• Category Archives Freezing Rain
  • Friday Morning Rambles…

    I. Bitter Cold: We’re adding another morning below zero to an already impressive (and growing) list of frigid lows this winter.  Take a look at these morning lows in the sub-zero club:

    • 12.27.17: – 3°
    • 12.31.17: – 1°
    • 01.01.18: – 10°
    • 01.02.18: – 12°
    • 01.04.18: – 3°

    So far, IND has already dropped to 8° below this morning and we’ll throw another morning of sub-zero lows on the table Saturday (many will fall to between 8° and 15° below) as an arctic high settles overhead.

    II.  Messy Storm: An approaching storm system late in the weekend will spread moisture into the arctic air mass and concern for a wintry mix of snow, sleet, and freezing rain remains Sunday evening into Monday morning.  Overnight data suggests an initial thump of snow followed by several hours of freezing rain for most of central Indiana.  Certainly, close attention is warranted for this event as we progress through the weekend.

    III.  Milder: Once the early week winter event blows by, a milder southwesterly air flow will pull us out of the freezer for a couple of days during the middle of next week.  In fact, highs will likely go north of 50° Wednesday-Thursday.  Break out the shorts!

    IV:  Leader-Follower: An interesting pattern awaits late next week as an arctic cold front pushes east.  Rain will spread into the region late in the week as the first surface low tracks through the Great Lakes.  We think a second low pressure system will develop on the pressing arctic boundary Thursday night into Friday and it’s this low that poses a wintry component to interior portions of the east.  Is that across the Ohio Valley (such as the European model suggests) or along the Appalachian chain (GFS)?  That’s up for debate and there’s no way to settle things right now.  We’ll continue to keep an eye on things and update accordingly.

    V: January Thaw: The overall pattern will get engulfed with milder, Pacific air during the second half of the month and the end result will be a rather dramatic flip from arctic cold to above normal conditions as a classic January “thaw” develops.  After the significant and prolonged arctic feel, many won’t complain of this pattern relaxation.


  • Snow Develops Wednesday; Renewed Arctic Air…

    Highlights:

    • Wednesday powder
    • Fresh batch of arctic air
    • Messy late weekend storm

    Snow Develops Wednesday Afternoon…Upper level energy will move across the region Wednesday and result in snow overspreading the northern half of the state (especially from Indianapolis and points north) during the afternoon and evening.  While snowfall amounts won’t be particularly impressive (generally 1″ or less), roads will likely get slick in relative quick fashion prior to the evening drive.  You’ll want to leave extra time on your evening commute home.  Otherwise, blowing and drifting snow will develop tomorrow night into Thursday as fresh arctic air pours into the area.

    Attention will shift to lake effect snow across northeastern portions of the state Thursday before another ripple of energy drops southeast and sparks additional snow showers across central parts of the state to wrap up the work week.  Saturday will be dry and very cold.

    Clouds will be on the increase overnight Saturday into Sunday morning and a mixed bag of precipitation will overspread the region Sunday PM.  We still have a few more days to watch things unfold, but concern remains for an icy cocktail of sleet and freezing rain after a potential initial burst of snow.  While warm air advection (WAA) will likely win out, we’re afraid it’ll be very difficult to warm the surface enough to prevent ice from becoming an issue Sunday afternoon into early Monday.  Cold air will sweep back in here Monday evening into Tuesday with snow showers and gusty winds.

    Upcoming 7-Day Precipitation Forecast:

    • Snowfall: 1″ to 3″
    • Rainfall: 0.10″


  • Prolonged Bitterly Cold Pattern Rolls Along…

    Highlights:

    • Dangerously cold pattern
    • Midweek snow showers
    • Messy weekend

    Take The Cold Seriously…Dangerously cold conditions will continue this week.  With clear skies and a fresh snowpack, temperatures will quickly tumble tonight into double-digit below zero territory across most of central Indiana.  Add in even the slightest wind and wind chill values will plummet to 20 to 30 degrees below zero.  Limit time outside, check on your neighbors, and ensure your pets are cozy indoors, as well.

    Next up on the agenda will be upper level energy moving southeast across the region Wednesday.  This will spark an area of snow showers with light accumulations for our hump day followed by reinforcing bitter cold to close out the week.  Additional upper level energy and some lake moisture will provide the chance of snow showers Friday in spots, as well.

    A more widespread and significant storm system will arrive over the weekend.  Clouds will increase Saturday night into Sunday morning and a messy mixture of snow, sleet, and freezing rain will invade Sunday afternoon and evening.  Renewed bitterly cold, arctic air will plunge southeast early next week.  Additional sub-zero days are likely just beyond the forecast period…

    Upcoming 7-Day Precipitation Forecast:

    • Snowfall: 1″ to 3″
    • Rainfall: 0.10″


  • Saturday Morning Freezing Rain Update…

    More widespread precipitation is spreading across central Indiana this morning.  Most of this precipitation is falling as freezing rain.

    Radar at 7:19a.
    Radar at 7:19a.

    Modeled forecast radar continues to show moisture streaming across the region through around the lunchtime hour before diminishing.

    9a forecast radar
    9a forecast radar
    12p forecast radar
    12p forecast radar

    Temperatures will remain around 30-32 degrees along and north of the I-70 corridor as this rain falls so it’ll freeze on contact.  Allow extra time if you must travel and slow down.  Due to our phenomenal road crews and marginally cold temperatures, we don’t expect major travel issues this morning, but do use caution if traveling.  A light glaze of ice (around 0.10″) is possible on elevated surfaces, including tree limbs and power lines.

