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Sunday, January 31, 2016

Heavy Snow and Blizzard Conditions Tuesday

A major winter storm is expected to pass through parts of the Midwest on Tuesday, bringing a range of high impact weather to the region. The track of the system is becoming more apparent as we close in on 48 hours out from the onset. There is high confidence that 6"+ of snow will fall in a large region from northern Kansas to the U.P. of Michigan. Some areas in question include far southeast Wisconsin and the Minneapolis metro area. It will depend on just how much warm air works in and how strong the dry arctic high pressure to the north will be, respectively. 

Theis area of low pressure will ride along a tight temperature gradient and the 250mb jet stream at higher levels. Notice the forecasted temperatures off the GFS model (via weatherbell) in the attached image. This clashing of a cold airmass vs a warm moist airmass will add fuel to the system. Even severe weather and tornadoes are expected to develop south and east of the track on Tuesday. Furthermore, blizzard conditions are expected across Kansas, Nebraska and Iowa on Tuesday and gusty winds with a fluffy snow will create reduced visibilities at times. 

The system is currently crashing on shore this afternoon, and is finally reaching a part of the world where weather observations and data will be ample. This "landfall" will aid in an even more accurate forecast, giving more tools for meteorologists to look at and allow weather models to do what they do best. The track of the system does seem to be in good agreement. However, the potential of poor data achieved over the Pacific Ocean will now be sampled on the west coast and some minor tweaks to the forecast are still possible in the next 24 hours. Be sure to keep it here to midwest weather or follow the meteorologist on Twitter. Thanks for reading. 

Thursday, January 28, 2016

Groundhog Day Blizzard Unfolding Next Week

Computer models and data/observations are continuing to increase confidence in a high impact winter storm to start off next week. The question is who and where sees the bulk of the extreme weather. Right now the system that is forecasted to work into the Midwest is still out in the middle of the Pacific Ocean, where data is relativity sparse. A lot can change as this disturbance evolves, but the idea of a low pressure ejecting from the Rockies on Monday looks concrete. Blizzard condition are expected to develop in parts of Kansas as we head into Monday and Tuesday. The highest confidence is located in this location, as we have a good evidence that this piece of energy will cross through the four corner regions and dump heavy snow and high winds northwest of the track. Meanwhile, the question of exactly where it goes next us still somewhat up in the air. A stronger system would phase more to the west, while a weak system looks to pass through the Chicago area. Current model guidance is leaning towards a low pressure tracking over Chicago, which would dump the heaviest snow from central Iowa to Northern Wisconsin, similar to this Winter Storm. On the left is a variety of model solutions for this winter storm through a process called ensembling. This process gathers observations and runs the model numerous time. After it is ran with the most current data and observation it is than ran again with 22 different tweaks in the data to make up for error and lack of data across the Pacific Ocean. A few degrees or miles of certain features can certainly affect what happens downstream. It like a pebble in lake, the further away you get the less uniform the waves look. As we get closer in time, the exact track will continue to be easier to pin down and increase confidence. Be sure to keep it here to Midwest Weather as we will have a snow map out over the weekend. You can follow the blog meteorologist on Twitter or 'like' us on facebook. Thanks for reading.

Wednesday, January 27, 2016

Strongest Winter Storm in 2016, thus far

A major winter storm is poised to pass through the Midwest to start off the month of February. History and climatology suggests it will take the ideal track as is ejects from the Rocky Mountains early next week. A band of 6-12" of snow will likely set up north and west of the track as it heads into Canada. At this moment, model guidance suggests that this axis of heavy snow will line up from north central Kansas to Lake Superior. Areas further east will see a wintry mix and all rain, while areas further west will see less snow. The shaded blue area on the map is the most likely location of accumulating snow. This track will likely fluctuate east and west through the next several days, but will need to be watched very closely through the rest of the week. Be sure to follow us on facebook and twitter for even more updates.

Below are different ensemble runs of the US weather model, the red numbers indicate the strength and location of each possible storm location. Still a large range of possibilities. As we get closer to the event, this range of solutions will consolidate and confidence will grow. 


Tuesday, January 12, 2016

Powerball Odds of Winning Compared to Extreme Weather Events

With the craze and possibilities of a one billion dollar plus lottery, its easy to get caught up in the chance of winning. The odds of winning (on one ticket) are close to 1 and 300,000,000. The following will examine and attempt to put this number in perspective, as it relates to extreme weather events. Some of the data/odds are calculated from dividing through the total population, while some will be more regional in terms of probability.





