30 Day Ag Weather Outlook MD – VA – TN- NC – SC (Mon. Morning, March 13, 2017)

— Written By Barclay Poling
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Good morning,

I am expecting to hear back this morning from growers who are presently assessing their Crop Status and Condition – you may wish to do this very quickly this morning before “precipitation events” begin later today (Monday). Having a good handle on Crop Status and Condition at this time is necessary to understanding how this Cold Event may impact your crop, and finally on Crop Protection Strategy. Last evening, we heard some discussion from one grower, Eric Hunter, Easley, SC, who has been “processing” recent changes in his forecast (possibility of 15 F minimum on Thur morning), and based on past experience with irrigation system freezing up at such low temps, his decision may now be to not attempt sprinkling on covers.

I have had an experience with a main line that froze up at Clayton Central Crops during a windborne freeze with temperatures in the teens, and we were unable to get the water running again after about 2 a.m. Thank goodness we had a single layer of row covers on the crop, and we managed to save our emerged tight buds, but everything else got zapped! Back in those years (early 90s), this whole idea of sprinkling on row covers for windborne freeze conditions was just being tried for the first time (by us). I have seen growers have success (keeping open blossoms alive), with this approach with temperatures into the teens, but the sprinkling must remain continuous! You also must have a digital thermometer with thermocouples (at least 5) inserted into individual blooms beneath the covers to monitor “the patient’s” temperature. If blossoms are going below 31 F, you are beginning to enter a critical moment. If they go below 28 F for perhaps just a matter of 10-12 minutes, they’re dead! The good news is that those tight flower buds are much tougher, and it was a pleasant surprise for me to see that this stage had survived despite “losing our irrigation at 2 a.m.” on that fateful night – the covers that had become an “igloo” of ice did trap some ground heat, and kept that stage alive. One last point, it is a well known fact that fruit crops can do some amount of super-cooling in sub-freezing conditions if they are DRY. There is not a lot of good data on this phenomenon in strawberry, but I am well aware of its importance in grapes, and I have discussed super-cooling in grapes in this paper cold protection in winegrapes. What it amounts to is that if you have DRY ROW COVERS going into the BIG DADDY freeze nights (Wed/Thur & Thur/Fri), and NOT WET OR FREEZING UP,  it could mean that your strawberry reproductive tissues (green fruit, open blossoms, popcorns and emerged tight buds), may be able to drop below what we normally assume to be the critical temperature of that plant part by perhaps 2 F. But, you cannot take advantage of super-cooling if those plant tissues become frozen up, and I have seen situations where soaking rains just before a deep-freeze event have resulted in plants becoming frozen into the covers, and there can be no doubt that the benefits of having a row cover are seriously compromised when this happens. Over the last week or so, I have had a number of new growers and extension agents contacting me, and there is no doubt that all of this is quite overwhelming! One new grower in the western piedmont of NC purchased an irrigation for his 3 acres of strawberries, but does not have a row cover. Given the kind of weather we’ll be experiencing in the week ahead, I think it is fair to say that an irrigation system by itself is not going to be a satisfactory approach, especially for a grower with no prior experience in running a sprinkler system under such dire conditions as these. Basically, we are now looking at a weather system that is every bit as dangerous as Easter freeze of 2007. Perhaps you have heard it said about sprinkler systems that in windborne freeze conditions (sub-freezing temps and winds of 10 mph, or greater), you are better off doing nothing at all. That is a very true statement. If you are running a sprinkler system that doesn’t have the capacity to handle high winds, incredibly low dew points and temperatures in the teens, your crop will “do better” if you don’t run at all. However, if you can get your hands on a row  cover at this last minute, that would be an excellent option, and would allow you a chance of saving those emerged tight flower buds. TWO COVERS would be even better!

overhead irrigation

Fig. 1. Having a reliable irrigation system + row covers, is your best shot at protecting the entire crop (all the stages) in the kinds of conditions we’ll likely be seeing this Wed/Thur and Thur/Fri – this is an inspiring photo from a young new grower up in Southern NJ who is using the row cover + sprinkling approach in some very very tough conditions up there.