    Temperatures will go above freezing this afternoon across most of central Indiana and precipitation will end.  Highs both today and Sunday should top out in the middle 30s across the region.

    5p forecast radar
    5p forecast radar

    Lows tonight will settle back down into the middle to upper 20s, but dry conditions should remain for most of the night.

    10p forecast radar
    10p forecast radar

    Our next round of precipitation looks slated for a Sunday morning arrival and, similar to this morning, this precipitation will likely fall as a mixture of light rain and light freezing rain.

    Updated 7-day out later!  Have a great Saturday!


  • Surge Of More Widespread Precipitation Saturday Morning…

    Light freezing rain and drizzle has been falling across central Indiana this evening, mainly from the city, itself, and points south. A light glaze of ice has been reported into the forecast office in Monrovia and Plainfield. 

    For the next several hours, patchy light freezing rain and drizzle will continue, but nothing in a widespread, “uniform” fashion (great news for those night owls out and about).

    However, we do note some of the higher resolution forecast models suggesting a waive of more widespread precipitation arriving into central Indiana Saturday morning. This most likely pushes in sometime between the hours of 7a-9a and encompasses the heart of the state, including Indianapolis. 

    This “slug” of moisture will continue to fall across central Indiana through the morning hours before tapering off and diminishing around lunchtime. The afternoon and evening should be void of any widespread precipitation of significance. 

    While this won’t be a crippling event by any stretch of the imagination, be careful for slick spots Saturday morning and allow road crews room for salting. In general 0.05″-0.10″ of glaze still seems like a good bet for most central Indiana neighborhoods by lunchtime Saturday. 

    More in the morning! Have a great night!


  • Quick Friday Evening Notes…

    1.)  While we’re still expecting freezing rain across central Indiana tonight into the early morning hours Saturday, dry air will really limit totals.  Instead of the 0.10″-0.20″ of glaze per our first idea, we’ll cut that in half and say anywhere from 0.05″-0.10″ possible across central parts of the state tonight into Saturday morning.  This, obviously, won’t be enough to create power concerns or downed tree limbs, but could be sufficient enough to create slick spots in places.  Light freezing rain should increase in coverage across central IN from 10-11p.  Allow extra time to reach your destination tonight and early Saturday and slow it down.  All in all, this is not a significant event for central Indiana.

    Additional waves of light precipitation (rain mixed with freezing rain, primarily north of I-70) will be with us for the weekend, but similar to tonight, this won’t be a big deal and shouldn’t result in any need to cancel your weekend plans.

    2.)  A more significant surge of moisture will come out Monday night into Tuesday as low pressure (finally) pulls northeast out of the central Plains into the Great Lakes.  Localized amounts around 1″ will be a good bet, along with a warmer southwest flow.

    3.)  We’ll turn briefly cooler (still above average) mid week, before a stronger push of mild air late week.  Widespread highs in the lower-middle 60s seems like a good bet heading into next weekend and a rare January White Leg Alert may have to be issued.  😉

    4.)  Enjoy the January thaw while we have it.  Guidance continues to align and suggest winter roars back with authority to close January (last week of the month) before potentially locking in as we move into February and well into March.  More on this later this weekend.

    Complete updated 7-day will be published late tonight or early Saturday!


  • Weekend Ice And Heavy Rain Next Week…

    Screen Shot 2017-01-12 at 7.08.19 AM

    Highlights:

    • Turning colder
    • Freezing rain develops Friday night
    • Wet times continue

    Active Times; Excessive Rainfall Risk Next Week…The overall weather pattern remains very active AND very wet.  By the time all is said and done, an additional 3″ of rain is possible for a widespread portion of the region by the middle of next week, with locally heavier amounts.  Lets time it out.

    The focus in the shorter-term is for colder air to build in.  Temperatures today will fall (after a spring-like feel during the wee morning hours).  We’ll be in the 30s by mid to late afternoon and below freezing later this evening.  Arctic high pressure will continue to force cold, dry air south across central IN as we wrap up the work week.  At the same time, warm, moist air aloft will ride over the cold air trapped at the surface and trouble looms by Friday night.  We expect light freezing rain to develop after dark and continue into Saturday morning.  As disturbances move along the arctic boundary, additional precipitation (mostly light) will overspread central Indiana from time to time over the weekend.  We want to continue to reiterate that a 1-2 degree temperature difference will mean a tremendous difference between additional ice accumulation and plain ole cold rain.  Thinking is that the freeze line will shift north of the I-70 corridor Saturday afternoon before settling south towards I-70 again Saturday night and Sunday morning.  We still have time to fine tune things, but as of now it seems likely that anywhere from 0.10″ to 0.20″ of glaze (freezing rain) will be possible across most central IN communities Friday night into Saturday.

    We’ll get rid of the freezing rain early next week and bust back into a warm southwesterly air flow.  Models are struggling with the precise details of how things evolve in the early-mid week period, but confidence remains very high on continued wet times.  In fact, the GFS pulls a slug of 1.5″ precipitable water values (PWATs) north into the state the middle of next week and suggest the heavy rain threat remains Tuesday and Wednesday.  By the middle of next week, we have to start becoming concerned for flood potential across the region.

    Hang in there, we’ll see the sunshine return…some day.

    Upcoming 7-Day Precipitation Forecast:

    • Snowfall: 0.00″
    • Rainfall:  2.50″ – 3.00″ 


  • 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.