The 00Z March 28, 1984 upper
air isotach analysis at 300 mb showed a strong
120 to 140 knot jet streak along the base of an upper level trough
extending from Texas to Mississippi (Figure 2). The 500 mb analysis showed
a low cutting off over the Texas Panhandle with a strong mid-level jet
rounding the base of the upper trough with diffluent flow aloft developing
over the western Gulf states (Figure 3). By 12Z on March 28, the
upper air charts showed an intense shortwave trough progressing
rapidly across the southern United States. The center of the trough was
over northeast Arkansas with 500 mb winds of 80 to 90 knots (Figure 4). At
850 mb at 12Z, 50-60 knot winds were present with dewpoints
increasing to 10 to 13 degrees Celsius. This strong 850 mb jet coupled with
dual 95-knot jets at 500 mb led to a strongly sheared pre-storm environment
over the Carolinas on March 28 (Figure 5).
Figure 2. 300 mb Isotachs at 00Z March 28,
1984 showing strong jet max across Texas into Mississippi.
3. 500 mb Heights at 00Z March 28, 1984 shows cutoff low over the Texas
panhandle and jet max rounding the base of the low.
4. 500 mb Heights at 12Z March 28, 1984 showing closed upper low over
Northeast Arkansas with diffluent flow aloft.
5. 850 mb Heights showing 50 to 60 knot jet along with 10 to 13 degree
Celsius air being transported into the Carolinas. Dual 95- knot jets at 500
mb are superimposed to show development of wind shear.
At the surface, the 15Z surface analysis
(Figure 6) showed a strong but broad area of low pressure over the
Tennessee Valley. From the low, a warm frontal extended from Mississippi
into Eastern South Carolina. This front gradually lifted north into eastern
North Carolina during the day. A very strong mesoscale low formed on the
front over Georgia by 20Z (Figure 7) and rapidly deepened to 978 mb, and
began to race east-northeast across South Carolina. The airmass
became very unstable across Eastern North Carolina during the afternoon
with lifted index values down to -10C with 60 to 80 knots of deep layer
6. Surface Analysis at 15Z
March 28, 1984 showing warm front extending east from strong but broad low
pressure over the Tennessee Valley.
7. The 20Z Surface Analysis on March 28, 1984 shows strong 978 mb mesoscale
low developing east of Atlanta, Georgia.
deepening and acceleration of the mesoscale low occurred during the late
afternoon hours. As of 21Z (Figure 8), the low had dropped to 976 mb and
was located just east of Athens, Georgia. It was about this time that the
first of the family of violent tornadoes touched down in Newberry, South
Carolina. From this point, the surface low raced east-northeast at speeds
up to 65 mph across central South Carolina into eastern North Carolina.
Surface based CAPE values in excess of 3000 J/Kg were observed in northeast
South Carolina with 60 to 80 knots of deep layer shear.
Figure 8. The 21Z Surface Analysis March
28, 1984 shows strengthening surface mesoscale low near Athens, Georgia.
The first violent tornado of the day developed around this time near
Newberry, South Carolina.
the mesoscale low had moved to just northwest of Columbia, South Carolina
with a trough extending east and northeast to near Greenville, North
Carolina. The family of tornadoes tracked near the trough as the surface
low raced to the east-northeast. As the low moved into southeast North
Carolina by 01Z on March 29 (Figure 9), surface winds were strongly backed
along the warm frontal boundary, signaling strong low-level helicity. The
tornadoes exited eastern North Carolina by 03Z March 29, as cold air surged
in behind the exiting low pressure.
Figure 9. Surface Map at 01Z March 29,
1984 showing strong (978 mb) surface low over southeastern North Carolina.
Strong tornadoes were affecting eastern North Carolina at this time.
Timeline of Eastern North Carolina
Tornadoes (times approximate)
815 pm – Tornado enters Duplin County from
Sampson County producing extensive F4 damage in Faison and Calypso before
hitting Mount Olive in Wayne County. The tornado travelled 21 miles and was
as much as ¾ mile wide.
830 pm -
F3 tornado touches down and moves through the southeastern portion
of LaGrange in Lenoir County, injuring 81 but causing no deaths.
845 pm – the deadliest tornado of the entire
outbreak caused 16 deaths and 153 injuries in Greene and Pitt County. The
tornado was up to ¾ mile wide and caused extensive damage to the
southeastern suburbs of Greenville including damage at East Carolina
University. Nine fatalities occurred in Pitt County with seven in Greene
County. The fatalities occurred in Greenville, Winterville, Ayden and Snow
Hill. See Figure 10 for a
closer view of the Eastern North Carolina tornadoes.
Figure 10. Tracks
of the 3 tornadoes affecting the Newport/Morehead City (MHX) County Warning
major change in National Weather Service warnings occurred due to this
outbreak. The subsequent disaster survey report recommended that the
National Weather Service begin using tornado “call to action”
statements in severe thunderstorm warnings issued during tornado watches.
Storm Prediction Center
U.S. Significant Tornadoes, Thomas Grazulus, 1860-1991.
Historical Tornado Cases for North America, Jonathan