Some Changes in NC Forecast (2pm Sunday, Jan. 19, 2014)

— Written By Barclay Poling

Summary for NC:  While temperatures from this Arctic clipper are now going to be somewhat colder on both Wed and Friday this week, the absolute minimums are not nearly so threatening as the freeze the state experienced Jan 6/7. If the forecast for your area is for temperatures in the low teens, or colder, it may be good insurance to re-apply row covers by this Tuesday, or sooner.

And this is an interesting option…

The one unknown with this freeze is how the duration of freezing temperatures below 20 F may impact the crop. Ideally, I would be able to access another table showing the duration of temperatures below 15 F and 10 F, but maybe next year AWIS will have those additional thresholds available as well. In the meantime, it would beinteresting to note how many hours your area will be below 20 F this week, and later we can cut some crowns and examine the condition of the flower buds to see if there was any damage? Please be sure to leave an uncovered section of row for  a good comparison. 

The economics of re-applying covers?

If you already have row covers ON the crop now, then you have nothing to do this afternoon except watch the football game, and maybe at half-time you can double-check  your row covers to see that they are well pinned down. I asked a few growers last week how much labor is required for them to pull a cover back on (from being rolled up in the field), and the answers I got were from 2-3 hrs/acre. For a row cover re-application costing maybe $30-$40/acre for labor, it might be a good insurance investment to make in areas that will be dropping into the low teens and single digits, and will also be having a pretty significant number of hours below 20 F from Wed through Saturday, like Louisburg ( 36 hrs).

The change in the forecast from yesterday…

The forecast has changed! For example, Asheville will now see a minimum of 6 F on 1/23, whereas it was only heading for a low of 9 F in yesterday’s AWIS forecast for 1/23. Also, it will now be even colder on Friday. In Greensboro it will likely be 15 F on both Wed and Fri morning. Previously, Thursday  was going to be the low temp for the week ahead.

Table 1. While you were sleeping – change in forecast from
January 18 forecast to January 19 forecast for several locations
Minimum Temperature by Date
Location Forecast on: Jan 22 (W) Jan 23 (Th) Jan 24 (F) Jan 25 (S)
Asheville 18-Jan 9 8 8 12
19-Jan 6 13 6 16
change -3 5 -2 4
Greensboro 18-Jan 18 18 16 21
19-Jan 15 20 15 24
change -3 2 -1 3
Siler City 18-Jan 16 14 14 16
19-Jan 13 17 13 20
change -3 3 -1 4
Louisburg 18-Jan 15 13 13 16
19-Jan 12 16 11 19
change -3 3 -2 3
Kinston 18-Jan 23 15 19 19
19-Jan 20 16 19 21
change -3 1 0 2

Here is the AWIS state map for NC on Wed and Fri:

nc wed min Figure 1. Min temp map for Wed (1/22). The light green indicates 14-16 F.

nc fri min

Figure 2. Min temp map for Fri (1/24)

How many hours will the temperature be under 20 F this week in NC? Just click on this pdf to see how many hours of temperatures  at or below 20 F will accumulate in your location:  NC HOURS BELOW 20 F

What really caught my attention in this next table is how Louisburg (Franklin Co – piedmont) will have more hours of sub-freezing temperatures below 20 F this week than Asheville!

Table 2. Temperature duration forecast for 5 NC locations
Hours at or Below 20 F
Location Jan 22 (W) Jan 23 (Th) Jan 24 (F) Jan 25 (S) Sum
Asheville 13 5 13 0 31
Greensboro 9 2 9 0 20
Siler City 10 9 10 1 30
Louisburg 11 11 12 2 36
Kinston 1 10 2 0 13

AWIS Temp Mins for NC this week: NC MIN Temp Jan 19 to 25

Good luck!

Dr. E. Barclay Poling
Professor Emeritus
Department of Horticultural Science

Campus Box 7609, 162A Kilgore Hall

NC State University
Raleigh, NC 27695-7609