Sunshine from earlier today will be the brightest sky over Central Indiana until Friday. Between now and then there is much changing weather to track, and high winds are very likely Halloween.
Beginning this evening with the arrival of light rain mainly after 6pm. If you’re heading down to the Pacers home opener expect to drive back home in rain, and possibly areas of dense fog.
Latest model guidance, and real-time observations along the Ohio River, show a saturated stratus layer level creeping northward into Central Indiana overnight. This will result in areas of dense fog, drizzle and near steady temps in the mid/upper 50s the next 24 hours.
Highs Wednesday will likely happen at 7 or 8pm. Expect most of tomorrow to be a cool and damp. In my blog post Monday I touched on the strong wind “potential” for Halloween across the Ohio Valley. Latest model guidance does nothing but support this notion. Below is the NAM model wind speeds at roughly 2,500 feet at 5pm on Halloween. Notice the wide spread swath of 45 to 50mph wind cranking across Central Indiana.
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The images below are model soundings for Indianapolis at roughly the same time on Thursday. This is essentially a vertical look at the wind field in relation to height from the given model data sets. I’ve circeld the wind barbs just above ground level that near 60mph, and two parameters called Storm Relative Helicity (amount of spin in atmosphere) and Convective Available Potential Energy (CAPE). While the amount of spin is extremely high, there is very little atmospheric instability due to a thick/saturated cloud layer overhead.
So what does this all of this mean? If there’s one thing you take away from this blog… it’s that damaging wind is a very real threat Thursday with or without you hearing thunder. With winds that strong just above the surface, a line of showers could help mix some of that wind energy to the ground.
Bottom line…a period of 30-40mph+ gradient winds (from intensifying low pressure over the Great Lakes) is likely Halloween with “potential” for stronger/severe gusts. I suspect Wind Advisories and/or High Wind Warnings will be issued in the future for this event. Unfortunately it peaks during trick-or-treating time… so make plans for indoor events now.
1 to 2″ rain amounts are likely, making this one of the wetter Halloweens on record. Rain and a wind threat continues into midnight, before the strong cold front passes by 8am Friday.
Stay tuned for upgrades to the wind and/or severe threat – Sean Ash
Computer models latched onto a potential wind machine impacting Halloween nearly a week ago. I’ve watched and waited to see if that trend would continue.
Morning models continue to show a rather robust low level wind field cranking across the Ohio Valley Thursday, in response to a deepening area of low pressure in the Great Lakes.
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“Modeled” wind fields around 5,000 feet are a very impressive 70mph+. Whether or not a line of low-topped storms or showers will tap into the low-level jet (LLJ) is to be determined…and hinges on atmospheric instability.
That’s the biggest forecast question at the moment, along with timing of rain. Will clouds/rain keep the atmosphere stable? To be determined, but for now there is a “risk” of severe wind gusts.
Regardless of severe wind (58mph+)… a 30-40mph gradient wind (due to the strong low pressure system) is likely along with a good chance of rain at some point during Thursday. Despite the rain and wind, this will be Central Indiana’s warmest Halloween since 2008.
In a perfect world clouds and morning showers keep instability at bay and the severe “potential” never materializes. Definitely stay tuned to the Skytrak13 weather team as we fine tune the timing and degree of instability in the days to come – Sean Ash
Less wind and cloud cover certainly made a world of difference today… and made the mid 50s much more enjoyable than Saturday.
Crystal Helderman braved the raw wind Saturday to capture some amazing fall color in Brown County at Ogle Lake. Please feel free to share your weather pictures anytime via Twitter, Facebook or email.
We’re in store for a pleasant evening with temperatures holding in the 50s past 7pm. Under a clear sky and light wind, low temperatures are heading back to down to the freezing mark (or colder) for the morning commute and bus stop.
The chilly start gives way to a mild finish Monday, with highs nearing 60 degrees in Indianapolis and lower 60 in western Indiana.
We’re advising viewers to soak up the sun and fall color Monday before clouds and rain return Tuesday.
