values plummeting to 40-50 degrees below zero Monday into Tuesday…

Permanent link to this article: https://indywx.com/2014/01/02/rare-and-potentially-crippling-winter-storm-brewing/

Jan 01

Triple Threat Of Dangerous Winter Weather Ahead…

You can always catch your latest 7-Day Video Forecast in the video player to the right of this post.

We continue to be very impressed with what’s ahead, winter weather-wise, for central Indiana over the course of the upcoming 10 days.  Simply put, what’s at stake is a 10-day period of winter weather that could rival the all time greats in terms of snowfall and cold.  It’ll certainly be interesting to watch things unfold in the days ahead.

Here are some quick-hitting bullet points of what we’re eyeing…

  • Accumulating snow late tonight-Thursday
  • Accumulating snow late Saturday night-Sunday
  • Coldest air since 1994 early next week
  • Dangerous cold and wind chill values to 40 degrees below zero

First things first and that’s tonight’s and Thursday’s snow event. We think snow becomes widespread across central Indiana prior to, or around, midnight.  The low pressure system that will aid in snow production across our region Thursday AM is organizing across the central Plains this evening and this will move east northeast with time between now and Thursday morning.

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Latest high-resolution simulated model data shows the snow increasing in coverage across central Indiana around midnight.

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We think the period of heaviest snow comes during the early to mid morning Thursday and will result in a horrible rush period on area roadways.  Accumulating snow ends by noon and is replaced with falling temperatures, gusty northwest winds resulting in blowing and drifting, and scattered lake-driven flurries.

All eyes will then shift to storm number two set to arrive late Saturday night into Sunday.  An arctic boundary will moves towards the region Saturday night and Sunday and help surface low pressure develop.  All of our medium range models (GFS, Canadian, European) are on board with a developing surface low in the Ark-la-tex region late Saturday night/ early Sunday morning and can be seen below.

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There are still some questions that we have in regards to the extreme snowfall forecasts off some computer models, and we’ll stick with our initial call made here last night of an additional 3-6″ of snow late Saturday night-Sunday for now.  We come up with that range based off an all model blend, including raw numbers, operational data, and ensembles.  An extremely strong arctic high pressure system will be plunging south and will limit how far north the heavy snow makes it.  That said, snowfall ratios and an initial impressive thermal gradient will lead to a heavy snow storm for some parts of the Ohio Valley region Sunday.  Stay tuned.

As early next week approaches (and I’m all settled in to enjoy what I hope to be Auburn’s second National Championship in 4 years), the coldest air since 1994 will be blowing into the region.  Downright dangerous wind chill values of 40 degrees below zero will be possible Monday into Tuesday and result in extremely dangerous conditions to be outdoors for any period of time.

Here’s a look at the latest wind chill idea:

plotterForecast lows of 15 to 20 degrees below zero will be likely early next week across central Indiana with afternoon highs struggling to make it to zero.

Prepare now for a significant triple threat punch of snow and cold in the days ahead. Stay tuned!

Permanent link to this article: https://indywx.com/2014/01/01/triple-threat-of-dangerous-winter-weather-ahead/

Jan 01

Things Progressing As Planned; Double Shot Of Snow Love…

It’s great to be back in the good ole weather office and craft a post about the upcoming weather pattern- a pattern that should be pointed out to be progressing along as planned.  Simply put, if you like winter weather, this is the pattern for you.

If you haven’t had a chance to read the posts from the past couple weeks, please be sure to do so as we laid the ground work as to why we were buying a cold, wintry pattern returning:

As we look ahead over the upcoming (7) days we’re tracking two accumulating snow opportunities and one big slug of downright bitter (and dangerously cold) air.

First things first and that’s the snow event ahead Wednesday night into Thursday.

We currently think snow overspreads central Indiana late Wednesday night into the wee morning hours Thursday.  Snowfall accumulations with system numero uno will likely be in the 2-4″ range for many neighborhoods across central Indiana.

The latest high-resolution NAM model shows the snow moving in and becoming moderate to briefly heavy during the wee morning hours Thursday:

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Heaviest snow with system #1 falls prior to noon Thursday with light snow and gusty winds lingering for the PM.

