• Weekend Of Changes: Storms To Snow…

    Highlights:

    • Big changes this weekend
    • Relatively calm Thanksgiving week
    • Chilly Thanksgiving

    Storms To Snow This Weekend…An approaching storm system will lead to an active open to the weekend.  Beforehand, thankfully, we’ll close the work week out on a rather quiet note.  The daytime hours will remain dry before moisture begins to return this evening.  An initial round of showers will move across central Indiana (thinking between 8p-9p) before steadier and heavier rain and embedded thunderstorms blow into town Saturday.  A strengthening surface low will move from the central Plains tonight and into the southern Great Lakes Saturday.  This will lead to a briefly milder surge of air Saturday morning into the early afternoon before a cold front sweeps through the state and leads to a sharply colder close to the day.  Right ahead of the cold front, a skinny, but potentially intense, line of thunderstorms will track across central Indiana late Saturday morning into early Saturday afternoon.  Damaging wind gusts are possible as this thin line of storms advances across central and southern Indiana.  Winds will then shift around to the northwest and help drive much colder air into the region through the afternoon and evening.  In fact, we’ll turn cold enough to allow precipitation to end as a touch of wet snow Saturday evening.

    We’ll wrap up the weekend and kick off Thanksgiving week on a much calmer note.  Chilly high pressure will build in Sunday, allowing sunshine to return, but temperatures will run around 15° below normal.  A dry cold front will pass through the state Tuesday.  With the exception of a wind shift and a few more clouds we really shouldn’t expect much more in the way of “excitement.”  This will allow unseasonably cool air to return for Thanksgiving, itself.

    Upcoming 7-Day Precipitation Forecast:

    • Snowfall: Trace – Dusting
    • Rainfall: 1.00″ – 1.50″


  • Digging Deeper As Winter Nears…

    Thanksgiving is only a week away (where on earth does time go?!) and more and more folks are asking what we think winter will hold for central Indiana.  In case you missed it earlier this fall, here’s our official Winter Outlook.

    We’re continuing to dig in and monitor new data that’s streaming into the office, as well as ocean profiles.  With that said, we wanted to share some of our findings with you this morning with respect to how various ocean regions can impact our weather this winter.

    We’re noticing significant changes, particularly in the north Pacific, with the famous “warm blob” emerging (image 1). This is a big factor that aided in persistent cold; wintry weather during the ’13-’14 winter (images 2-3). Notice the difference from last year, too (image 4). This isn’t a full blown cold PDO (Pacific Decadal Oscillation) yet, but trending in that direction and “ups the ante” for cold, wintry conditions, locally this year.

    What makes seasonal forecasting so challenging (and fun :-)) are the multiple features that can impact a forecast.  We’ve talked about the importance of ENSO (various types of Nino and Nina events) in past updates, as well as low solar and QBO.  All of these moving parts and pieces are coming together in a manner that seems to be favoring more of a cold, wintry regime, locally, this year.  Is that us saying another blockbuster 2013-2014 winter awaits?  Absolutely not (there are other differences noted above with the SST configuration).  However, it is suggesting that this winter will be absolutely nothing like the past couple…

    Might want to think about getting the snow blower tuned up!

    More later today on the short-term.  Make it a great Thursday!


  • Multiple Cold Fronts Keep Us Busy…

    Highlights:

    • Wet Wednesday
    • 2nd cold front Friday night
    • 3rd cold front arrives Tuesday night

    Busy Weather Pattern…Rain is pressing into central Indiana this morning ahead of the first of three cold fronts we’re tracking between now and early Thanksgiving week.  Rain will be most widespread this morning into the early afternoon hours before diminishing mid to late afternoon.  Reinforcing chilly air will blow into town tonight and we’ll be in between storm systems Thursday.

    Our second storm system will lead to increasing clouds Friday afternoon with showers and thunderstorms arriving overnight into Saturday morning.  Due to the slower timing of this storm, the late week severe threat has diminished significantly.  Nonetheless, it’ll be a windy afternoon and we’ll notice rising nighttime temperatures Friday as the cold front approaches.  Morning rain will continue Saturday before a sharp transition to much colder conditions with falling daytime temperatures.  We’ll kick off Thanksgiving week on a dry and cold note.

    Finally, yet another cold front will approach Tuesday night.  Once this front sweeps through the state, the coldest air of the season will settle into the area just in time for Thanksgiving.

    Upcoming 7-Day Precipitation Forecast:

    • Snowfall: 0.00″
    • Rainfall: 1.50″ – 1.75″


  • Busy Week Of Weather…

    November is off to a chilly start and longer range data suggests the chill grows more significant as we venture through the second half of the month.  Officially, IND is running more than 1° below normal through the 12th.

    Despite an active weather week ahead, the open to the new work week will be rather uneventful.  Weak high pressure will keep us dry today and Tuesday.  Fog and low clouds should give way to an increasingly bright sky by this afternoon (still more clouds than sun today) and partly cloudy skies Tuesday.

    Our next weather feature approaches Wednesday in the form of a cold front.  This will return showers to the area midweek.  Rainfall amounts Wednesday should generally fall in the 0.25″ to 0.50″ range.

