Nov 16
Good evening, Hoosiers! Showers are developing now, and these will increase in coverage and intensity as we progress through the overnight. As we move into the wee morning hours, don’t be surprised if you’re awoken with loud claps of thunder, gusty winds, brief heavy rain, and small hail. That said, we think overnight thunderstorms remain below what would officially be considered “severe.”
Here’s a look at the simulated radar later tonight, valid at 2am local time, courtesy of the HRRR model.
As for Sunday, we continue to look over the latest data and our thoughts haven’t changed. It still appears the two biggest threats will be from damaging straight line winds and the possibility of quick spin-up tornadoes associated both within the squall line, itself, but also with any individual severe cells that develop before “morphing” into the squall line. It should also be pointed out that even outside thunderstorms, southwest winds will howl across central Indiana, periodically gusting upwards of 40-45 MPH even outside of thunderstorms. Hunker down…
The latest high-resolution NAM suggests the possibility of super cells entering western Indiana early Sunday afternoon before organizing into a squall line as it moves through central and western Indiana. This line will mean business as it moves east across the state, and latest data suggests the most significant severe threat for central Indiana will be from 12 noon through 6p, moving west to east. By sunset Sunday, most of central Indiana will see a much needed (and much colder) wind shift to the northwest, ending any threat of severe weather.
Permanent link to this article: https://indywx.com/2013/11/16/late-saturday-night-thunderstorms-develop-overnight-update-on-sunday/
Nov 16
We continue to monitor Sunday’s severe weather outbreak very closely. Simply put, the latest data suggests all of central Indiana will be under the gun for a potentially dangerous and life threatening severe weather event Sunday. The bullet points highlighted in our previous post haven’t changed, but we note tornado parameters may be even more impressive per latest data. Unfortunately, I’m afraid multiple tornado touchdowns will be reported across central Indiana tomorrow afternoon, followed by a more widespread damaging straight line wind event mid to late evening. Certainly please keep abreast of the latest watches and warnings that will come tomorrow.
Showers and thunderstorms will develop tonight, but will remain below severe levels. The latest NAM simulated radar shows the developing showers and thunderstorms tonight.
Fast forward to Sunday evening and we note a line of severe thunderstorms moving through central Indiana, including a potential widespread damaging wind event.
Also, just to let you know, we’re also monitoring next weekend for another possible big weather event. This time we’re not talking severe weather, but possibly a major early season arctic attack… The latest European model isn’t holding back. Could a cold Thanksgiving week be shaping up? We’ll monitor closely.
Permanent link to this article: https://indywx.com/2013/11/16/some-saturday-afternoon-thoughts/
Nov 15
We’re zoning in on severe weather details for Sunday and have posted some simulated radar data below that may suggest what area radars look like Sunday afternoon and evening. That said, here are the quick important bullet points to remember for Sunday:
Latest high-resolution simulated radar shows the squall line moving across the state Sunday afternoon and evening. This is courtesy of the Weatherbell Analytics model suite. Stay tuned for much more information and be sure to follow us on Twitter (@indywx) for updates on the go!
The latest outlook from the Storm Prediction Center highlights Sunday’s severe weather threat. As you can see below, this storm will impact a large portion of the Mississippi and Ohio River Valleys so please take note and keep abreast of the latest weather conditions should you have travel plans Sunday.
Permanent link to this article: https://indywx.com/2013/11/15/more-on-sundays-severe-weather/
Nov 14
We continue to analyze the latest data concerning our pending severe weather episode ahead Sunday. Today’s information continues to point towards the threat of not only a damaging straight line wind event, but the potential of multiple tornadoes across the central Ohio Valley. The tornado threat would most likely occur with any individual super cells that develop Sunday afternoon. The damaging straight line wind event would then be associated with what’s likely to be a squall line associated with the cold frontal passage Sunday night. Needless to say, Sunday will be busy weather day across not only the Hoosier state, but for many folks across the Mississippi River Valley into the Ohio Valley. Additionally, widespread heavy rain is also a good bet. Let’s look at some data:
First, let’s look at some rainfall numbers. The ECMWF (European forecast model) and GEM (Canadian forecast model) are the most aggressive with rainfall totals approaching the 2″ mark for many areas of central Indiana between Sunday and Monday. The GFS isn’t as bullish, forecast a little more than half an inch on it’s latest run. Officially we’ll go with a blend of all three models and suggest widespread 1″ type rains across central Indiana during the Sunday-Monday period.
