The upcoming forecast period will be met with unseasonably cool and dry conditions. While we have some showers to track this evening (mostly from Indianapolis and points north), the large majority of the rest of the period above will feature an extended period to dry out with considerable amounts of sunshine. The downside? Clear skies and calm winds at night with a late season arctic high dominating will result in a couple of additional frosty nights ahead. The coldest mornings appear dialed up Wednesday and Thursday. Mid 30s will be common with a few reports of low temperatures around freezing for outlying communities. The next opportunity for rain won’t arrive until Sunday afternoon/ evening. With high pressure dominating, severe weather isn’t expected, locally, and will remain below normal for the rest of the country.
Many find themselves waking up to the upper 30s this morning.
While certainly chilly by May standards, we’ll be even colder tomorrow morning. This will come behind a passing upper level disturbance that will likely kick up another round of scattered thunder (some storms may contain small hail) this afternoon and early evening. Lows Saturday morning may rival records in spots. The record low in Indianapolis tomorrow morning is 31° set in 1976 and 1947.
We still anticipate a Mother’s Day soaker (rain may begin around sunset Saturday after what should otherwise be a very nice day), including embedded thunder. Rainfall totals with this system will check-in between 1.5″ and 2″ for most, including locally heavier totals above 2″. The axis of heaviest rain is forecast from Indy and points north with the latest American model guidance and central and southern portions of the state from the European guidance. Expect the consensus of modeling to improve on precisely where the heaviest totals setup over the next 24 hours.
The primary purpose of this morning’s post is to look at the chilly start to May and where we think things are headed for the 2nd half of the month.
The “revved up” MJO (into the traditionally cold May phases) initially is what tipped us off to the cold open to the month. For those that have been paying attention to the modeling, you could see how the data had to continue correcting colder and colder up until “real term.” Officially, we’re running 1.6° below normal so far, but with the cool in the week ahead, that will grow much more impressive in the days to come.
This should come as no surprise with us set to move strongly into Phases 2-3 over the course of the upcoming 7-10 days. Note greatest temperature departures from normal occur across the Ohio Valley in these phases in May.
What’s more interesting is what transpires after this period (mid and late May). The MJO is expected to head into the “null phase” for a time.
One could extrapolate the data and build a case we’re headed for phases 7-8 to close the month. If so, things would moderate (against the norms) by Phase 8.
This is something we’ll watch. If we do, indeed, get into Phase 8 prior to Memorial Day, we’d expect the heat to build to close the month. The transition will likely be less significant though. The thinking here is still relatively cooler than normal mid-month before moderating closer to and/ or slightly above normal prior to Memorial Day.
From a precipitation perspective, the pattern continues to look quite active for the foreseeable future.
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A relatively weak storm system will lead to plenty of clouds today and a couple of light passing showers (better chance of steadier rain downstate). This system will blow by to our east tonight and allow a drier air mass to build into the region as we move through the 2nd half of the weekend, complete with a return of sunshine! Enjoy the sunny and much warmer open to the week as significant changes await by Wednesday. Before this, a strengthening southwesterly air flow will push high temperatures into the lower 80s Tuesday! Attention will then shift to a complex and multifaceted storm system that will deliver heavy rain and thunderstorms (potential present for a couple stronger storms midweek that we’ll continue to monitor) in rounds Wednesday through Friday. While it won’t rain the entire timeframe, periods of heavier rain can be expected. We’ll dry things back out heading into next weekend.
Central Indiana will continue to feel the affects of the low pressure system that resulted in periods of storms yesterday through the remainder of the weekend. A rather persistent light to moderate rain is expected today along with gusty winds and cooler air. This system will pull east of the region Monday and allow for drier air to return. The bulk of the remainder of the forecast period looks dry and seasonably cool. We’ll continue to keep an eye on upper level energy scooting to our east midweek. This is expected to result in a few instability-driven showers for our friends across northeastern IN into OH, but continues to look like it’ll just miss central IN.
Frosty conditions are still possible Thursday morning, especially if we can clear out any lingering clouds from the aforementioned upper energy. The next opportunity for better coverage of light showers won’t come until next weekend. Overall we only expect 0.25” and 0.50” of rain in the week ahead- most if not all of which falls today.