The Struck by Lightning Odds:

Certainly, struck by lightning is one of the more common methods in comparing lottery odds to a single event, but lets go deeper. The odds of being struck in one year are 1:1,190,000, so you would need to but 245 Powerball tickets of different numbers to have the same odds as being struck by lightning in a year. Or you could buy 10 tickets to have the same odds at winning a million dollars. The odds of being struck by lightning in a lifetime is: 1:12,000. You are around 2 times more likely to get struck by lightning twice in a lifetime than win the Powerball. So let's say you buy a Powerball ticket for every drawing in your life for 80 years, odds suggest you are only 3 times more likely to be hit by lightning. Not bad right? It would just cost you $16,640 to buy a ticket every drawing for 80 years, assuming you buy just one ticket. On a side note, the general population, along with improved technology has decreased lightning deaths from over 400 in 1940, to just over 20/year recently, so these odds continue to become more rare!

The Hit by a Tornado Odds:

Most tornado deaths occur from Strong to "Violent" tornadoes, which is defined by the national weather service as EF-3 or larger. This number makes up less than 10 percent of all tornadoes in a year. According to the National Cimatic Data Center most states in the Midwest average about one EF-3 to EF-5 tornado per 50,000 square miles (lowest values in Michigan, highest in Missouri and Kansas). With this data we can estimate the odds of a particular tornado striking your house. Let's say the average path length of a Strong to violent tornado is 5 miles long and a quarter mile wide. This brings the chance of one of these tornadoes hitting a certain point in the Midwest to: 1: 62,500. Now within this path, only a few houses will see the strongest of winds, about 5% of the affected area. This gives your house a 1:1,250,000 chance of getting hit by the violent and damaging tornado winds. This means you are 233 times more likely to get hit by a tornado, living in the Midwest, than win the Powerball.

The Odds of Dying in a Hail Storm:

While hailstones can reach the deadly size of softballs, or even larger, deaths by a hail storm are very uncommon. Large hail is formed when thunderstorm or supercell updrafts become very strong and have the ability to lift hail stones further into the atmosphere. They can then grow larger and larger with time before they are heavy enough to break through the updraft. Some of these smaller stones will get "flung" outside of the updraft and ahead of the larger hail. Luckily, this provides some lead time for the largest of hail, allowing people to seek shelter in time. The odds of getting killed by hail in United State is: 1:734,400,000. Meaning you are 2.5 times more likely to win the Powerball then die from lightning in a year. There have been some events where 9 People have Died in a powerful hail storm, but most have been outside the United States. Deaths have also decreased in the past few decades with advanced warning by the National Weather Service and more effective communication.

The Odds of your House Hit by a Meteor:

Here's an example where the Powerball is on your side. The odds of a meteor hitting you house are 1:182,138,880,000,000! Meaning you are 623,333 times more likely to win the Powerball with a single ticket than to see a meteor on your house. This means, you are MORE LIKELY to win the Powerball twice (if you buy 20 tickets) then to get hit by a meteor. Nice odds right?

Thanks for stopping in at Midwest Weather! We have a Facebook Page and Twitter

Works Cited
"How Dangerous Is Lightning?" NWS Lightning and Heat. Web. 12 Jan. 2016.

"What Are the Odds Of Being Struck By Lightning?" DiscoverTheOddscom. 2012. Web. 12 Jan. 2016.

"Scott Sabol's World of Weather." : Odds of Getting Struck by Lightning and Other Weather. Web. 12 Jan. 2016.

"Some Probability Estimates." Violent Tornado Probability. Web. 12 Jan. 2016.

"Historic Winters Have Delighted, Frustrated and Imperiled - The Boston Globe." BostonGlobe.com. Web. 12 Jan. 2016.


Saturday, January 9, 2016

Quick Hitting Winter Storm Across Chicago to Lower Michigan

An area of low pressure will pass through the Midwest and Great Lake Saturday through Sunday. This rapidly developing cyclone will filter in just enough cold air on the back side of the track to drop a general 3-6" with higher amounts in Michigan, where the storm will be stronger and lake enhancement will be in play. Winter weather advisories and winter storm warnings will also be in effect across these regions. The official NWS forecast is attached.

