October is the beginning of the fall season for us here in the Foothills and Western Piedmont, a season that can give us all varieties of weather. Without a doubt this past month didn’t fail in that respect as October 2017 was definitely one month that we’ll never forget as the Western Carolinas witnessed everything from a late season tropical system, to a classic autumn flash flood/severe weather outbreak to the first frost and freeze of the cold season.
The two big stories of the month in general was the above normal rainfall that impacted our coverage area along with two bouts of severe weather that included a pair of record breaking tornado outbreaks in this region for this time of the year.
First off heavy rainfall impacted all eight counties of the coverage area at some point during the month. The first bout of heavy rain was at a result of the remnants of Hurricane Nate back on October 8th. Thankfully the rainfall totals with Nate were not excessive in nature as the region has been dry for an extended period of time leading up to the event. That allowed the majority of the water to flow through local river basins without causing much in the way of danger.
Not the same could be said for our second heavy rain event. In some locations the rainfall amounts were excessive and resulted in flash flooding. The heavy rains that fell on October 23rd caused flash flooding/landslides in sections of Burke, McDowell and Rutherford Counties on what was already fairly saturated grounds after heavy rains just two weeks prior.
A third rain event in the range of 1-2+ inches occurred just this past weekend along the eastern slopes of the mountain. Like the first rainfall event it did not result in much flooding.
The hardest hit spots in October as a whole were in the foothills and along the immediate Blue Ridge where three separate heavy rainfall events overlapped. A few localized spots picked up 2x-3x normal rainfall amounts for the month of October, one of the driest months on average during the year. Here is a list of totals based off COOP stations and CoCoRaHS gauges. All locations in the coverage area finished at or above normal for the month.
Marion: 11.36 inches (3.5 avg)
Pleasant Gardens: 10.87 inches (3.5 avg)
Lake Lure: 10.57 inches (4.1 avg)
Forest City: 5.86 inches (3.77 avg)
Lenoir: 8.81 inches (3.4 avg)
Morganton: 7.2 inches (3.54)
Hickory Regional Apt: 5.56 inches (3.35 avg)
Lincolnton: 4.87 inches (4.14 avg)
Shelby: 4.42 inches (3.8 avg)
The above average rainfall in October is a stark change to the past couple years where dry fall weather yielded a very dangerous forest fire season across the Western Carolinas...
The second and bigger story from the month of October was the two severe weather outbreaks that occurred in the month. It was truly a historic month for severe weather and specifically tornadoes.
It all started on the 8th as Nate was rapidly pulling north through the Southeast US. Computer models out ahead of the storm a couple days honed in with the potential of severe weather and possible tornadoes as the outer bands of Nate moved in from the southwest during the afternoon of the 8th and lasted through the night. The circulation of Nate provided a natural shear mechanism as it moved into the region but it was an alarming amount of CAPE (Convective Atmospheric Potential Energy) or “thunderstorm fuel” that really got our attention as it showed up on model data about 36 hours prior to event.
Once that all came together, a tornado outbreak ensued across the Western Carolinas. A corridor just east of the immediate Blue Ridge was impacted on that day. The first tornado Warning of the day occurred just north of Rutherfordton and extended to just southeast of Marion in the early afternoon. There was no confirmation of a tornado with that cell but there was definite rotation noted per radar images and spotter reports.
Shortly after that the worst action began to form out ahead where the models prior to the event showed the highest CAPE values. By mid/late afternoon rotating thunderstorms moved from Upstate South Carolina northeast into sections of Cleveland, Burke and Caldwell Counties. Along that corridor a handful of tornadoes did touch down on that afternoon, three of them in fact. The worst being an EF-1 in Eastern Burke and Southern/Eastern Caldwell Counties causing quite a bit of damage in the Connelly Springs, Lake Rhodhiss, Granite Falls, and Sawmills Communities. This storm continued moving northeast just to the east of Lenoir eventually entering into Wilkes County.
Even after the main rotating cells moved outside of the coverage area, strong winds aloft moved through creating additional issues with downed trees and power lines. Once Nate moved through, three tornadoes were confirmed in our coverage area and nine total in the Carolinas extending from near Spartanburg and Laurens SC to the NC/VA border…
The extent of a severe weather event was record breaking in that for Burke, Caldwell and Cleveland Counties those warned cells were the first recorded tornadoes on record in the month of October in modern record keeping ( dated back to 1950’s) that in itself was impressive.
This already significant event shockingly was topped by something even more damaging two weeks later. A very deep trough and closed upper low moved through the Southland on the weekend prior to the 23rd before slowly lifting into the Mid-Atlantic and New England. The trough that briefly went “negative tilt” along with no surface wedging feature evident once again put the region under a high shear environment with enough CAPE in place to allow everything to come in place for another severe weather outbreak.
By mid afternoon of the 23rd action was already starting to fire up as a line of severe thunderstorms and heavy rain were moving through the Upstate. That line advanced into the Western Piedmont and Foothills. Once all was said and done Monday evening, most of those locations impacted by the November 8th severe weather was once again ground zero. This time around the region was delivered an even harder hit as a total of four confirmed tornadoes touched down in the coverage area with several more in surrounding areas of the Western Carolinas.
Cleveland County alone were involved with three separate confirmations, the first being an EF-2 that entered into the Southwest corner from Cherokee County SC lifting less than two miles inside of the NC/SC border. The second was a brief EF-1 that entered from Southeast Rutherford County to a position just east of Polkville in Upper Cleveland. The third twister which was a re-generation of the first supercell was an EF-1 that begin near Lawndale and skirted northeast through Upper Cleveland County and into Southwest Catawba County.
The images posted below indicate the broad rotation that was involved with this feature. Multiple vortices were able to develop among the main mesoscale feature. The multi-vortex facet began back across Upstate South Carolina as Spartanburg County was hit by both areas of rotation including the city of Spartanburg where EF-2 damage was confirmed along Business 85.
It was during the late afternoon hours of the 23rd where things got more intense as that meso approached the I-40 Coridoor. Damage reports began to come in just prior to 5 pm in the Longview area of far Western Catawba County from this cell. Then reports of damage at Hickory Regional Airport and LP Frans Stadium trickled in indicating clearly that another tornado had touched down.
The only caveat to this feature is that the obvious tornado was also surrounded by a surge of straight-line winds that doppler radar and survey crews estimated reached in excess of 100 mph at times. This corridor of damage impacted Eastern Burke, Western/Central Catawba, most of Caldwell and Alexander Counties. Our weather team along with other survey crews were able to confirm EF-2 damage with this re-generation that continued northward into Wilkes County and eventually into Southwest Virginia before finally dissipating later in the evening.
The similarities in storm tracks with both severe weather events last month were eerie. The best news that we can report is due to proper warning notifications there were very minimal number of injuries as a direct result of the storm and no direct fatalities.
The combination of the two outbreaks in October were quite remarkable…posted below are some additional images and information from the separate events.
The month of October ended with a couple shots of cold Canadian air with the stoutest blast occurring just 48 hours ago with freezing temperatures in the lower elevations of Western North Carolina for the first time helping end the growing season for some. And for our friends in the High Country the first accumulating northwest flow snow event started Sunday and lasted into the early hours of Monday morning laying down a dusting in some locations with a couple inches along the high peaks above 5000 ft.
All in all this past month was very active in terms of weather of many different types across the Western Carolinas…rain, wind, flooding, tornadoes, cold.
Could this extremely variable pattern continue into November? Only time will tell…