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| Vol. 23, No. 18, September 19, 2008 |
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| In this issue Landscape and nursery New insecticide products are providing excellent and affordable protection of ash trees from emerald ash borer Fall color outlook Preparing landscapes for winter Soil test price increasesTurfgrass Autumn turf tips Stigmina found associated with needle cast on blue spruce in Michigan Diplodia/Sphaeropsis shoot blight of Austrian, red and Scotch pine is rampant in Charlotte area of stateAround the home Fall invading insectsOther news Employee dismissal Weather news |
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| Final issue for 2008 This is the last issue for the 2008 season of the Landscape Alert newsletter. Included in this issue is an index of articles to help guide readers through the topics covered this year. Educators and specialists have worked hard to inform readers about current issues and crop production throughout the last few months. Now we would like to hear from you! Please send us suggestions on topics that you would like us to cover in 2009. Take our survey at to let us know how you are benefiting from the newsletter and to give us feedback on improvements for the print publication and web site. Please send your comments via catalert@msu.edu or mail them to the address on the back of this newsletter. Indicate whether you are referring to our fruit, vegetable, field or landscape edition. Thank you. -Joy Landis, editor, Andrea Buchholz, asst. editor, Victoria Morris, associate editor |
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New insecticide products are providing excellent and affordable protection of ash trees from emerald ash borer
Ash protection in East Lansing, Michigan 2005 – 2008 (mean dbh = 12.0 inches)
Ash protection in Adrian, Michigan 2006 – 2008 (Mean dbh = 15 inches)
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| Fall color outlook Our rapid shift from hot, dry weather around Labor Day, to the heavy rains of a week ago make forecasting Michigan’s fall color more dicey than usual. Many trees in the mid-Michigan area and other parts of the state were beginning to shed leaves in response to our hot Labor Day weekend and the dry weather that preceded it. Now that soil moisture has been replenished in many areas it should help the trees to hang onto their leaves and give a good fall show. The intensity of fall leaf color is largely determined by the weather in late September and October. Clear days and cool nights help to provide the best color. Adequate soil moisture helps the trees to hang onto their leaves and increase the duration of the show. If things dry out again or you’re in an area that didn’t get five inches of rain last weekend you may still get good color, but the display will be short. My advice is to plan your fall color trip early this year and follow one of the various fall color websites or hotlines. Beginning September 10, fall color watchers looking for the best viewing opportunities can call Travel Michigan at (888) 78-GREAT (784-7328) for color updates provided by AAA Michigan each Wednesday through October. Updates also will be on the Internet at AAA.com (go to News/Safety page), or visit www.michigan.org. Additional fall color updates are also available form the United States Forest Service www.fs.fed.us/news/fallcolors/ and the Foliage Network www.foliagenetwork.com |
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| Preparing landscapes for winter With football season in full swing and leaves about to turn color, we come to the sad realization that snow will be flying before too long. Landscape plants in Michigan face an array of environmental challenges, but it’s safe to say that winter is the toughest season for environmental, or abiotic, injuries. This is largely because there are so many different ways that winter conditions can injure plants. Types of winter injury Freezing injury: When cold temperatures drop below the hardiness level of plants, freezing injury may occur. In the middle of winter (mid-January to mid-February) plants reach their maximum hardiness and can usually withstand even the most bitter cold. Where we encounter problems is during the winter acclimation and de-acclimation phases. So if we get a record cold night in late November or, more commonly, extremely cold temperatures following a late winter warm-up, we can see freezing injury. Freezing injury usually appears as die-back in the spring. Depending on the plant, die-back may be limited to branch tips or the entire tree or shrub may die-back to the ground-line. When thinking about freezing injury, it is important to