Fall Freeze Risk, August 2019 (Table 1)

August 8, 2019

Al Dutcher - Associate Nebraska State Climatologist

Table 1. The odds (%) of an early fall hard freeze (28°F or less), calculated using 2019 GDD accumulations from emergence to July 31 and applying 1981-2010 GDD average accumulations for August 1 to the average first hard freeze date. The table (stacked in two parts) shows the odds for four emergence dates. (Source for the hard freeze dates: National Centers for Environmental Information Normals, Means, and Extremes Database). See related story, Calculating the Odds of a Hard Freeze, for more information.
	AVG. FREEZE	EMERGENCE: 4/29					EMERGENCE: 5/13
LOCATION	Date	1900	2100	2300	2500	2700	1900	2100	2300	2500	2700
Scottsbluff	5-Oct	0	0	10	63	100	0	0	30	60	100
Ord	10-Oct	0	0	0	4	50	0	0	4	25	71
O’Neill	13-Oct	0	0	0	17	63	0	0	7	23	70
Concord	11-Oct	0	0	0	0	23	0	0	0	7	50
Sidney	11-Oct	0	0	31	76	100	0	0	48	86	100
North Platte	12-Oct	0	0	3	20	53	0	0	3	33	70
York	20-Oct	0	0	0	0	0	0	0	0	0	0
West Point	14-Oct	0	0	0	0	13	0	0	0	0	33
McCook	18-Oct	0	0	0	4	9	0	0	0	4	17
Red Cloud	12-Oct	0	0	0	0	0	0	0	0	0	0
Beatrice	21-Oct	0	0	0	0	0	0	0	0	0	0

	AVG. FREEZE	EMERGENCE: 5/27					EMERGENCE: 6/10
LOCATION	Date	1900	2100	2300	2500	2700	1900	2100	2300	2500	2700
Scottsbluff	5-Oct	0	0	60	96	100	3	60	100	100	100
Ord	10-Oct	0	0	4	50	96	0	11	61	100	100
O’Neill	13-Oct	0	0	17	57	96	0	17	63	96	100
Concord	11-Oct	0	0	3	33	87	0	6	53	96	100
Sidney	11-Oct	0	10	67	100	100	5	67	95	100	100
North Platte	12-Oct	0	3	20	53	92	3	20	56	96	100
York	20-Oct	0	0	0	0	22	0	0	0	30	81
West Point	14-Oct	0	0	0	27	70	0	0	37	83	100
McCook	18-Oct	0	0	4	9	48	0	4	17	52	81
Red Cloud	12-Oct	0	0	0	0	26	0	0	6	57	90
Beatrice	21-Oct	0	0	0	0	16	0	0	0	20	64

Average first fall hard freeze (28°F or less)

The Emergence Date Freeze Occurrence values in Table 1 are derived by using the 30-year normals period (1981-2010) to determine the percentage of time that a freeze occurred before GDD accumulations reaching the defined threshold. This was done by determining the GDDs accumulated in 2019 from the listed emergence dates and adding the GDDs from August 1 through the average hard freeze date for the 1981-2010 period.

Black numerals signal that 50% or less of the time a freeze would occur. Red signals that freeze criteria would be meant more than 50% of the time. The values listed are the percent of the time it would have occurred. Data was provided by the High Plains Climate Center's Applied Climate Information Service.

This table separates the state into three distinct zones: the northern, central, and southern thirds of the state. Stations selected run from west to east for each zone.

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Freeze Risk