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Stormy Saturday Evening Forecast

Good Friday morning bloggers,

Kansas City Weather Time-Line:

  • Today: Increasing clouds, wind, and humidity. South winds 15-20 mph.  High:  77°
  • Tonight:  A slight chance of a brief shower or thunderstorm between midnight and 6 AM.  Low:  64°
  • Saturday morning:  The Kansas City Marathon starts early Saturday and there is just a 10% chance of rain. It will be partly cloudy and windy.  South winds 10-20 mph.
  • Saturday afternoon and night:  The chance of rain increases to 50% by 5 PM.  The Rain chance then increases to 100% by 9 PM.  Thunderstorms are likely. There is a slight risk of severe thunderstorms with the wind shifting to the west and northwest.  High:  77°
  • Sunday:  Rain ending by 7 AM.  The clouds will move out, and then it will be dry for the Hollywood 400.  High:  68°

Weather Summary:

A storm system is approaching aloft as you can see below. This is a trough that is moving inland over the western states now and it will head east over the plains states by Saturday afternoon:

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The energy from this storm will begin splitting Saturday. A second system will be diving south through the northern plains early next week with a cold front strengthening and moving across the plains by mid-week.  The weather pattern continues to set up for the season and we will learn a lot more in the next two weeks. We will worry about the next two weeks and the overall weather pattern later. For now, let’s take a look at the surface set up for Saturday:

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There is a risk of severe weather on Saturday:

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The enhanced slight risk is showing on this probabilistic outlook from the SPC in the red and hatched areas. This is the area storm chasers are most likely going to be heading towards tomorrow.  Kansas City is in a slight risk. Last week when we had severe weather it warmed up to 85 degrees. It will not be as unstable in this set up.  Wide spread thunderstorms are likely late Saturday afternoon through Saturday night with the main risk being damaging winds and some large hail. The best chance of a tornado or two will be on that enhanced risk area. Last weekend there were no tornadoes at all despite strong conversation from the SPC in that direction. They are only hinting at a chance of a couple of tornadoes in this weekends set up.  An interesting take away from this conversation is that this is the second thunderstorm event in as many weekends. Hmmmmmmm!

Thank you for sharing in this weather experience featuring Weather2020 and the cycling weather pattern.  Go over to Weather2020, click on the blog, and join in the conversation.

Gary

A Storm Comes Into The West & Takes Aim On KC

Good morning bloggers,

The Kansas City Chiefs are out west near the fire ravaged Napa Valley.  Just north of Oakland is where this fire disaster that has claimed 42 lives is beginning to get under control.  Some rain would help, and take a look at the forecast for midnight after the Chiefs vs. Raiders game will be long over:

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This storm coming into the west will begin producing some snow around Lake Tahoe, and it has been completely dry this month until this system moves in tonight.

12z & 18z GFS rainfall forecast totals from Wednesday:

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The map above shows the rainfall forecast from yesterday mornings GFS model, and this one below is from the 1 PM model run (18z)):

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The axis of the heavy rain forecast shifted north and west. Now, did this trend continue?  The European Model has not had nearly as much rain, until now:

Screen Shot 2017-10-19 at 6.54.34 AM

So, now we have some consistence in the rainfall forecast, and look at the wet conditions across the Pacific northwest, and it does dip down a bit into California.

1The storm system that will be responsible is coming into the west coast tonight.  This energy will then carve out a trough as it approaches the plains states. And, then look at all of that energy coming across the Pacific Ocean. This is becoming an increasing factor for next week with the models all over the place on what is forecast to happen next.  This map is showing the 500 mb flow, around 18,000 feet up as described a few days ago. This level of the atmosphere shows the cycling weather pattern the best.  The energy coming into North American next week is forecast to develop a rather deep trough in the east, but then it is also forecast to lift out fairly rapidly, and then get replaced by something like this next map below:

