Feb 01
The initial surge of moisture has, for the most part, come and gone- dropping one half to one inch of snow for many across central Indiana. Overnight computer model data…
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Permanent link to this article: https://indywx.com/2015/02/01/3a-sunday-morning/
Jan 31
An incredibly difficult and challenging forecast is in store for central Indiana over the course of the next 24-36 hours. I want to get out front with this right from the get go: bust potential is high with this type set-up, as a jog 10-20 miles north or south of the surface low will mean the difference between half a foot of snow and plain cold rain. As it stands now, and after careful consideration of every piece of data available, here’s our updated snowfall map:
I still am not sure any one piece of data is handling the interaction between the arctic high to the north and the developing low to our southwest “perfectly.” As such, additional fine tuning will have to take place tonight. That arctic high is powerful at nearly 1045mb. From a meteorological standpoint, it’ll be a fascinating battle watching the fight play out.
As you can see, we’re going to be looking at a very tight thermal gradient and it, unfortunately, appears to set itself up directly over the I-70 corridor. Precipitation type and amounts are the biggest challenge within the I-70 corridor. Further north, confidence increases rather significantly for a crippling snow storm. For central Indiana, this will be a very wet and heavy snow event before ending as a drier, powdery snow on the back end. As winds increase Sunday afternoon/ evening, the heavy “paste” like snow won’t blow around as easily as it would if it was drier. Further north the snow consistency will be drier and blowing and drifting will be severe (in the 8″-12″+ zone).
In the shorter-term, rain and a wintry mix will arrive into the region as early as early as 6-7 o’clock.
Stay tuned. Another post will hit here late tonight (midnight-ish). In the meantime, we’ll keep our thoughts coming at @indywx through the afternoon.
Permanent link to this article: https://indywx.com/2015/01/31/crippling-snow-storm-for-some-just-wet-for-others/
Jan 31
Overnight model data remains very much out of agreement with one another concerning Sunday. The struggle continues trying to figure out the precise track of the low and the influence…
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Permanent link to this article: https://indywx.com/2015/01/31/saturday-morning-rambles-4/
Jan 29
Early forecast model data into the office tonight suggests we remain on track for a disruptive widespread snow storm this weekend. We note the timing is speeding up just a…
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Permanent link to this article: https://indywx.com/2015/01/29/late-night-update-snow-storm-brewing/
Jan 28
Quick video update on our thinking tonight, as well as a look at the weekend…
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Permanent link to this article: https://indywx.com/2015/01/28/wednesday-evening-thoughts-2/
Jan 27
The video goes into the detail around our weekend thoughts. Is a winter storm brewing?
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Permanent link to this article: https://indywx.com/2015/01/27/weekend-thoughts/
Jan 27
Forecast models have been printing out wintry solutions for the upcoming weekend- particularly Saturday night through Super Bowl Sunday.
The GFS 500mb charts between 12z Monday and this morning show the key with this potential storm. Note the difference between yesterday (top) and today (bottom). The GFS model brings more energy out and the result is a stronger storm system.
Timing between cold and moisture associated with storm systems has been the important missing link this winter with bigger storms. Does that trend continue this weekend? Snow lovers hope not…
A key ingredient that has been missing in the past is a big area of high pressure north of the region supplying cold air as surface low pressure tracks in a favorable position for wintry precipitation. Models do suggest not only renewed arctic high pressure building down the Plains region Sunday into Monday, but also a 1040mb high over the northern Lakes region. This would help go a long way in keeping cold air flowing into the region.
What about the sensible weather here?! Keeping in mind that this is still an event 5 days out….. The GFS model suggests mostly a snow event north-central, but also brings in a wintry mix of icy precipitation and rain across the southern half of the state. The Canadian forecast model (not shown here) is more suppressed and leads to an accumulating weekend snow event across the region and targets southern portions of the state for heaviest snowfall. The European model is the most “ideal” scenario for central Indiana snow lovers and leads to a significant snow event across the heart of the state.
Note the European forecast model track a wave of low pressure in an ideal location for heavy snow across central Indiana before intensifying and hammering the Northeast region.
We’ll continue to keep a close eye on this developing situation. Stay tuned….
Permanent link to this article: https://indywx.com/2015/01/27/keeping-an-eye-on-the-weekend/
Jan 23
Quick update this morning on the various model solutions for Sunday’s clipper system:
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Permanent link to this article: https://indywx.com/2015/01/23/sunday-clipper-various-model-solutions/
Jan 22
The past 5-7 days have featured a common “January thaw-” something typically seen in even the coldest Januarys. The coming 5-7 days will see a “step down” process of colder weather, interrupted by a day or two of milder southwest breezes. In the longer range, we hold firm on the idea of more sustained cold, and potentially frigid air, setting up shop to open February.
See the GFS track the clipper through the lower lakes this weekend. This is a mild track for central Indiana and will keep the accumulating snows over the Lakes region, extending into northern portions of the state. Some light snow will fly here late Sunday night/ early Monday, but accumulations should be minimal.
A brief surge of arctic air will invade early next week and may be accompanied by light snow Tuesday.
A brief southwesterly flow will allow milder air into the region by the middle of next week, but we caution this will be brief.
Much colder times loom to open February, potentially with a winter storm. Obviously with this being in the 8-10 day period, there will be a lot of time to watch the storm potential. Models have struggled mightily with storms this winter so far. We’re much more confident on the cold, and potentially downright frigid air at that (still don’t think we’ve seen the coldest air of the winter yet). Note the GFS sees the arctic highs “lining up.”
The European ensembles and operational are also keying in on the cold and wintry pattern closing January and to open February:
Initially the cold attacks the northeastern portions of the country, but “backs” west with time in the longer range:
Days 5-10
Days 10-15
The NAEFS and CFSv2 see the colder pattern returning:
We still think there’s a lot of “winter” left in the coming months. Many folks enjoy snow Christmas into January, but begin to crave spring in February and March. This is the type pattern that can be quite “ugly” for spring lovers as colder and snowy weather can push well into the spring months… (Noted that we still have a lot of catch up to do in the snow department, but we’re not ready to say we won’t make up for “lost time”).
Permanent link to this article: https://indywx.com/2015/01/22/step-down-process-to-cold-before-the-return-of-truly-frigid-times/
Jan 21
I’m hearing rumblings out there that you can’t get sustained cold across Indiana without a negative Arctic Oscillation (AO) and/ or negative North Atlantic Oscillation (NAO). I would ask those with that belief to please explain the following:
January temperature anomalies month-to-date show widespread cold (even accounting for the January thaw the past week).
The first two weeks of the month were downright frigid and this was in the face of an AO that was not just positive, but strongly positive.
To take this a step farther, the recent relative warmth has come with a negative AO.
Bottom line is that a ton of drivers are trying to take the wheel this winter. Admittedly, that makes things incredibly difficult for forecasting- short-term or longer range. That said, coming out with a “blanket statement” that you can’t have sustained cold without a negative AO or NAO is a flat-out lie and we wanted to address it. Teleconnections can help many times with coming weather patterns, but not always. This winter is a prime example of that.
Quick note on the clipper system- all forecast models today have taken the primary impacts (at least from a snow standpoint) north of the immediate region (central Indiana). Heaviest snows are favored across the Great Lakes, extending down into northern IN. We’ll continue to keep a close eye on things…
Permanent link to this article: https://indywx.com/2015/01/21/facts-are-facts/