2018 is already flying! As we welcome in March here are the weather statistics for IND (Indianapolis).
- Average highs start off in the middle 40s on the 1st and rise to the upper 50s on the 31st
- Average lows are in the upper 20s to begin the month and increase to the upper 30s by month’s end
- We average 3.56″ of precipitation, including just under 3″ of snow
Before we look forward to March, let’s review where we’ve been in February. After a very cold start to the month, eastern ridging really flexed it’s muscle and resulted in spring-like conditions for the better part of the past couple weeks. As we type this up late on the 28th, IND is running 5° warmer than average. (It’s been a wet month, too, as we’re close to 2.5″ above normal in the precipitation department).
The early spring “fling” has lulled many into believing winter’s finished. While the worst of the winter is certainly behind us, we continue to think a dose of “reality” awaits as we progress through the better part of the first half of March. To be more specific, we feel the period March 6th through the 20th will offer up below average temperatures and an active pattern- capable of producing wintry threats.
We note the (2) main drivers this time of year (the AO and NAO) are running negative through mid-month, which favors cold.
Sure enough, modeling is going to the pattern that will produce below normal temperatures (doesn’t appear to be anything particularly frigid, but colder than average, nonetheless) through mid-month.
With blocking in place, an undercutting jet will serve to deliver an active storm track.
Keeping in mind March winter events need multiple items to come together to create impactful situations, it’s also important not to simply “buy in” to the idea that just because it’s been warm lately that winter is finished. March can be a wild month, as long-time Hoosiers are aware. The pattern we’re heading into over the next 10-14 days is one that’s been void most of the winter (high latitude blocking in place) and can serve as the player needed to flip a “nuisance” variety late-winter event to one that’s much more significant. We’ll need to remain on guard for the potential of one or two “more significant” wintry events as we move through the first couple weeks of the month.
Finally, looking ahead, there’s an argument that can be made that we flip the script towards milder times through the last (10) days, or so, of March. We note (as shown above) the AO and NAO trend neutral-to-positive mid and late March. Secondly, the EPO is also expected to flip positive for the second half of the month and this is warm signal, locally, as shown. Majority of guidance also takes the MJO into the “null” phase late month.
The end result is one that should promote colder than average times over the next couple weeks, overall, along with an active storm track. With blocking in place, the potential of one or two more significant late-winter events are on the table, and we’ll have to fine tune specifics as the individual storms come. While confidence is high that someone within the Ohio Valley region is likely to still deal with a big-hitter event, there’s no way to get specific until the individual players are on the field. Thereafter, the pattern should begin to transition to one more conducive for “stick and hold” spring conditions during the latter portion of the month.
II. Our next weather maker will arrive midweek and provide a few showers Wednesday (not a huge deal from a precipitation perspective). However, as a deepening surface low tracks into the Great Lakes Thursday morning, a period of heavier rain and even thunder is possible. In general, this looks like a 0.50″ to 1.00″ type event.
III. Somewhat cooler air will whip in behind the low, allowing leftover precipitation to end as a couple wet snowflakes across the northern half of the state Friday morning. The bigger story will be the “bumpy” start to Friday with strong and gusty north winds.
IV. High pressure returns for the weekend and with it will come a return of sunny skies. Though the mornings will be frosty, afternoon temperatures will “warm” to pleasant levels, especially with the increasingly strong early-March sun angle.
V. Looking ahead, let’s keep a close eye on the second week of March. Potential is present for a stormy period to emerge under the block. We note the GEFS and EPS (respective ensembles of the GFS and European models) are in relative agreement on a stormy, cold look during this time frame. While far too early for specifics, the potential is there for a rather widespread wintry event from the Plains into the Northeast.
Our Saturday morning will be dominated by soaking rains as moisture continues to stream across the Midwest and Ohio Valley, including central Indiana. Add in temperatures in the lower to middle 40s and you have our official approval to sleep in this morning. 🙂
Widespread rain and embedded thunderstorms will return by evening, and forecast radar products at 8p and 2a Sunday show the stormy times well:
A couple of storms may become strong to severe (especially downstate). Accordingly, the Storm Prediction Center has expanded the threat of severe weather to encompass more of the state.
After early morning storms head east Sunday, high pressure will build in with drier conditions and increasing sunshine Sunday. It’ll be a very nice close to the weekend, and calm, pleasant conditions will continue as we progress through the early portions of the new work week.
Embedded thunderstorms may target southern Indiana late tonight and Friday morning before more widespread thunderstorms (a couple could become strong) Saturday. The Storm Prediction Center (SPC) has included the southern half of the state in a “marginal risk” of severe thunderstorms Saturday.
All total, additional rainfall between now and Sunday morning should reach 2″ to 3″ across a widespread portion of the southern half of Indiana with locally heavier amounts.
We’ll finally dry things out as we close the weekend and head into early next week as high pressure settles overhead.
Next week will begin a pattern transition from the unseasonably warm weather we’ve enjoyed as of late to a colder regime for the first half of March. We note models continue to tank the NAO and AO.
Accordingly, the models are seeing the trough and associated colder than average pattern returning to the eastern half of the country as we rumble through the first half of March. With such a strong block in place, this can turn into an active pattern for a couple weeks to go along with the cold. Both the GEFS and EPS agree on the overall look.
While there’s no way to get specific on the individual storm threats that will eventually come with this pattern, the potential is present for a few storms to “bowl” underneath the block through the first 10-15 days of the month. Each storm will have the capability of delivering wintry precipitation, but this can also be a tricky time of year where most, if not all, ingredients need to come together to create significant wintry events. In a winter that’s been frustrating to central Indiana snow lovers (frigid, but dry first half and milder, wetter second half), perhaps it would be fitting to get a couple good snow dumps in March (when most are wanting and ready for spring)…
Steadiest rains will fall across the northern third of the state Tuesday with scattered downpours through the morning and afternoon hours across central Indiana.
After a quieter time of things most of Thursday, we’re tracking three additional waves of moisture Friday and through the weekend. At times, rain will be heavy, and we’ll certainly have to be on guard for water rise and increasing flooding issues as the weekend arrives.
By the time all is set and done Monday morning, we forecast additional widespread 3.5″ to 5″ rainfall totals with locally heavier amounts.