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This map shows a very deep trough just west of Kansas City on Halloween.  This is quite fascinating to watch our weather pattern evolve. The massive change in the pattern happened two weeks ago, and now we are experiencing the evolution of the pattern that we will be experiencing during the next year. This deeper trough over the plains has already shown signs that it may very well be a big feature this year in these first two weeks. I will attempt making a video and posting it later to showcase how this may “fit” this new and unique pattern.  This would be “very good” for us weather enthusiasts that live near Kansas City. 5

Today will be another great day in Kansas City. Let’s track the models today and we can continue this discussion in the comments section.  Thank you for spending a few minutes of your day and sharing in this weather experience featuring Weather2020 and the cycling weather pattern (LRC).  Go to the blog at Weather2020 and join in the conversation.

Gary

A Quiet Weather Picture Nationwide

Good morning bloggers,

The weather pattern over most of the United States is quite calm. There is a Winter Weather Advisory in effect for the Arctic coast of northern Alaska, but other than that it is really a tranquil day:

Screen Shot 2017-10-18 at 8.41.49 AM

The largest advisory on today’s weather map is the Red Flag Advisory for the northern plains where it has been dry and quite warm this week for this time of the year.  The next impacting storm will be coming into the west coast Thursday and this will bring a chance of rain and thunderstorms to Kansas City by Saturday.  We will look deeper into this storm system in tomorrows blog and on 41 Action News tonight.

The influences on the winter forecast:

Puzzle-2

  • The LRC is the center piece of the cycling pattern.  There are other influences that will help shape this big atmospheric puzzle.
  • The Arctic Oscillation is one big piece to consider (AO)
  • The North Atlantic Oscillation (NAO) is one big piece to track
  • La Niña is developing, but it has not been established yet
  • There are other wild cards to consider

The AO and NAO:

Screen Shot 2017-10-18 at 8.32.22 AM

Screen Shot 2017-10-18 at 8.32.38 AM

Both the NAO and AO are forecast to dip negative during the next seven to ten days.  This is after the early part of this weather pattern had AO and NAO indexes in the positive.  When these indexes go deeper into the negative there is an increased chance of blocking and an increased chance of cold blasts developing over North America. Let’s follow these closely in the next few days.

La Niña:

Screen Shot 2017-10-18 at 8.34.13 AM

The phase of ENSO just took a big dip in the past week after it appeared that the tropical Pacific waters were warming a bit. The forecast from the CFSv2 forecast is for the cooling to continue and a La Niña to develop during the winter months.

The La Niña developments have my attention the most at the moment, but just like last winter when a weak La Niña started forming, the cycling pattern was only influenced by this phenomenon. The bigger piece of the puzzle is the LRC.  I saw a few more winter forecasts in the past two weeks. I have probably seen dozens of them now.  These forecasts are not considering the biggest piece of the puzzle. Any forecast that comes out before now may be able to make a very broad forecast for this winter with very little chance of being accurate, but if they do not consider the biggest piece of the puzzle how can they have any credibility.  This is how I look at it. We are still less than two weeks into this years cycling pattern. We are about to experience around 30 to 40 more days of this pattern that have not happened yet, so hang on for the ride. We will learn so much more in the next 30 days.

Thank you for sharing in this weather experience featuring Weather2020 and the cycling weather pattern.  Go to Weather2020.com and join in the blog conversation over there. I will likely be doing a Facebook Live tonight to discuss the developing weather pattern.

Gary Lezak

 

Gary

The Evolving 2017-2018 Weather Pattern

Good morning bloggers,

Kansas City Weather Time-Line:

  • Today: Nearly Perfect. Sunny with light winds and a high of 71°
  • Tonight:  Clear and refreshing. Low:  49°
  • Tuesday:  Mostly sunny and nearly perfect again. High:  73°

The weather pattern is cycling and regularly, but at this time of the year something incredible is happening right before our eyes. The weather pattern that we experienced last year got wiped out by the end of the first week of October and we have now been experiencing the very beginning of the 2017-2018 pattern since around October 6th or 7th.  The new LRC is just now setting up and it continues to evolve for another few weeks. We must continue to be patient before we make too many conclusions. Last year we had a 56 to 61 day cycle centered on 58.5 days. The year before that it was 47 – 52 days, centered on 49.5 days. The cycle length is just one of the three main aspects of the LRC.  The other two are that a unique weather pattern sets up between October 1st and November 30th, and long-term long wave troughs and ridges become established. These features are where storm systems reach their peak strength and where storm systems reach their weakest strength most often.  These features are just beginning to show up and I do not know where they are yet, no one can tell this early if we use the centerpiece of the big atmospheric puzzle, the LRC.  How many of you have jumped to conclusions by looking at the error ridden computer models?

