How much longer can cold, wet weather continue?
An active jet stream indicates this weather will likely continue to the end of April.
Given the recent string of cold, wet, and gray weather – including several inches of new snow across much of northern Lower Michigan on April 19 – the most frequent question at the State Climatologist’s Office lately has been, “How long can this go on?”
Given a very active and energetic jet stream across the Lower 48 states, the short answer to the question is probably through the end of the month at least. However, there is one significant new wrinkle: above normal temperatures are likely at least for a day or two early next week.
In terms of rainfall, the active jet stream will lead to at least two major weather systems across Michigan through early next week. These could lead to more widespread rain and possibly some snow in the north. Spring fieldwork delays are therefore likely to continue for at least another week.
In the day to day forecast, look for mostly fair and dry weather statewide on Thursday (April 21). Overnight Thursday, the next low pressure system will approach the state from the central Great Plains, bringing the threat of more rain south and rain or snow in the north. Rain and a few thunderstorms will be possible Friday and early Saturday as the system tracks northeastward through Wisconsin and Upper Michigan. Precipitation totals with this system are expected to be lighter than those of the past 24 to 48 hours, generally ranging from 0.1 to 0.25” south to a half inch or more north. Sunday will be mostly dry north with a continued chance for a few showers south.
Yet another low pressure system is forecast to move through the region Monday through Wednesday of next week. This system will likely be stronger than Friday’s system, and include the threat of widespread heavy rainfall and severe weather. Temperatures will slowly moderate from highs in the low 40’s north to near 50 south Thursday and Friday to the upper 40’s to low 60’s Monday. Lows will warm from the 30’s Friday to the upper 30’s to low 50’s by Monday. High temperatures back into the 70’s are likely on Tuesday and possibly Wednesday of next week.
Further ahead, latest NOAA Climate Prediction Center medium range forecast guidance suggests an upper air trough across western sections of the North America next week gradually shifting to the Midwest by the end of the month. The 6-10 day and 8-14 day outlooks (for April 25-29 and April 27-May 3) call for a continuation of wetter than normal weather across Michigan and much of the Great Lakes region. Significant changes are expected as mean temperatures are forecast to range from near normal levels across the Upper Peninsula to above normal levels across Lower Michigan during the 6-10 day time frame and fall back to below normal values statewide during the 8-14 day time frame. Given good agreement among the various forecast models, forecaster confidence is considered above normal for both time frames.