Tuesday, January 5, 2016

Some Snow, Excessive Cold Brought down by a Polar Vortex Piece.



The coldest air mass of the season is on the way for the beginning of next week. Temperatures will run 15-25 degrees below average across much of the Midwest by Sunday, this trend will work east through the middle half of the month. There is little doubt that with the combination of winds and cold temperatures, wind chill advisories will be issued sometime next week. This weather will affect the Minnesota Vikings vs Seattle Seahawks NFL game on Sunday, set to be played in Minneapolis at noontime. The temperature will likely stay below zero for the duration of the game, with windchills well below zero. The cold will begin to be a major storyline in the next few days. 

The overall pattern of cold is brought to us from the weakening strength of the Polar Vortex. Measured, in part, by the Arctic Oscillation, the AO (for short) is forecasted to tank by the weekend. With this circulation weakening, lobes of cold air are allowed to be displaced from the north and reach down to lower latitudes. Think of it as a spinning top, when its strong all of the top is focused in the center of rotation, but when it starts to wobble, it begins to poke further away from the center of rotation. The same thought process is effective when thinking about the polar vortex. The cold is further tapped into thanks to a couple open wave system, or weak areas of low pressure that are expected to pass through the Midwest over the next couple days. The GFS (global forecast system) model for snowfall is attached above, courtesy of weatherbell. A general 3-5" of snow is possible over the next several days. Contrary to some posts on twitter and facebook you may have seen, this will not be a large system! Partially due to the fact that to energy in the four corners region will be ejected in pieces, instead of one large cluster. Either way, behind the system(s) winds will shift out the northwest and usher in much colder air into the region. Another surge of cold is forecasted on the European model, as seen in the animation above, next week. Below is a look the forecasted wind chills for Sunday morning! They do not moderate much through the next 48 hours, as temperatures and winds continue to be cold and strong, respectively. 


Sunday, December 27, 2015

HEAVY SNOW and near Blizzard Conditions Monday

A strong cyclone will move into the Midwest Monday into Tuesday from the south. Ample moisture and enough cold air will be in place to drop excessive amounts of snow across the area. This system is already responsible for 3 FEET of snow in West Texas and is poised for the Midwest. We will not see quite that much, but many areas have the potential to reach a foot of snow with this system. Exactly where the heaviest bands set up will play a major role in who sees these high totals. Western Iowa to far southeast Minnesota looks to be in the hot zone for the heaviest snow, with the U.P. of Michigan also seeing some lake enhancement, where totals over a foot will be common by Tuesday. Another complication to the forecast and travel conditions will be some sleet and freezing rain mixing in for a period of time in eastern Iowa and southeast Wisconsin. Warm aloft, will poke in from the southeast and create a narrow layer of melting. Just how far that can get north will effect snow ratios and snow totals. While this may cut into totals a tad,  snow and sleet accumulations will still be substantial across these areas, a winter storm warning is in effect across these parts and points north and west.

On the right is the expect start time for either snow (in Iowa, Minnesota and Wisconsin) or sleet/rain (in Michigan). Once the band reaches you area, expect it to stick around for 18-24 hours. The snow will be heavy at times, with snowfall rates of around an inch an hour expected during the height of the event, before wrapping up late Monday night into Tuesday morning. Some flurries and snow showers could linger into Tuesday across Minnesota and Wisconsin, as cold air aloft works into the area, snow totals less than an inch expected Tuesday.

Furthermore, gusty winds in Eastern Iowa and Southern Wisconsin will also bring major issued to the areas. Combined with the freezing rain potential, wind gusts over 40mph could cause major issues, including power outages. Blizzard criteria may be reached in southern Wisconsin and parts of Iowa tomorrow afternoon. This will need to be watched closely heading into Monday. The map on the left shows the GFS modeled peak wind gusts Monday evening, courtesy of weatherbell. Thanks for stopping by Midwest Weather and be sure to like us on Facebook and Follow me on Twitter!