Before we go further, we also want to highlight that winds will be strong and gusty Sunday even well away from any thunderstorms. Winds will likely gust to 40-50 MPH simply by the tightening pressure gradient as surface low pressure begins to “bomb out” (rapidly intensify) on it’s journey into the Great Lakes region.
The dynamics are somewhat scary with this event and, as stated above, suggest not only an enhanced straight line damaging wind event, but also the potential of multiple tornadoes associated with any super cells that get going Sunday afternoon, well ahead of the squall line. Despite a cold, dry air mass in place currently, the aforementioned strong southerly winds will help transport dew points into the lower to middle 60s come Sunday afternoon. This will only help add fuel to the fire for storm development.
Let’s take a look at the official Severe Weather Outlook for Sunday, courtesy of the Storm Prediction Center. Some highlights from their most recent discussion:
SOME UNCERTAINTY LINGERS...BUT TRENDS IN THE MEDIUM RANGE FORECAST GUIDANCE ARE INCREASINGLY SUGGESTIVE OF THE DEVELOPMENT OF AN ENVIRONMENT SUPPORTIVE OF AN OUTBREAK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDDLE MISSISSIPPI VALLEY EASTWARD THROUGH MUCH OF THE OHIO VALLEY ON SUNDAY.
A 90+ KT 500 MB JET STREAK NOSING THROUGH THE OHIO VALLEY...COUPLED WITH STRENGTHENING SOUTHERLY WARM SECTOR 850 MB FLOW...PERHAPS IN EXCESS OF 70 KTS ACROSS PARTS OF THE OHIO VALLEY INTO THE LOWER GREAT LAKES...WILL CONTRIBUTE TO VERY STRONG DEEP LAYER WIND FIELDS AND SHEAR. IT ALSO APPEARS INCREASINGLY PROBABLE THAT THIS WILL COINCIDE WITH AN INFLUX OF SEASONABLY HIGH MOISTURE CONTENT AT LEAST AS FAR NORTH AND EAST AS THE LOWER OHIO VALLEY...CONTRIBUTING TO SUFFICIENT CAPE FOR VIGOROUS STORM DEVELOPMENT. SUPERCELLS WITH A RISK FOR TORNADOES WILL BE POSSIBLE...PARTICULARLY IN EARLY STAGES OF CONVECTIVE DEVELOPMENT...PERHAPS AS EARLY AS MID DAY ACROSS PARTS OF THE MIDDLE MISSISSIPPI INTO LOWER OHIO VALLEY VALLEY
EVENTUALLY...THOUGH...ACTIVITY PROBABLY WILL EVOLVE INTO A SQUALL
LINE WITH DAMAGING STRAIGHT-LINE WINDS BECOMING THE MOST PROMINENT
SEVERE THREAT.
Permanent link to this article: https://indywx.com/2013/11/14/heavy-rain-and-severe-outbreak-sunday/
Nov 13
As I write this, many Hoosiers are awaking to temperatures at downright bitter levels, despite the fact it’s only mid November. The official low here at IndyWx.com HQ was a frosty 18 degrees and a far cry from the normal low of 37.
The early season bitter air mass has even settled in across portions of the Deep South and Coastal Plain. Amazingly, snow was reported along the Carolina coastline last night (almost unheard of for mid November). Note the deep freeze penetrating far into the Deep South. My home town of Auburn, AL dipped to a frigid 27 degrees this morning. Again, very rare for so early in the season.
It’s my job to look at what is behind these expansive early season bitter attacks of air (by the way, another bitterly cold air mass is ahead next week). In my opinion, a lot of the early shots of impressive arctic air has to do with the widespread early snow and ice pack developing across the Northern Hemisphere. We wrote about this first back on October 17th and the snow and ice pack has only been growing since. The latest image shows a very impressive and vast snow and ice pack for so early in the season. As early season cold moves south into the Lower 48, it doesn’t have much time to modify as it passes over the growing early season snow pack.
As we look ahead, despite the weekend warm-up, another impressive shot of arctic air will plow into the Hoosier state early next week (perhaps even colder than this current air mass). The European forecast model, once again, shows temperatures 12-18 degrees below normal by early next week.
Temperatures currently are running well below normal in similar areas modeling is sticking the “heart” of the cold next week.