1This first map shows the 500 mb flow, around 18,000 feet up. The 500 mb level just happens to be around half way up through the atmosphere in weight. The top of the atmosphere is 0 mb because there is no weight above that level. The surface pressure is closer to 1,000 mb, with the average surface pressure being 1013.25 mb (29.92″).  So, 500 mb is literally half way through the atmosphere in weight, and this happens to be located close to 18,000 feet above us or in the troposphere where the weather we experience here on earth happens.

This map shows the pattern developing right now.  The flow is fairly flat. Where the flow buckles next is rather important. But, also keep in mind we are already ten days into this pattern and in this very early stage we already have experienced some bucking near Missouri. Look at what is forecast to happen next:

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By 7 PM Sunday, or 00z Sunday, a trough is again forecast to intensify as it approaches the Missouri River Valley.  This will make it 15 full days of the pattern where this is where the flow intensified. This is an important factor. Hopefully you are still with me here.  Take a look at what happens next:

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The strongest storm of this early season is forecast to form over the Great Lakes at the 500 mb level by around one week from now.  This buckling of the flow is once again on the models. Let’s see what happens before we jump to any conclusions.  A big ridge forms out west.

The first huge difference from last year:

Last year on this date California was getting blasted by a very wet series of storm systems. This year it is completely dry out there so far, and this next storm will just provide a glancing blow to the far northern part of California leaving the fire devastated areas dry again. This is not a good development for California.

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The first trough swinging by this weekend produces this surface set up for Saturday night. And, then look:

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The big buckling of the flow finally produced this over the east. It is still odd, in some respects as this model doesn’t show a major storm there, which could be a factor, but I just won’t be able to put my LRC finger on it until we get into next week.

So, I recommend patience, patience, patience. Once we know the pattern, we will be able to know when the computer models are right, and when they are likely wrong.  Right now we are just finding out. There are other factors to consider and we will go over these tomorrow.

Have a great day and thank you for sharing and participating in this weather experience featuring Weather2020 and the cycling pattern.

Gary

 

Gary

Great Fall Weather then Changes

Good Monday bloggers,

The weather has calmed down and we are in for some great fall weather through Friday.  There is a tremendous amount of jet stream energy racing across the Pacific Ocean and this is a sign of some major pattern changes as the new cycling pattern evolves.

Let’s go through the nice weather, then the changes.

TONIGHT: Lows will be in the 40s, about 10 degrees warmer than Monday morning. This is right about where we should be for this time of year.

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TUESDAY: This will be a terrific Tuesday with near perfect temperatures in the low 70s and a south breeze at 5-15 mph.

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WEDNESDAY: There is very little change in the weather, just a few degrees warmer, which means a wonderful Wednesday.  A cold front to the west will fall apart as it moves east. The wind will be from the south to southwest at 10-25 mph, so a bit more of a breeze than Tuesday.

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This is a satellite image of the Pacific Ocean Monday afternoon. You can see the stream of clouds from Japan to Canada indicating a strong west to east jet stream.  Some of this energy will become a trough near the west coast by Thursday.  This trough will then move into the Plains and Midwest this weekend, changing our weather.  The jet stream will remain strong into the weekend and next week.  This will lead to a major pattern change in about 10 days and this will be a big player in the 2018-19 LRC.

