Category: Forecast Discussion

Jan 19

Winter Just Keeps Going And Going And Going…

As I write this, central Indiana is undergoing yet another winter storm that will dump a fresh 3-5″ of snow by midnight Sunday morning.  We’re well on our way to reaching the snowiest January ever at IND and with the pattern ahead through the end of the month, we very well may just do it.  Before we discuss snow, let’s take a look at the coming shots of arctic air.

While no weather event is identical to another, it’ll be rather easy to compare the coming arctic attack to that which we experienced earlier this month.  That said, there are a couple of important things to consider.  This next wave of arctic air will blow into town when “average” temperatures are at their lowest of the calendar year.  Secondly, data continues to suggest this isn’t just one arctic plunge, but more of a longer duration event when compared to the bitter blast earlier this month.  Needless to say, we’ll need to go into our preparation mode for another round of severely bitter air for the upcoming week.

Let’s look at the model data- note the eastern trough re-amplifying through the period, backing up our idea that this is a rather prolonged arctic event ahead.  As of now, we focus on late in the work week/ next weekend when air temperatures plunge to their respected lowest values (below zero), but want to stress the entire period will be downright cold (much colder than normal), and the long duration event will put more strain on pipes, etc. than a quick-hitting, in and out, arctic outbreak…

When we talk about a longer duration arctic outbreak we’re talking about the possibility of below zero temperatures Wednesday night, Thursday night, Friday night followed by another arctic push that sends lows below zero next Sunday and Monday nights. Stay tuned.

The winter of 2013-2014 is off to a record pace as far as snow totals go.  While we’re not staring at any sort of significant winter storm over the upcoming week, a fast northwest flow can present challenges galore, and any clipper stands the chance to be an “overachiever” as they race southeast over the upcoming week. We fall back on the disclaimer we’ve mentioned in previous posts with clipper systems…the track and strength will be tough for forecast models to iron out until 24-48 hours out.  Secondly, with arctic air firmly in place, snow ratios will be more common around the 20:1 level as opposed to the “normal” 10:1 ratio.

Let’s look at the upcoming snow threats over the next several days…

Our first light snow threat blows in tomorrow night into Tuesday.

GFS1

 

 

 

 

 

 

 

We then target Wednesday night-Thursday.

GFS2

 

 

 

 

 

 

 

Finally, we’ll keep a close eye on late week/ next weekend for yet another potential snow event.

GFS3

Permanent link to this article: https://indywx.com/winter-just-keeps-going-and-going-and-going/

Jan 16

Another Brutally Cold Pattern Setting Up…

The coming several days will result in a continuation of adding to an already expanding snow pack across central Indiana. (We think a 3-5″ band of snow falls for some central Indiana communities Saturday evening and we’ll post on this Friday).  That “ups the ante” for a potentially second round of cold air that flirts with records as we begin to wrap up the month of January and head into February.

Here’s a look at the latest ensemble package out towards Days 8-10 (Jan 24th-26th time period) and we note a near text book pattern for a severe arctic outbreak across the eastern half of the country.  We want to point out the high latitude blocking combined with a frigid cross-polar fetch.  The GFS and European forecast models (amongst a slew of others) are in excellent agreement on the brutally cold pattern setting up shop, which only adds to our confidence level.

arctic

Okay, okay…the fancy maps above may look confusing to some (and rightfully so), so what does all of this mean to you?  We think we’re looking at multiple nights that feature below zero low temperatures across central Indiana, and potentially in the double digit below zero range yet again.  (Wind chills will be even colder).  We’re looking at the type of cold pattern that could produce multiple days with high temperatures in the single digits to lower teens.

Yes, the winter of 2013-2014 just keeps on keepin’ on and truly shows no signs of letting up.  Hunker down, friends!

Permanent link to this article: https://indywx.com/another-brutally-cold-pattern-setting-up/

Jan 15

Reviewing The Snowy Details…

After a brief thaw, winter’s set to return with authority in the days and weeks ahead.  In fact, the overall long range weather pattern looks colder and snowier than average into early February, at least.

A current look at the National Radar shows the next clipper system taking shape to our northwest this evening.

usa_None_anim

A dive into the latest model data continues to highlight two distinct opportunities for accumulating snowfall in the days ahead.  The first comes Thursday into Friday while the second (potentially more robust) snow maker arrives Saturday afternoon and evening.  By the way, my hat’s off to the GFS for jumping on Saturday’s system well in advance of the other modeling.  Sometimes it’s easy to hammer the GFS, but it should be pointed out during the model’s shining moments, as well.

