Georgia Frost Update and Suggestion on Using Drip Beneath Row Cover (5:25am, Friday, April 7, 2017)

— Written By Barclay Poling

THIS IS THE LATEST MINIMUM TEMP MAP FOR GA FOR SATURDAY MORNING – NOTE THE SIGNIFICANT CHANGE THAT HAS TAKEN PLACE IN LAST HOUR (THE MINIMUM TEMP MAP ISSUED EARLIER THIS MORNING IS IN FIGURE 1 OF THIS ADVISORY)

6:24 a.m.

NOTE: since this advisory was issued at 5:25 a.m., 4/7/17, there has been a significant CHANGE in the forecast! In the 5:25 a.m.  advisory I focused on Rome, GA. But, at 6 a.m. this morning a revised forecast was issued by AWIS for ROME and other locations in GA (new forecast: ROME UPDATE at 6 a.m. Friday), so please check the latest information in the AWIS 10 Day Hourly Forecast (below) for a city or town nearest your farm. ALSO, please note the CHANGE IN AWIS FROST/FREEZE FORECAST (AT BOTTOM OF ADVISORY) OF  “LITTLE IF ANY FROST DUE TO CLOUDS AND WINDS” FOR TOMORROW MORNING to  “NEAR FREEZING COLD LOCATIONS” AND “FROST LIKELY”  IN NORTHWEST GA!

Good morning,

I do not normally do daily state by state frost updates, but the AWIS minimum temperature map for Saturday morning (April 8) is indicating temperatures close to freezing  in some areas of northern GA for April 8th (Fig. 1). The pink area indicates minimums of 30-32, and the dark blue 32-34. In North Carolina and Virginia where I spend most of my time, we are very wary at this time of the year of minimum temperatures in the 34-36 range (light blue). Of course, if winds stay up above 5 mph, then you would think an area like Rome, Ga Rome would be SAFE with a minimum of only 37 F! But, if you click on ROME AWIS, you will see they are showing FROST at 5 a.m., despite winds of 5 mph! How can that be? It is a question that plagued me as a young extension specialist at NC State in the 1980s. I don’t know how many times growers would say to me, “I had a killing frost Dr. Poling at 38 F.”   The answer is fairly simple. The  minimum of 38 F relates to a weather shelter temperature at 5 ft (for AWIS).

Location, location, location! How often in real estate do you hear, “Location, location location.”  Same thing here! On a radiation frost night,  the temperature at the ground level (where your strawberry blossoms are), can be significantly lower than up at 5 ft! And, if it gets to 32 F at the strawberry canopy level in BEFORE SUNRISE on Saturday in Rome, GA, ice crystals will form first on those strawberry blossoms open to the sky. That is something you want to keep from happening!

The other concerning factor in the Rome, Ga, forecast Rome are these very high dew points (34 F at 5 a.m.). With this much moisture in the air, it will be quite easy for frost to form on ground level vegetation. My hope is that winds will still be “light” in the morning, as several of us have observed “frost under covers” when the winds become completely calm in a situation like this. Yes, I would favor sprinkler irrigation in a situation like this except most growers are now harvesting berries as well. So, if you are already harvesting, row covers would be an excellent way to handle this cold event, except there is this crazy chance that you could get frost forming under the covers in the early morning before sunrise on Saturday morning. And, frost under a cover is never a good thing!

USE DRIP IRRIGATION BEFORE DAWN.  In North Carolina and Virginia, I know a number of growers who are very pleased with using drip irrigation beneath row covers in radiation type frost events. We have encountered problems with using drip in windborne freeze conditions like March 14-17, 2017. But, for tonight and tomorrow morning, we are not dealing with anything remotely like what happened back in mid March. Dripping under row covers in a radiation frost type cold event can add 1-2 degrees of warmth beneath the row cover, and that is often just enough to keep the air temperature beneath the cover from dropping below 32 F.

In Rome, GA, for example,  I would start it up around 4:30 a.m. – 5 a.m. and let it run for 3 hours (sun rises at 7:19 a.m.). We just never know about these wind forecasts, and if the winds really die down, it may be a plan plan to run the drip irrigation in the early morning on Saturday because of this very moist air (dew point 34). So, if you are in an area where there is a forecast for an air temperature of 36 F, or lower, and your only protection method is with a row cover, then plan to run the drip for maybe 3 hours before sunrise. Good luck!

