AWIS Weather Update (3/10/2018): Rain / Snow Sat-Mon, Frost Nights Tue-Thur in Most of NC

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Dear all,

Rain and snow are predicted, starting today afternoon through Monday. After this weather front passed from W to NE, minimum temperatures in the low 30s, upper 20s are predicted for the mornings of Tuesday – Thursday (see below). Maximum Temperatures are predicted to be in the upper 50s in some regions.

This can be a challenging time: protect your blossoms from cold injury on the one hand and try not to advance the crop on the other hand. The decision how often and when to pull on and off row coves is really based on many factors such as overall crop stage, market readiness, labor availability etc.

As a rule of thumb, if you don’t protect at all right now, you will most likely not have a crop in three or four weeks. Especially growers with early varieties which are partly in bloom already (such as Sweet Charlie) should protect as good as they can.

Air temperatures above 50 F will most likely lead to temperatures under a row cover which will lead to crop enhancement. Overcast days with lower light intensity are better to handle than days when direct sunlight can heat up the air under a row cover.

Especially in frost events (radiation events), the temperature at your blossoms can be much lower than the minimum predicted temperature in a weather report.As I discussed with at few growers over the last days and Barclay has indicated yesterday ( p.m.-friday-march-9-2018/) predicted air temperatures are based on measurements in 2m (6.25ft) height. 

At the Rockingham County Strawberry Meeting a few days ago, I’ve met a grower who has the good practice to measure temperatures at the blossoms with a handheld temperature measurement device ( p.m.-friday-march-9-2018/\)

He and others reported that temperatures at blossom level can differ as much 5 F and more to air temperatures in 2m height.

That means that the temperatures at your blossoms can easily exceed the protection you get from a row cover! Table 1 indicates the level of protection row covers give you.

Table 1: Maximum Protection of Row Covers 

Light Medium Medium Heavy
Weight (oz/yd) .06oz 1.0oz 1.2oz 1.5oz
gsm 20 grams 34 grams 40 grams 51 grams
Protection 27F 24F 22F 20F

At this time of the year, having a second strategy of protection could decide about the loss of fruit. Double covering or cover-sprinkling might be options.

At the Central Crops Research Farm in Clayton, NC we decided to leave covers off over the weekend. However, in many regions that strategy would be too risky right now. Piedmont min temperatures will be lower over the weekend and it is advisable to leave covers on.

Precipitation Forecast:

Figure 1: Predicted Rain Saturday (3/10/2018) to Monday (3/12/2018). 

Fig. 2: Predicted snow accumulation in Northern North Carolina and Virginia. Most Snow Accumulation will occur Sunday and Monday (see regional weather reports)

Minimum Temperatures:

Fig.3: Predicted minimum Temperatures for the nights of Tuesday (3/13) to Thursday (3/15). Grey areas indicated air temperatures can go down to 26-24F.

From Tuesday (3/13) to Thursday (3/15) predicted air temperatures can go down to 26-24F! That definitely pushes the limits of even one row-cover. Please be prepared for a second method of protection in those areas (see hourly forecast below).

North Carolina:

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


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


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

South Carolina:

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


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

As always I hope that helps. Please let us know if you have questions,



Written By

Photo of Mark Hoffmann, N.C. Cooperative ExtensionDr. Mark HoffmannSmall Fruits Extension Specialist, Assistant Professor, Strawberry and Grape (919) 352-8006 mark.hoffmann@ncsu.eduHorticultural Science - NC State University
Posted on Mar 10, 2018
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