• Category Archives Winter Storm
  • 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!


  • Heavy, Wet Snow “Thump” This Afternoon…

    The set-up:

    A cold front is stalled across TN and lower Ohio Valleys this morning.  Meanwhile, upper level energy is moving out of the north-central Plains.  This upper level energy will continue to slide southeast and “feed” a developing surface low along the stalled front by evening.  Strong frontogenesis is forecast and this will aid in development of localized heavy snow bands and associated intense snowfall rates by afternoon, continuing into the evening.  (If you’re interested in learning more about frontogenesis and it’s impact on winter weather, please read this fantastic paper).  Here’s our updated snowfall forecast.  Please note snow amounts won’t necessarily follow the clean lines below, but this is our best idea as of now.

    SnowEvent2.8.17FinalTiming:

    We expect initial light to moderate snow to impact northern areas this morning, but it’s not until this afternoon when the “real deal” begins.  The onset of heavy snow will set-up just north of the city and the “bulls eye” with this event from a heavy snow perspective may very well paint itself across Indy’s northern suburbs, including several hours of heavy, wet snow from 12p-5p.  Moderate to heavy snow will then shift south to encompass the city, itself, mid to late afternoon, including the rush hour.  We highly recommend getting home early today if at all possible as the heaviest snowfall rates for the city, itself, will likely center on the evening rush.  Things will likely be very, very messy for travel as heavy wet snow falls.  In periods of heaviest snow, visibility near zero can be expected, especially just north of the city.

    Forecast radar 1p, courtesy of Weatherbell.com.
    Forecast radar 1p, courtesy of Weatherbell.com.
    Forecast radar 4p, courtesy of Weatherbell.com.
    Forecast radar 4p, courtesy of Weatherbell.com.
    Forecast radar 6p, courtesy of Weatherbell.com.
    Forecast radar 6p, courtesy of Weatherbell.com.

    Snowfall should begin to diminish and pull east between 7p-8p for most of central Indiana.  Cold air will follow as lows tonight dip into the middle teens for most with a significant snowpack down.  Highs Thursday will only top out around 20.

    As always, be sure to follow us on social media (Twitter: @indywx, Facebook: IndyWx.com, Instagram: IndyWxCom) for more updates on the go!  Be safe and happy snow to all!


  • Icy Set-Up This Weekend…

    Unfortunately, a strong arctic high still looks like it’ll descend into the upper Mid West Friday before moving east over the Great Lakes (Saturday) and into the northeast (Sunday).  This will help shove a cold front south to the upper TN Valley Friday and dense, cold air will bleed south to encompass central Indiana as we wrap up the work week.  As we progress into the weekend, warm moist air will override the shallow cold air locked in place at the surface.  Ripples of energy will move along the boundary and periods of more concentrated, steadier precipitation will fall.  Significant ice accumulations (greater than one quarter inch) will be possible for portions of central Indiana.

    gefs_ptype_ens_ky_14GFS ensemble members above show the overall good agreement on a central IN ice set-up for portions of the weekend.

    Timing:  As of now, I think most of Friday is dry and cold before moisture overspreads the region late Friday night into Saturday.  Additional waves of moisture will push through the region during the second half of the weekend, as well.

    Confidence:  We have very high confidence on at least light to moderate icing in the Friday night – Saturday time frame, but confidence on additional icing thereafter begins to drop, thanks to disagreement in modeling.  The GFS is warmer for the second half of the weekend and would reduce the threat of significant ice build-up as some brief thawing would be in place in between waves of moisture thanks to temperatures rising into the middle 30s.  However, the European model is much colder and keeps IND below freezing Saturday and Sunday, with nearly half an inch of liquid during that time frame.  That’s downright concerning and would result in significant issues with potentially downed tree limbs and power lines.

    We do have concern the European could have a better handle on things right now.  Modeling is notorious for underestimating the strength and depth of the cold air with these arctic highs and similar overrunning events of the past.  Stay tuned.