Fig. 1. Minimum temperatures for Georgia on April 8, 2017. You may wish to examine more detailed information below if your strawberry farm is in an area that might be going below 36-38 F (teal). The GA Temp Outlook provides excellent information on minimum temperatures for numerous locations in GA, and the AWIS Hourly information gives additional information on whether there may be “F”rost potential.

Ga Temp Outlook

10-DAY DETAILED HOURLY WEATHER FORECASTS

Albany_Municipa Alma/Bacon_Co Americus_AP Athens_Municipa
Atlanta/DeKalb Atlanta/Fulton Atlanta_Intl_Ar Atlanta_Paulding
Augusta/Bush_Fi Augusta_Daniel_F Bainbridge_GA Blakely_AP
Brunswick_GA Brunswick/Glync Canton_GA Carrollton_AP
Cartersville_AP Claxton_AP Columbus_GA Covington_GA_AP
Dalton-Dalton_M Douglas_Muni Dublin/WHBarron Fitzgerald_AP
Fort_Benning Ft_Stewart/Wrig Gainesville_AP_G Greensboro_GA
Homerville_AP Hunter_(AAF) Jesup_AP La_Grange
Lakeland Lawrenceville_AP Macon_AP Marietta
Marietta/Cobb Milledgeville_AP Moultrie_Muni_AP Newnan-Newnan_C
Peachtree_City Rome_GA Savannah Statesboro_GA
Swainsboro_AP Sylvania_AP_GA Thomaston_AP Thomasville_AP
Thomson_GA Tifton_AP Valdosta Valdosta/Moody
Vidalia Warner_Robins_A Washington_GA Washington_GA
Waycross_AP Winder_AP

PLEASE GO BY THE AWIS GEORGIA FROST/FREEZE ADVISORY IMMEDIATELY BELOW…YOU MAY BE INTERESTED IN NOTING HOW MUCH THIS FORECAST HAS CHANGED IN THE LAST HOUR BY COMPARING THIS ADVISORY TO THE ONE ISSUED EARLIER TODAY. FOR EXAMPLE, AWIS IS NOW SAYING “NEAR FREEZING COLD LOCATIONS” AND “FROST LIKELY”  FOR NORTHWEST GA (FOR SAT MORNING). EARLIER TODAY, THE FORECAST WAS “LITTLE IF ANY FROST DUE TO CLOUDS AND WINDS” FOR NORTHWEST GA. BOY! THAT’S A PRETTY DRAMATIC PIVOT!

AWIS Weather Services, Inc. Georgia Frost/Freeze Forecast
Produced at  503 a.m. CDT on Fri Apr  7 2017

... Forecast for Tonight ... Northwest Georgia                       
NWS Fcst Zones 1-5, 11-12, 19-20, 30-31           

**** NEAR FREEZING COLD LOCATIONS  ****
****  FROST LIKELY ****

Lowest Temperatures:      34 - 38
Rome_GA Min                 38 
Range Dewpoint Temps:     27 - 36
Range Wetbulb  Temps:     35 - 42
AVG Wind Direction/Speed:   N  8                          
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17  04/14/17
  --------  --------  --------  --------  --------  --------
   40 - 44   46 - 50   50 - 54   52 - 57   50 - 54   53 - 57
--------

North Central Georgia                   
NWS Fcst Zones 6-9, 13-16, 21-23, 25, 32-37, 44-45

**** FREEZE COLD LOCATIONS  ****
****  FROST LIKELY ****

Lowest Temperatures:      32 - 41
Dahlonega Min               35 
Durations at/below 32:     0 -  1
Range Dewpoint Temps:     27 - 34
Range Wetbulb  Temps:     35 - 41
AVG Wind Direction/Speed:  NW  7                          
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17  04/14/17
  --------  --------  --------  --------  --------  --------
   37 - 47   42 - 52   46 - 57   49 - 58   48 - 58   49 - 59
--------

Northeast Georgia                       
NWS Fcst Zones 10, 17-18, 24, 26-29, 38-40        

**** FREEZE COLD LOCATIONS  ****
****  FROST LIKELY ****

Lowest Temperatures:      31 - 38
Hartwell Min                37 
Durations at/below 32:     0 -  2
Range Dewpoint Temps:     27 - 35
Range Wetbulb  Temps:     36 - 41
AVG Wind Direction/Speed:  NW  6                          
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17  04/14/17
  --------  --------  --------  --------  --------  --------
   36 - 43   41 - 49   45 - 52   48 - 55   46 - 53   49 - 57
--------

West Central Georgia                    
NWS Fcst Zones 41-43, 52-57, 66-70, 78-80, 89-93  

