Changeable Weather Christmas To New Years…

It’s hard to believe we’re only a few days from Christmas!  Through the 22nd, Indianapolis is running a whopping 6 degrees below average.  Cold rules across the Lower 48, month-to-date.

ncep_cfsr_noram_t2m_anomThis is, of course, is in stark contrast to December 2015.

conus_mtd_t2max_anom_2015As we move forward, an active pattern awaits between now and the end of the year.  This comes after a few days to catch our breath, including moderating temperatures leading up to Christmas.

An initial wave of moisture will lift northeast and result in a rather gloomy day Friday with increasing rain chances Friday afternoon and evening.  Initially, precipitation won’t make it to the ground, but we should saturate the column enough that rain reaches the ground for most of central IN by evening.  Showers continue Friday night into the wee morning hours Christmas Eve.  (If traveling towards Chicago, a wintry mix and snow will be a good bet Friday PM).

hires_ref_ky_18Christmas Eve will feature overcast skies with areas of fog and drizzle, but the majority of the concentrated rain should fall south of the region.  Santa’s ride into central IN should be uneventful, weather-wise.

Christmas Day will start off with temperatures in the mid to upper 30s along with cloudy conditions and an increasingly gusty breeze that will shift out of the southeast to the south Christmas night.  Shower chances will be present by the evening before giving way to more widespread showers and embedded thunder overnight into Monday morning.  Temperatures will be stuck in the 40s most of the daytime Christmas before rising into the upper 50s predawn Monday.

gfs_ptype_slp_indy_17Temperatures will fall through the day Monday and we should run much closer to seasonable temperatures next week.  A couple of additional storm systems will have to be monitored for rain and snow prospects the middle of next week and again around New Year’s Eve/ Day.  Initially, we’ll be rather mild, but there may be more in the way of cold air readily available to make the storm system around New Years “more interesting” from a wintry perspective.

Longer term, we have to wonder if the negative EPO isn’t about to take control just past the New Year.  More and more data is coming around to the idea that the arctic hounds may (yet again) be on the attack early January… Time will tell and we’ll continue to keep a close eye on things.

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Pattern Moderates, But Stays Busy…

screen-shot-2016-12-20-at-6-17-58-pmHighlights:

  • Fast-moving storm system scoots north
  • Wintry mix Friday night?
  • Christmas night t-storm?

Chilly, But “Less Harsh”…The average high and low in central Indiana to wrap up December fall in the upper 30s and lower 20s, respectfully.  While much milder than we’ve been, temperatures will be very close to seasonal norms as we rumble into Christmas weekend.  A fast-moving storm system will scoot across the Great Lakes region Wednesday afternoon.  Reinforcing chilly air (not of arctic origin) will blow in Wednesday night and Thursday.  While a flurry could fly Wednesday night into Thursday morning, this won’t be a big deal.

We’ll then shift our focus to Christmas.  An initial wave of moisture could result in a light wintry mix as early as Friday night.  Initial thinking is that this won’t be a big deal as a quick transition to rain should take place early morning Christmas Eve, but, nonetheless, we’ll keep a close eye on things.  A light shower may still be around Christmas Eve, especially during the first part of the day.  Christmas Day, itself, should feature mostly dry, windy, and mild conditions.  Wind-blown showers are possible by afternoon before intensity increases Christmas night, including the potential of a strong thunderstorm.  The cold front will sweep through the state Monday morning with colder and windy conditions continuing Monday into Tuesday.

Longer-term, we remain confident that the “relaxed” state in the bitterly cold pattern will continue.  However, please know that doesn’t mean we won’t have to deal with wintry threats over the next couple of weeks.  An active storm track will continue through the Ohio Valley…

Upcoming 7-Day Precipitation Forecast:

  • Snowfall: Dusting – 1″
  • Rainfall: 0.50″ – 1.00″
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Frigid Open To The Week; Wet Christmas?

screen-shot-2016-12-19-at-8-58-45-amHighlights:

  • Bitterly cold to open the week
  • Mid week snow chances
  • Wet Christmas

Bundle Up…The frigid theme of December 2016 continues as overnight lows dipped to between 3 and 6 below zero for most central IN reporting sites.  By the way, IND is running (6) degrees below average, month-to-date.  Needless to say, December 2016 (top) is nothing like December 2015 (bottom).