    Impacts:  Greatest concern right now is for icing on exposed and elevated surfaces (bridges, tree limbs, power lines, etc.).  With the milder air of midweek, along with marginally cold air, it’s possible crews will be able to keep roads passable during this event.  Additionally, something else to consider is the rate of precipitation.  While bad for elevated ice build-up, if precipitation rates are heavy enough, this can help reduce ice build-up on roadways.

    Summary:  We still have concern for the potential of an impactful ice event this weekend through central Indiana.  Winter Storm Watches (and potentially Ice Storm Warnings) may be hoisted by the National Weather Service later this week for this event.  Despite an overall high confidence in at least some icing impacting the region, questions do remain in regards to the temperature profile later in the forecast period this weekend, and caution the slighted deviation in surface temperature can make all the difference to impacts.  At the very least, low pressure should pull out of the southern Plains early next week and this will serve to push enough warm air northeast to change everything over to plain ole rain early next week as we rise into the 50s.


  • Quick Word On Next Weekend…

    I’m as fired up as I’ve been all winter for the potential of next weekend.  Does that mean “it has to happen?” No, but with all due respect to the southeast ridge (it’ll have it’s say with our weather mid/ late week with a couple days of warmth, relative to average), when I see a strong, sprawling arctic high descend into the Plains and Lakes, trouble always looms- especially when you have resistance from said ridge.

    It’s far too early to determine the precise details with regard to precipitation type and placement, but folks living in the Ohio Valley and Mid West should monitor the forecast for next weekend.  You’re not going to move an arctic high out of the way and modeling will be forced to “correct” with time.  Speaking of modeling, anticipate to continue seeing wild swings from run-to-run over the next few days.

    That said, when push comes to shove, at the end of the day I anticipate waves of low pressure moving northeast along a pressing arctic front next weekend, with all sorts of precipitation types in play.  In my opinion, an impactful event looms from a snow and ice perspective through a widespread portion of the Mid West and Ohio Valley next weekend…

    At the very least, it’ll be another fun week in the forecast office!

    Hope your Saturday is treating you well!  More later!


  • Saturday Morning Rambles…

    1.) Coast-to-coast cold:  The Lower 48 is waking up in an ice box this morning as widespread arctic air and below normal temperatures engulf the country (minus the FL peninsula this morning).  The arctic express will remain with us through the weekend, including temperatures once again tonight that threaten to dip into the sub-zero range across central Indiana.  Highs today will only reach the middle 10s and upper 10s to lower 20s Sunday.  Bundle up and stay warm.

    t02.) Expanding Snowpack:  65.4% of the country is covered in snow this morning.  The cold, arctic high suppressed the winter storm threat south as we alluded to in previous posts.  Places across the Deep South that aren’t used to wintry precipitation are waking up to snowy and icy conditions this morning, including MS, AL, GA, SC, and into the Mid Atlantic.  Heavier snowfall accumulated across east TN, including 5″-8″ in the high country.  Heavy snow also fell through western and central NC and Blizzard Warnings are up in rare areas including VA Beach this morning.

    nsm_depth_2017010705_national3.) Moderating Temperatures:  Our air flow will back around to the southwest and this will help temperatures begin to moderate early next week (around freezing Monday and all the way to around 50 Tuesday).  As the moderating trend gets underway, we may have to deal with a brief period of freezing drizzle/ freezing rain Monday evening.

    gfs_ptype_slp_conus2_134.) Rainy Midweek:  A more significant surge of moisture will arrive midweek and result in periods of moderate to heavy rain Wednesday PM into Thursday.  Potential is present for 1″+ during this timeframe.

    gfs_pwat_conus2_245.)  Weekend Wintry “Fun And Games?”  A tremendous battle will take place next weekend between a strong and sprawling arctic high pressure system and the southeast ridge.  In between it’ll be fascinating to watch things unfold, and as you’d imagine, that includes Indiana.  Despite the southeast ridge flexing it’s muscle, the concern here is that the shallow dense arctic air will “ooze” south and present an icy set-up for portions of the Ohio Valley and Mid West for the weekend.  We still have some time to watch this, but the potential of significant icing is very much present for some and this will require a close eye through the week.

    gfs_t2m_a_f_conus2_31


  • Bitter Weekend; Changeable Weather Next Week…

    screen-shot-2017-01-06-at-6-33-47-pmHighlights:

    • Bitterly cold weekend
    • Big shift in temperatures next week
    • Icy set-up late next week?