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This is the upper level flow for Friday and you can see a trough in the western USA with a big ridge in the eastern USA.  This means we will see the dry and warm weather east of the Rockies through Friday and then the trough will move east increasing rain chances.  There is uncertainty in the pattern after Saturday as the system may break into two pieces.  One will race east across the Great Lakes and fall apart.  The second piece may form a closed low in the southern Plains.  If this happens, clouds and rain may persist south of I-70 Sunday and Monday.

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The end of week storm system will bring some rain to northern California, but the trend is towards much less amounts and coverage.  I guess a little is better than nothing.

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As the storm system crosses the Rockies it will interact with Gulf of Mexico moisture and the rain coverage and amounts will increase and heavy rain is possible this weekend from eastern Oklahoma to eastern Kansas to Iowa and western Wisconsin. We will be updating this and all of the changes in the coming days this week.

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Have a great week.

Jeff Penner

There Was Not One Tornado In The United States Yesterday

Good Sunday morning bloggers,

DSCN4563I snapped this picture yesterday as the storm was rolling into the south side of the KC metro area. This thunderstorm ended up bowing out and producing a 65 mph wind near Greenwood, MO around 30 minutes from this moment. You can see Sunny The Weather Dog ready to come back inside as the wind and rain had just started.  Farther north, there was a severe thunderstorm that created 65 mph winds over north Kansas City leading to some pretty big trees getting knocked down. This thunderstorm produced over 2″ of rain as it moved across the north side of the KC metro area.

There were strongly worded discussions that came out yesterday suggesting the tornado risk being rather significant. This system certainly had the strength in the upper levels and some conditions at the lower levels that raised these concerns, but something was always a bit off yesterday and in the end there was not even one tornado reported over the entire region.  The surface low ended up over Iowa, as it was supposed to be, and the trailing cold front was northwest of the area of thunderstorms. There was a tropical influence with a plume of moisture coming in from Mexico and the Gulf of California. This plume of moisture helped induce showers and thunderstorms most of the day over northeastern Kansas and this likely affected the instability just enough to keep these thunderstorms from becoming discreet cells.

Here are the severe weather reports from Saturday:

today

And, here is one of the trees knocked down:

North Kc

This is what a 65 mph wind is capable of doing. There were a few other big trees knocked down. Wow!

The weather pattern continues to evolve and the new cycling pattern as described by the LRC is beginning to show up. The key word is “beginning”. So, I once again am asking everyone to be patient and let’s wait and see how this evolves in the next three to four weeks. We just must wait another few weeks as the pattern is still setting up. The early evidence over the past 10 days has been fascinating.

The weather should become quite nice for the Steelers/Chiefs game this afternoon. GO CHIEFS and have a great Sunday everyone. Go to Weather2020.com and join in the conversation as we share in this weather experience.

Gary

Active Saturday Weather

4:34 PM Update:

Screen Shot 2017-10-14 at 4.30.24 PM

This is really fascinating. The thunderstorms have been north of a weakening warm front that is just about dissipated, and southeast of the advancing cold front. When the cold front catches up and passes through the thunderstorms, then they will likely  intensify. The main risks are some hail and damaging winds.  These will be out of the KC viewing area by 11 PM.  Let’s see how this evolves, but no supercells formed as of 4:34 PM.

Previous entry below:

Good Saturday bloggers,

You can have a second season of severe weather between the middle of September and the middle of October.  Well, today is one of those days as we have a warm and humid air mass in the area as a strong cold front and system move across the Plains this evening.  So, let’s go through this weekend.

Here is the severe weather risk from the Storm Prediction Center as of 8 AM.  This may change later based on how the day evolves.  This means how much cloud cover and rain will occur during the day as this will be key in to determining on how unstable the air mass becomes ahead of the cold front.  If there is more rain and clouds, then the severe threat drops.  If there is more sun, then we could have a severe weather problem this evening.

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SATURDAY 2 PM: Temperatures will be in the upper 70s to low 80s with lots of clouds.  There may be more showers and thunderstorms with the clouds than this model shows.  These temperatures are just barely warm enough to support severe weather.

