Questions Around Next Week’s Arctic Front…

Your complete 7-Day forecast can be found in the video to the right of this article.

We continue to keep a close eye on the developing weather situation here late next week.  Many questions remain in regards to the track, timing, and strength of the cold air associated with an arctic cold front that will result in record-breaking cold for portions of the country next week.  How much fight will the southeast ridge put up as the front progresses east?  Will we have to deal with a wave of low pressure along the arctic boundary, potentially leading to some wintry “mischief” around these parts?  We hope to give some clarity around those questions by looking at some of the latest data below.

First, let’s take a look at the various model solutions for late next week.  It should be noted that the latest run of the National Weather Service’s GFS forecast model has taken a turn to look more like the overnight run of the European forecast model and suggests we have to deal with a wave of low pressure moving through here Friday into Saturday of next week, leading to the threat of wintry precipitation.  Taken at face value, this would suggest the threat of an accumulating snow event for central Indiana Friday night into Saturday morning of next week.  This is in stark contrast to the 0z GFS run signaling dry, cold weather during the aforementioned time frame.

Here’s a look at the latest GFS solution, valid next Friday evening:

gfs_namer_180_1000_500_thick_s

There’s relatively good agreement in the GFS ensembles, but, again, we’ll have to fine tune the details.  It’s encouraging to see the agreement in the pattern evolution, though, this far out.

f192

Here’s a look at the latest European forecast, again valid for next Friday evening.

As we spoke about above, the 0z ECMWF run suggests we have to deal with a wave of low pressure in the cold air here next Friday into Saturday.  Similar to the latest run of the GFS model, there would be the potential of accumulating snow here.  The ensembles are on the left and the operational run is on the right.  The precise details will have to be ironed out, but we note relative agreement here.

Geopotential32at32500hPa_North32America_192

The latest Canadian forecast model also sees the wave of low pressure along the pressing arctic front, but suggests the wave is too far south to result in any sort of significant snowfall accumulation for central Indiana.  (As of this post time, the 12z Canadian ensemble package hadn’t arrived).

cmc_precip_mslp_east_31

So, with all of that said, we still have plenty of time to watch things unfold in the coming days.  What are we confident in as of today?

  • Brutally cold arctic air invading the northwest early in the week before slowly spreading east and south as we progress through the week.
  • We’ll be in a much warmer (though very brief) pattern here Thursday as highs zoom into the middle 50s to near 60 with rain.
  • We target the arctic front to blow through here during the day Friday.
  • While we’ll turn MUCH colder than normal next weekend, we aren’t looking at the brutality of the cold that our friends out west will have to deal with.

What are the answers that have to be ironed out this week?

  • Strength and depth of the cold air coming east.
  • Strength of the upper ridge over the Southeast US.
  • The resistance of the ridge will be crucial into determining where the “wintry precip. zone” sets up shop.

A Closer Look At Thursday

* A video update was posted late last night and talks about the rain, bitterly cold weekend ahead, and  looks at Thanksgiving.  Scroll below for that update.

Today will feature scattered light to moderate rain, but as noted last night, that rain will grow more widespread tonight.  The latest HRRR simulated radar shows that well.

hrrr_ref_indy_14

High temperatures today are forecast to reach the middle 50s, per the latest HRRR.

hrrr_t2m_max_indy_10

We’re still tracking major league early season arctic air due in here this weekend.  Take a look at just how far below normal these temperatures are come Sunday (shown in degrees celsius).  Wow!  Our forecast high of 24 will be the coldest November day in 13 years and a whopping 25 degrees below normal!  Thanks, as always, to Weatherbell Analytics model suite for this data.

gfs_t2max_anom_ma_29

 

Wednesday Evening Video Update: Rain Moving In; Arctic Blast This Weekend

http:/ Tonight’s Video Highlights: We talk rain and amounts for Thursday and Friday. The coldest air of the season and coldest November day in some 13 years is ahead! A…

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Wednesday Forecast: A Bitterly Cold Start

Updated 11.12.13 @ 8:50p

Zionsville, IN After waking up to half an inch of snow, sunshine engulfed most of the region Tuesday. The vitamin D didn’t help temperatures moderate much as highs were more like mid to late December as opposed to mid November. We discuss a warming trend below, after a frigid start to your Wednesday.

Status-weather-clear-iconWednesday: Mostly sunny; 19/ 39

A strong area of high pressure will move overhead Wednesday and help supply a mostly sunny sky.  Despite the sun, it’ll be another unseasonably cold day.  Many outlying communities will begin the day in the upper teens before rising into the upper 30s to near 40 by afternoon- a solid 15 degrees below normal.

Status-weather-clouds-iconThursday: Partly cloudy; 28/ 49

The same high pressure that will be directly overhead Wednesday will begin to move east Thursday. This will put our region in a southwesterly air flow and allow temperatures to begin moderating. After another cold start, highs will push towards the 50 degree mark Thursday afternoon.

Status-weather-clouds-iconFriday: Partly cloudy; 35/ 52

We’ll wrap the work week up with a few more clouds and temperatures still slightly cooler than normal, though much milder than those we’re dealing with now.

 

Status-weather-showers-day-iconSaturday:  Turning cloudy with PM showers (0.20″); 40/ 59

Model data continues to hint at increasing clouds and the threat of afternoon light rain. We’ll initially have to overcome the dry air mass in place, but by afternoon/ evening we should have scattered showers beginning to impact central portions of the state.

Status-weather-showers-scattered-iconSunday: Cloudy with rain likely (0.45″); 52/ 60

More widespread rain will arrive for the second half of your weekend.  Highs will approach 60 and should we see any sunshine (not looking likely at this point), temperatures could go into the lower to middle 60s. While temperatures will be much warmer we’ll have to contend with rain Sunday.

Status-weather-storm-night-iconMonday: Showers and possibly a thunderstorm (0.50); 34/ 63

A strong cold front will blow through the state Monday evening. Out ahead of the front, an impressive surge of warmer and more humid air will move north and encompass central Indiana during the day. In fact, latest model data suggests dew points reach the lower 60s Monday. The combination between the warmer, more humid air in place and an impressive surge of arctic air behind the front could team up to produce a clap or two of thunder with the moderate to heavy rain threat Monday afternoon as the front moves through. Temperatures will then crash Monday night.

Status-weather-snow-scattered-day-iconTuesday: Scattered snow flurries; 24/ 34

The big story Tuesday will be the much colder air mass rushing into the state on strong and gusty northwest winds. Just enough moisture may linger to create the chance of scattered snow flurries.