Table 1. Thinking through different factors like crop stage and condition, and the latest forecast for your area and farm, are key to making the best decision on a cold protection strategy.
1. Crop status  (3/13)  By Variety Crop Condition? Damage? By Variety

Open blossom?

Popcorn

Tight buds

What is remaining?

Open blossom?

Popcorn

Tight buds

2. Cold event Min temp 3/16 (Thur)  Wind speeds?  Wet covers?  Frozen covers?
3. Crop protection? Irrigation alone  Row cover alone  H20 + Row Cover
 What actual approach, or approaches will you use?  -only works to about 7-8 mph winds; big concern evaporative cooling and freezing up Double covers? if dry can be very effective  – need sprinkling to be uniform and continuous

flower stages photo and chart

30 Day Ag Weather Outlook MD – VA – TN- NC – SC

We have updated the online 30 day forecast below – sorry for slight delay in getting this out. Even though our forecast badly missed the timing of the very cold outbreak this past weekend,  we think weunderstand what is behind  the current very complex weather pattern and why the forecast models are having such a hard time with the forecasts even a few days out. We think the basic problems with the model forecast are caused by:

(1)  The fact that there is a very strong (stronger than usual) thermal gradient from north to south across North America (see the new “items of interest” graphic at the bottom of this advisory). Thus small changes in the wind pattern can rapidly evolve to large difference in the thermal pattern across the US.

(2)  The northeastern Pacific and northwestern Atlantic sea surface temperatures patterns favor northern hemispheric atmospheric thermal and jet stream patterns that tend to cause cold weather systems to drop out of Canada into the southeastern US. Over time the sea surface temperatures used by the  forecasts models tend to resemble climatology which cause the model to lose the forcing that creates the cold weather pattern in the eastern US.

The following are our forecast trends and reasoning for the next month.

The upcoming week will be another very cold and active weather period. There is reasonable weather forecasts model agreement until about Mar 20. After a week, the the forecast models tend to diverge in their forecast solutions and vary from run-to-run even for the same forecast model. So after March  20 the US, Canadian and European models all show somewhat different forecasts. So after March  20 there is condsiderable uncertainty in the details of the forecasts in terms of timing of systems. However the atmospheric forcing resulting from El Nino-La Nina-Sea Surface Temperature patterns and the North American snowpack – atmospheric  thermal  pattern strongly indicate conditions will generally favor below normal temperatures with above normal  precipitation.

On the longer term, the seasonal forecasts continue to be uncertain because some large  scale forcing factors favor above normal temperatures conditions and some favor below normal temperatures in the eastern US. The ENSO cycle remains near neutral, but  seems to be slowly switching from weak La Nina to weak El Nino conditions. Features of both a typical La Nina and El Nino are still evident in the tropical and global patterns.

Trying to balance all the factors, our  best estimate is that the April to May time frame  will tend to see more seasonal temperatures and drier conditions from the mid Atlantic to southeast US. We will make  a comprehensive analysis of the long term factors and trends over the next week and update the seasonal outlook in next week’s forecasts.

trend map

Forecast discussion day 3 – 5  (15 Mar – 17 Mar) Temperatures very cold, well below normal; scattered snow showers early in the period. To start the period, a strong “nor’easter” will be moving into the Canadian Maritimes causing a strong northwest wind flow in the eastern US. At the same time a very large cold “arctic” high pressure system will be slowly moving southeast out of central Canada into the region. This will result in very cold temperatures, in the range of 15 – 30 F below the seasonal average, from early to late in the period and only warming to 8 – 12 degrees below normal by late in the period. Expect the period to be mostly dry with only the chance of some widely scattered snow showers in the eastern half of the forecast region very early in the period. Expect high temperatures to range from the upper 20s in the far north of the region to the upper 40s in the southern sections of the region early to mid-period. Expect low temperatures to range from the low 10s to mid 20s. Expect temperatures to warm about 10 degrees by late in the period. Precipitation amounts will likely be light in the 0.00 – 0.10” range.

