September’s precipitation was dominated by Hurricane Ian, whereas fall-like temperatures accompanied the official season change. That has set us up for a well timed leaf coloration transition this yr.
Ian Stamps Out Re-Rising Drought
A stretch of dry climate by means of most of September abruptly ended with a tropical torrent on the final day of the month. Based on the Nationwide Facilities for Environmental Info (NCEI), the statewide common precipitation of three.84 inches ranks as our Sixtieth-driest September since 1895. Word that a few of Ian’s rain fell after midnight on October 1, so it would rely towards the October complete.
The most important rain occasion early within the month was within the southern Mountains on September 4-6. A stationary entrance parked throughout the area dropped greater than 6 inches of rain in some areas, with the very best quantities in Transylvania County. A CoCoRaHS observer east of Brevard recorded a four-day complete of 10.34 inches over Labor Day weekend.
After that, the center of the month was particularly dry because of a high-pressure sample over the Carolinas. By September 21, Elizabeth Metropolis had acquired solely 0.17 inches of rain all month, and the northeastern nook of the state fell again into Average Drought (D1) as these rainfall deficits and impacts to stream ranges and crop situations degraded.
Heading into the ultimate day of September, components of the state had seen lower than an inch of rain all month, together with simply 0.78 inches in Raleigh following an August that was nearly equally dry.
However on September 30, Hurricane Ian roared ashore in South Carolina and introduced the month to a moist, windy finish throughout North Carolina. Storm totals by means of the morning of October 1 exceeded six inches throughout components of the Coastal Plain.
The 5.92 inches at Hatteras on September 30 was extra rain than that web site had acquired within the earlier ten weeks mixed. That was additionally the wettest single day there since Might 30, 2016, when Tropical Storm Bonnie handed simply offshore.
Elizabeth Metropolis additionally rebounded because of Ian and completed the month with 4.49 inches, on par with the conventional September rainfall of 4.52 inches.
At some coastal websites, Ian alone wasn’t sufficient to utterly get better from the dry begin to the month. Wilmington had 5.15 inches complete in comparison with a month-to-month regular of 8.69 inches, and Greenville completed 2.75 inches under regular, regardless of the three.4-inch complete from Ian on September 30.
Nevertheless, Ian actually helped us avert a good drier September destiny, and it washed away all drought throughout japanese North Carolina. After the storm, streamflows surged and soil moisture ranges have been at or above regular besides in components of the Nice Smoky Mountains. These far western areas acquired little rain from Ian and have seen an introduction of Abnormally Dry (D0) situations on the US Drought Monitor.
Ongoing Warmth Will get an Autumn Adjustment
A summer-like begin to September was balanced by a fall-like remaining week. For the month as a complete, NCEI studies a statewide common temperature of 70.5°F, or our 57th-warmest September up to now 128 years.
Early on, the warmth confirmed no indicators of going away, and September picked up the place August left off. Charlotte had eight days in a nine-day interval hit 90°F or increased between August 26 and September 3.
Wilmington had eight days all month with temperatures within the 90s, which has solely occurred three different occasions in September up to now 30 years – in 1993, 2010, and 2019.
The warmth peaked on September 22, hitting 98°F in Raleigh, 96°F in Charlotte and Lumberton, and 94°F in Wilmington, every of which set or tied the every day file excessive.
Late that night time, our temperatures got here crashing down with a chilly entrance that coincided with the equinox; extra on that under. Our first fall air mass of the yr meant excessive temperatures largely within the 70s and dew factors within the 30s and 40s for the final week of September.
The top of the month even introduced a wintry chill in some areas. As Canadian excessive strain in-built from the northwest on September 28, a number of western websites noticed temperatures at or under freezing.
Apparently, it wasn’t our mountaintop websites that noticed the coldest temperatures, since a nostril of hotter air starting round half a mile above sea degree stored websites like Bearwallow Mountain and Grandfather Mountain within the mid to higher 30s.
The good air sank within the surrounding valleys, and websites like Candler hit 27°F, Celo dipped all the way down to 29°F, and Waynesville reached 30°F – its first below-freezing night time of season, practically two weeks earlier than the common first fall freeze date of October 10.
That was additionally an enormous distinction from the place the month began. After its 4th-warmest summer season on file based mostly on the common low temperatures, Waynesville had a string of eight consecutive nights with temperatures within the 60s from September 4 by means of 11, properly above the common September low temperature of 52.9°F.
That made fall’s arrival really feel much more abrupt – and welcome – throughout the state.
Fall Sends the Leaves into Motion
We often talk about seasons by their meteorological definition, grouped by calendar months for the sake of year-to-year consistency and climatological similarity. Nevertheless, we couldn’t assist however discover that this yr, the astronomical first day of fall – the equinox, when the solar crosses straight over the equator – was a significantly better match for our transition to fall-like climate.
On the afternoon of September 22, simply earlier than the equinox at 9:03 pm, temperatures climbed properly into the 90s, past even our regular summertime ranges. After that night time’s chilly frontal passage, temperatures the subsequent day have been comfortably and seasonably within the 70s.
In Raleigh, the 23-degree distinction between every day excessive temperatures of 98°F and 75°F was the best on both facet of the autumn equinox since 1995, when the excessive hit 87°F on September 22 and simply 62°F the next day.
With the warmth disappearing and but to return, our fall-like climate has been a cue for leaves to start their annual adjustment to shades of purple, orange, and yellow.
As we’ve beforehand described with assist from Appalachian State biology professor Dr. Howard Neufeld, inexperienced chlorophyll pigments in leaves start eroding as days get shorter, temperatures get cooler, and enzymatic processes decelerate.
That makes method for these different colours that both construct up starting within the spring or – as in purple maples – begin forming within the fall to forestall leaves from absorbing an excessive amount of photo voltaic radiation.
This yr, these pure cues have arrived proper on schedule, and the leaves are already responding.
“We had good, cool climate the final 7 to 10 days [of September],” stated Neufeld, who famous an on-time arrival of peak coloration within the Boone space — round 3,000 toes in elevation — this week in mid-October.
One wildcard with this yr’s climate was Ian’s winds. Neufeld stated that impression was felt primarily at excessive elevations, the place leaves have been already nearing their peak when the storm hit. That’s as a result of the colour change course of features a breakdown of cell partitions and leaves finally being minimize off from their bushes as vitamins and water cease flowing backwards and forwards.
“So if it will get wet and windy close to peak coloration, you may get a whole lot of leaf drop,” he added.
Elsewhere, Ian had much less of an impression, which provides much more hope for a vibrant present this fall.
“When leaves are inexperienced, they’re nonetheless firmly held on the tree, and blustery winds and rain received’t take down too a lot of them,” stated Neufeld. “Some, however not all.”
For lately dry and drought-stricken areas, together with components of the japanese Piedmont and northern Coastal Plain, Neufeld stated the rain ought to assist stop an early leaf drop from bushes similar to tulip poplars which are delicate to dry situations.
Barring a warmth wave later this month, Neufeld expects a virtually on-time arrival of fall colours throughout the state. He’ll be monitoring situations all through the season in his Fall Colour Report and Fall Colour Man Fb web page.
As these first shades of foliage present up this month, we are able to assume again to that one September chilly entrance on the primary day of astronomical fall that obtained the ball rolling, and the leaves altering.