That said, we don’t have much down time as system #2 is set to arrive late Saturday night into the wee morning hours Sunday.  The weather situation is one that features an arctic boundary sinking south over the region Sunday morning with a wave of low pressure organizing along the middle Mississippi River Valley. The surface low is expected to move northeast Sunday and help spread precipitation into the greater Indianapolis and central Indiana region. With cold air in place, this precipitation is likely to fall in the form of snow.

While we have a couple of days to keep an eye on the Saturday night-Sunday time period, the likelihood of additional accumulating snow is growing with each and every model run.  The “ridiculously” early call on the Saturday night-Sunday time period, based on a variety of raw numbers, medium range models, and ensembles would suggest 3-6″ of additional snow is ahead during the aforementioned time period.  Again, we caution confidence ins’t as high as with system #1, due to the time period, but please be sure to stay tuned.

The GFS shows widespread snow falling across the region Sunday, with a favorable surface low track for accumulating snow across central Indiana:

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Following the second snow system, model data continues to suggest we have to deal with some downright dangerous air. In fact, this would be the coldest air in many a year across central Indiana and many other locations of the Mid West and even into the Deep South.  Forecast lows in the double digit below zero range are possible following the second snow maker and associated arctic front early next week….

Needless to say, I hope you like winter weather!

Permanent link to this article: https://indywx.com/2014/01/01/things-progressing-as-planned-double-shot-of-snow-love/

Dec 23

Impressive Cold Pattern Looming; Beware Of The Northwest Flow…

We continue to be very impressed with the cold pattern that’s looming.  Even before the warm up and thaw last week, we made mention that the seeds were being planted for a very cold close to December and open to 2014.  Latest data continues to back this idea up.  Additionally, in the longer term, there are some goings on that would suggest we better hunker down for a colder than average January.  While December will finished colder than average, a colder than average January can really hurt the pocket book as “average” temperatures are obviously even colder than December.

Today’s 12z ensembles are locking in on the pattern than can deliver one shot after the other of arctic air in the 8-10 day range.

test8

As for the snow, we still think we need to watch the models around the New Year for the threat of some southern stream energy interacting with the available cold air.  That said, even without the southern stream, one must remain abreast of the challenge that a northwest flow pattern can produce.

Forecast models have a difficult time handling clipper systems in these type of patterns until within 24-48 hours within an event.  Many times what appears to be a rather “harmless” clipper 4-7 days out can suddenly turn much more robust once the model catches onto the track and ability to literally squeeze out any and all available moisture from a cold air mass.  Furthermore, the “normal” 10:1 snow ratio, many like to use, doesn’t apply in the least to these type systems.  In cold environments you can easily get what’s called the “fluff effect” and snow ratios are more in the 20-30:1 range.  Needless to say, it’s a challenging pattern that will keep us on our toes over the coming couple of weeks.

To summarize, we’re extremely confident on a colder than average close to December and open to January.  We’ll have to monitor fast moving clipper systems that modeling will struggle with until right up to the event.  Finally, we’ll keep a close eye on the potential interaction of the southern stream and cold air around the New Year time period for the possibility of a storm of “more significance.” Stay tuned!

Permanent link to this article: https://indywx.com/2013/12/23/impressive-cold-pattern-looming-beware-of-the-northwest-flow/

Dec 20

Colder Than Normal Pattern Set To Return

Before we go into the cold pattern that is looming, our current forecast of severe flooding developing across central Indiana this weekend remains.  Our projected precipitation numbers remain in the 3-4″ range for most of central Indiana, but there will be some higher totals reported.  Combine that with the recent snow melt and the stage is set for potentially a severe and dangerous flooding event.

As we look ahead to the next weather “challenge,” it has to do with temperatures.  As we’ve talked about in previous posts, our weather pattern flipped to one that has been predominantly colder than normal back in the middle of October.  Despite a handful of days, cold has dominated the pattern.  Before our current thaw temperatures were averaging 5 degrees below normal for the month of December.  While the recent thaw is certain to reduce the anomalous cold, the last week of December could send us right back to readings much colder than average, helping put the exclamation point on the month as far as cold goes.