remember that roots are much less cold hardy than the above-ground portion of the plant. If you are over-wintering container or B and B material, make sure plants are properly heeled-in to protect the roots for the winter. Salt damage: Last winter’s heavy snowfall forced road crews to use large amounts of de-icing salt. As a result we had lots of reports of salt damage to plants. Sodium chloride is the most common de-icing material and can damage plants in a variety of ways. Alternative de-icing materials that also contain chloride, such as calcium chloride, also have the potential to cause damage. For small-scale de-icing, consider alternative materials that do not contain chloride such as calcium magnesium acetate. Where exposure to conventional de-icing salt is unavoidable, use burlap or canvas to shield plants from salt spray or splash. Yes, I realize this isn’t always an aesthetically pleasing look, but it the most effective way to keep plants healthy through the winter. Snow and ice breakage: Heavy snow and ice can wreak havoc on trees with weak branches. Once trees have dropped their leaves it’s an excellent time to inspect the branch architecture of your trees. Look for large limbs with evidence of decay and narrow crotch angles. People that work with hazard tree evaluation think in terms of targets; if a branch failed what would it hit. A questionable branch overhanging your carport or your kid’s bedroom should be inspected by a professional arborist. Winter desiccation: As the name implies winter desiccation is actually a form of drought stress. It occurs on conifers and evergreen broadleaved plants when temperatures begin to warm, usually in late winter, but the ground is still frozen. As leaves begin to lose water through transpiration, the plant cannot absorb water since the ground is frozen and the plant desiccates. As with salt injury, protecting plants is the best remedy, especially for evergreens on exposed sites. For more information on these and other environmental plant injuries, please see MSU Extension Bulletin E-2996 “Abiotic Plant Disorders - Symptoms, Signs and Solutions - A Diagnostic Guide to Problem Solving.” The bulletin is available from the MSU Extension Bulletin office or as a full-color pdf file at: http://www.ipm.msu.edu/cat08land/pdf/9-19abiotic.pdf |
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| Soil test price increases The MSU Soil and Plant Nutrient Laboratory announced a price increase effective October 1. County Extension offices will receive a copy of the new schedule next week. The regular field test will cost $10, up from $9, but the regular lawn and garden test will increase to $12, reflecting the additional service often required interpreting those. If you have several crop areas that need to be tested, September is a fine time to get them done, or at least to purchase the prepaid boxes from your Extension office ahead of the increase. |
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| Autumn turf tips The deluge of rain the state received last week has certainly revived turfgrass that had been struggling from dry conditions the previous six weeks. Now the challenge is catching up with the flush of growth the rain has produced. Go slow on mowing if you haven’t been able to cut since last weekend as it is likely the turf has elongated several inches in just the past five days. If you have room to raise the height of cut this might be the time as it will make it easier to mow through the abundant growth. Fall fertilization The benefits of any Labor Day fertilizer applications are certainly being felt now, but if you haven’t applied a fertilizer and are still interested in giving the turfgrass a boost, fall is definitely a great time to fertilize. A fertilizer application in the fall will allow the turf to recover from any summer maladies and will help the turfgrass store carbohydrates that will be used next spring to initiate growth. Fall broadleaf weed control Fall is the ideal time to control broadleaf weeds because the weeds are storing carbohydrates in their root system and are more susceptible to herbicide applications. So if your turf has been overtaken by a bevy of broadleaf weeds, applying a herbicide now will make a difference in what you battle next year. Apply the herbicides on a sunny day when rain is not in the forecast for 24 hours. We want the herbicides to dry on the leaf surfaces and not be immediately washed off. The abundant rain ensures the turfgrass and weeds are actively growing right now, which is important to ensure the herbicides will be taken up and transported within the weeds. There are many different herbicides that could be used including the most common three-way