Agricultural Weather Forecast for April 6, 2021
April 6, 2021
MSU agricultural meteorologist Jeff Andresen presents weather forecasts focusing on farmer’s interests to the MSU Extension fruit team.
- I guess, certainly the short of it is spring conditions continue and will for the next couple of weeks. Although, we are looking at an unsettled weather pattern coming up here over the, certainly, the short-term future. I'll talk more about that in a second. Looking at the weekend review, and this is actually a day displaced, this is last Monday through Sunday. With the cooler weather of late last week, you can see which we brought our mean temperatures down for the week, actually to a degree or two below normal. It's been a while since we've seen that. Much of the spring has certainly, since late February has been warmer than normal. But last week was a little bit of an exception. On the right-hand side are our observed precipitation totals. These do not count some of the showers and thunder showers that we saw yesterday morning or at least not all of it across Southern parts of the state. But over most of the state, drier than normal conditions continued. So some of the, I guess longer-term patterns have continued, although again, some changes in the near term future. Looking at the weekend review, one of the biggest events, I think, certainly in terms of ag or ag impacts was the freeze event or cold event on overnight Thursday into Friday morning. There's quite a bit here on this particular graphic. So bear with me, but we did have a piece of Canadian or Canadian origin air mass move through the state, abnormally, unusually dry air with this kind of Thursday night, if you were watching this, as I was, some of the dew point temperatures in the middle of this air mass in interior Northern lower Michigan actually got down into the low single digits, above zero ends. When we see that, the dew point temperature of course, we use as a little bit of a, sometimes as a guide to how cold the air temperatures could get if we completely go still at clear calm. Fortunately, it did not but we did have a widespread cold. On the right hand side here, this is a summary of the minimum temperatures, the overnight temperatures. And what you can see are, well if you can't read the graphics or the legend here, generally upper teens across much of the well the Northwestern part of the lower peninsula to the low 20s down as you go to the Southwest. Up on that end, I've got two media grants here, one from Sparta, just North of Grand Rapids here from our environment weather site there. This is the 66-foot tower. And you can see here temperatures below freezing for most of the overnight hours. This particular site got down to 18 degrees. And temperatures down below 20 degrees here for about three hours, mostly just before sunrise. It had a lot to do with wind and as I mentioned, the real saving grace, I think that kept temperatures from going much further lower than they did was we did have wind to stir things up. One exception up here in the upper right-hand corner, are environment with a site up at Onekama, Bear Lake up in Manistee County, there we did go completely calm in temperatures this site, and this is definitely an exception rather than the rule, got down to eight above on again on Friday morning. And you can see that, the red here series for temperatures in the upper right. Prolonged and very, very hard freezing conditions at that particular site. So it again, shows you how important it is when we have wind in these types of events with very, very dry air. Looking at temperature for the season, and these are in degree-day totals here starting on March 1st up through Monday, or up through actually, this is up through Sunday, the totals here on the left-hand side and on the right, I've got again for for Sparta, which is fairly representative. One of the questions we've had repeatedly this spring is how close are we or how much ahead everyone, I think appreciates that we are at a normal and we are. And then this follow up question that is we're a solid one to two weeks, calendar weeks ahead of normal, in some cases more than that. Again, given where we can be at this time of the year. But, one of the questions of course is how close are we to 2012, which was the warmest March on record by far and nothing even close in the records on that. And the graphic on the right, I think, illustrates that, yes we are significantly ahead of where we are normal, but fortunately, nowhere near where we were in 2012. That will probably stand for a long, long time as the warmest or certainly the warmest quickest spring on record. So yes, we're ahead, but not extremely. So not like anywhere like 2012. The totals there, again, less than a third of what they were in 2012. So that a little bit of perspective about where things are right now. One of the other things that sort of snuck up on us here over the last few weeks is dryness and the lack of precipitation. We've been missed by several systems that have gone through the Midwest. And as a result of that abnormally dry conditions, at least as defined by the National Drought Mitigation Center have spread eastward into the upper Midwest and the great lakes as you can see with the graphic. This is the most recent one from, this is still from last week. It does not reflect rainfall as of yesterday. But still, 97% of Michigan in either D zero, abnormally dry, or the D one category, which is moderate drought. And the graphic here, you can see the at least the driest areas in the state are in the far Southern lower peninsula where most almost all of that D one is. So something to keep an eye on, but remember that we are coming out of the driest time of the year climatologically and things moisten up, certainly, climatologically as we move into the warm season. That's when we get most of our precipitation. So better to have this now than a few months later during the