**** NEAR FREEZING COLD LOCATIONS  ****
****    PATCHY FROST  ****

Lowest Temperatures:      35 - 42
La_Grange Min               37 
Range Dewpoint Temps:     28 - 40
Range Wetbulb  Temps:     36 - 44
AVG Wind Direction/Speed:  NW  6                          
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17  04/14/17
  --------  --------  --------  --------  --------  --------
   41 - 46   46 - 51   50 - 56   53 - 59   53 - 58   53 - 58
--------

Central Georgia                         
NWS Fcst Zones 46,48-51,58-61,71-74,81-85,94-98,10

**** NEAR FREEZING COLD LOCATIONS  ****
** PATCHY FROST PROTECTED AREAS **

Lowest Temperatures:      35 - 40
Byron Min                   39 
Range Dewpoint Temps:     28 - 40
Range Wetbulb  Temps:     36 - 44
AVG Wind Direction/Speed:  NW  6     Long Periods of Calm 
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17  04/14/17
  --------  --------  --------  --------  --------  --------
   38 - 44   45 - 51   50 - 55   53 - 58   53 - 58   52 - 58
--------

East Central Georgia                    
NWS Fcst Zones 62-65, 75-77, 86-88, 99-101        

**** NEAR FREEZING COLD LOCATIONS  ****
****    PATCHY FROST  ****

Lowest Temperatures:      34 - 41
Waynesboro Min              35 
Range Dewpoint Temps:     31 - 40
Range Wetbulb  Temps:     35 - 46
AVG Wind Direction/Speed:  NW  6                          
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17  04/14/17
  --------  --------  --------  --------  --------  --------
   37 - 45   45 - 52   51 - 57   53 - 59   53 - 60   52 - 62
--------

Southwest Georgia                       
NWS Fcst Zones 102-104, 120-126, 142-145, 155-158 
** PATCHY FROST COLDEST LOCATIONS **

Lowest Temperatures:      38 - 42
Bainbridge Min              41 
Range Dewpoint Temps:     30 - 38
Range Wetbulb  Temps:     39 - 45
AVG Wind Direction/Speed:  NW  5     Long Periods of Calm 
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17  04/14/17
  --------  --------  --------  --------  --------  --------
   41 - 45   48 - 53   53 - 57   55 - 59   55 - 59   54 - 58
--------

South Central Georgia                   
NWS Zones 105-106,108,110,127-133,146-149,159-163 
** PATCHY FROST COLDEST LOCATIONS **

Lowest Temperatures:      38 - 42
Tifton Min                  42 
Range Dewpoint Temps:     32 - 40
Range Wetbulb  Temps:     37 - 45
AVG Wind Direction/Speed:   V  2     Long Periods of Calm 
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17  04/14/17
  --------  --------  --------  --------  --------  --------
   41 - 45   48 - 52   52 - 56   55 - 58   56 - 59   55 - 59
--------

Southeast Georgia                       
NWS Fcst Zones 113-119, 134-141, 150-154, 164-166 
** PATCHY FROST COLDEST LOCATIONS **

Lowest Temperatures:      37 - 47
Jesup_AG Min                39 
Range Dewpoint Temps:     32 - 45
Range Wetbulb  Temps:     38 - 48
AVG Wind Direction/Speed:  NW  5     Long Periods of Calm 
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17  04/14/17
  --------  --------  --------  --------  --------  --------
   41 - 51   47 - 59   51 - 62   52 - 63   54 - 63   54 - 63
--------

For more detailed information visit www.awis.com or call 888-798-9955. Copyright 2017 AWIS Weather Services, Inc. All rights reserved.
AWIS Weather Services, Inc. Georgia Frost/Freeze Forecast
Produced at  504 p.m. CDT on Thu Apr  6 2017

... Forecast for Tonight ... Northwest Georgia                       
NWS Fcst Zones 1-5, 11-12, 19-20, 30-31           
**** LITTLE IF ANY FROST DUE TO CLOUDS/WIND **** 

Lowest Temperatures:      37 - 41
Rome_GA Min                 41 
Range Dewpoint Temps:     31 - 40
Range Wetbulb  Temps:     38 - 43
AVG Wind Direction/Speed:  NW 14                          
AVG Sky Condition:     Mostly Cloudy

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/08/17  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17
  --------  --------  --------  --------  --------  --------
   34 - 38   40 - 44   45 - 49   50 - 54   51 - 56   47 - 52
--------

North Central Georgia                   
NWS Fcst Zones 6-9, 13-16, 21-23, 25, 32-37, 44-45

