| Date of Events |
Surface Features |
500-mb Pattern |
Classification |
March 11-12, 1963
(Nighttime event) |
Warm front (W-E) over TN valley w/ approaching low pressure and associated cold front (N-S) |
Strong southwest flow (70 knots) ahead of trough over Plains states |
Synoptic |
October 4, 1964
(Daytime event) |
Slow moving cold front (SW-NE) w/ strong tropical low pressure ('Milda') over lower MS valley |
Weak southwest flow (20 knots) |
Synoptic |
July 27, 1969
(Daytime event) |
Outflow boundaries located over southern Appalachians |
Weak southwest flow (20 knots) w/ closed low over Great Lakes region |
Meso-high |
August 4, 1969
(Nighttime event) |
Weak stationary front (SW-NE) over southern Appalachians |
Trough over TN valley w/ weak southwest flow (20 knots) |
Frontal |
May 27-28, 1973
(Nighttime event) |
Quasi-stationary front (N-S) over southern Appalachians w/ prefrontal squall line approaching from west |
Closed low over Plains states w/ strong southwest flow (60 knots) |
Synoptic |
August 13, 1973
(Daytime event) |
Outflow boundaries over southern Appalachians w/ stationary front (W-E) over Ohio valley |
Weak short wave over southern Appalachians w/ west flow (30 knots) |
Meso-high |
September 13, 1973
(Daytime event) |
Weak stationary front (W-E) w/ weak tropical low pressure over lower MS valley |
Weak southwest flow (20 knots) w/ weak ridge over Mid Atlantic states |
Frontal |
May 22-23, 1974
(Nighttime event) |
Prefrontal trough (SW-NE) w/ weakening cold front (SW-NE) over Ohio valley |
Deepening trough over TN valley w/ southwest flow (30 knots) |
Synoptic |
May 28-29, 1976
(Nighttime event) |
Strong, slow moving low pressure over west TN w/ occluded front (NW-SE) extending over southern Appalachians |
Closed low over mid MS valley w/ south flow (30 knots) |
Synoptic |
July 27, 1976
(Daytime event) |
Outflow boundaries located over southern Appalachians w/ prefrontal trough (W-E) over the Ohio valley |
Weak southwest flow (15 knots) w/ weak ridge over Mid Atlantic states |
Meso-high |
September 7, 1977
(Daytime event) |
Weakening tropical low pressure over AL approaching stationary front (W-E) over southern Appalachians |
Weak trough w/ southwest flow (25 knots) |
Tropical
('Babe') |
November 5-6, 1977
(Nighttime event) |
Weakening tropical low pressure over GA w/ trough (NW-SE) over southern Appalachians |
Closed low over AL w/ strong southeast flow (40 knots) |
Tropical
(Unnamed) |
July 20, 1979
(Daytime event) |
Weak stationary front (W-E) over TN valley |
Weak trough over mid MS valley w/ weak southwest flow (20 knots) |
Frontal |
March 20, 1980
(Daytime event) |
Warm front (W-E) moving north w/ approaching low pressure and associated cold front (N-S) |
Deepening trough over Plains w/ strong southwest flow (40 knots) and weak ridge over Mid Atlantic states |
Synoptic |
June 1, 1987
(Daytime event) |
Outflow boundaries over southern Appalachians |
Weak short wave trough over mid MS valley w/ southwest flow (25 knots) and ridge over Mid Atlantic states |
Meso-high |
August 21-22, 1990
(Daytime event) |
Outflow boundary (W-E) located near quasi-stationary front (N-S) over southern Appalachians |
Weak trough w/ weak west flow (15 knots) |
Meso-high |
March 27, 1994
(Nighttime event) |
Surface trough (W-E) located ahead of approaching strong cold front (SW-NE) |
Strong southwest flow (75 knots) ahead of strong trough over Plains |
Synoptic |
June 26, 1994
(Nighttime event) |
Prefrontal trough (SW-NE) over TN and Ohio valleys ahead of approaching cold front (N-S) |
Deepening trough over TN valley w/ strong southwest flow (50 knots) |
Synoptic |
October 4-5, 1995
(Nighttime event) |
Strong tropical low pressure approaching stationary front (SW-NE) over TN valley |
Closed low over AL w/ strong south flow (50 knots) |
Tropical
('Opal') |
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