September noticed a well timed change of seasons and principally dry climate, other than Ophelia. That tropical storm was a part of an lively month throughout the Atlantic.
From Summer season into Fall
Sweltering warmth gave option to extra seasonable circumstances in September, so it averaged out as a barely hotter than regular month total. The Nationwide Facilities for Environmental Info (NCEI) studies a preliminary statewide common temperature of 71.0°F and our Fiftieth-warmest September since 1895.
The month began the place August left off, with excessive warmth throughout a lot of the state. With excessive strain blanketing the Carolinas, our temperatures rose properly into the 90s in the course of the first week of the month, peaking on September 6.
On that date, Raleigh reached 102°F, then equaled that mark on the next day, making it the primary September on file there with a number of days exceeding 100 levels. Our ECONet station in Durham topped out at 100°F, and even Roxboro – whose northerly location and better elevation usually makes it one of many cooler spots within the Piedmont – reached 97°F, which was its first day that heat since October 2019.
We received a short break from the warmth when a chilly entrance moved by way of on September 9, however summer season made one final push the next week, with temperatures once more hitting the higher 80s to low 90s by September 12.
After that, a sequence of common frontal passages and cooler excessive strain methods to our north stored the warmth from constructing again, and as a substitute left us cooler and fewer humid, simply as we’d count on from the autumn.
![Autumn Arrived and the Tropics Got here Alive in September Autumn Arrived and the Tropics Got here Alive in September](https://climate.ncsu.edu/wp-content/uploads/2023/10/temp_summary_Sep2023-1024x512.png)
We even had our first nippy mornings of the season, together with on September 19, when low temperatures dipped into the 40s within the Mountains and rural components of the Piedmont.
Barring an October warmth wave, we’ve seen our last 90-degree days this yr, and for the second yr in a row, the arrival of fall-like climate occurred proper on time, each by the calendar and our climatology.
Greensboro final hit 90 levels on September 7, in comparison with a historic common last 90-degree day of September 10. Raleigh’s final 90°+ studying on September 12 matched its historic common prevalence. And New Bern and Wilmington, which additionally hit 90°F on September 12, noticed that milestone inside 3 to 4 days of the historic common.
In Siler Metropolis, the primary evening under 50 levels – a crisp 46°F on September 16 – occurred simply in the future sooner than its common up to now this century.
Cool, clear nights like that ought to assist make this one other good yr for fall colours. Dr. Howard Neufeld, a professor of biology at Appalachian State College, lately famous on his Fall Colour Man web page that the colour change is properly underway above 4,000 ft, and the altering leaves are complemented this yr by the brilliant purple berries on mountain ash timber.
Contemplating the sunny climate within the forecast and extra cool nights probably starting this weekend – each of that are key triggers for timber to supply their colourful pigments – Dr. Neufeld expects this yr’s colour change to proceed roughly in keeping with the typical timing, which implies peak colour from mid- to late October within the Mountains, progressing eastward into the Piedmont by early November.
![A photo of changing leaf colors and mountain ash berries in western North Carolina](https://climate.ncsu.edu/wp-content/uploads/2023/10/mtnash_CarversGap_Oct2023.jpg)
Dryness Shifts Westward
A lot of the state was drier than regular in September, however some coastal areas picked up heavy rain from Tropical Storm Ophelia. In keeping with NCEI, the preliminary statewide common precipitation was 3.56 inches, which ranks as our 52nd-driest September out of the previous 129 years.
Notably throughout the Mountains and Foothills, wet days had been uncommon final month. Asheville had solely 5 days with measurable rainfall and just one with not less than a half-inch of rain in the course of the frontal passage on Sunday, September 10.
It completed the month with 1.66 inches complete, or 2.10 inches under common, of their Seventeenth-driest September out of the previous 72 years. Hickory matched that rating with 1.83 inches, or 2.20 inches under common.
Shelby was even drier, with solely 0.62 inches all month and its Ninth-driest September out of 97 years with observations. Their final September as dry as this was in 2019, when a fall flash drought emerged throughout western North Carolina.
Within the Piedmont, circumstances ranged from very dry in Charlotte, which had solely 0.88 inches and tied for its Nineteenth-driest September since 1878; to close regular in Chapel Hill, which completed with 3.61 inches, inside a half-inch of its common September rainfall; to barely moist in each Greensboro and Raleigh, which had 5.38 and 5.48 inches, respectively, final month.
