Event Summary
     National Weather Service, Raleigh NC

August 21, 2017 Solar Eclipse
Updated 2017/09/21

Event Overview

On Monday, August 21, 2017, a total solar eclipse tracked across the continental United States from the Pacific to the Atlantic coasts. The path of the total solar eclipse, where the moon completely covered the sun, was seen from Salem, Oregon to Charleston, South Carolina. This path included a small fraction of extreme southwestern North Carolina. Most of North Carolina experienced a partial solar eclipse where the moon covered part of the sun's disk. The maximum percentage of the sun obscured by the moon ranged from 100% in Franklin NC, to around 98% in Charlotte, 94% in Greensboro, 93% in Raleigh and 87% in Elizabeth City. The maximum obscuration occurred from around 2:35 to 2:50 PM EDT.

This GOES-16 animation below originated from the CIMMSS Satellite Blog was provided by the State Climate Office of NC. The preliminary, non-operational imagery shows the shadow of the moon moving southeast across the eastern United States.

The preliminary, non-operational GOES-16 imagery shows the shadow of the moon moving 
southeast across the eastern United States.

Impact on Temperatures

Forecasters anticipated the eclipse would result in a temperature drop during and just after the eclipse period. Some of the preparations for this were highlighted in a post on the Collaboration for Improved Meteorology in the Mid-Atlantic and Southeast blog. Across central NC the temperature change ranged from around 4 to 8 degrees (note a large temperature drop in Greensboro was enhanced by a rain shower that dropped 0.15 inches of rain.) Most locations experienced the daily high temperature just prior to the eclipse.

Table with information on the eclipse time and 
impact across central NC

One-Minute Temperature Traces from ASOS Stations

Hourly temperature trace for RDU

Hourly temperature trace for FAY

Hourly temperature trace for MEB

Hourly temperature trace for GSO

Hourly temperature trace for INT

Hourly temperature trace for BUY

Impact on Clouds

Cumulus clouds were noted across much of the Mid-Atlantic during the afternoon of August 21, 2017. While there were a few rain showers in Northwest Piedmont and Triad area and across the mountains of western North Carolina, most of the clouds in the area were shallow cumulus clouds. Satellite imagery showed that a large majority of these weakly driven clouds faded away during the eclipse and generally did not redevelop. Some of the clouds associated with the rain showers which had a stronger maintenance mechanism did persist subsequent to the eclipse.

A before and after satellite view of the Mid-Atlantic is shown in the GOES-16 visible image [preliminary, non-operational] below (click on the image to enlarge.) The image on the left is from 1257 PM EDT (1657 UTC) just prior to the eclipse and the eclipse while the image on the right shows clouds across the area at 357 PM EDT (1957 UTC). It can be seen, especially in the enlarged photo that most of the shallow cumulus clouds across the Carolinas have dissipated with the decreased insolation.

Preliminary, non-operational GOES-16 visible satellite imagery 
shows a view of the clouds at the beginning and end of the eclipse - click to enlarge

Other Resources

NASA Eclipse Web Page
Explore Radiation & Temperature Data from the Eclipse from the State Climate Office of NC