Saturday, December 26, 2015

Possibly Travel Crippling Snow and Ice Storm on the way


A major dynamic storm system is currently dropping heavy snow as far south as northern Mexico, and is poised to charge north into the Upper Midwest. All types of weather will be likely, from rain to freezing rain to sleet and snow. While the snow will be heavy, the real story could be a major icing event. Over a quarter inch of ice is possible, combine this with high winds, and a serious situation could unfold on Tuesday. Model consistency is not to the point where we would like it at this point, but the map above draws out the "most likely" scenario. Most models do take the heaviest snow from central Kansas north through Lake Superior. This has also been the trend to bring the storm more northwest than originally forecasted. However, there has been some model runs that shift the storm southeast and lay down 6-12" of snow in eastern Iowa to southern Wisconsin and Lower Michigan. This will need to be a trend to watch. Either way, a widespread swath of 6"+ is very likely across the Midwest Monday into Tuesday. The thought is that this model (the GFS) will shift northwest again to follow its other fellow models, in the next few runs. Be sure to monitor the latest forecasts and keep it here to Midwest Weather for updates, You can also follow me on Twitter for more discussion.

Below is a look at two major weather models. **NOT A FORECAST** But it does show the spread in challenges given to a meteorologist. Using a general 10 to 1 liquid to snow ratio:


Monday, December 14, 2015

El Nino to Stand its Ground through the New Year



At this point in the winter it is no secret that El Nino is strong, and has already toppled records, depending on what index you look at. With that said, it certainly continues to play a critical role on the weather across the Lower 48. Over the weekend, record high temperatures were recorded in 23 states, mainly east of the Mississippi River. This unprecedented warm stretch of weather is thanks to a large ridge that has persisted over the eastern half of the country. This blocking, pushes the jet stream north and allows warmer weather from lower latitudes to move north as well. While some people may be ready for winter, mother nature has different ideas. Besides a brief cool down later this week, the rest of December looks to stay on the warm side, east of the Mississippi River.

However, this battling of air masses could set up a major storm system around Christmas. Current indications are that it will be cold enough for snow north and west of the track. We are still 10 days out from the event, so the track is in question, but the best guess would take it up from the southern Plains to the Upper Mississippi River Valley. It looks to the be the best shot for a white Christmas across the most populated areas in the Midwest, besides Tuesday-Wednesday for areas further west...see snow map below. Be sure to check back for updates on this possible Christmas Winter Storm in the coming days!




Sunday, November 29, 2015

Winter Storm Monday into Tuesday

Heavy snow is expected to break out ahead of a developing area of low pressure and area of warm air advection. The snow will begin Monday morning for most places. I wide swath of 6-10" from Sioux City to Minneapolis is expected. Areas near the Mississippi River will battle warm air surging north from the Gulf of Mexico on Monday, hense the heavier snow west. Higher terrain will amplify snow total in southwest Minnesota, where over a foot of snow is possible. Many of the short term models do indicate numerous areas on banding, so a large gradient in final snow totals is expected. One city could maybe have 8" but 30 miles to the east or west might end up with 3". It will depend exactly where each band sets up. Unfortunately it can be tough to forecast such events, but the most likely amounts are plotted above. Thanks for stopping by at Midwest Weather. Check out the tabs above for more weather information, especially the computer snow output page! 

Heavy Snow Monday into Tuesday across the Midwest



Heavy snow is expected to break out ahead of a developing area of low pressure and area of warm air advection. The snow will begin Monday morning for most places. I wide swath of 6-10" from Sioux City to Minneapolis is expected. Areas near the Mississippi River will battle warm air surging north from the Gulf of Mexico on Monday, hense the heavier snow west. Higher terrain will amplify snow total in southwest Minnesota, where over a foot of snow is possible. A FULL UPDATE will be posted later this evening, including an official Midwest Weather snow map.

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Thursday, November 19, 2015

Band of Heavy Snow to Coat Major Midwest Cities

A developing storm system will bring widespread heavy snow to the Midwest Friday into Saturday ahead of the coldest air of the season. The heaviest of snow looks to fall south of I-90 and north of I-80 on Friday. Models did come together in recent runs, HOWEVER, the european model has trended south in the last few hours. It is one of the more reliable models and could be on to something. With that said, the map to your left puts weight on prior runs as well as recent ones, a blend of models. For many areas across parts of Northern Iowa and Southern Wisconsin, this will has the potential to be the heaviest snow since the 2013-2014 season, depending exactly where the heavy band sets up! Winter storm watches have already been issued for the northern half of Iowa east through the WI/IL border. Most of these will kick over to winter storm warnings by the late afternoon or Friday morning time period. Otherwise, winter weather advisories will be issue just outside the band of heavier snow.