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Though still chilly, temperatures will moderate into mid week before our next system rolls in.  Clouds will increase Wednesday and give way to a chance of snow showers Wednesday night into Thursday morning as upper level energy rotates overhead.  Models likely will have to play “catch up” again with this mid week system and we’ll keep a close eye on data.

As we look at Christmas, itself, a warmer regime looks to build in, courtesy of a southwest flow.  This is in response to the southeast ridge flexing it’s muscle and driving a rather intense storm system northwest through the Plains states.  Blizzard conditions will likely result northwest of the low track while showers and thunderstorms develop in the warm sector, including the MS Valley into the Ohio Valley.  We’ll introduce a chance of thunderstorms into our Christmas Day forecast, as well.

Longer-term, a rather significant pattern shift will continue to close the month of December into early January and this will drive a shift from the bitterly cold conditions to much milder times as we open 2017.  Winter fans, have no fear, the seeds are already being planted for a return to frigid and active times just beyond the new year…

Upcoming 7-Day Precipitation Forecast:

  • Snowfall:  Dusting – 1″
  • Rainfall: 0.50″ – 1.00″

Icy Concerns Grow Again Tonight…

After a night of freezing rain, many roadways throughout central IN remain glazed over and hazardous as of this update.  If you absolutely don’t have to travel today, please don’t.  Allow road crews to do their job.  Additionally, we have growing concerns of a new round of freezing rain to sleet and eventually snow tonight.  Lingering moisture on roadways will result in “flash freeze” conditions and treacherous travel tonight into Sunday.

First, a tip of the hat to short-term modeling, including the NAM, for suggesting we’d have a very difficult time eroding the shallow arctic air at the surface across most of central IN today.  While we never bought into the mid/ upper 50s idea the GFS and Euro were once suggesting, we did initially think 40s were in store today.  Forget about it.  Mid to potentially upper 30s are the best we can do today and temperatures will crash this evening as not one, but two, arctic fronts push through central IN.  Even if we didn’t have additional precipitation inbound tonight, “flash freeze” conditions would develop from lingering moisture and lead to renewed problems on area roadways.  Throw in another wave of low pressure riding along the pressing arctic front and a whole slew of problems will develop yet again from a freezing and frozen precipitation perspective.

Note the incredible temperature gradient from downstate to central and northern Indiana early this afternoon.

hrrr_t2m_indy_6The heavy, dense, arctic air will win out as evening turns into nighttime.  Indianapolis is back to the freezing mark around 6p and into the 20s by 9p.

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hrrr_t2m_indy_13Temperatures will continue to fall through the day Sunday and by Monday morning central Indiana will be in the single digits, with below zero readings across northern parts of the state.

hires_t2m_indy_49Wind chill values of 10 to 20 degrees below zero will be common by Sunday night into Monday morning across central Indiana.

gfs_windchill_indy_8Areas of drizzle and freezing drizzle will continue across the region into the early afternoon, but begin to expand in coverage and intensity once again by evening.  Note the area of freezing rain expand across central IN, including Indianapolis, between 4p and 7p.

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7pFreezing rain will eventually begin to mix with sleet and eventually transition to light snow during the overnight from northwest to southeast.  A coating of snow to less than 1″ is a good bet on the new icy glaze that develops tonight.

When you factor in the current hazardous conditions in place along with the fresh push of arctic air and precipitation tonight, it’s a good idea to hunker down inside and remain off area roadways.  We have big concerns of new travel problems developing by evening across central Indiana.  By this time tomorrow, our attention will turn to the bitterly cold air and dangerous wind chill values developing.

More later, including prospects of snow around Christmas.  As always, you can follow our updates on social media by following us on Twitter (@indywx) and Facebook.  Stay safe!