The latest 8-10 day ensemble plots showcase a very cold pattern to end December.  Cross polar flow gets involved, helping lead to some bitterly cold air around these parts.  We note excellent agreement between the GFS and European forecast models, helping to further increase our confidence in the cold pattern ahead.

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But it doesn’t stop there…  We note long range data suggesting this cold pattern continues well into January.

The latest European forecast ensembles showcase the cold continuing to reload into the first week of the month.  This is an impressively cold look, considering we’re still a couple weeks out and that these are a multitude of individual computer model runs averaged together to come up with this solution.

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As we watch the evolution of the cold pattern, it’s important to turn to the “goings-on” with the upper air pattern.  Note the reorganization of the polar vortex and, equally as important, the placement of the polar vortex.  For the purpose of giving you a couple of different viewpoints of the evolution of the pattern we’ve pasted a Northern Hemisphere and North America perspective.

Note how the polar vortex reorganizes itself and decides to set up shop over Hudson Bay and Baffin Island by early January.  This is significant in that it promotes multiple reinforcing shots of arctic air into the eastern half of the country and backs up what the data above would suggest in the cold pattern that appears to be looming as we move forward…

Sunday, December 22nd

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Friday, January 3rd

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What does all of this mean?  That the current “thaw” is very brief.  The seeds were being planted for a return of the cold pattern earlier this week and it all begins Sunday night.  As the data above would suggest, the arctic cold appears to reinforce itself as we go through time and an overall prolonged colder than normal pattern appears to be setting itself up.

Additionally, we’ll have to handle winter storm systems as they come (and they will), but the pattern is one that very well may promote fast-moving clipper systems moving southeast out of Canada.  While most of these clipper systems don’t drop tremendous snowfall totals, the more potent clippers can deposit several inches of snow and serve to “feed back” and turn what’s initially a cold, dry pattern into one that’s suddenly snowy.  We’ll keep an eye on that.  Furthermore, the southern stream may also decide to add a little “excitement” into our forecast late December or early January.

Needless to say, there’s a lot of weather to talk about in the days ahead…

Permanent link to this article: https://indywx.com/2013/12/20/colder-than-normal-pattern-set-to-return/

Dec 19

Thursday Morning Weather Rambles

As always, your latest 7-Day Video Forecast can be found to the right in the video player.   1.) A milder southerly air flow allowed us to remain above freezing…

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Permanent link to this article: https://indywx.com/2013/12/19/thursday-morning-weather-rambles/

Dec 18

A Lot Of Weather To Talk About…

Mother Nature seems determined to put us weather forecasters to hard work as we get set to head into the Christmas season and welcome in 2014.  We’re tracking a major flood situation that will unfold across central Indiana over the upcoming weekend, followed by a reload of the cold and potentially a storm with a more wintry component as we get closer to the New Year.

First things first and that’s the significant flood threat in the short-term period.  Without trying to go into scare tactic mode, current model data would result in a downright dangerous flooding event for many low lying and flood prone areas this weekend.  Rainfall numbers are extremely impressive with this event and with a deep tropical connection, widespread 3-4″ totals are certainly likely, including some localized higher amounts.  Note the latest European chart, courtesy of the model suite off Weatherbell Analytics.  Needless to say, the Gulf of Mexico is officially “open for business” and will help contribute to excessive rainfall totals and, as stated above, potentially a dangerous flooding event this weekend across central Indiana.

ecmwf_uvz850_noram_16

Latest numbers averaged off a variety of computer models would place just under 4″ of rainfall down by noon Sunday, most of which falls between Friday and Sunday morning.  We note (2) waves of enhanced rainfall intensity set to impact the region.  As of now we’re targeting Saturday afternoon and again late Saturday night/ Sunday morning for extremely heavy rain, shown below.

ecmwf_slp_precip_mc_14ecmwf_slp_precip_mc_17

We still have time to watch the data and monitor the track of the storm.  It’s possible the “heaviest of the heavy” axis of rain shifts somewhat in the days ahead,  but it’s also important to note that even a light to moderate rain event combined with a frozen ground and a solid snow pack still in place will lead to flooding problems here across central Indiana.  The question of whether or not we’ll deal with flooding here this weekend shouldn’t be asked, but instead the question that remains is just how severe will the flooding be?  Stay tuned and if you live or work in a flood prone area, we would recommend preparing now for flooding.