    Heavy Winter Gear Required…We’ll watch a significant winter storm impact the southern states this weekend with heavy snow and ice accumulations.  Here on the home-front, expect bitterly cold conditions with dry skies.  Clouds tonight should keep most areas around zero.  That’s frigid in and of itself, but should skies clear, temperatures will easily fall below zero.  Very cold conditions remain Sunday.

    We’ll back our air flow around to the southwest early next week and this will help give temperatures a big boost by the mid week period.  Gusty southwest winds and showers will be with us, as well.

    A complex weather pattern will set up to close out the week.  The clash of air masses between a sprawling strong arctic high and an equally impressive southeast ridge will be fun to watch, but not to forecast.  It’s very possible unseasonably warm conditions of Thursday give way to much colder weather going into next weekend as the arctic high helps “ooze” dense, shallow, cold air south.  At the same time, waves of low pressure will move along the pressing arctic front and periods of heavy precipitation will result.  Conditions should grow cold enough by Friday into Saturday for the precipitation to fall as an icy mixture of sleet and freezing rain across portions of central Indiana.  Stay tuned.

    Upcoming 7-Day Precipitation Forecast:

    • Snowfall:  Trace
    • Rainfall:  1.50″ – 2.50″


  • 12.23.16 Ensemble Discussion On The 6-10 Day…

    *A fresh 7-day will be updated late tonight or early Christmas Eve.*

    Modeling continues to suggest a colder return looms as we close out 2016 and open 2017.  We’ve discussed the implications of a negative EPO and it certainly appears as if, at least initially, the negative EPO will do the “dirty work” to drive a colder regime in the 6-10 day period.

    gefs_epo_12

    epoold_neg_12decWe note ensemble data is suggesting high latitude blocking tries to develop towards Day 10.  Recall this was the missing ingredient in the bitterly cold blasts of air that occurred during the first few weeks of December.  Both the GEFS and EPS agree on the increasingly blocky look to the pattern by Day 10.  This would help drive a cold, stormy pattern by early January.  Instead of storms cutting, we would see more suppression.  With a “stubborn” southeast ridge, things could get interesting across the Ohio Valley from a wintry perspective….

    gefs12z122316

    eps12z122316We don’t want to jump the gun, but it the positives can “hook up” over the pole, we stand the chance of locking into a rather lengthy cold, snowy regime as we rumble deeper into the heart of winter.

    Given the look, it’s no surprise we see the 12z teleconnections want to continue the trend of a negative look to the NAO and AO in the medium to longer term.

    12zeuronao122316

    12zeuroao122316Summary:  A rather mild regime remains as we rumble through Christmas before trending more seasonable next week.  From a wintry perspective we need to continue to keep an eye on the period around New Year’s Eve/ Day.  Confidence continues to increase on the potential of a return of arctic air come early January.


  • Busy Winter Pattern Continues…

    screen-shot-2016-12-10-at-8-24-08-amHighlights:

    • Snow arrives tonight for central; northern parts of the state
    • Even colder air coming
    • Pattern of storms and rumors of storms

    Snow Develops Tonight…Today is mostly dry and cold, including a mostly cloudy sky.  Clouds will lower and thicken this afternoon and give way to light snow late tonight across north-central Indiana and points north.  As milder air is pulled north Sunday, snow will transition to a wintry mix and eventually a cold light rain across central Indiana.  Further north, this will remain mostly snow before transitioning to a wintry mix.  Precipitation will end for everyone Sunday night.

    Here’s the current thinking on storm total snowfall with this event. (Click to enlarge).

    snowfallmap121116We’ll open the work week with dry and cold conditions, but all eyes will be on the next arctic front by this time.  It’ll blast through here the middle of the week with even colder air than what we’re currently “enjoying.” 🙂  Expect sub-zero wind chills mid week.  Snow showers and gusty winds remain in the mid week forecast and will require fine tuning as we draw closer.  A quick note, medium range modeling and beyond will really struggle in run-to-run consistency with such a pattern.  The slightest difference in handling respected upper air energy will lead to dramatic changes in the sensible weather the modeling paints.  There’s no sense in changing the forecast daily (or, in some cases, multiple times per day, only to change it back to where we began as time draws closer).

