Fall begins with dip in temperatures but summer heat will return

STREAK SNAPPED

For the first time in two weeks, the afternoon temperature did not reach 80 degrees in Indianapolis, however, the warm spell isn't over just yet.

The decided downturn in temperatures and humidity bring on the refreshing feel after a lengthened stretch of unseasonably warm if not hot weather. The passing cold front has settled south late Monday, and winds are blowing in from the northwest late day.  We are importing the milder air and are expecting that late tonight and early Tuesday we are headed to a low of 55 degrees in the city.  This will be the coolest here in over three months!  The last time Indianapolis officially dipped to 55° or cooler was June 14 (47°).

RAIN ARRIVED

We needed the rain and still need quite a bit more. The Sunday night and early Monday rainfall of just over a third-of-an-inch was the largest in 29 days. September's rainfall deficit is still near 2" below, and after the rainfall, we are still ranked as the 9th driest on record.

Rain chances look quite spare again for the upcoming work week, with minimal coverage expected late Wednesday and again early Friday. A rise in temperatures and humidity late week could bring about a few scattered thunderstorms entering the weekend, but wide-spread rainfall is lacking at this distance.

FALL BEGINS

Astronomical fall began Monday, precisely at 3:50 a.m. That was the exact time when the most direct rays of the sun reached the equator and marked the start of Autumn in the Northern Hemisphere.

We're losing daylight quickly this month. Since the first, we've lost 57 minutes of daylight.

For record keeping, we use the months of September, October and November as meteorological fall. Fall 2019 is already impressive in the lack of rain and the level of heat thus far.

Since September 1, 74% of the days have been above normal averaging as the WARMEST to-date since 1939 (80 years). The past 15 days have been above normal, and the stretch may roll on.

Temperatures are cooler now, but it is temporary. Heat and humidity are expected to return in a big way entering the weekend and holding well into the opening days of October. A 90° day could still be in the offing, along with a possible record or near record high early next week.

A resurgent ridge in the jet stream for the eastern half of the nation will return, and a upper-level high (late season hot dome) is to become anchored again in the southeast U.S. as October opens. This has been the default fall pattern for now and will allow unseasonably warm to record level heat to take hold again starting this weekend. Temperatures could reach 90 degrees Sunday and Monday. The record high for September 30 is 89°. Could that record fall? Stay tuned!

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