broadleaf weed control mixtures. As with any pesticide application always make sure to wear the appropriate safety attire and follow all label recommendations. The greatest shortcoming of killing broadleaf weeds at this time of year is that you really don’t get to watch them die. In many cases you may not see the obliteration of these weeds this fall,but next year they won’t be there or you will have at least reduced their numbers. Fall seeding If you’re going to reseed an area,now is the time to get going. We are probably past the ideal seeding window, but if you can still get seed out in the next week it will probably have enough time to establish before winter, at least as long as winter isn’t really early this year. Along the Grand Rapids-Lansing-Detroit corridor you are probably safe to seed until around October 1 and have enough time for the seed to germinate and survive the winter. If you’re north of that line and still want to seed, hope for a warm fall. Consider that seed is relatively inexpensive and if you’re not doing a huge area I wouldn’t worry too much, if it doesn’t survive the winter you’ve got some practice in this fall and will be ready to go next spring. Core aeration Another fall turf activity is core aeration. Golf courses throughout the state have been and are still punching holes in fairways and greens. Core aeration improves soil aeration (oxygen which roots need to grow), relieves compaction, and removes organic matter. Some will even follow core aeration with overseeding to spruce-up some thin areas. Any homeowners considering core aeration should make sure that all underground wires, such as shallowly buried invisible doggy fence wire, irrigation pipes, and sprinkler heads are well marked to avoid any unforeseen disasters. Mulching leaves If you look closely you can already see some leaves changing which means we’ll soon see leaves falling. If you haven’t tried to mulch leaves back into the turf maybe this is the year you start. Here’s what you need to know to successfully mow leaves into the turf. First of all make sure your mower has a sharp blade, after a long season of mowing the blades may be dull at this time of year and trying to chop up leaves will be more challenging with a dull blade. Second, raise the mower as high as it will go and mow at your normal speed, don’t “rev” the throttle to the high jackrabbit setting and blaze around the yard. Try to mow the leaves when they are moist from the morning dew, but don’t mow them when they’re really wet. This will prevent the leaves from blowing all over the place and will help with your allergies. Finally, don’t let the leaves pile up too high before you mow, too high would probably be greater than three to four inches of leaf depth on the turf. Mulching leaves helps the turf by returning nutrients and organic matter which can be especially beneficial on poor soils. Final mowing Many people ask about lowering the mowing height for the final mowing of the year. When you get past the leaf mulching period in the fall and the turf has essentially stopped its top-growth, it is ok to lower the mowing height to clean-up the turf and prevent the turf from being too tall going into winter. I would recommend that you lower the mowing height no more than one notch on your mower, typically one half inch. This will help you clean-up any left over leaf mulch or debris and give the turf a little trim before winter sets in. |
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| Stigmina found associated with needle cast on blue spruce in Michigan In the December 2006 issue, the North Dakota State University extension service publication Tree Talk, (http://www.ag.ndsu.edu/trees/whatnew/Tree_Talk_Newsletter.htm), authors Jim Walla (forest pathologist) and Kasia Kinzer (plant pest diagnostician), NDSU Department of Plant Pathology, report that a fungus, Stigmina lautii had been discovered on spruce in North Dakota. The article has a short history of the problem and good descriptions of spruce afflicted with problems and photos of the potential pathogen. We have seen this same fungus on blue spruce needles in Michigan for the past few years, but it had not been found often and certainly was not found as abundant as either Rhizosphaera kalkhoffii, a fungal pathogen known to cause Rhizosphaera needle cast disease or Setomelanomma a fungus with an unknown role in diseases of spruce. This summer we began to see more Stigmina on blue spruce than in previous years. I want to share our 2008 observations with you because this may begin to provide some insights into a new spruce problem and what we may or may not know about it. On this blue spruce plantation in north central Michigan, Rhizosphaera