middle of the latter part of the growing season. But at least it's something to keep an eye on. Well, in terms of the forecast, we've got a very similar map to what we had yesterday at this time, there's a stationary frontal boundary draped across portions of central and southern lower. This is what led to the showers and thunderstorms yesterday morning. It's still here and just as importantly, it marks the Northern edge or Northeastern edge of a very, very abnormally warm and moist subtropical air mass more south. And if you've looked at the weather maps last couple of days, if you saw high temperatures in places as close as Northern Illinois or Eastern Iowa, well into the 80s. We are gonna be on the very edge of that air mass, at least portions of the state are here for the next couple of days. But that frontal boundary, again, marks the leading edge, Northern edge of that. We're also gonna have a couple of impulses move along this particular boundary, along the US Canadian border with initially here, the threat of more showers here over the Northern part of the state here today. Then continuing as scattered showers and thundershowers tomorrow. But the next best chance after today in the North will be statewide on Thursday and I'll show you, put the maps in a little bit of motion. By tomorrow morning, you can see that funnel boundary has advanced North ward with some of the warm air again, surging northward. You can also see a low pressure system get organized out here over the central Missouri Valley. That's the system I talked about for Thursday. Still lingering a chance tomorrow for a little bit more is again, in the Northern part of the state. The South should be dry. One of the other things we'll note with this besides the abnormally warm temperatures across central and Southern lower, we will be flirting with 80 degrees. Probably we'll hit 80 in a couple locations. There'll be a strong southerly wind with, again, counter-clockwise flow around the system out of the South. So almost some early summer-like conditions here for both today and tomorrow. By Thursday, the low pressure gets a little bit closer. You can see a frontal boundary moving towards the state. This is a statewide, this is gonna be our best chance for rain here at least in the next couple, starting overnight Wednesday into early Thursday and then continuing during the day on Thursday and then lingering some wraparound precept lingering on Friday. There is another after this. There's a likelihood of another weather system here this weekend on this Saturday, Sunday timeframe. So we're in a pretty active weather pattern at least here for the next several days to the better part of the week. Unsettled would be a good term here. But overall, when we look at precipitation totals for the week, not expecting anything really unusually heavy with any of these, but there will be repeated chances and so when you add all these up, again, with what's expected Northern parts of the state today, statewide on Thursday and then the additional rainfall this weekend, you can see for most of the state, at least a half to one inch with maybe some more localized or heavier totals than that especially as you go up into upper Michigan. So we will be putting or taking a little bit of a bite out of that precipitation deficit that we've accumulated here since late February. So definitely wetter than we have been over the recent past. Looking into the medium range forecast guidance. One thing is consistent at least for the short to medium term and that is a well upper air ridging across Eastern North America. Very, very high likelihood of continued warmer than normal temperatures. Even though after the frontal boundary, that's what our system goes through on Thursday, we will see temperatures cool off. They'll still be above normal. They're at least 20 degrees above normal, both today, tomorrow, and probably Thursday but we'll be moving back from highs in the 60s and into again, near 80 in the Southern part of the state. The other thing to note too about the next few days are minimum temperatures in the Southern part of state are not gonna go below the mid 50s. So we're gonna be racking up a lot of degree days. Lots of warmth out there, should see a lot of development especially with now some addition of some water, some precipitation here recently. So we expect a lot to happen over the next several days. By the weekend, our temperatures will fall back a little closer to normal but still above where they should be. Mainly upper 50s and 60s for highs and then lows in the 40s to low 50s. So still above normal, we'll probably be there along that level for a good chunk of next week. So the six to 10-day outlook is still calling for warmer than normal mean temperatures. It does, given a lot of chances for precipitation. It still puts us in above normal. I think there's less confidence about that than there is about the temperature. With eight to 14-day timeframe though, know that there are some changes possible and the medium range forecast guidance is beginning to suggest maybe some kind of a regime change or pattern change here as we move into latter part of April. And that as you can see the we've had a flattening out here there's still a split flow with the Northern branch and Southern branch across North America. The important thing about that is is that what that split flow, typically, we keep the really cold air masses out of the lower 48 States. And that's obviously a really important factor at time of the year. And you've also still got a strong West to East subtropical or Southern branch. That's where a lot of the weather systems are embedded. We've seen that pattern for a lot of the winter in early spring thus far. But I think the big news about that is it typically keeps the coldest air out of the lower 48 or at least it tends to, not that it can't happen, but it's less likely. But given this change to a more West to East