Over Columbus Day weekend Sue and I were out of town for a mini-vacation, visiting my sister who lives near the Connecticut shore. Prior to leaving Hartwick, we covered up the tomato and pepper plants. Upon returning Monday evening, we noticed that pumpkin foliage (not under cover) was quite scorched from frost. Neighbors told me that the day before (Oct. 13), frost was everywhere, not just car windshields.
I checked my records to verify the timing of spring 2024’s earliest thunderstorm: April 14. That event is significant since it enables one to predict when the first killer frost of autumn should strike six months hence. What caused this storm was the southern branch of the northern jet stream surging northward. With this, a moisture-laden warm air mass slammed into a drier cold air mass. This merger caused huge condensation, and simultaneously great electrical activity, accompanied by a rapid drop in air temperature. Exactly one-half year later, the jet stream is supposed to do the exact opposite, allowing a frigid air mass to penetrate our region.
Scientifically, here’s the basis behind this first fall frost forecast (FFFF). The climatological factor calling the shots here is the jet stream polar drift rule. This states that the first electrical storm of springtime (in latitudes near the 45th parallel, halfway between the equator and North Pole) will be followed half-year later by autumn’s first killer frost. The 45th north parallel passes between Plattsburgh, NY, and Burlington, VT.
That’s how the jet stream phenomenon is supposed to play out – unless El Niño or La Niña “misbehave.” El Niño (Spanish for little boy) is said to take place when the Pacific sea surface temperature (PSST) rises by more than 1.5º C above normal for that particular time of year. La Niña (Spanish for little girl) occurs when PSST drops by more than 1.5º C below normal for that time of year. With the climatological tug-of-war between El Niño and La Niña being relatively normal last April, I felt comfortable making that FFFF six months down the road.
The dynamic between El Niño and La Niña is framed by climate change. With increasing global surface temperatures, the frequency of drought and greater storm intensity become more likely. More water evaporating into the atmosphere means more fuel to foster the creation of powerful storms. More heat in the atmosphere and warmer ocean surface temperatures help increase wind speeds in tropical storms. Rising sea levels expose higher land mass locations not usually subjected to erosive forces of waves and currents.
That said, this past April 14’s weather happening made me feel comfortable in predicting that our area (most of Central New York) could expect its FFFF on/about Oct. 14.
Climate’s “little girl” will likely be taking the Northeast’s center stage soon. She isn’t here yet, but has 60% chance of emerging in early November, according to the Climate Prediction Center. Upon arrival, she should stick around all winter and likely persist into at least early spring of 2025. When we include leap year, a half-year is defined as 182.63 days. So my forecast panned out at the 182-day mark. With that successful prediction, my forecast score card stands at 26-6.
Since the early 1990s, when I started conducting these tallies, there were several instances where I recused myself from forecasts, due to overly rambunctious niños and niñas. That most recent math gives me a score of 81.25%.
Three days after the first killing frost just mentioned, the wee hours temperature on my remote-sensing thermometer bottomed out at 27º F, so even covered tomatoes and peppers perished. But soon our area was officially comforted with Indian summer as temperatures rebounded upwards. Wikipedia defines Indian summer as “a period of unseasonably warm, dry weather often sometimes occurs in autumn in temperate regions of the northern hemisphere. Several references describe a true Indian summer as not occurring until after the first frost, or more specifically the first killing frost.”
What my neck of the woods experienced in the last few days satisfied both definitions. More research revealed that weather historian William Deedler wrote that Indian summer can be defined as “any spell of warm, quiet, hazy weather that may occur in October or November,” though he noted that he was “surprised to read that Indian summers have been given credit for warm spells as late as December and January.”
Deedler also noted that some writers use this term referring only to New England’s weather, “while others have stated it happens over most of the United States, even along the Pacific coast.”
Citing Wikipedia again, “Although the exact origins of the term are uncertain, it was perhaps so-called because it was first noted in regions inhabited by Native Americans, or because the natives first described it to Europeans, or it had been based on the warm and hazy conditions in autumn when Native Americans hunted.”
Examining this term a little more scientifically, we find most climatologists agree that Indian summer is typically caused by a sharp shift in the jet stream from the south to the north. The warm weather may last from a few days to over a week and recur multiple times before winter arrives for good.
Thus, Indian summer is a good time to feed living crops – not bare corn stubble – soluble nutrients, particularly winter forages. These include wheat, rye, triticale (a hybrid of the first two), speltz and barley. Soluble nutrients that can be fed to these species include urea (hopefully in protected form), mono-ammonium phosphate, diammonium phosphate and injected liquid manure slurry.
New York field research has found that up to 60 lbs. of nitrogen/acre increased spring yields of autumn-planted triticale by 43% on fields without prior spring/summer manure applications. These will be taken up and metabolized by these winter forages. Some growers still call them cover crops.
Leave A Comment