Temperatures: Lower 20s rising to near freezing by Sunday night
Wind: SE to S 5-15 MPH
Blowing/ drifting: Minimal to non-existent
After a cold and quiet open to the weekend, a disturbance will overspread moisture over the top of a modifying (still cold enough for trouble) air mass as we close the weekend. Snow will likely reach Indianapolis and surrounding communities late morning Sunday, continuing into the afternoon hours. Snowfall intensity will be light with occasional moderate bursts. As relatively milder air aloft gets pulled north, precipitation will end as light freezing rain Sunday evening. While we don’t anticipate heavy accretion, a light glaze will likely be noted on top of the freshly fallen snow Sunday evening.
It’s feeling just a little bit different across the region this morning- to the tune of more than 30 degrees colder than this time 24 hours ago. Cold extends south all the way to Brownsville Texas. Speaking of Texas, wintry precipitation is flying across the Hill Country this morning…
Back here on the home front, cold is the story this weekend. Highs may creep into the lower 20s this afternoon, but wind chill values will remain in the single digits below zero to 5 above through the day. Light snow showers will end and we’ll introduce more in the way of sunshine through the afternoon.
Dry conditions will remain through Sunday morning, but a storm system will organize to our southwest, eventually delivering moisture into central Indiana Sunday afternoon into the evening. We remain unimpressed with this feature, but light snow is a good bet during this timeframe. Early thinking would deliver between a coating to an inch and there’s also the potential of a light “glaze” atop the snow Sunday night as milder air aloft begins to win out.
“Dueling” low pressure systems will lead to continued unsettled conditions through Tuesday. The initial low will track into the Great Lakes while a secondary area of low pressure forms along the Mid-Atlantic coast. The end result will be a briefly milder time of things and periods of rain Monday afternoon and Tuesday (0.50″ to 1″ amounts) before cold air whips back in here Wednesday.
Lingering left over moisture will fall as scattered snow showers in the sharply colder air Wednesday.
Our next storm system will deserve a watchful eye in the Thursday-Friday time frame, but it’s far too early for specifics in this hectic pattern.
The active pattern is set to remain, along with progressively colder air as we rumble into the 2nd half of February. Above normal precipitation is anticipated, including above normal snowfall in the 2/18 through 3/10 period.
The stage is set for winter’s return. With that said, the upcoming week will likely feature a “transitional” time of things before winter returns with more authority during the 2/18 through 3/10 time period.
While the positive AO will continue to be heard from in the more immediate term (forcing the active storm track into the Ohio Valley and Great Lakes), this should eventually give way to a negative AO by mid and late month. Factor in a Phase 8 of the MJO and developing negative NAO and winter weather lovers will likely have a 2-3 week period of “fun and games,” including the potential of a couple significant events, along with well below normal cold late February and early March.
That said, this isn’t last year. Recall it was around this time that we were initially “faked out” by a wintry February when in all actuality it was a case of delayed, but not denied, with the worst of winter (relative to average, and in the means from a snow perspective) occurring in March and April. There are growing indications that we should actually have a spring this year, but more on that at a later time. 🙂
Let’s take a look at some of the latest long range modeling, starting with teleconnections first (always the basis of a long range forecast).
Simply put, the GEFS teleconnections line up for a return of colder than normal conditions during the middle to latter part of February. We love to see the agreement in the teleconnection states (trending negative AO (image 1) and NAO (image 3) and trending positive PNA (image 2)).
The latest European Weeklies would also agree. Note the strongly positive AO (image 1 below) at present dips negative during the 2nd half of February.
The European Weeklies like the idea of the PNA at least getting to neutral late month into early March.
Also of importance is what the Weeklies do with both teleconnections by mid-March (this would support a warmer pattern, overall).
Since we’re talking about the European Weeklies, while we can’t show the model output itself, it should be noted the model does deliver cold back into the region in rather widespread fashion during the last couple of weeks of February and into the first week of March.
Other model data paints a similar picture as noted below between the GEFS and CFSv2 Weeklies:
Days5–15
Days 15-25
Days 20-30
But, like other data would suggest, the CFSv2 is also in agreement that as early March gives way to the middle of the month, warmer times loom…
Days 30-40
(In the event you missed it this morning, we reviewed the updated JMA Weeklies earlier here).
The latest MJO update continues to back up the idea of colder times returning mid and late February, continuing into early March, as noted below. Remember, this time of year, Phases 8 and 1 are colder phases for our neck of the woods.
To summarize, we expect this upcoming week to begin the transition back towards an overall colder and increasingly busy time of things from a wintry perspective. Those will snow removal interests should anticipate above average snowfall during the 2/18 through 3/10 time frame. The aforementioned period also should run colder than average, as well. However, those tired of winter, hang in there- hope is on the horizon once to mid-March and we should actually enjoy a pleasant spring this year after missing out in ’18!
The Storm Prediction Center (SPC) has significantly expanded the “slight risk” area to include a large portions of the state.
While a fresh batch of heavy rain will move into central Indiana later this morning (another 1″ to 2″ is a good bet for most communities), the focus shifts to a window where severe thunderstorms will be possible during the early to mid afternoon.
A warm front will lift north through central IN late morning and this will allow relatively warm and moist air to briefly surge as far north as a Logansport to Fort Wayne line.
Note dew points will spike to 60 to 63 degrees over much of central and eastern IN this afternoon.