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SATURDAY EVENING: The cold front will be pushing across the area with rain and thunderstorms along and behind the front.  How severe will these thunderstorms become?  Again, it depends on how warm it gets this afternoon and that depends on how much sunshine breaks out.  Rainfall amounts will range from around .25″ to 1.25″ whether we see severe weather or not.

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MIDNIGHT TONIGHT: The rain and thunderstorms will be moving quickly and in KC it will be dry, windy and much cooler with temperatures dropping towards the 40s.  The thunderstorms will be along I-44 and moving away very fast..

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SUNDAY MORNING: It will be clearing, windy and cold with wind chills in the 30s as lows drop to the low 40s.

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SUNDAY AFTERNOON: It will be sunny and much cooler with highs 55° to 60°.  The wind will be less from the northwest at 10-15 mph.  So, if you are headed to the Chiefs game, bring a jacket, as by the second half temperatures will be dropping to around 50°. The Sporting KC game begins at 6:30 PM.  So, it will be dry with a light breeze, but temperatures will be in the 40s, dress appropriately.

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Here is the Kansas City weather time line for today.  It will be mainly dry in KC through 11 am-Noon with scattered showers and thunderstorms possible this afternoon.  The main threat for widespread strong to severe thunderstorms occurs 5 PM to 10 PM.  The extent of the severe weather will be determined on how warm it gets this afternoon and that will be determined by the extent of the cloud cover and rain.  We lean with the more clouds and rain solution, but we have to watch this closely.

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After today it looks dry for 5-7 days with temperatures back to the 70s by Tuesday.

Have a great weekend and keep an eye to the sky.

Jeff Penner

Last October Vs. This October Out West

Good Friday Morning Bloggers,

If you have wondered if there is a difference from last October to this October let me end the discussion with this:

gfs_apcpn_namer_45

This forecast rainfall map above shows the total precipitation for the next 300 hours ending October 25th. Near Kansas City most of that 1″ of rain comes from this weekends chance of showers and thunderstorms. The big difference that is rather telling is out west where they are dealing with a major fire disaster that is ongoing.  Look at San Fransisco east to Lake Tahoe in the Sierra Nevada mountains.  Most of that region is not forecast to even have 0.01″ of total precipitation during this rather critical time frame.  Last October, South Lake Tahoe had 5.04″ of liquid from a series of very wet storm systems that blasted California from October 14th to 18th. This then returned in December, February, and April.  That early series of storms was good news for that reason, and bad news as well. The good news is that the drought got obliterated in the next few months.  The bad news is that there was significant flooding.  This year the bad news is that the fire disaster is ongoing and there is no rain in sight. This is a huge difference from last years pattern to this year. One of many huge differences. According to the LRC a unique pattern is setting up right before our eyes. We are around one week into this pattern, so let’s hang on for a few more weeks before we make any conclusions, but the first evidence is in out west.

This weekends set up:

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This forecast map above shows the surface forecast valid at 10 PM Saturday night. A low pressure area is forecast to be in northern Illinois with a cold front trailing southwest to just southeast of KC by this time frame.  A line of thunderstorms is likely with some severe thunderstorm producing a main threat of damaging winds and large hail. The SPC doesn’t even mention tornadoes, but it is still something to monitor closely.  Look at what happens to this storm system by Sunday evening. Snow is forecast to fall in Canada while a weak line of showers and thunderstorms tracks across New York trailing southwest to Alabama. West of this are it is completely dry all the way to the Pacific Ocean.

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Severe weather risks:

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The risk is below slight today, and then there is a this slight risk of severe thunderstorms tomorrow from northwest Illinois southwest to southeastern Kansas.