needle cast had been well managed. Well-timed sprays in the spring had suppressed Rhizopshaera to non-detectable levels in the population of trees. However, by mid-summer 2008, it looked as if the trees had a needle cast disease on the lower branches. The casting needles were year two and year three needles. Current year needles were not affected. The second and third year needles were turning purple or brown, dying and dropping off the stems. These needles had a black fruiting body replacing the white wax plugs similar to Rhizosphaera under observation with a hand lens. Under the higher magnification in the lab, the fruiting bodies were obviously not Rhizosphaera, but Stigmina. This was the largest amount of Stigmina on blue spruce we have seen in the state. While we do not know much about Stigmina, we now know that what controls Rhizosphaera does not control Stigmina because either the fungicide could not handle Stigmina, or the timing of the fungicide was not appropriate for Stigmina. If you have been spraying with chlorothalonil-based fungicides and not finding acceptable control of your blue spruce needle cast problems, you may not have Rhizosphaera needle cast, it might be Stigmina. In the photos you will be able to see typical Rhizosphaera fruiting bodies on blue spruce needles, Setomelanomma fruiting bodies on the stem of blue spruce, not on the needles, and Stigmina on the needles of blue spruce. Pay attention to the shapes of the Rhizosphaera and Stigmina fruiting bodies because at first they can look like each other. The presence of Stigmina makes the needles look dirtier than a Rhizosphaera infected needle. Also, the Stigmina fruiting bodies called sporodochia look like little spiders while the Rhizosphaera fruiting bodies look like smooth bowling balls. We have not seen needles infected with both Rhizosphaera and Stigmina, yet, but there is nothing that we know of that could rule that out. We have observed stem infection with Setomelanomma and needle infection with Stigmina on the same branch. We will be ready to study this potential new problem on blue spruce in 2009. |
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| Diplodia/Sphaeropsis shoot blight of Austrian, red and Scotch pine is rampant in Charlotte area of state Last week I was called by a resident of Charlotte (Eaton County) who was wondering if anyone knew why so many pine trees in his city were dying. I jumped in the car and went to see what he was talking about. In touring the area with him, I found that he was correct; large numbers of landscape Austrian, Scotch and red pine are diseased and many are dying. I noticed that most of these trees were severely afflicted with Sphaeropsis tip blight. This was covered in an article in the May 9, 2008 Landscape Alert, “Management of Diplodia/Sphaeropsis shoot blight of Austrian, Red and Scotch pine.” This disease, while severe on annual growth usually does not kill trees, so a follow up inspection this week with Jill O’Donnell, Christmas Tree ICM educator, showed the involvement of bark beetles, which was not surprising. The large numbers of dead and dying trees are around houses, parks, schools, churches and in windbreaks. There are a lot of dead trees that will need to be removed. Right now, the red needles are blending with the turning maples and dying ash, but next spring many homeowners will realize that these trees are not going to push new buds. This disease is widespread throughout the state because droughts in previous years have stressed the trees, and wet springs have spread the spores to the susceptible tree species. Why so many pines have died in the Charlotte area is anyone’s guess, right now. If you live in the Charlotte area, and your red, Scotch, and Austrian pines are stressed, shoot blight will appear next year and you may want to be ready to manage this disease next spring. Do not cut out diseased portions of the trees that have infections when the needles are wet and remember your cutting shears can carry the spores of the pathogen. Also, in landscape situations, you must rake up cones which are a major source of the spores. Manage this disease with a package of treatments including turf removal under the tree; apply mulch and water, the 10 inches of rain this past weekend will probably suffice until next year. By eliminating the grass under the tree, it will remind you not to apply fertilizer to the trees. Use no-nitrogen fertilizer. Prune out dead tips during dry weather and clean pruners with a bleach mixture as shears can carry spores and establish new infections. Use Cleary’s 3336 thiophanate methyl or chlorothalonil for chemical control if needed. In the landscape, consult a professional tree care expert.