zonal pattern, you can see a couple of things. And there's even a hint and I'll just bring this up in some of the guidance that we would see some troughing develop here over central and Eastern parts of North America later in April. And if we do that, we probably move to at least back to normal, if maybe not even a below normal. You can see a hint of that here in the eight to 14-day timeframe. This is 13th through 19th. Michigan's sort of on a gradient here, warmer than normal to the North but a little cooler than normal as you move South down in to the Ohio Valley and into the central corn belt. So the next change, probably, maybe the third week or so in April look for something different. Also calling for that same time drier than normal conditions. And I think that I believe in as well. I think that after this weekend, maybe early next week, we will see fewer weather systems, fewer chances for precipitation than what we have this week. And then finally, the long lead outlook. These were revised last week by NOAA's Climate Prediction Center. April's on top here. A very, very strong call for a warmer than normal mean temperatures. Now, remember, we're already almost one week through April. This is for the whole month and some of the above normal or the odds here, statistics for above normal temperatures are at the early part of the month. And it's gonna average out whatever happens at the end, but still the forecast is strongly calling for a milder than normal mean for April. No real direction on a precipitation, that's the equal chances here. So no forecast direction. But for the longer period here, for the April through June, and this is also true one month beyond that out into the middle of summer, still calling for warmer than normal. But also for increased odds of above normal precipitation. That is a result of, well, a lingering La Nina event. That's what the plume is here. We still have La Nina conditions in the equatorial Pacific but they are weakening and expected to return to near neutral here in the next month or two and remain there for the growing season. So we're at the very, very end of that. And I think this is the last probably vestige or piece of those La Nina conditions. But, I would also note that we have seen very few conditions typical of La Nina in this winter. And that's unusual, it happens sometimes. But in this particular winter, we just did not see much of a strong link with La Nina, with our winter. And that was true for a lot of North America and the lower 48 States as well. So take it with a little bit of grain of salt, perhaps. At least again, especially the above normal precipitation odds. It's probably a little bit on pushing the envelope. Beyond that, for the second half of the growing season, the outlook's still do, for what it's worth, still do call for warmer than normal favor, warmer than normal mean temperatures but no direction on precipitation. So a little bit different than what you see here, but still definitely warmer than normal is a theme for a lot of our forecasts today. So, summarizing. As I mentioned, abnormally warm, especially for the Southern half of the state and unsettled with a continuing chance for rainfall here into the weekend. Though, best chances are today and then again on Thursday, and then a third opportunity statewide this weekend. And we could see some fairly significant rain, quarter to half an inch in many areas. Temperatures will fall back from abnormal warmth here over the next 48 to 72 hours back to still above normal, but cooler, by the time we get to the end of the work week into the weekend and lots of degree day accumulation. So we'll be looking at a big surplus next week when we talk about where we are. In our medium range forecast guidance, still suggesting milder than normal. Although, a hint of a change towards late April. And as you just saw for the extended, the long leads also warmer than normal with, well, a little bit of variety on the precip from wetter than normal early to dry or to known forecast direction later on. And that's all I have here. Anyone have any questions this far? - Yeah, thanks so much, Jeff, for that report. Let's open it up to questions and see what people are thinking about the weather. - Jeff, this is Bill. The thing that kills us are these drops into freezing weather. So. What's the chances of that. Are we? (Bill chuckling) - Right, and that was one of the reasons I mentioned this. At least, of course climatologically, even in the Southwest and Southeast corners of the state, which are warmest, climatologically, parts of the state we still have a few more weeks, at least, statistically where we have to deal with freezing temperatures. It moves into early May, typically, as you go outside of those areas into a central and Northern parts of the state, or even later. So we've still got a few weeks on the calendar what climatology tells us the risk of freezing temperatures. But as I mentioned, that jet stream, that split flow is really critical because as we move, especially into the middle and latter part of April, physically, you have to have an upper air pattern that allows one of these Arctic or Canadian origin air masses access to the lower 48. And given the pattern we have now, it's really difficult for that to happen. Even though we did see a quick, a reminder late last week in a generally warm pattern, we saw three days where one of those air masses did make it down. But overall, statistically, if you look at that pattern we just talked about that jet stream pattern, it's less, it's certainly. Doesn't mean it can't happen, but it's much less likely. And that will be the case, I think, for the next one to two weeks. Now, beyond that, we'll have to wait and see. Statistically again, there still is a risk. But, I think the risk is less than what it would be in many seasons. So, any other questions? - All right, thank you very much, Jeff. Every spring is different.