From the SPC:  Thunderstorm development with a threat for isolated large hail and wind damage will be possible from the southern High Plains into the Midwest Saturday afternoon and evening.  A strong short-wave trough is expected to progress across the northern/central Rockies into the High Plains by 7 PM Saturday as 500 mb flow increases downstream across Nebraska/Iowa/southern Minnesota.  While this feature will lag the delineated severe risk corridor somewhate, a synoptic front should stall across the central Plains/mid Missouri Valley region Friday and will serve as the focus for convection by mid-late afternoon.  Latest short-range guidance suggests a narrow zone of strong boundary-layer heating will be noted from the Texas Panhandle northwest across south-central KS into northern MO and southeast IA.  Forecast soundings suggest surface parcels will reach their convective temperatures around 4 PM to 5 PM and frontal ascent should encourage thunderstorm development along the wind shift, especially by early evening as the front begins to surge southeast.  High precipitable water values, in excess of 1.5″, will not prove conducive for steep mid-level lapse rates but low-level heating is expected to aid buoyancy and a robust squall line should evolve with a strongly sheared environment. Wind damage and some hail are the primary threats, especially across Kansas/Missouri into southeast Iowa as adequate buoyancy will extend into this region where large-scale forcing for ascent will be greatest. While short-wave trough will only glance the southern High Plains, some severe threat should extend into the Texas Panhandle where low-levle lapse rates will be steeper than northern latitudes.

There is also a chance that a few thunderstorms will form over northern Missouri this evening near the front. There is some capping today, but temperatures and humidity are rising.  We will be monitoring these developments closely on 41 Action News.

Thank you for spending a few minutes reading the Action Weather Blog featuring the Weather2020 and the cycling weather pattern. Go over to the blog on Weather2020 and join in the conversation and let us know if you have any questions.

Gary

A Foggy Start To The Day

Good morning everyone,

The day begins with fog and low clouds across all of Kansas City this morning  Low clouds that spread across the sky are called stratus clouds. Fog is a stratus cloud that is on the ground. You can see the extensive low clouds on the 2-4 satellite picture that can be seen at this link:  The 2-4 Satellite picture  Here is an explanation of the shortwave minus long wave IR:

  • Shortwave minus longwave IR:
    Shortwave IR images only scratched the surface of the importance of the shortwave IR channel data. It was stated that the shortwave IR channel is sensitive to both reflected AND emitted IR energy at about 3.9 microns. While the sun is illuminating clouds, a very large portion of the measurements MAY be contributed by reflected energy. I use the word may because it depends on many things. The amount of reflected energy depends upon the relative angle between the sun, clouds, and satellite. It also depends upon the reflecting material: ocean, land, sandy deserts, snow-covered ground, ice particles and water droplets in clouds. It is these last 3 items which we care about most. These data have potential to discriminate clouds composed of water versus those composed of ice particles. A general rule of thumb: clouds composed of water REFLECT much more shortwave IR energy than clouds composed of ice or snow-covered ground. The amount of reflection is dependent upon the size of the water drops and ice particles. At night, reflection is not contributing to the measurements and any differences between water and ice/snow are purely emission. The water drops EMIT less energy at 3.9 microns than at 11 microns whereas ice particles EMIT nearly the same amount at the two wavelengths. Therefore subtracting the shortwave IR data from the longwave IR data produces negative values for clouds composed of water and near-zero values for ice/snow clouds. So what? Well, if you work on aircraft icing problems like we do, this data can be a goldmine. These data are also useful in detecting low stratus clouds and fog.

Screen Shot 2017-10-12 at 7.20.09 AM

The dark colors show where the low clouds are located and the KC KSHB-TV viewing area is pretty much all encompassed by these clouds.

Kansas City Weather Time-Line:

  • This morning: Cloudy with fog. The stratus deck will stay thick through around noon. Temperatures near 50°
  • This afternoon: A south breeze increasing to around 10-15 mph will help move the clouds north and the sun should “burn” them off. The sun should come out with a high around 71°
  • Friday: Mostly sunny and becoming humid with south winds 10-25 mph. High:  83°
  • Saturday:  Periods of clouds with a chance of thunderstorms. The chance is 20% during the morning increasing to a 90% chance during the late afternoon or evening. High:  81°
  • Sunday:  Decreasing clouds with northwest winds 10-20 mph and decreasing by evening. Dry for the Kansas City Chiefs and Sporting KC games.  High:  60°

Saturday’s trend:

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There has been a trend on all of the models for the storm moving across the middle of the nation on Saturday to just zip by very quickly.  This map above shows this trend well. The cold front will have already passed KC by around 6 or 7 PM and it would be moving fast. This would limit the chance of thunderstorms to a short window from 4 PM to 8 PM with the severe weather risk a bit lower due to the surface low forecast to be way up in Wisconsin. Let’s see if these models continue this trend today.

