(Des Moines) The state of Iowa spent most of February in an effective Arctic outbreak of cold air from an Artic intrusion. State Climatologist Justin Glisan says it was the coldest start to February since 1936. Temperatures averaged 15-20-degrees below average over the coldest stretch given the average temperature.
Glisan says the warmup late in the month balanced out the average temperature to about 12-degrees below normal, the fourth or fifth coldest on record.
The southwest corner of the state received about 10-to-15 inches of snow- one of the state’s snowiest parts for the month. Glisan, it’s interesting to note, in February, there was a big dip in the jet stream over the Midwest, allowing the Arctic air to intrude and hence a cold February. He says the opposite is happening now.
Glisan says in terms of March’s temperature behavior and noticing an elevated chance of higher than normal temperatures meshing well with the short-term outlook. He says March, April, and May appear to follow the same pattern. As far as precipitation, it’s showing a wetter than normal signal.
Glisan says a 60-percent probability exists for a transition from the current La Nina phase, a cold anomaly in the Pacific Ocean that affects thunderstorm activity within that basin and affects the jet stream over the central part of the United States, to Enso neutral. Glisan says if it does occur, wetter conditions will prevail from late spring into early summer. Glisan says that transition will not be known for a month or two.