![The September 2023 precipitation summary infographic, highlighting the monthly average temperature, departure from normal, and comparison to historical and recent years](https://climate.ncsu.edu/wp-content/uploads/2023/10/precip_summary_Sep2023-1024x512.png)
Precipitation was additionally extremely different throughout the Coastal Plain, largely relying on the place the heaviest rain from Ophelia fell. Among the many areas hit hardest by the storm, New Bern was an inch above regular in its Twenty second-wettest September since 1948, and Roanoke Rapids was 2.75 inches above regular in its Tenth-wettest September since 1972.
Farther south and west, it was significantly drier. Lumberton had just one.93 inches all month, or simply 42% of its month-to-month common, and Fayetteville had 2.22 inches in its driest September since 2013.
The excellent news from September is that Ophelia’s rain fell on lots of our driest areas, so that they completed the month with a web enchancment on the US Drought Monitor. That included the elimination of Average Drought (D1) within the northeast, the place the summer-long drying pattern lastly slowed down.
Whereas Elizabeth Metropolis was nonetheless barely under regular for the month, and stays 8.21 inches under regular over the previous six months, the rain from Ophelia helped groundwater ranges leap by 1.5 ft within the biggest single-event enhance since late April.
As dryness light within the east, it emerged within the west, primarily within the southern Mountains, the place streamflows fell under regular in September. If October stays dry – and present outlooks recommend it would – then these areas may see drought emergence much like final yr, when leaves on the timber had been vibrant, however as soon as fallen, they contributed to an uptick in fall wildfire exercise.
![A comparison of drought maps from September 5 and 26, 2023, in North Carolina](https://climate.ncsu.edu/wp-content/uploads/2023/10/USDM_comparison_Sep2023-1024x300.png)
An Energetic Atlantic
Final fall, a well timed tropical storm – Nicole in mid-November – was the eventual reply to drought worries for a lot of western North Carolina. The identical could possibly be true this yr, particularly given the flurry of latest exercise throughout the Atlantic.
That’s an enormous change from a month and a half in the past, when the tropics had been largely idle. After Hurricane Don dissipated in July, no storms shaped within the first half of August, which made NOAA’s up to date outlook calling for above-normal exercise appear questionable.
However since then, the tropical Atlantic Ocean has remained traditionally heat, and the storms have certainly adopted. The six storms forming in August included Idalia, which introduced our first spherical of tropical rainfall this yr.
September noticed a further seven storms kind, plus the redevelopment of Gert over the central Atlantic. The strongest of them was Hurricane Lee, which briefly reached Class-5 standing and finally impacted Maritime Canada as a robust remnant storm.
Together with storms that carried over from August, the ten named storms lively throughout September tied for essentially the most ever recorded in a single month within the Atlantic, together with September 2010 and September 2020.
For sure, these predictions for an lively Atlantic season have already confirmed correct, with 17 named storms plus an unnamed subtropical storm again in January, in comparison with the latest 30-year common of 14 tropical storms per season.
![A map of global sea surface temperature anomalies as of September 30, 2023](https://climate.ncsu.edu/wp-content/uploads/2023/10/SST_anomalies_2023-09-30-1024x622.png)
With sea floor temperatures throughout the basin nonetheless working as much as 3 levels above regular and two months left within the official hurricane season, we’ll probably add extra storms to this yr’s depend, doubtlessly even tapping into the supplemental checklist of storm names, which was modified from the Greek alphabet to extra normal names after the record-breaking season in 2020.
And as for the El Niño, which we famous may restrict Atlantic exercise as soon as stronger upper-level winds kicked in, it’s nonetheless rising and searching like a average to robust occasion will likely be in place for the winter.
By late September, some robust upper-level winds had been blowing throughout the Atlantic, however primarily north of the principle improvement area between Africa and the Caribbean. That might grow to be extra of a barrier to tropical formation over the ultimate months of the season, however tropical exercise must also stay potential within the heat Gulf of Mexico.
And by the top of the autumn, we nonetheless count on the everyday El Niño-induced jet stream sample bringing moisture-rich storms to our south and east to take form, as CPC’s newest seasonal precipitation outlook suggests.
So whereas drought and its impacts are potential this fall, the lively tropics and an anticipated strong jet stream by the winter may imply wetter climate on the horizon.
The contents throughout the article have been equipped by way of Newswire for Finencial.com, go to