We will look into the pattern and the thunderstorm risk in tomorrows blog and on 41 Action News tonight. Thank you for sharing in this weather experience and let us know if you have any questions. Go to the Weather2020 blog to join in the conversation.

Gary

Forecasting The Next Storm System

Good morning bloggers,

Kansas City Weather Time-Line:

  • Today: The clouds move out with sunshine returning: Light winds. High:  62°
  • Thursday:  Some morning fog, then sunny and nearly perfect with a light north wind from 5-10 mph. High:  74°
  • Friday: Mostly sunny and becoming humid. South winds increasing at 10-25 mph. High:  84°
  • Saturday:  Partly cloudy with a 50% chance of showers and thunderstorms during the day and a nearly 100% chance of thunderstorms Saturday night. Flooding and some severe weather is possible. High:  80°
  • Sunday:  Rain ending early and drying out for tailgating and the Chiefs game. It will be dry for the Sporting KC game as well.  Cooler with a high of 63° dropping into the 50s by 6 PM in the fourth quarter of the Steelers/Chiefs game.

Screen Shot 2017-10-11 at 7.14.20 AM

There is a risk of severe weather on Saturday as the next storm system moves across the plains. One of the big differences to these severe weather risks in October and November from how they look in the spring is the amount of daylight we have.  We are now three full weeks into fall and we have about the same amount of daylight as there is three weeks before the beginning of spring. There are severe weather risks and outbreaks at any time of the year depending on the strength of these storm systems and other parameters such as low level moisture available and heating ahead of these systems. If the conditions all come together you can have big severe weather set ups.  Some of the conditions appear to be coming together for strong to severe thunderstorms on Saturday or more likely Saturday night across parts of Kansas, Missouri, and Iowa.  The risk from the Storm Prediction Center for day 4 is shown on the left.

A storm system is approaching aloft by early this weekend as you can see on this 500 mb chart:

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This is a rather energetic series of waves that are carving out this trough aloft that is approaching.  High levels of humidity will be pulled in from the Gulf of Mexico, and there is a stalling front that will be approaching Kansas City on Friday.

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This map above shows a forecast for the cold front with some strong surface ridging over Nebraska behind this front.  The trough aloft that is approaching is also strong enough to cause the pressure to begin falling and the front will stall as a result. Look at the front 24 hours later in this 7 PM Saturday surface forecast:

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Now back to the timing of this and the “time” of the year. 7 PM is now 30 minutes past sunset, so it will be dark.  This will begin limiting the instability, but before sunset there should be enough heat and humidity to create initial strong to severe thunderstorms with hail and damaging winds the main risk, but a few tornadoes can not be ruled out near and ahead of where that surface low over Iowa is located.  For KC it looks like a slow moving line of thunderstorms Saturday night that could produce very heavy rainfall amounts from 1″ to 3″.

Yesterday we showed you the Arctic Oscillation and the North Atlantic Oscillation going into the positive. Today we show you how fast these indexes can change as they are just tied to the error ridden computer models. Once we know this years LRC (Cycling Pattern Hypothesis) better we will know so much more. The cycling pattern is evolving and KC just had two early storm systems with this third one on the move and about to affect the plains.

Screen Shot 2017-10-11 at 7.26.16 AM

The Arctic Oscillation is positive right now. Let’s see where it goes in these next two very critical weeks.

Thank you for participating in this weather experience featuring Weather2020 and the cycling pattern. Let us know if you have any questions. We continue to have some great discussions on the Weather2020 blog. Go over there and join in and share with the rest of us.  Have a great Wednesday.

Gary