As we continue rumbling into the colder, snowier months ahead, one has to at least wonder what the overall impact of the early season expansive snow and ice cover during October and November will leave on the winter of 2013-2014…
Permanent link to this article: https://indywx.com/2013/11/13/no-secret-behind-the-early-bitter-shots-of-air/
Nov 12
Updated 11.12.13 @ 8:50p
Zionsville, IN After waking up to half an inch of snow, sunshine engulfed most of the region Tuesday. The vitamin D didn’t help temperatures moderate much as highs were more like mid to late December as opposed to mid November. We discuss a warming trend below, after a frigid start to your Wednesday.
Wednesday: Mostly sunny; 19/ 39
A strong area of high pressure will move overhead Wednesday and help supply a mostly sunny sky. Despite the sun, it’ll be another unseasonably cold day. Many outlying communities will begin the day in the upper teens before rising into the upper 30s to near 40 by afternoon- a solid 15 degrees below normal.
Thursday: Partly cloudy; 28/ 49
The same high pressure that will be directly overhead Wednesday will begin to move east Thursday. This will put our region in a southwesterly air flow and allow temperatures to begin moderating. After another cold start, highs will push towards the 50 degree mark Thursday afternoon.
Friday: Partly cloudy; 35/ 52
We’ll wrap the work week up with a few more clouds and temperatures still slightly cooler than normal, though much milder than those we’re dealing with now.
Saturday: Turning cloudy with PM showers (0.20″); 40/ 59
Model data continues to hint at increasing clouds and the threat of afternoon light rain. We’ll initially have to overcome the dry air mass in place, but by afternoon/ evening we should have scattered showers beginning to impact central portions of the state.
Sunday: Cloudy with rain likely (0.45″); 52/ 60
More widespread rain will arrive for the second half of your weekend. Highs will approach 60 and should we see any sunshine (not looking likely at this point), temperatures could go into the lower to middle 60s. While temperatures will be much warmer we’ll have to contend with rain Sunday.
Monday: Showers and possibly a thunderstorm (0.50); 34/ 63
A strong cold front will blow through the state Monday evening. Out ahead of the front, an impressive surge of warmer and more humid air will move north and encompass central Indiana during the day. In fact, latest model data suggests dew points reach the lower 60s Monday. The combination between the warmer, more humid air in place and an impressive surge of arctic air behind the front could team up to produce a clap or two of thunder with the moderate to heavy rain threat Monday afternoon as the front moves through. Temperatures will then crash Monday night.
Tuesday: Scattered snow flurries; 24/ 34
The big story Tuesday will be the much colder air mass rushing into the state on strong and gusty northwest winds. Just enough moisture may linger to create the chance of scattered snow flurries.
Permanent link to this article: https://indywx.com/2013/11/12/wednesday-forecast-a-bitterly-cold-start/
Nov 12
As we progress into the second half of November and December, friends and family begin to hit the road for holiday travel. It’s also at this time where winter weather enthusiasts begin to wonder when that first “true winter storm” will arrive. As we look towards this period, it becomes more important to note the state of the “big three” teleconnections. These include the PNA (Pacific North America pattern), NAO (North Atlantic Oscillation), and AO (Arctic Oscillation). While it’s impossible to predict, with 100% certainty, the weather based solely off these teleconnections, they can be very good indicators of where the pattern may be heading in the next couple three weeks.
In a “perfect world” for those wanting cold and wintry weather here across the Hoosier state you want to see a positive PNA, which promotes western ridging and eastern troughiness (associated with cold weather). Additionally, you want to see a negative AO and NAO (promotes high latitude blocking and corresponding cold, arctic, air is shunted south into the Lower 48). What do the teleconnections currently show?
Taken at face value, this suggests a cold and potentially wintry pattern may ensue to close out November and as we go into December. We’re looking at an AO and NAO trending negative and a PNA trending positive. *It should be noted that, at times, a negative NAO can be so strong that it supplies the cold air, but can also lead to a suppressed storm track- south of the available cold air…
Each storm provides it’s own set of challenges and must be dealt with as they come. We can look at past storms and patterns (called analog forecasting) to help get an “idea” as to what patterns and storms in front of us may produce, but no storm is identical to the other. At this early stage in the game, it appears as if a pattern is setting up that could provide “wintry mischief” just at the time when most folks want it- for the Thanksgiving and Christmas season.