forecast map

Forecast discussion day 6 – 8:  (18 Mar – 20 Mar) Temperatures remain below normal; scattered rain/snow early to mid-period then rain western section late in the period. Expect the cold high pressure system from the last period to remain across the region during this period keeping temperatures 5 – 10 F below normal. Also expect two weak frontal systems to move through the high pressure from west to east bringing rain and snow showers early and rain showers late in the period. Expect high temperatures to range from the mid 30s in the north to low 50s in the south. Low temperatures ranging from the upper 30s to mid 20s. Precipitation amounts will likely in the 0.30 – 0.50” range.

forecast map

Forecast discussion day 9 – 11:  (21 Mar – 23 Mar) Temperatures cool to back to well below normal; rain showers and scattered thunderstorms likely early to mid period. A cold front will movie through the region from the northeast to southeast followed by another strong cold high pressure system, once again bringing the temperatures well below normal. The cold front will likely bring showers and scattered thunderstorms to the region. Expect high temperatures to range from the mid 30s in the north to low 50s in the south. Low temperatures ranging from the upper 30s to low 20s. Precipitation amounts will likely in the 0.15 – 035” range” range.

Forecast map

Forecast discussion day 12 – 14:   (24 Mar – 26 Mar) Temperatures warm to slightly below normal; Wide spread rain (snow in the higher elevations) early to mid period. It is still very early for details, but expect the possibility of a strong low pressure system to form in the upper Mid West US and move east through region over the period. Expect periods of wide spread rain with snow in the higher elevations during the forecast look ahead period. Expect high temperatures to range from the low 40s to low 60s. Low temperatures ranging from the upper 20s to low 30s. Precipitation amounts will likely in the 0.15 – 035” range.

U.S. temperature outlook

Day 15 – 30 Temperature Outlook 1 Apr – 16 Apr

U.S. Precipation outlook

Day 15 – 30 Precipitation Outlook 1 Apr – 16 Apr

Outlook discussion day 15 – 22:     (27 Mar – 3 Apr) Early indications are that temperatures will be below the seasonal average and precipitation above the seasonal average during this period. Outlook discussion day 23 – 30:  (4 Apr – 11 Apr) Early indications are that temperatures and precipitation will be near the seasonal average during this period.
General Seasonal Outlook Mar – May 2017
Expect the forecast region to be generally warmer and wetter than normal for the period Mar – May 2017. The storm track and position of the semi-permanent Atlantic high pressure system will promote warm and moist southerly flow from the Southeastern states into the Mid-Atlantic states during the period. With abundant moisture and expected precipitation, expect that there will be a tendency for the minimum temperatures to be well above normal and the high temperature averaging only slightly above normal.

Spring 2017 Outlookmap

MD

10-DAY DETAILED HOURLY WEATHER FORECASTS

Aberdeen Andrews_AFB Annapolis_Naval Baltimore_Sci_Ce
Baltimore/Wash Cambridge/Dorche College_Park_AP Cumberland_AP
Easton_MD Fort_Meade Frederick_MD Gaithersburg_AP
Hagerstown_AP Leonardtown Middle_River Oakland_MD_AP
Ocean_City_AP Patuxent_River Salisbury Stevensville_AP
St_Inigoes/Webst Washington_DC_AP Westminster_AP

VA

10-DAY DETAILED HOURLY WEATHER FORECASTS

Abingdon Ashland_VA Charlottesville Chesapeake-Ches
Culpeper Danville Dublin/New_Riv Emporia_VA
Farmville Fentress_Naval_A Fort_Belvoir/Da Fort_Eustis/Fel
Franklin/J_B_Ro Hillsville Hot_Springs/Ing Jonesville_AP
Langley_AFB Leesburg/Godfre Louisa-Louisa_C Lynchburg
Manassas_Muni(A Marion/Wythev Martinsville Mecklenburg/Bru
Melfa/Accomack Newport_News Norfolk_Hampton_ Norfolk_NAS
Norfolk_VA Oceana Orange_VA Petersburg_(AWO
Quantico Richlands_AP Richlands_VA Richmond
Richmond_Chester Roanoke Shannon_Arpt Stafford_AP_VA
Staunton-Shenan Suffolk-Suffolk Tappahannock_AP Virginia_Tech_A
Wakefield_AP Wallops_Island Warrenton_Fauqui Washington_Dulle
West_Point_VA Williamsburg_VA Winchester_Rgnl Wise/Lonesome_P

