Heat Wave May 25-31, 2019

Overview

Unseasonably hot temperatures occurred late May, which resulted in several broken temperature records across the Southeast. Statewide, both South Carolina and Georgia achieved the 2nd warmest May on record. Locally, temperatures for the month of May were 5-6 degrees above monthly averages. Charleston International Airport (CHS) and Savannah International Airport (SAV) had 4 consecutive days of 100+ degree days. Both climate sites saw the earliest 100 degree date on record. This helped May 2019 become the warmest May on record for both sites. See the complete top 5 list in the Public Information Statement. Temperature records date back to 1938 at the Charleston International Airport (CHS); 1870 in Downtown Charleston (CXM); and 1874 at the Savannah International Airport (SAV).

Interestingly, on May 27, these hot conditions caused the steel on the Ben Sawyer Bridge in Charleston County to expand, which impacted the opening and closing of the bridge. The bridge was closed to vehicles and maritime traffic for several hours.

It was also quite dry through this period. The combination of little to no rain, low relative humidity values and the persistent hot temperatures allowed drought conditions to expand over parts of the area. Most impacts from the developing drought was in the agricultural community. In Allendale and Hampton counties, farmers reported that dryland corn fields were beyond recovery, and many other crops were struggling to grow and could be lost.

Synoptic Discussion

A strong ridge of high pressure developed and remained anchored over the Southeastern United States during the last week of May 2019, which included the Memorial Day weekend. This high pressure prevented afternoon showers and thunderstorms and negated the normal cooling influence of the Atlantic Ocean. While this type of weather pattern can typically produce heat waves during the summer, this high pressure was unusually strong for late spring. As a result, we experienced the hottest temperatures ever recorded in May.

NOAA/ESRL Composites for the period May 25 - May 31, 2019

500 mb Height Mean	850 mb Height Mean

500 mb Height Anomalies	850 mb Temperature Anomalies

Daily Observations

Maximum Temperatures from Official Climate Sites

	CHS	CXM	SAV
5/25/2019	97*	90	100*
5/26/2019	100*	99*	102*
5/27/2019	100*	100*	101*
5/28/2019	101*	98*	101*
5/29/2019	101*	97*	99*
5/30/2019	99*	87	99
5/31/2019	95	87	94

Observation period is midnight to midnight LST.

*Set new daily record

New all-time record high May temperature

Maximum Temperatures from Cooperative Observer Sites

	South Carolina					Georgia
	Jamestown	Moncks Corner	Summerville	Walterboro	Yemassee	Brooklet	Rocky Ford	Sapelo Island
5/25/2019	97	97	96	95	95	95	91	91
5/26/2019	100	98	99	99	99	98	95	95
5/27/2019	101	99	99	99	100	99	98	98
5/28/2019	101	99	99	99	100	100	100	97
5/29/2019	102	100	101	99	101	100	100	96
5/30/2019	102	101	100	100	100	99	100	97
5/31/2019	102	102	100	98	99	99	96	96

Observation period is the 24-hour period ending at 7 or 8 AM.