Now, as we look ahead and focus on the Christmas to New Years period our thoughts will shift from a flood threat in the near term to one that’s more wintry.  We’ll turn dramatically colder Sunday afternoon behind the big rain storm and that will set the stage for a colder-than-average run up to Christmas. In fact, latest raw numbers off some forecast model guidance has some frigid readings ahead next week (upper single digits not ruled out for lows).

The upcoming 10 days off the European forecast model charts show an interesting scenario with the coming thaw, but the key word is brief.  Note days 6-10 are back into a colder-than-normal regime.

tavg_anom_ecmwf_conus_1

Additionally, we think we’ll have to deal with another storm prior to the New Year period and with the colder air back in place, there’s the threat we could have to contend with a wintry side to the next storm.  The details with storm number two will have to wait until we finish dealing with the first storm and associated serious flood threat it’s presenting.

Permanent link to this article: https://indywx.com/2013/12/18/a-lot-of-weather-to-talk-about/

Dec 16

Major Storm Brewing This Weekend, But Details Are Murky…

During the late summer and early autumn months we were trying to look at the big picture and potential drivers in the overall weather pattern for the upcoming winter and openly admitted the challenges that were ahead.  Here we are now into the second half of December and a much colder and snowier-than-average month is a virtual lock at this point.  Furthermore, consider this has all taken place without the presence of a favorable NAO or PNA.  Sometimes you have to look for other drivers in a pattern- in this case, the EPO, as well as a growing early fall snow pack across the border to our north.  Additionally, we made mention of the likelihood of a southeast US ridge periodically making itself known through the winter of ’13-’14.  You can read all of our thoughts posted earlier this fall here, or by clicking the Thoughts On Winter ’13-’14 page above.

As we look ahead towards the upcoming wintry challenge, we’re confident of the overall pattern, but the sensible weather that’ll ensue is still up for great debate.  “Gut” tells me central Indiana will be looking at a rain to freezing rain scenario, but this is far from set in stone, and sometimes forecasters who go simply off their instinct can get burned.  The pattern is one that (once again) will feature a pressing arctic front against resistance from the southeast US ridge.  With this type of scenario, I would advise against looking at each and every individual operational model run, but instead invest time studying the ensembles- an average of several multiple model runs as opposed to just one operational model run.   I can guarantee a variety of wild solutions ahead in the days to come, based off the operational runs. (Heck, just the past 24 hours have been reason enough to have the dramamine on hand :-)).  That said, let’s take a look at the latest GFS and European ensembles, two models that we rely heavily on in the mid range weather pattern.

First, the GFS, valid Saturday through Monday.

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Now, here’s a look at the latest European ensembles (left), again valid Saturday-Monday.

Geopotential32at32500hPa_North32America_120Geopotential32at32500hPa_North32America_144 Geopotential32at32500hPa_North32America_168

So what do all of these cool maps tell us?  Simply put, that “wintry mischief” is brewing for the weekend.  That much we know, but the details have to be ironed out.  It’s likely heavy snow and a significant ice storm looms for some of the Mid West and Ohio Valley for the upcoming weekend.  Is that Indianapolis or Chicago?  Perhaps in between?  It’s too early to know.  Additionally, in the “warmer” sector, heavy rains are likely to combine with an impressive early season snow pack for some to lead to flooding concerns.

A couple of additional items to note. Many times at this stage in the game (still 5+ days out) with this type of pattern, forecast models really struggle with handling low level cold air.  Cold air is very dense and, in this type of set up, can easily drain much further east and south than forecast at this juncture.  Additionally, sometimes the modeling can put too much “umph” into the associated surface wave that moves along the arctic front resulting in a further north track than what may actually occur when the event draws closer.  Just something to keep an eye on as we draw closer…

Needless to say, it’ll be particularly important to keep a close eye on the developing weekend forecast as we move forward.  It’s likely folks in the Ohio Valley region have to deal with significant precipitation amounts in the Saturday-Monday time period, including rain, freezing rain, and snow.

Permanent link to this article: https://indywx.com/2013/12/16/major-storm-brewing-this-weekend-but-details-are-murky/

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