NC

10-DAY DETAILED HOURLY WEATHER FORECASTS

Ahoskie-Tri-Cou Albemarle_AP Andrews Asheboro
Asheville_Munic Beaufort-Michae Boone_NC Burlington-Burl
Cape_Hatteras_AG Chapel_Hill-Hor Charlotte Cherry_Point
Clinton_NC Concord_NC Currituck_NC Edenton-Northea
Elizabeth_City Elizabethtown_NC Erwin-Harnett_C Fayetteville_AP
Fort_Bragg/Simm Franklin/Macon_C Gastonia-Gaston Goldsboro_AFB
Goldsboro_NC Greensboro Greenville_AP_NC Hickory
Jacksonville Jacksonville_(A Jefferson_AP_NC Kenansville-Dup
Kill_Devil_Hills Kinston_AP Lexington-David Lincolnton_AP
Louisburg_NC Lumberton_AP_NC Mackall_AAF Manteo/Dare_Co
Maxton Mcalf_Bogue_Fiel Monroe_AP_NC Morganton-Morga
Mount_Airy-Moun New_Bern North_Wilkesbor Oxford_NC
Piney_Island_Bom Pope_AFB Raleigh-Durham Reidsville_AP
Roanoke_Rap_AP Roanoke_Rapids_R Rockingham_NC Rocky_Mount-Wils
Roxboro_AP Rutherfordton Salisbury-Rowan Sanford_NC
Shelby_AP_NC Smithfield_AP Southern_Pines Southport_NC
Statesville-Sta Tarboro_AP Wadesboro_AP Washington-Warr
Whiteville_NC Wilmington_AP_NC Winston-Salem

SC

10-DAY DETAILED HOURLY WEATHER FORECASTS

Aiken_AP Anderson_Co_Air Barnwell_AP Beaufort_Cnty_AP
Beaufort_SC Bennettsville_Je Camden_AP Charleston_Exec_
Charleston_Muni Cheraw_AP Chester_AP Clemson-Clemson
Columbia-Columb Columbia/McEnti Columbia_Metro Conway_AP
Darlington Florence_SC Georgetown_AP_SC Greenville_Donal
Greenville_Down Greenville-Spart Greenwood-Green Hartsville_AP
Hilton_Head_AP Kingstree_AP Lancaster-McWhir Laurens_AP
Manning_AP Marion_AP_SC Moncks_Corner_AP Mount_Pleasant_A
Myrtle_Beach Newberry_AP North_Myrtle_Be Orangeburg-Oran
Pickens_AP Rock_Hill Spartanburg_Down Summerville_AP
Sumter_AP Sumter_SC Walterboro_AP Winnsboro_AP

GA

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

KY

10-DAY DETAILED HOURLY WEATHER FORECASTS

Bowling_Green Covington Danville-Powell_ Fort_Campbell
Fort_Knox/Godma Frankfort_AP Glasgow_KY Henderson_City
Jackson_KY Lexington_KY London_Corbin Louisville_AP
Louisville/Bowm Middlesboro_AP Monticello_KY_AP Murray_AP
Owensboro_AP Paducah Richmond_Madison Somerset(AWOS)

Special State Frost/Freeze Forecasts

AWIS Weather Services, Inc. North Carolina Frost/Freeze Forecast
Produced at  504 a.m. CDT on Mon Mar 13 2017

... Forecast for Tonight ... Northeast NC Coast                      
Currituck/Camden/Pasquotank/Tyrrell Counties      