The timing of the snow has a larger role than usual. With it being so warm in recent weeks, and months for that matter, ground temperatures are rather high. A large portion of the snow will come at night which only amplifies the efficiency of snow accumulation on the surface. It will take a bit to accumulate on pavement, but the temperature and snow rate should overcome the warmer pavement temperatures relatively quickly.

Regarding timing, the storm looks to really ramp up by Friday afternoon. After about 12:00, a band of heavier snow will begin to train over central Iowa through Southern Wisconsin and Lower Michigan. Most of the snow will fall Friday evening into Saturday morning across these areas. This sets up a couple snowy college football games, such as the Northwestern @ Wisconsin games on Saturday. Otherwise, the map should give a general idea when the snow will begin to coast grassy surfaces!


Behind the system winds kick up out of the northwest and usher in cold air from Canada, here is a look at low temperatures for your Sunday. Very cold!...especially with fresh snow cover, off the 12z GFS model. It could be short lived however, as a surge of warm air is possible around Turkey Day! Maybe 15-25 degrees above average!


Wednesday, November 18, 2015

The Transition to Winter to Bring Accumulating Snow

A major pattern change is in the works for the end of the week. This change in weather will make things feel like mid-December across the Midwest and will be a shock to system for many. The surge of cold air will also bring the threat for accumulating snow in a narrow band over parts of Iowa to lower Michigan. Models are beginning to come together this afternoon, but still some uncertainties to work out in the next 24 hours or. The storm system has yet to come on shore the Pacific Northwest, where it can be better sampled in the weather balloon networks and ground reports. Once this happens, the model discrepancies will generally become filtered out. With that said, we will not publish a full snow map at this time, but rather give a more general forecast. As the system emerges out of the Plains it is expected to strengthen and drop several inches of snow on the back side by Friday evening. The heaviest of snow looks to fall from North Central Iowa to the WI/IL border to central Michigan. A half foot of snow will be possible in these areas, with more possible in SE Wisconsin and Lower Michigan as the storm ramps up and lake enhancement aids in the snow development. Be sure to check back for updates, our full snow map and forecast will be posted by this evening our early tomorrow afternoon. In the meantime, check out our social media platforms on the right hand side of the page.

Tuesday, November 17, 2015

Snow, Cold, Winter, Oh My

A pattern change is ongoing across the entire United States this week. A trough in the west will push east in the coming days and cold air funneling in from the north will bring the contrast in temperatures needed for atmospheric lift and precipitation. A wave of low pressure will develop along this boundary and move through the southern Great Lakes by the early weekend. On the cold side of the system a band accumulating snow will set up on the backside of the track of low pressure. We have plotted where "plowable snow" will set up according to three major numerical weather models, or 3"+ of snow. Some models takes the system up through lower Michigan and deepen the surface pressure. This could drop heavy snow over Lower Michigan and ramp up lake effect snows on the back side of the cyclone as it pulls away Saturday and Sunday. The potential exists for nearly a half foot of snow in areas such as Chicago through Grand Rapids, Michigan, with 2-5" as our best estimate over Iowa. With it being 4-5 days out there are a few discrepancies and issues in the forecast:

*The timing...warm ground and pavement temperatures would limit accumulations if the snow comes during the day, accumulates more efficiently at night
*The track...where the low pressure goes will determine the general area of snow
*Phasing...if this storm cuts north as it passes east of the Mississippi River heavier snow could fall

Either way, the storm will bring in northwest winds by Saturday and Sunday which will usher in much colder temperatures across the Midwest by the weekend and beyond. Low temperatures for Sunday morning are plotted below, off the ECMWF model. Notice the lows will be ~10 degrees cooler in areas with fresh snowfall, due to radiational cooling. Keep it here to Midwest Weather for updates throughout the week.

Monday, November 16, 2015

First Midwest Winter Storm?