Back to the near-term… We think widespread snow overspreads central Indiana Thursday morning and continues through the majority of the day and on into Friday in varied intensity.  By the time all is said and done, 2-4″ of new snowfall will be likely across central Indiana, with some locally higher amounts possible.

Here’s a look at the latest HRRR simulated radar valid 10am Thursday. Some moderate to briefly heavy snow is possible late morning into the afternoon.

hrrr_ref_indy_16

Of interest, we note forecast models carrying a vigorous upper level disturbance across the state Thursday night/early Friday and this will help carry accumulating snow into Friday for some.

500mb

We’ll note an intrusion of briefly drier air Friday afternoon into Saturday morning, but by this time all eyes will be focused on the next clipper system that promises to keep snow shovels and plows busy for parts of Indiana into the weekend.  We think snow overspreads the region from northwest to southeast Saturday afternoon and evening.  Steadiest snow falls Saturday night and could accumulate to the tune of a few inches by daybreak Sunday within the axis of best moisture.  Just to the north of the clipper’s track will be where you find the highest snow totals with Saturday’s system and the precise track of this clipper will be tough to iron out with any sort of certainty until Friday evening.  Stay tuned.  By the way, the snowy and cold events keep on keepin’ on in the longer range…

gfs_ptype_slp_east_12

 

Permanent link to this article: https://indywx.com/reviewing-the-snowy-details/

Jan 15

Series Of Fast Moving Snow Makers…

A series of fast moving snow makers will make for busy times in the good ole forecast office in the days (and weeks) ahead.

Of course we’re dealing with scattered snow showers this morning, but this really isn’t a big deal as accumulations will be nothing more than a dusting for most communities.

Our next clipper system will deposit light snow and snow showers across the region Thursday and Friday.  Short-term, high resolution data, highlights the chance of some light accumulation Thursday into Friday- generally an inch or less for most.  Here’s a look at the latest simulated radar valid Thursday morning at 8am and Friday at 4am:

hires_ref_indy_32

 

hires_ref_indy_52

We then look ahead towards Saturday when potentially the best shot of accumulating snow arrives.  The GFS has been leading the way on this system and now other forecast models are following it’s lead.  It’s important to note that these northwest flow systems can be over-achievers (as mentioned in previous posts) and the “fluff effect” can really kick into gear thanks to high snow ratios with the cold air.  We’ll continue to monitor this.  As of now, we think a few inches of snow is possible Saturday as this clipper moves through.  Stay tuned…

gfs_ptype_slp_east_15gfs_ptype_slp_east_16

Permanent link to this article: https://indywx.com/series-of-fast-moving-snow-makers/

Jan 13

Cold, Snowy Pattern Reloading…

I sure hope you’ve taken time to get out and enjoy a couple of days of milder air (temperatures have run 10-12 degrees above seasonal levels the past couple days) and even some sunshine.  Given what I see coming down the road, the trend that looks to take a colder turn this week may really go into the tank week two.

Here’s an overview of the latest GFS and ECMWF ensemble data out at Days 8 through 10 (January 21st-23rd).  Both of these, more trusted, mid to long range computer models suggest a cold pattern locks itself into the East once again, and spells for colder than average temperatures and potentially a snowier than normal regime.

test8

 

 

 

 

 

 

 

We’ll now dive a little deeper into the forecast model vault, courtesy of the unbelievable Weatherbell Analytics model suite (can’t brag on that company enough).  We’re looking at the Northern Hemisphere Upper Air Pattern, courtesy of the European ensemble control run from this afternoon.

Note the mid week trough set to deliver a return of arctic air into the region.  That’s reinforced with a late week trough and renewed arctic air.  Both cold air masses will be capable of producing light accumulating snow across the area.

Per yesterday’s post, as we get into the early to middle portion of next week, we’ll have to keep a close eye on the potential of the southern and northern branches of the jet stream phasing, which would lead to a significant winter storm across some parts of the eastern half of the country (far too early for specifics or details).

We then note the Polar Vortex recharges itself and threatens to turn the last week to 10 days of January very cold.  How cold is yet to be determined, but I think it’s a safe bet sub-zero temperatures aren’t finished with our area just yet.

Intrusions of very cold arctic air will “pinwheel” around the Polar Vortex and likely lead to a bitterly cold end of January and open to February…

Permanent link to this article: https://indywx.com/cold-snowy-pattern-reloading/