Stay tuned…
Permanent link to this article: https://indywx.com/2013/11/12/pattern-showing-signs-of-more-sustained-wintry-weather/
Nov 12
Hoosiers are awaking to roughly half an inch of snow across the majority of central Indiana. The forecast went as planned overnight and we’ll keep a close eye on the lake effect band of snow hammering the Indiana snow belt. Short term, high resolution, data (below) suggests snow showers move back into north-central Indiana by late morning/ early afternoon- primarily north of the Indianapolis metro.
Otherwise, it’s going to be a cold day with temperatures only rising into the middle 30s. This is much more like December as opposed to mid November and a solid 20 degrees below the average high of 54.
We have another “fun time” ahead in the mid range and we’ll begin to discuss the next storm potential later tonight. As you can see, the GFS and ECMWF are in all sorts of disagreement below…
Permanent link to this article: https://indywx.com/2013/11/12/a-closer-look-at-tuesday/
Nov 11
Here’s a quick video update on the light snow inbound… Much more later!
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Permanent link to this article: https://indywx.com/2013/11/11/monday-evening-video-snow-update/
Nov 10
Updated 11.11.13 @ 8:30a
Zionsville, IN Despite some wind (top wind gusts this weekend reached around 30 MPH) and a chilly Sunday, the weekend was a beautiful one, complete with lots-o-sunshine! A more active time of things is ahead to kick off the work week. We discuss below…
Monday: Increasing cloudiness with PM rain showers transitioning to light snow (0.50″); 28/ 46
The day will dawn with some sunshine, but clouds will be on the increase and showers won’t be far behind. This is all part of the early season arctic cold front we’ve been talking about. We think showers (initially rain) arrive into north-central Indiana as early as the early to mid afternoon hours before pushing fairly rapidly south. It’s towards late afternoon/ early evening rain begins to transition to snow. Light snow will continue into the nighttime hours and potentially accumulate to around half an inch across most of central Indiana.
There are a couple of items we’ll have to monitor closely through the overnight and that’s the exact placement of what should be some impressive bands of lake effect snow streaming off Lake Michigan. While the more significant accumulations, upwards of half a foot for the Indiana snow belt, will remain well north of us, there is the chance a more concentrated band of snow could reach as far south to impact portions of north-central Indiana late Monday night into Tuesday morning and result in accumulations of an inch or two for localized communities. Again, this will have to be handled as a “NowCast” scenario and isn’t set in stone. If locally heavier snow accumulations do develop with the localized lake enhancement, the majority of this would be north of our immediate coverage area.
Temperatures will plummet Monday night into the lower to middle 20s on a gusty northwest wind. Needless to say, slick spots could develop on area roadways Monday night.
Tuesday: Scattered AM snow showers (localized 0.50″); 22/ 35
We’ll keep an eye to area radars Tuesday, particularly in the morning hours as scattered snow showers (potential lake enhanced snow for localized spots) continue. Conditions will be much more like winter than fall so plan to bundle up. In fact, temperatures will average close to 20 degrees below average for afternoon highs. Any lingering snow showers or flurries will begin to dissipate during the afternoon, paving way for a clear and very cold Tuesday night.
Wednesday: Sunny; 19/ 42
High pressure will be overhead Wednesday and help supply a day filled with sunshine, although it’ll remain MUCH colder than normal. We’ll awake to the upper teens followed by highs reaching the lower 40s Wednesday afternoon.
Thursday: Partly cloudy; 28/ 49
Temperatures will begin to moderate slowly Thursday as high pressure moves to our east. This will set the stage for a return southwesterly air flow and corresponding milder regime, albeit slowly. After yet another cold and frosty night, temperatures will make a run at 50 degrees Thursday afternoon.
Friday: Mostly cloudy; 35/ 49
A weak weather system will scoot through the region Friday and lead to an increase in cloud cover. Thinking, at least for now, has the area trying to recover from the cold, dry air mass in place so any sort of precipitation will, most likely, be tough to come by. That said, we’ll continue to monitor to see if we need to introduce a scattered light shower into our Friday forecast.
Saturday: Cloudy with developing light rain; (0.25″) 39/ 52
The early look at next weekend places the region under a southerly flow of air with moisture making a return north, potentially out ahead of a rather significant storm system we’ll have to deal with early next week. The end result will initially be a rather cloudy, gloomy time of things, including developing light rain Saturday.
Permanent link to this article: https://indywx.com/2013/11/10/monday-forecast-snow-develops-this-evening/