Models, trends and the atmospheric set-up are look increasingly favorable for accumulating snow across the heart of the Midwest. A band of snow will develop along a line of frontogenesis, or an area where the difference in temperature across two points is increasing. These bands of precipitation can be tough to pin down exact locations, because they can be so narrow and not fully reliant on the track of low pressure. With the said, models are starting to finally agree on the location of such an event. The darker shade of blue is the location currently thought by numerical weather models to have the best chance of moderate snow accumulations. Either way, cold air will funnel in behind the system and bring the coldest temperatures of the season to much of the eastern half of the country by the weekend. A very similar situation set up last November, Post from Last Year, almost a carbon copy! That storm, like many sections of temperature gradient induced snows, trended north with time. This and prior model runs is why we included areas such and Minneapolis to Green Bay in the potential for accumulation. Now the real question, how much are we talking? Well, model runs in recent days have been impressive, but it looks like a general 3-5" with isolated amounts of 6+"  where possible banding could set up. The higher amounts look to develop east of the Mississippi River, lesser amounts west. This will need to be watched closely in the coming days, as we look to pin down the exact location of moderate snow. The pattern looks to kick over to cold and stormy beyond 5 days through the end of the month. You can always watch the snow models come in yourself on our Computer Snow Output page. Keep it here for updates throughout the week and our first snow map of the season when the event gets closer.

**Next update scheduled by Tuesday, 2pm CDT**

Tuesday, October 20, 2015

Official Midwest Weather Winter Forecast & Outlook 2015-2016

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It's that time of year again, the leaves are changing, the presence of hoodies is on the rise and the wonder of what winter may bring proves intriguing. Long range forecasts are used by businesses to manage risk or manage supply of weather-demand products, they are becoming increasingly important. In the general community, long range forecasts provide for good debate and curiosity. Some people live for the snow and cold, and some could do without. No matter what side of the spectrum you fall, anticipating the upcoming winter can put you in the correct mantra and even plan ahead for those crazy few months of weather. Alright, let us dive into the Midwest Weather Winter Forecast for 2015-2016! Full forecast at the bottom of the page.

Discussion:

Long range or seasonal forecasting can prove to be a challenging endeavor, but understanding the moving parts of the "winter weather system" is not impossible. The key is to understand what factors have the strongest signal to the winter ahead. Last year we were able to pin down isolated features, such as the massive Siberian snow pack and record cold lake temperatures. These features added value to the analog years (or years with similar atmospheric and surface conditions) we chose. This year, we are in and heading to a plateau of near record El Nino conditions. The merit and significance of the warmer than average ocean temperatures in the Pacific will be discussed later.

Current State of Climate System, and ENSO:

Let us begin with Ocean temperatures, or from now on to be called SSTs, sea surface temperatures. Ocean temperatures are the most stable indicator, as water temps do not rapidly change, especially near the equator. Below is a map plotting the SSTs compared to the running mean from 1981-2010 as a good sample size, courtesy of Tropical Tidbits:

There are several areas to point out on this plot, many of which will provide significant clues into the fate of our upcoming winter. The vast area of above average SSTs in the Central Pacific are classified as the positive or warm phase in the southern oscillation, also called ENSO, but more commonly known as El Nino (Saturday Night Live Clip).  This feature on the planet is a stable indicator this winter, as ocean temperatures are forecasted to stay well above normal. However, the trend is to head back towards a neutral standing and possibly La Nina in a year, time will tell. Below is a probabilistic forecast from the Climate Prediction Center, CPC Link.


Furthermore, in relation to ENSO, the waters in the western Pacific are also relevant. Not so much the fact of warmer or colder than average, but rather the location of the gradient from warm to cold. In the Central Pacific a circulation in the vertical, called the Walker circulation develops. It is the main driver of prolonging the ocean anomalies. In an El Nino year, relative low pressure sets up in the Eastern Pacific and high pressure in the Western Pacific. Convective activity sets up in the east and tranquil weather in the west. Consequently, a cold pool of water will set up in the west. This year that transition sets up near the international dateline. This location is key as it affects the mid-latitude jet, and is very similar to the location in 1997 and 1983, which will be helpful in determining analog years, which we will get to further down.