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| Fall invading insects Autumn is the time of year when we humbly and gratefully thank our lucky stars for surviving, though possibly not unscathed, the summer onslaught of biting insects, stinging insects and other annoying arthropods. However, we are not out the woods yet. There could be a large numbers of insects out there waiting to invade our homes and businesses. I say “could be” because we won’t know that for sure until we get the first few frosts of the season. There are four species of fall invaders that routinely show up on the outside walls of our homes looking for a nice crack or crevice to crawl into to protect themselves from our extreme winter weather, a depressing thought all by itself. I don’t think these bugs intentionally seek out our homes for this purpose. It’s just that our homes provide so many places for these bugs to hide in to pass the winter. As nighttime temperatures cool many of us will begin to see these insects congregating on the outside of the south and west facing walls of our homes. The unlucky may see thousands of them. If they just stayed on the outside of our homes I think most people would not mind them so much, but they don’t stay on the outside. In bad years hundreds may find their way inside to the very space where we spend the winter. In general, these bugs are harmless: most do not bite; they do not eat fabrics, stored foods, wood or pets; and they do not lay eggs in the house. For most of the people I talk to about these bugs, the fact that they are harmless is of little or no consequence. Most people would rather not share their living space with a bunch of annoying, albeit harmless, bugs. What to do, what to do? Many people who offer advice on reducing these unwelcomed guests suggest sealing exterior cracks and holes with caulking to prevent their entry inside. This may work on older homes with clapboard siding, but no amount of caulk is going to keep them out of a home with vinyl siding. Vinyl siding and soffits are not tightly nailed down; these are nailed loosely or as they say in the trade, “hung.” It is done this way to allow these vinyl panels to expand and contract with changing temperatures. Fall invading insects can find their way around the edges of these loose panels and into wall voids and attics. If homes were not heated these bugs would likely be content to go dormant and spend the winter in these cozy confines. Unfortunately our homes are heated and this warmth keeps these bugs active, they find their way into the living space probably around baseboards, window and door moldings, openings for electrical outlets and fixtures, openings for heating/cooling vents and other such pathways. There is very little that can be done once the bugs are inside the walls. In homes invaded by these bugs, it is very common and likely that one will continue to see them throughout the winter. Even aggressive and costly insecticide applications may not be effective because it is nearly impossible to treat every hidden area that may be harboring insects. Sealing cracks around electrical outlet boxes, switches and light fixtures, and around window and baseboard molding on the inside walls will help keep the bugs trapped within the walls. In older homes with double-hung windows equipped with pulleys, insects commonly enter living areas through the pulley opening. Masking tape applied over the opening will keep insects from entering through this route. A vacuum cleaner is an effective method of removing the sluggish, slow moving bugs from the house. Spraying the outside walls of homes, especially the south and west facing walls, with a long lasting insecticide registered for this use in September can help reduce the number of insects entering homes. These sprays should be applied when the first bugs are noticed congregating on outside walls. Before treating the whole house, spray a small test area to make sure the insecticide does not stain the siding or paint. Be sure to read and follow all directions on the pesticide label. Spraying the outsides of homes will, no doubt, involve spraying above one’s head. Be sure to wear protective clothing such as a wide-brimmed hat and raincoat. Eye goggles are a must. What bugs can you expect to see? The bugs that we are most likely to see on our homes this fall include the multicolored Asian lady beetle, cluster flies, foreign grain beetles and everyone’s favorite: the boxelder bug.
In kinder and gentler times when ladybeetles were not overwhelming, we would not recommend killing the beetles because they are beneficial insects, but desperate times often require desperate measures. The Asian multicolored ladybeetle is not a protected species, another popular rumor. Spraying the exterior to help reduce the number of these swarming insects may not be a politically or socially correct action, but treating one’s home is an option. It is difficult to imagine that the overall population of multicolored ladybeetles will be much reduced by folks spraying homes. Those who fancy the cute little beetles can vacuum them up and then release them some distance away from their house. Cluster fly The cluster fly is another species that enters homes in late summer and early fall in search of protected sites in which to spend the winter. Cluster flies resemble the common house fly, but differ in that they have a patch of yellow hairs under their wings. The cluster fly maggot is an internal parasite of earthworms and the flies are among the first to be active in the spring. They can be observed buzzing around yards just above the ground. They lay their eggs in cracks in the soil and the eggs hatch in about three days. Newly hatched maggots grab onto earthworms as they slither by and burrow into the worm to feed. Four to five weeks are required to complete a life cycle. The worm does not usually survive the experience. There are up to four generations of cluster flies in Michigan each year. Treating yards with insecticides to kill earthworms has not been shown to be effective in reducing the number of flies entering homes.