Tuesday will start dry, but clouds quickly move in after a chilly start. Showers are fair game by 4pm, but more likely after 4pm. The cloudy/showery combo will make it tough for temps to climb into the mid 50s Tuesday.
This marks the beginning of a damp stretch that includes another good chance of rain Wednesday, and long range guidance agrees Halloween will be wet and windy.
Current modeling suggests an inch of rain is likely Thursday, and the “potential” for strong to severe wind gusts. However, “if” the modeled clouds and rain remain prevalent Thursday… instability may be weak enough to keep strong/severe winds from mixing down to the surface. For now we wait and watch the progression of a storm system that’s several days away. Much can/will change in the forecast regarding strength/timing. Bottom-line: confidence is high on rain Thursday… to be determined if severe “potential” becomes reality.
The damp weather mid-week comes with a mild, humid air mass…as dewpoints creep toward 60. You’ll be able to give the heaters a break for a day or two before cooler air returns heading into next weekend. Thanks for reading the blog and have a great evening – Sean Ash
Many areas have seen snow and sleet showers today, and that mixed bag of precip will slide southward and out of Central Indiana by 8pm.
Above are just two examples of the wintry precipitation from today. Temperatures underneath the cloud cover were some 20 degree below normal… but what we’ve been expecting for nearly a week.
As of 4pm, the high in Indianapolis is only 40 degrees which is a record low max for this date and the city’s coldest October “high” temperature in 20 years.
Tonight temperatures will make a run at another record… the record low, which is 25 set in 1887. Our forecast high of 26 would be the city’s coldest October “temperature” since 1997. With or without the record, a hard freeze is likely area wide.
Clouds clear later this evening in the wake of our sleet/snow maker and temps plummet without a blanket overhead to insulate the little warmth we do have from daytime.
Thankfully the clear sky will allow for a decent rebound Friday afternoon as highs near 50 degrees. That’s still well below normal, but much more pleasant than today.
Saturday will be even warmer but the trade off will be a breezy southwest wind up to 30mph.
Next week looks at or slightly above normal, but good chances of rain between Tuesday and Wednesday mornings. Much uncertainty regarding the evolution of an Ohio Valley storm system on/around Halloween… with large model differences. For now there is storm potential, but to be determined if we’re on the warm or cold side of the storm track. Stay tuned, have a great evening and thanks for reading the blog – Sean Ash
Despite the sun, temperatures will be some 10 to 15 degrees below normal this afternoon. But this pales in comparison to the set up Friday morning that will deliver near record lows in Central Indiana.
At 1pm windchills are hovering around 40, and expect sun to mix with scattered clouds occasionally.
Another clipper system races late tonight and early Thursday morning… on a more southern track that will have a bigger precipitation impact on the areas along/south of I-70.
Rain again will mix with snow, and it’s possible a few locations could see a grassy accumulation like this morning.
This feature will reinforce the unseasonably cold air that’s already in place. The center of Canadian high pressure nears the region by Friday morning, providing the ideal set up for maximum cooling… a clear sky, light wind, cold air mass.
For nearly a week we’ve targeted Friday morning as the coldest of this late November-like stretch, and we’re still on target to near record lows.
Cloud cover and wind will be the key to the cooling. Stay tuned for an updated 7 day forecast later this afternoon that includes a weekend warm up – Sean Ash
Sun is quickly being covered up by clouds racing into Indiana, and a hint of a clipper system that’s dropping some snow upstream.
Dopper 13 Radar is in winter mode and detects a fair amount of blue in northern Illinois and Iowa… indicative of snow mixing in with the rain.
A Skytrak13 WeatherBug camera in Sandwich, IL (southwest of Chicago) offers ground truth of what’s falling. This clipper will cut across the I-70 corridor overnight and deliver the first flakes of the season… especially for areas along and north of I-70.
It’s beginning to rain in northwest Indiana, and all bets off for dry weather in the Indianapolis metro after 4pm. Colder air north of the clipper track changes rain to snow, and chances of seeing flakes increases after 8pm. It may precipitate hard enough to allow areas of all snow to see an accumulation on grassy surfaces/roof tops. But road surfaces will be too warm for accumulation and remain wet.