The North Pacific:

ENSO is not the only determining factor, relating to ocean temperatures, next we look to the North Pacific and North Atlantic for more answers. The North Pacific is proving to be the largest wild card in our winter forecast, but let's discuss. At the moment, the eastern shore of the Pacific is seeing above average SSTs, the ocean circulation is slightly weaker, allowing for less upwelling along the coast. This observation does coincide well with the so called, "Super El Nino" of 1997.
This map above was made using an online program courtesy of the Earth System Research Labratory. It shows the SSTs of September through November in 1997 relative to average. This is also described as the warm phase of the Pacific Decadal Oscillation, or PDO. Historic data can be found Here.The Pacific Ocean temperatures match up very well to current conditions. However, an active period in the Gulf of Alaska is working to cool the ocean surface as storm systems continue to roll through the region. Strong surface winds bring cold water to the surface through a process called Ekman pumping. Watching these SSTs evolve over the next couple months could influence our winter, but the current thought is that these waters will stay above average, via climate models. 1997 does provide guidance in terms of the Pacific Ocean, but looking at the Atlantic, this year tells a whole different story.

The North Atlantic:
In terms of the Atlantic, 1957 proves to be a better comparison. The AMO index (Found Here) from 1957 is near 0.2, while this year we stand at 0.3. The confidence is higher that theses waters will stay cool through the season. With the presence of melting fresh water near Greenland and the weakening of the Gulf Stream, the water of the North Atlantic has been cooling for several months now and models hold steady through the winter.


Analog Analysis:

Looking at the variability in ocean temperatures over the course of the previous decade is a proven way to forecast the future, "Learn from your history." However, it may be very difficult to simply look at maps of the oceans to understand exactly whats going on. Dozens of teleconnection indices have been developed to quantify the oceans and atmosphere. We will look at three of the largest players in seasonal forecasts, or the ones that are the most stable; the ENSO, PDO, and AMO, mentioned earlier.  

The Method: 

Since ENSO will certainly be the largest influence in the Midwest weather winter forecast 2015-2016, the strongest El Nino episodes in the last 70 years were examined and the top 11 were chosen. These are the years that will pass through our analog analysis. On the left is historical data from the strongest correlation years, and current data below it. A positive PDO is characterized by warm water in the Gulf of Alaska stretching down through the East Pacific and Central Pacific, with the AMO considering conditions in the North Atlantic. These values were then scaled to give equal weight in determining how similar they are to current data, with the AMO given the least weight, since it is down stream of the Midwest. 

Scaled and weighted values give us a ranking a how similar the conditions of the oceans were in prior years. The ranking gives us an insight into how similar future weather may be in the long run. This analog forecasting method for the Midwest winter forecast 2015-2016 did prove valuable in Last Year's Outlook. It is no surprise that 1957 an 1997 were among the top, but a few other years did make tho list. The red colored years are the top 3 El Nino Episodes since 1950. The following maps will look at a monthly composite of these analog years as they compare to the normal values over the course of the previous century. 

The top 10 analog years were examined and given these weights:

 |1957: 25% | 1987: 20% | 1997:15% | 2002: 10%  | 1991, 1965, 1986, 1982, 1963: 5%

Results:







In general, we are looking at a warm and wet start to the season, with relatively cooler and dry weather working in as we close out winter. March is somewhat of a wild card. It will depending on how "wavey" or amplified the jet stream becomes and with a weakening El Nino expected by that time, March is a month to watch, and is not included in our winter forecast.

Putting the whole season together, precipitation values look like this, according to the analogs:
And overall temperature values look like this, according to the analog years:
The Climate models also agree! Check them out below.





There is a lot of agreement between analogs, models, overall patterns, and local effects. Confidence is very high that a warm winter will exist in northern regions, and a drier than usual winter will persist in the Ohio Valley. Overall snow is tougher to predict this year, with near average expected, but the potential exists for a few storms to skew some averages, more discussion below. 

THE OFFICIAL FORECAST: Be sure to share with your friends, the good/bad news!

After several weeks of deliberation and research, we finally come to the official Midwest Weather winter forecast. Based on the prior, it is no surprise we are looking for above normal temperatures across the Midwest, with the warmest air in the northern Great Plains and Great Lakes, cooler south. Lake temperatures are warmer than last year, via GLCFS, which among others is a large factor that trends to a longer lake effect season, but still overall less snow, with the absence of large cold air outbreaks. The past couple winters have featured a dominantly northwest to southeast jet stream, yet this year it will be much more zonal, west to east. Any amplification in the jet could bring us some large winter storms. It looks to be more active than past years, as storms systems originating from the west will have more moisture to tap into, than ones from the northwest. Depending on where each individual storm tracks, snow amounts could be below or above average in the highlighted area. With that said, it does look like more winter storms and less clippers (1-3"/2-4" like systems). Thanks for checking us out, we will continue to bring the latest forecasts heading into the Winter season. 
Feel free to ask questions across Twitter and Facebook, links below. Any personal inquiries can be directed at verstegentanner@gmail.com.