    Finally, yet another winter weather maker awaits for the end of the week.  Clouds will be on the increase Friday with snow (or a wintry mix) developing at night.  It’s a busy, cold pattern…

    Upcoming 7-Day Precipitation Forecast:

    • Snowfall: 1″ – 3″
    • Rainfall: 0.10″ – 0.25″


  • Quick Word On The Weekend Storm…

    It’s been a ridiculously busy day and a longer post will arrive late tonight, including the updated 7-day.

    Models continue to struggle on the evolution of things this weekend. The GFS (including the most recent 18z run) remains warm, with brief snow/ mix transitioning to mostly a rain event for central parts of the state.  If correct, heavy snows would be confined to the northern third of the state.  On the other hand, the European is less robust with the low and presents an overall flatter (weaker) look.  Plentiful moisture overruns the cold air at the surface to lead to an impactful wintry event for central Indiana before ending as rain just prior to resurgent arctic air roaring in.  This is ironic as the Euro led the charge in the “amped up” idea yesterday.  The Canadian (GEM) is a blend between the two, leaning more towards the GFS.

    While cold certainly overwhelms the pattern over the next couple weeks, as mentioned, the specifics with each storm will require a great deal of attention.  IF (big IF) the flatter idea wins out, this will be a colder system and the result will be more wintry precipitation vs. liquid.  However, if the GFS’ idea in a deepening low into the lower Lakes comes to fruition, it’ll be mighty tough for this to be much more than a brief snow/ mix to mostly rain event for central IN, especially without blocking in place currently.

    In our opinion, we’re still another 24 hours out from having this thing nailed down.  Stay tuned.

    Full updated 7-day, including fresh thoughts on the weekend, late tonight!


  • Would You Rather Be In The Game Fighting To Win, Or Sitting On The Bench?

    The pattern over the upcoming 10-15 days presents a whole slew of challenges, but has the potential to be one winter enthusiasts remember for a long time.  Arctic air is beginning to press and will eventually overwhelm the pattern by the end of the week.  Additionally, a second and third surge of arctic air will be inbound next week.  Each arctic plunge may become more severe as we go, especially if we can get a snowpack down.  The potential is on the table for sub-zero temperatures (not even counting wind chills) by mid-month.  That, my friends, is not normal for December, and is in stark contrast from Decembers of recent memory.  Whether or not we get one “big ticket” event, or deal with a parade of storms that lay snow down is up for debate and will require burning the midnight oil in the good ole weather office as we progress through the next couple weeks.

    mid-dec2016The overall set-up is certainly an intriguing one.  Cross-polar flow seeds pressing arctic air into the pattern (again, it comes in “waves” over the next couple weeks, each subsequently stronger).  What’s of particular interest is the battle that develops between a tag-team of ridges- SW and SE (at times these will put up more resistance than the other).  Long-time Hoosiers know that when cross-polar flow gets involved it can “suppress” storms, but rest easy in knowing that the SE ridge will provide resistance.  In fact, some across the lower Ohio and TN Valleys may eventually complain that the southeast ridge is providing too much resistance.

    As confident as we are in the overall dramatic flip in the pattern to one capable of producing severe winter weather over the next couple weeks, per usual, the devil is in the details.  Expect a tight gradient between areas where heavy snow begins to stack up and little to nothing- at least initially.  Additionally, depending how things evolve, icing events may eventually require attention for portions of the lower Ohio Valley and TN Valley as that shallow arctic air “oozes” south over what may become quite the impressive snowpack north.  This will require further attention in week 2.

    At the end of the day, there will be “haves” and “have nots” when it comes to storms (always are) and each will require our attention and fine tuning.  However, if you’re a lover of winter weather, it’s hard not to sit back and smile at what’s in front of us over the upcoming couple weeks, especially compared to the past couple Decembers.

    Needless to say, we’re on the field and in the game…