    A stronger storm will impact the region as we close out the work week.  Strengthening low pressure will track into the Great Lakes and drag a trailing cold front through our region Friday evening.  A briefly milder southwesterly air flow will push temperatures close to 60° Friday afternoon/ evening before the sharply colder push of air blows into town for the weekend.  The transition may include strong to severe thunderstorms Friday PM, and the Storm Prediction Center (SPC) has outlined a large portion of the region under a severe risk Friday.  It’ll be important to stay tuned to future updates.  Even outside of potentially damaging thunderstorm gusts, non-t-storm winds will gust over 40 MPH Friday.

    Once the cold front sweeps through the region, a sharply colder air mass will plunge into the Ohio Valley for the weekend.  Overnight data has trended even colder and would suggest falling Saturday temperatures (most of the day will be spent in the 30s) and highs only in the lower to middle 30s Sunday.

    Speaking of cold, Thanksgiving week is looking unseasonably cold, and there’s also the potential of early-season snow (far too early for specifics).


  • Tracking A Couple Of Cold Fronts This Week…

    Highlights:

    • Calm open to the work week
    • Two cold fronts impact the region
    • Much colder air blows in this weekend

    Calm Open; Busy Close…The work week will open with weak high pressure in control of our weather.  This will result in sunshine returning along with unseasonably chilly conditions (average highs are in the mid 50s this time of year).

    The first of two cold fronts will push through the state Wednesday.  Clouds will increase Tuesday evening and showers will blow into town Wednesday morning.  Breezy and chilly conditions will go along with the damp weather.

    A second (stronger) cold front will impact the area to close the work week.  Strengthening low pressure will move through the Great Lakes Friday evening and help pull a briefly warmer air mass into the state.  Showers and thunderstorms will be widespread ahead of the approaching cold front and a few of these could be strong to severe.  We’ll keep a close eye on things over the next couple of days and update accordingly.  Strong and gusty southwesterly winds will reach 40 MPH+ before shifting around to the northwest once the trailing cold front sweeps through the region.  This will drive a sharply colder air mass southeast and the potential is there for lingering moisture to end as a touch of wet snow late Friday night.  The weekend will feature dry, windy, and unseasonably cold conditions.

    Upcoming 7-Day Precipitation Forecast:

    • Snowfall:  Trace
    • Rainfall: 1.00″ – 1.50″


  • Unseasonably Cold; Weekend Ends Messy…

    Highlights:

    • Filtered sunshine today
    • Raw and messy Sunday
    • Fast-moving weather pattern next week

    Bundle Up…Wake up temperatures are more like we’d expect in late December as opposed to early November, including lower to middle 20s across central Indiana.  Filtered sunshine will eventually give way to a thickening cloud deck late.  Those clouds will be a harbinger of things to come as moisture overspreads the region Sunday morning.  Look for a cold, raw close to the weekend with periods of light rain (sleet may mix in with the rain during the onset early Sunday, but this won’t be a big deal).

    We’ll open up the work week with dry and chilly conditions before a couple of fast-moving systems impact our mid and late week weather.  Clouds will increase Tuesday and showers will arrive at night, continuing into Wednesday.  Our next (stronger) storm will arrive to wrap up the work week.  A southwesterly air flow will inject briefly milder air Friday morning and may be sufficient enough to create a couple of thunderstorms.  We’ll then transition to a much colder, windy regime to wrap up Friday with falling temperatures.

    Upcoming 7-Day Precipitation Forecast:

    • Snowfall: 0.00″
    • Rainfall: 1.00″ – 1.50″


  • “Block Ready To Rock?” Cold Pattern Developing Around Thanksgiving…

    Model data continues to suggest a Greenland block will develop as we progress into late-November.  This kind of pattern creates a “log jam” of sorts in the weather pattern and is the type pattern notorious for unseasonably cold regimes across our region.  The overall agreement between various models raises our confidence in this pattern unfolding as Thanksgiving nears.

    Such a pattern illustrated above, per the European ensemble (image 1) and the GFS ensemble (image 2), would help drill a tongue of unseasonably cold air through the northern Plains, into the Mid West, and across the East.

    A look at the 00z teleconnections this morning shows 3/4 “big boy” drivers going to that cold look for late-November, as well:

    We’ve been discussing early snow cover across Canada and the northern tier for weeks and how models would have to “correct” colder as they realize the air masses traveling over the snowpack won’t be able to modify as they normally would without that snowpack.  The differences between this November and last are startling and show how the early snowpack is beginning to “feedback” on itself leading to early-season cold air.

    2016 snowpack and temperatures anomalies through the first week of November:

    2017 snowpack and temperatures anomalies through the first week of November:

    Given the overall look to the pattern downstream, I anticipate the cold will continue to “press” and eventually overwhelm the pattern east as we progress through the second half of the month.

    To close, we expect a developing Greenland Block to help drive an unseasonably cold late-November, including the Thanksgiving holiday.  This is the type pattern that can also help generate early season wintry “fun and games,” however it’s far too early to be specific with any sorts of potential wintry events that may eventually come in this pattern.  Stay tuned.