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Thanks for stopping by out 2015-2016 Winter Forecast, an update may be posted in November, depending on how much conditions in the North Pacific change, or if there is any new development in ENSO. In the meantime, be sure to keep it here to Midwest Weather for all the latest in weather forecasts and stories around the area. 

Tanner Verstegen
Bachelors in Atmospheric Science
University of Wisconsin-Madison

Thursday, October 8, 2015

Once Hurricane Oho to Bring Record Warmth to the Midwest

It's happening again! A tropical cyclone is set to have a major impact on the weather across the United States. Remember Nuri last year (Nuri Post)? It brought a major pattern change, one to a cold trend. Oho, seen below, is set to have the opposite effect. Its track takes it north right on into the jet stream, which will help to build a ridge to the east of its track. This ridge will then propagate to the east and set up over the mid-section of the country for the weekend, bringing widespread 80s and 90s the parts of the Midwest.
Building the ridge is one way to bring warm weather to the area, but another method is also in play. With the counter-clockwise rotation around the deepening area of low pressure the winds will be out of the SW and create an onshore flow from the Pacific Ocean. As this flow persists, heavy rains will fall in the mountains and air will be forced up the front range of the Rocky Mountains. As this occurs air parcels will cool as they rise to levels of lower pressure. This cooling will allow for saturation to occur and increase the amount of rain in the area.


Then on the lee side of the mountains the opposite will occur. The air that was once going up the mountain will fall down on the opposite side. This will bring warm weather through a process called orographic warming. The air is forced down to higher pressure, which will act to warm the air parcels. The image on the left is the GFS model for 850mb temps Saturday, notice the vast area of warmer temps through the Dakotas and points northwest? Orographic warming can be thanked, along with Hurricane Oho for the pleasant conditions!
The map attached to the right shows just how much above normal temperatures can get on Sunday. The high temperatures on Sunday will run 15-30 degrees above average and record highs will be in danger. Would not be surprised to see some 90s in the Northern Great Plains! The weekend will also feature dry Canadian air, with dew points in the 50s. It can definitely be described as Indian Summer, all aided from a Hurricane that once threatened Hawaii.


Tuesday, October 6, 2015

So Called, "Indian Summer" through mid-October

After a record warm September across much of the Midwest, the weather looks to hold its ground with more warm conditions. The pattern will set up to favor above normal temperatures through the next couple weeks, as the jet stream will push north into Canada and allow for winds to flow from south to north, bringing in warm weather. Precipitation will generally be limited through mid-October as the sun shine bright as we head into the meat of autumn.

Wednesday, September 16, 2015

Initial Winter Thoughts

We are back!! As the winter season nears, here are some initial thoughts on what the winter of 2016 will bring...It is starting to look more and more likely that warmer temps in the Pacific will hold the Polar jet stream further north than usual and keep the Midwest warmer than average. Big snows are still possible, with the best chance for above average snow in the southern Midwest feeding off the tropical jet. Otherwise we are leaning towards slightly below normal snow amounts, but certainty is lower for precipitation anomalies. One thing looks certain, above average temperatures do look very likely!

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Wednesday, June 10, 2015

Remnants of Hurricane Blanca to Dump Heavy Rain Thursday

Very heavy rain in on the way for Thursday across much of the Midwest. Flash Flood watches have already been issued and rightfully so. Moisture from Hurricane Blanca (which once made landfall in Mexico) will amplify an area of low pressure that will form over parts of the Great Plains. With a feed of moisture in from the Gulf of Mexico and Blanca's moisture, heavy rain will set up on the north side of the track of low pressure. A large swath of 1-4" will fall, with locally higher amoutns likely. Someone could walk away with near a half of a foot of rain by Friday. These types of totals can cause urban flooding and rising rivers. Be ready to take action if you reside in a low lying area. Meanwhile, severe weather to the south could drop local amounts of heavy rain and strong thunderstorms pass by. Below is the simulated radar off the 18z NAM Model for Thursday.