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| Employee dismissal Dismissal is the involuntary termination of an employee’s employment. Because emotions are often high, dismissals need to be handled with great care, or avoided. How can managers avoid dismissals? Careful selection, training, and management decisions serve to reduce the number of dismissals. In any case, a dismissal should only be considered after other options have been tried and did not lead to the desired results. Except in cases of gross misconduct, the dismissal should not come unexpected to the employee. Managers need to make sure that sufficient opportunities for changes were provided and a fair disciplinary process was followed. In addition, regular evaluation of an employee’s performance and a paper trail regarding performance appraisals and disciplinary actions is a must should a terminated employee challenge the dismissal in court. Michigan is an at-will employment state. What this means is that in the absence of a contract, the employee can resign at any time and for any reason and the employer can terminate for any reason or with no reason. Two exceptions apply in Michigan: the public-policy exception and the implied-contract exception. The public-policy exception prevents employees from being terminated for an action supported by the State’s constitution and statutes. For example, civil rights and equal employment opportunity legislation prohibit discharge based on an employee’s protected characteristics, including race, color, religion, sex, national origin, age, and disability status. Other examples are the reporting of dangerous workplace conditions, union activities, and the refusal to break the law on the employer’s request. The implied-contract exception is brought on by an employer’s oral or written assurances with respect to job security or disciplinary procedures. For example, an employee handbook describing procedures to be followed if disciplinary action becomes necessary or statements to the effect that no employee will be fired without just cause create an implied contract. Then the employer needs to follow the described procedures. Also, if a manager in charge of hiring, or the employee’s supervisor tells him or her that the employment will continue for as long as the work performed is adequate, an implied contract is created. If an employee’s dismissal does not comply with the law or does not comply with contractual agreements stated or implied in handbooks, application forms, or other company documents, it is considered a wrongful discharge. A wrongful discharge may be actionable in court. Even if a plaintiff does not prevail, management time and attorney costs are reasons to carefully review company policies before dismissal decisions, in particular when the dismissal is without cause. As a preventive measure employers need to review and regularly update their employment documents, if they want to ensure an at-will employment relationship with their employees. However, less job security may also result in less loyalty from the employees. Other important decisions in dismissal are how to conduct a termination interview and whether to offer severance pay. To read Dr. Bitsch’s complete newsletter go to her website at http://www.msu.edu/user/bitsch. Under “News” click on “Agricultural Labor Issues in Michigan” for a list of available newsletters. Please remember that these newsletters serve educational purposes only and do not constitute legal advice. |
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| Weather news Tropical visitors What a difference a week makes. During the latter half of the 2008 growing season, the majority of Michigan and the eastern Midwest region experienced much drier than normal weather, with less than half of normal precipitation mid-July through early September. Enter the Atlantic hurricane season. Relatively weak upper air winds and warm sea surface temperatures across the subtropical Atlantic basin have led to a very active season thus far, with 10 named storms. While hurricanes, generically referred to as “tropical cyclones,” and their remnants typically move poleward from tropical and subtropical origins at some point in their lifetime, it is somewhat unusual for them to impact Michigan and the Great Lakes region as the storms must make landfall in an area potentially upwind of the region and then upper air winds have to be just right to advect or transport the remnants here before the system completely dissipates. After making landfall, the storms weaken as they lose the major source or their energy, water vapor from a warm ocean, and if they move poleward and persist long enough, they may transform into their mid- and upper latitude sibling, the extra-tropical cyclone, the type of low pressure area that brings us the majority of our precipitation year-round. This year, we have really beaten the odds, as three separate tropical-origin systems have impacted the state. The first was Hurricane Gustav, or more precisely, its remnants, which initially made landfall in Louisiana and moved through Michigan on the September 3 and 4. This system brought over four inches of rain to western sections of the Lower Peninsula. Because