**** NEAR FREEZING COLD LOCATIONS  ****
**** LITTLE IF ANY FROST DUE TO CLOUDS/WIND **** 

Lowest Temperatures:      33 - 43
Dahlonega Min               37 
Range Dewpoint Temps:     30 - 37
Range Wetbulb  Temps:     38 - 43
AVG Wind Direction/Speed:  NW 14                          
AVG Sky Condition:     Mostly Cloudy

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/08/17  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17
  --------  --------  --------  --------  --------  --------
   31 - 41   37 - 46   41 - 51   46 - 56   49 - 59   45 - 56
--------

Northeast Georgia                       
NWS Fcst Zones 10, 17-18, 24, 26-29, 38-40        

**** NEAR FREEZING COLD LOCATIONS  ****
**** LITTLE IF ANY FROST DUE TO WIND **** 

Lowest Temperatures:      34 - 41
Hartwell Min                40 
Range Dewpoint Temps:     29 - 36
Range Wetbulb  Temps:     38 - 42
AVG Wind Direction/Speed:  NW 16                          
AVG Sky Condition:     Partly Cloudy

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/08/17  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17
  --------  --------  --------  --------  --------  --------
   30 - 37   35 - 42   40 - 48   45 - 52   48 - 55   46 - 53
--------

West Central Georgia                    
NWS Fcst Zones 41-43, 52-57, 66-70, 78-80, 89-93  
**** LITTLE IF ANY FROST DUE TO WIND **** 

Lowest Temperatures:      38 - 46
La_Grange Min               40 
Range Dewpoint Temps:     29 - 40
Range Wetbulb  Temps:     39 - 44
AVG Wind Direction/Speed:  NW 12                          
AVG Sky Condition:     Partly Cloudy

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/08/17  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17
  --------  --------  --------  --------  --------  --------
   36 - 42   41 - 46   45 - 50   50 - 56   53 - 59   51 - 58
--------

Central Georgia                         
NWS Fcst Zones 46,48-51,58-61,71-74,81-85,94-98,10

*** No Frost And/Or Freeze Danger Tonight ***

Lowest Temperatures:      41 - 46
Byron Min                   45 

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/08/17  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17
  --------  --------  --------  --------  --------  --------
   35 - 40   39 - 45   45 - 51   51 - 56   53 - 58   53 - 58
--------

East Central Georgia                    
NWS Fcst Zones 62-65, 75-77, 86-88, 99-101        

*** No Frost And/Or Freeze Danger Tonight ***

Lowest Temperatures:      41 - 47
Waynesboro Min              42 

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/08/17  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17
  --------  --------  --------  --------  --------  --------
   34 - 42   38 - 46   45 - 52   51 - 57   53 - 59   53 - 60
--------

Southwest Georgia                       
NWS Fcst Zones 102-104, 120-126, 142-145, 155-158 

*** No Frost And/Or Freeze Danger Tonight ***

Lowest Temperatures:      43 - 47
Bainbridge Min              46 

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/08/17  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17
  --------  --------  --------  --------  --------  --------
   38 - 42   42 - 46   47 - 52   53 - 57   55 - 59   55 - 59
--------

South Central Georgia                   
NWS Zones 105-106,108,110,127-133,146-149,159-163 

*** No Frost And/Or Freeze Danger Tonight ***

Lowest Temperatures:      42 - 46
Tifton Min                  46 

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/08/17  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17
  --------  --------  --------  --------  --------  --------
   39 - 42   43 - 47   48 - 52   53 - 57   55 - 58   56 - 59
--------

Southeast Georgia                       
NWS Fcst Zones 113-119, 134-141, 150-154, 164-166 
**** LITTLE IF ANY FROST DUE TO WIND **** 

Lowest Temperatures:      40 - 49
Jesup_AG Min                42 
Range Dewpoint Temps:     33 - 47
Range Wetbulb  Temps:     42 - 50
AVG Wind Direction/Speed:  NW 10                          
AVG Sky Condition:         Clear    

Extended Forecast: Range of Lowest Min Temperatures in the Above Zones
Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets)

  04/08/17  04/09/17  04/10/17  04/11/17  04/12/17  04/13/17
  --------  --------  --------  --------  --------  --------
   39 - 48   42 - 52   48 - 59   52 - 62   52 - 63   54 - 63
--------

For more detailed information visit www.awis.com or call 888-798-9955. Copyright 2017 AWIS Weather Services, Inc. All rights reserved.