Extended Period Of Unseasonably Cold Air…

Today will begin a rather extended period of unseasonably chilly air that will grip the region.  It’s not until the latter portions of next week that we should begin to see slowly moderating temperatures.

The reason for this is a persistent trough setting up over the Great Lakes and eastern portions of the country.  From time to time, individual disturbances will come racing along in the fast northwest flow aloft and help to reinforce the cold and also create snow potential.

Forecast models continue to show an eastern trough into the middle parts of next week.

 

This is an impressively cold pattern for so late in the season.

This is the type pattern that will promote multiple nights in the teens over the upcoming week.  We forecast coldest nights to be Saturday night, Sunday night, Wednesday night, and Thursday night.  Each has the potential to send neighborhoods into the middle-upper teens.

As far as snow goes, we still are keeping an eye on the early stages of the work week.  We’ll fine tune things this weekend, but models continue to show energy diving southeast Monday that would help snow overspread the region during the day, continuing into Tuesday morning.  This time of year, snowfall rates and time of day means a world of difference between snow flying in the air, versus accumulating.  The potential is there for light accumulation Monday night as reinforcing cold air pours in.

Stay tuned!  Much more later!

Thoughts Shift From Storms To Snow…

Before we discuss the weekend winter storm threat, we still have to get through the overnight period-morning hours Tuesday with embedded heavy rain and storms.  Some of these storms could offer up gusty winds and a few could be strong as they rumble across central Indiana Tuesday morning.

Most of the storms should push through west-central Indiana well before the morning rush hour.

Forecast radar 4am Tuesday.
Forecast radar 6am Tuesday.

Attention will then shift to the winter storm threat this weekend- particularly Friday night through early Sunday morning.  We still have to fine tune the all-important specifics, but confidence is rising on the possibility of a significant wintry event impacting at least portions of the region this weekend.  March snow events provide added headaches of dealing with the impacts of marginal temperatures, higher sun angle/ time of day, etc.  Conversely, the tight thermal gradients noted with most late season, spring snow events can be impressive, as they can quickly feedback, ultimately leading to swaths of thumping wet, heavy snow.  Hoosiers don’t have to think back too terribly far to some impressive and impactful March snow events.  Modeling today is in relatively good and surprising agreement, especially considering the lack of agreement models have dealt us weather ‘folk for the past few months.  🙂

GFS ensemble members are focusing in on a snow event this weekend.

It’s still early in the game and a lot can (and likely will) change with model runs over the next few days.  It’s wise not to make knee-jerk reactions to the operational model solutions, but instead understand the overall pattern driving the potential of this memorable March wintry event.  Anomalously cold air in southern Canada will spill south this weekend and help aid in the “fun and games” ahead.  At the same time, given the time of year, “suppression depression” isn’t likely as their will be resistance from the south-central Plains and southeast ridging in place.  As of now, we think the I-70 corridor could be the “sweet spot” for snow totals, understanding fine-tuning will be required moving forward.  Where a snowpack accumulates this weekend, expect temperatures Sunday night/ Monday morning to fall into the 10s.

Much more later!

Sunday Afternoon Rambles…

1.)  It’s another unseasonably pleasant afternoon across central Indiana.  Despite a gusty SW breeze (open county is approaching 40 MPH throughout central IN Sunday afternoon), the sunshine and warm temperatures are providing a phenomenal second half of the weekend.

Temperatures are running 20+ degrees above normal this afternoon.

2.)  Clouds will begin to increase tonight and give way to showers as we open the work week.  There will be plenty of dry time Monday morning into the afternoon, but a passing shower will remain in our forecast.  Heavier rain and embedded thunderstorms will arrive on the scene Monday night into the wee morning hours Tuesday.  As a whole, we expect between 0.50-1″ of rain, overall, by Tuesday morning.

Greatest rainfall coverage will arrive overnight Monday night.

3.)  We’ll trend cooler for the mid week stretch, but nothing “cold” for this time of year.  In fact, temperatures will remain above average as high pressure provides dry conditions.

Weak high pressure builds in for mid week.

4.)  Confidence is high on an active period of weather arriving for the weekend into potentially early parts of next week.  That said, despite overall high confidence on a busy time of things, the specifics remain “murky,” at best.  It’ll be important to check back for updates on the weekend forecast as we progress through the upcoming week.  Solutions range anywhere from a period of rain and storms to possibly some wintry “mischief.”  One thing seems certain and that’s for a period of colder air (below normal) arriving in the 8-10 day period.  In fact, the latest European model suggests overnight low in the 10s late next weekend.

The weather turns active next weekend.

Unseasonably Warm And Stormy Weather Gives Way To Late Week Chill…

Monday evening is running much warmer than this time Sunday across most of the central, including right here in Indiana.

This warmer regime is the sign of stormy times that will develop as we move into Tuesday.  An initial round of showers and thunderstorms will impact central Indiana Tuesday morning and the HRRR forecast radar is picking up on this nicely, especially during the predawn hours.

The wet, stormy start to the day will give way to a mostly dry time of things through the majority of the daylight hours Tuesday, but our concentration will be on the Tuesday night-Wednesday morning period, as the potential exists for some rather turbulent weather.

We note the National Weather Service’s Storm Prediction Center outlines all of the region for the chance of severe weather Tuesday night and also note the possibility the “enhanced” risk area may expand in future updates.  Additionally, given some of the ingredients we’re observing this evening, there’s also the possibility we may see an upgrade to a “moderate” risk for portions of the region.  It’ll be particularly important to pay attention to weather updates Tuesday night.  Primary concerns are for large hail and damaging winds in a possible squall line that develops ahead of an approaching cold front.  Additionally, if storms develop ahead of the primary line of storms, the potential exists for a couple of tornadoes.  Have a means of getting the latest watches and warnings Tuesday night.

Modeled radar suggests things may begin to get “busy” around these parts late evening and during the overnight.  The latest high resolution NAM (hot off the press as of this update) paints a rather ominous look as midnight nears Wednesday morning.

We then note modeling bringing the squall line through central Indiana during the overnight and predawn hours.  We’ll have to fine tune timing as we move through the day Tuesday, but we bracket the hours of 2a and 6a when a concentrated line of strong to severe storms rumbles through the state (northwest to southeast).  Hail and damaging straight line winds are of greatest concern, but a quick spin-up tornado can’t be ruled out.

Our weather will turn quieter, but colder, as Wednesday progresses into Wednesday evening, including blustery conditions with falling temperatures.

A fast-moving clipper system will dive southeast Thursday evening into early Friday morning and this could produce a snow shower, or two, across the region, but shouldn’t amount to much from a snow perspective (keeping true to the tune of the winter, heh?).  The bigger story will be the “rude” feel to the air mass as we wrap up the work week, as highs only reach the upper 30s with a gusty wind.

That said, the chilly late week conditions won’t last long, and a gusty southwesterly air flow will develop as early as Saturday.  This will help give temperatures a significant boost Saturday afternoon after a cold start to the day.  60° is possible Saturday afternoon and the mercury may approach 70° Sunday!

More updates in the AM!  Have a great night, friends!