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

Lowest Temperatures:      41 - 47
Elizabeth_City 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)

  03/15/17  03/16/17  03/17/17  03/18/17  03/19/17  03/20/17
  --------  --------  --------  --------  --------  --------
   29 - 35   24 - 31   23 - 32   37 - 43   39 - 46   38 - 45
--------

East Central/SE NC Coast                
Carteret/Pamlico Counties                         

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

Lowest Temperatures:      46 - 50
Morehead_City 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)

  03/15/17  03/16/17  03/17/17  03/18/17  03/19/17  03/20/17
  --------  --------  --------  --------  --------  --------
   29 - 34   25 - 28   22 - 30   30 - 39   40 - 44   45 - 46
--------

Southeast NC                            
NWS FORECAST ZONES 87-90,96-101                   
**** LITTLE IF ANY FROST DUE TO CLOUDS/WIND **** 

Lowest Temperatures:      39 - 47
Elizabethtown Min           42 
Range Dewpoint Temps:     34 - 50
Range Wetbulb  Temps:     37 - 50
AVG Wind Direction/Speed:  NW 11                          
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)

  03/15/17  03/16/17  03/17/17  03/18/17  03/19/17  03/20/17
  --------  --------  --------  --------  --------  --------
   25 - 31   21 - 27   23 - 30   29 - 41   39 - 43   43 - 49
--------

North-Central NC                        
Franklin County Area                              

**** FREEZE COLD LOCATIONS  ****
**** LITTLE IF ANY FROST DUE TO CLOUDS **** 

Lowest Temperatures:      31 - 42
Louisburg Min               31 
Durations at/below 32:     0 -  3
Range Dewpoint Temps:     21 - 32
Range Wetbulb  Temps:     32 - 37
AVG Wind Direction/Speed:  NW  8                          
AVG Sky Condition:         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)

  03/15/17  03/16/17  03/17/17  03/18/17  03/19/17  03/20/17
  --------  --------  --------  --------  --------  --------
   20 - 29   17 - 24   20 - 27   30 - 37   34 - 41   37 - 44
--------

North/Central NC                        
Alamance County Area                              

**** NEAR FREEZING COLD LOCATIONS  ****
**** LITTLE IF ANY FROST **** 

Lowest Temperatures:      33 - 38
Graham_AG Min               35 
Range Dewpoint Temps:     20 - 32
Range Wetbulb  Temps:     32 - 37
AVG Wind Direction/Speed:  NW  7                          
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)

  03/15/17  03/16/17  03/17/17  03/18/17  03/19/17  03/20/17
  --------  --------  --------  --------  --------  --------
   21 - 26   18 - 23   21 - 26   25 - 37   36 - 41   39 - 44
--------

South/Central NC                        
Richmond County Area                              

**** NEAR FREEZING COLD LOCATIONS  ****
**** LITTLE IF ANY FROST **** 

Lowest Temperatures:      34 - 41
Ellerbe Min                 41 
Range Dewpoint Temps:     25 - 39
Range Wetbulb  Temps:     34 - 40
AVG Wind Direction/Speed:  NW  8                          
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)

  03/15/17  03/16/17  03/17/17  03/18/17  03/19/17  03/20/17
  --------  --------  --------  --------  --------  --------
   23 - 29   21 - 26   24 - 29   37 - 39   38 - 41   43 - 46
--------

Interior/EC-SE NC                       
Wayne County Area                                 
**** LITTLE IF ANY FROST DUE TO CLOUDS/WIND **** 

Lowest Temperatures:      39 - 44
Goldsboro_AG Min            43 
Range Dewpoint Temps:     39 - 44
Range Wetbulb  Temps:     40 - 44
AVG Wind Direction/Speed:  NW 10                          
AVG Sky Condition:         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)

  03/15/17  03/16/17  03/17/17  03/18/17  03/19/17  03/20/17
  --------  --------  --------  --------  --------  --------
   27 - 30   22 - 25   25 - 28   29 - 38   38 - 42   41 - 44
--------

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