By 8am Wednesday the system zips out of the state… though some lingering flurries/snow showers are possible before sunrise tomorrow.
Indianapolis actually had a trace of snow last October 30th, but it’s been 20 years since the last “measurable” snow in the month of October. Many of you likely remember the big October storm of 1989 that dumped over 9″ in the city. Please share snow pics if you’re lucky enough to be in the sweet spot tonight.
The big story remains the unseasonably cold air. Today was our coldest start since April 20th, but the coldest night is a few days away. Record lows are in jeopardy Friday morning, when many areas drop into the low/mid 20s. An updated 7 day forecast is coming shortly – Sean Ash
A band of overcast continues to creep in from the west-northwest, and 1:30pm temperatures offer a clue of where the sun is shining.
Lafayette is parked at 50 degrees under cloud cover while Shelbyville reaps the reward of a brighter sky and mid 60s.
Sprinkles and showers are possible this evening as a cold front moves through Central Indiana. This front marks the beginning of the well advertised chilly change that produces the coldest temperatures in nearly six months tonight.
Downtown Indianapolis near the freezing mark for the first time since April 20th, and many locations north and northwest of the city (where clouds clear sooner) will dip below freezing. This is very near the climatological average, which is October 16th, and essentially the growing season.
A strong dip southward in the polar jet stream delivers the unseasonably cold air mass… and delivers a few “clipper” systems across the Great Lakes and Ohio Valley.
The first clipper arrives late Tuesday into Wednesday morning with rain that may mix with the potential for some snowflakes to mix in on the colder side of the clipper.
A second clipper moves through the I-70 corridor Wednesday night into Thursday. The atmospheric temperature profile will be colder, and offers a better chance to see some snowflakes mixing in. Accumulation is highly doubtful…unless it can snow hard enough, and long enough, to overcome a relatively warm ground.
While more of a novelty, the snowflakes serve notice on how we’re fast forwarding to late November-like weather… and the cold is definitely the bigger story this week. To put the air mass into perspective…. the “high” Thursday of 43 degrees will be what the “average” low is this time of year! Temperature departures of 15-20 degrees hold heading into the weekend.
Breezy and pleasant early this evening with temperatures still holding in the 60s at 6pm. Kickoff temperatures for the Battle of 18-12 at LOS will be around 54 and near 50 for folks heading home tonight. The roof will be open so be sure to take long sleeves and jacket to the game.
Wake up weather Monday will be partial sunshine and lows in the lower to mid 40s. FutureTrak 13 shows a weak, narrow line of precip in northwest Indiana. This delineates one of a few cold fronts to impact the Central Indiana this week… and what delivers our first installment of colder than normal air.
All bets off for dry weather Monday by 1-2pm. Though it’s not a given every city gets showers, it is a possiblity along the front.
Cloud cover exits Monday night into Tuesday morning and sets the stage for one of a few opporutnities this week to get to freezing. Notice lows Tuesday morning will be some 10 degrees below normal.
The upcoming pattern shift to much colder than normal air has been well documented by the Skytrak13 forecast team. We also talked last week about the season’s first snow flakes being possible in this air mass. That’s still in the forecast cards as an upper level disturbance rides the base of a southward digging trough in the jet stream. Rain showers will mix with snow showers Tuesday night, and likely to change to all snow showers by Wednesday 8am.
Though it’s not unheard of to see flurries or snow showers in October, this is a few weeks ahead of climatogoical norms for Indianapolis.
But the bigger story will be the cold! Daily high temperature departures will be in the 20 degree range, and a hard freeze could be setting up Friday morning with the center of Canadian high pressure settles closer to the Ohio Valley… clearing clouds, lightening wind and providing ideal ingredients for maximum cooling. We’ll see if that plays out. Get ready to crank up the heaters. Have a great evening and GO COLTS! Thanks for reading the blog – Sean Ash