The first day of May will bring miserably cold, rainy, windy weather, capped off possibly by a rare May snow.
Temperatures are expected to drop through the day Wednesday - the warmest period is likely to be in the morning. By midday, temperatures may have dropped into the upper 30s, according to the National Weather Service. Gusty winds and one-half to three-quarters of an inch of rain are possible during the day.
As temperatures bottom out in the low 30s overnight, it's possible that ongoing rain will turn to snow and some will accumulate, said Cathy Zapotocny, meteorologist with the National Weather Service in Valley. Amounts are hard to forecast, but less than an inch is expected in the Omaha area.
AccuWeather Inc., The World-Herald's private weather consultant, said higher amounts of snow, 3 inches to 6 inches, are possible if all the pieces of a complex puzzle fall together.
"Conditions have to be perfect," said Alex Sosnowski, senior meteorologist at AccuWeather. However, if conditions are perfect, upward of 10 inches of snow could fall in parts of northeast Nebraska and northwest Iowa.
The eastern Nebraska-western Iowa area probably reached its high temperature for Wednesday by 4 a.m. — 48 degrees, said Josh Boustead, a forecaster with the National Weather Service Office in Valley, Neb.
By tonight, he said, temps will fall to around 33 degrees.
Winds Wednesday will be out of the northeast at 20 to 30 mph, with 35 mph gusts.
Rain is expected to begin by noon Wednesday in the Omaha area, mixing with snow through Thursday morning.
“We will see some snow across the area,'' said Boustead. “A lot of it will melt on contact with the ground.''
The ground temperature in eastern Nebraska and western Iowa is around 60 degrees, he said.
High temperatures Thursday should reach about 40 degrees, he said, with rain returning to the Omaha area Friday night into Saturday. Temps will remain below normal in the upper 40s to around 50, he said.
Normal temperatures for early May are highs in the upper 60s and overnight lows in the mid-40s.
Monday, temps return to near normal with a high in the upper 60s, Boustead said, climbing into the low 70s by Tuesday.
May snows in eastern Nebraska and western Iowa are rare.
That's because the snow has to overcome warm ground, marginal temperatures and the greater, seasonal intensity of the sun. For snow to overcome this and to accumulate in significant amounts, it must fall at an extremely high rate for a long time, Sosnowski said.
According to National Weather Service records dating to 1884, Omaha has had snow four times in May, Lincoln once and Norfolk, six times,
The Weather Service in Valley checked its books and found that Omaha and Lincoln haven't had measurable snow in May in 46 years. Norfolk hasn't seen a measurable snow in May in 59 years. A measurable snow is defined as 0.1 inches of accumulation.
A May 3, 1967, a storm dropped 1 inch of snow in Omaha and 3 inches in Lincoln.
A May 2, 1954, storm delivered Norfolk its most recent May snowfall when a meager 0.2 inches of snow accumulated.
Omaha's latest snow on record occurred May 9, 1945, when 2 inches accumulated.
There is good news in the forecast -- temperatures aren't projected to drop anywhere near the 28 degrees that would constitute a killing freeze.
Because this particular storm is hard to predict, forecasters aren't sure whether rain will continue through the end of the week and into the weekend. The storm is tilting as it rotates, so it could wobble back this way with additional rain late in the week and into the weekend, Zapotocny said. That's why forecasters have indicated a chance of rain every day of the week.