the rain with this system fell in a steady, moderate intensity over a several hour period, in contrast with a heavy thunderstorm event in which the rain falls at sometimes torrential rates over short periods and runs off, the vast majority of the precipitation soaked into the soil profile. This past weekend, Michigan was visited by two more tropical systems. The first was the remnants of Tropical Storm Lowell, which made landfall in northwestern Mexico last week. The remnant moisture from this system was caught up in strong southwesterly low-level winds and transported into the Midwest. An extratropical upper air disturbance and cool front at the surface moved into the region last Friday, providing strong lift for the residual moisture. The result was a widespread area of heavy rain from Illinois and Indiana into southern Lower Michigan overnight Friday into Saturday. More than six inches of rain fell in the Chicago area, setting a new all-time record for precipitation in a 24-hour period. Just a day later, Hurricane Ike made landfall in the Galveston, Texas area. The southwesterly winds that brought the remnants of Lowell into the Midwest were still in place across the region, and Ike=s remnants moved quickly north and eastward into the Great Lakes region by early Sunday morning, Galveston is about 1,200 miles away from Michigan and it moved here in approximately 30 hours, which is an average rate of about 40 mph, with another round of heavy rain. Relatively strong winds, 15-25 miles/hour with higher gusts, were still present with the system as it moved through southern Lower Michigan. The spatial pattern of rainfall during the last 30 days illustrates well the movement of the three tropical systems into the Great Lakes (see Figure 1). More than 10 inches of rain have fallen at some locations across the southwestern Lower Peninsula, leading to flooding and water-logged soils, and some new rainfall records. Normal rainfall for this period generally ranges from three to four inches. Unfortunately, the recent rainfall generally missed some northern sections of the state, and drought conditions continue there. Finally, it is interesting to note that the wettest month climatologically over most of Michigan tends to be a summer month (e.g. June). However, September also shows up as the wettest month at some locations. After this past weekend, we at the State Climatologist=s office are very curious about the role of tropical moisture in our climate and how frequently it is a factor in Michigan, maybe more than we had suspected previously. A study is under way...
Looking ahead In contrast to the turbulent weather of the past week, high pressure across the Great Lakes region should lead to generally fair and dry conditions into next week. Temperatures will remain at or above near normal levels Saturday, with highs Thursday from the 60s north to the low and mid-70s south and lows generally from the mid-40s north to mid-50s south through the early weekend. A weak cool front will move through the state late Friday into Saturday, bringing the chance for showers and thundershowers, but given little moisture ahead of the front, any rainfall with the system should be light and isolated with most locations remaining dry. Temperatures will fall back a few degrees Sunday and Monday following the passage of the front, but warmer temperatures, highs back into the 70s to near 80°F in many locations, are likely again much of next week with the eventual formation of an upper air trough across western sections of North America and ridging across the east, which typically results in a warmer and drier than normal pattern in Michigan. The next chance for significant precipitation will likely be next Thursday or Friday as another cold front approaches the state. In the medium range time frame, forecasts follow the western troughing, eastern ridging upper air pattern described above, with National Weather Service 6 ‑ 10 day, covering September 24-28) and 8 ‑ 14 day, covering September 26-October 2, outlooks both calling for above normal mean temperatures statewide and near normal precipitation totals. It should be noted, however, that some of the computer model guidance used in the outlook is not in agreement, so forecaster confidence is considered relatively low, especially in the 8 - 14 day timeframe. Longer lead outlooks from NOAA's Climate Prediction Center (CPC) for the next few months in Michigan remain generally vague. The NOAA 30-day outlook for the month of September calls for cooler than normal mean temperatures across large areas of the Midwest and Great Plains regions. The outlook also calls for above normal precipitation totals across much of the southeast United States due to an active tropical storm season in the Northwest Atlantic Basin. For Michigan, the official outlook still places all of the state in the equal odds scenario of below, near, and above normal mean temperatures and precipitation totals. The NOAA outlook for September through November continues to call for increased odds of above normal temperatures state- and regionwide, but no forecast direction for precipitation (i.e. the equal odds scenario). |
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