It’s during the 1p to 5p window when we’re most concerned for the chance of a few severe thunderstorms ahead of the cold front. Damaging winds are of greatest concern, but anytime you have a warm front hanging around central Indiana with these kinds of setups, the potential of a tornado is in the back of your mind. I don’t foresee this being a major tornado outbreak whatsoever, but parameters do suggest the chance of a quick spin-up tornado is present, as well during this timeframe.
The cold front will crash into Indianapolis between 4p and 5p and you’ll certainly know it.
Strong and gusty northwest winds will blow sharply cold air into the region this evening and tonight. In fact, highs in the lower to middle 60s this afternoon will be into the 20s before midnight. Lows Friday morning will fall into the 10s and highs Friday will only top out in the lower 20s with wind chill values in the single digits most of the day.
After a dry open to the weekend, we continue to monitor the potential of a light wintry event Sunday into early Monday. This doesn’t appear to be a big deal, but the chance is there for an inch or two of snow for portions of the central and northern Ohio Valley during this timeframe.
Additional challenges await early and mid next week, but we’ll save those for updates later this afternoon or evening.
JMA Weeklies
The updated JMA Weeklies are in and in short suggest the southeast ridge continues to put up a fight over the next couple of weeks before getting “squashed” in the Weeks 3-4 timeframe.
This is in line with our thinking of the “transitional” period beginning this upcoming week. We think cold will begin to “push,” but isn’t ready to lock-in as of yet. There will be cold readily available to present more of a wintry potential with storms that track through the region when compared to this week, but we think it’s the period from 2/17 through early March that has the capability of featuring more sustained cold.
That’s a strong signal being painted by the JMA Weeklies in the Weeks 3-4 timeframe for widespread cold. Given that the MJO is forecast to swing into Phase 8 by this timeframe, along with the NAO/ AO looking to dip negative, the widespread cold look is a good idea to us during this particular time period.
Permanent link to this article: https://indywx.com/2019/02/07/dissecting-todays-severe-potential-winter-returns-looking-more-in-depth-at-the-new-jma-weeklies/
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Permanent link to this article: https://indywx.com/2019/02/06/wednesday-morning-video-update-heavy-rain-severe-threat-give-way-to-much-colder-air-and-a-potential-late-weekend-winter-event/
In the short-term, there’s no getting around the very active pattern in place. As we’ve been discussing, we’ll find ourselves “smack dab” in the middle of a battle ground between a stubborn southeast ridge and building cold to our northwest. The fight in between will yield well above normal precipitation over the next couple of weeks.
Over the upcoming (10) days, expect a roller coaster ride in the temperature department as the battle takes place. While the most anomalous warmth is taking place now (IND is on pace to set a new record high temperature before the end of the day), relative warmth will continue to dominate into midweek before colder air presses and wins out.
After Monday’s light rain, we’re targeting (3) opportunities for significant precipitation across the region:
I. Tuesday night-Wednesday (still may include a risk of freezing rain across north-central communities).
II. Wednesday night-Thursday morning
III. Thursday night-Friday morning (ending as light snow)
When all is said and done, model data is in agreement on significant rainfall totals across central Indiana (2″ to 3″ amounts will be common by Friday).
Thereafter, confidence is high on colder air returning as we close the week and head into next weekend.
Guidance suggests that we still need to remain abreast of the potential of a more widespread wintry event late next weekend and this is something we’ll continue to keep close tabs on as we progress through the upcoming week. As of now, this doesn’t appear to be a major event, but stay tuned.
As we look ahead, we’ll have to continue keeping a close eye on the MJO. Today’s update shows the majority of data swinging things into Phase 8 by mid to late month. Should that come to fruition, prospects of another significant cold spell loom large…
Fun times ahead- no matter how you look at it! 🙂
While we’re in the process of pulling out of the bitterly cold air mass, there’s no shortage of action when we look ahead at the upcoming couple of weeks.
Confidence remains high that the upcoming short-term period (Days 2-6) will flip to much warmer than average. A couple days that at least flirt with the 60 degree mark can be expected Sunday and Monday.
While rain will return to the forecast Monday, the milder air sure will be a nice change of pace from the bitterness of the past several days. Enjoy it!
With that said, there are continued indications that the warmth won’t hold.
As we look at the latest medium range ensemble guidance (Days 6-10), the GEFS and EPS are in relatively good agreement.
We note this is a pattern conducive for above normal precipitation during the period. With cold air likely to be “pressing” towards the region, it’s a pattern that has to raise an eyebrow for at least the potential of a wintry threat during this time frame. There should be plenty of low level cold air available late next week and next weekend. With the resistance shown from the SE ridge, potential “fun and games” are on the table during this timeframe as waves of energy likely ride along a slow (at times stalled) frontal boundary.
Keep an eye on the 2/7 through 2/10 window for possible wintry impacts, locally…
Attention will shift from the dangerous cold to an accumulating snow event across central and north-central Indiana this evening into the predawn hours Friday. We expect snow to begin reaching the surface (may take a little longer than models suggest due to the dry air in place initially) in western portions of the viewing area between 6p-7p and into central Indiana between 8p and 9p. Heaviest snow still looks to fall during the hours of 10p and 3a. Banding may result in periods of moderate to heavy snow during this time frame. Light snow will be ongoing across southeast Indiana around 7a Friday before departing the state shortly thereafter.
