Severe Plains

Another Developing Winter Storm

// December 29th, 2010 // No Comments » // General Forecast, General Information, Severe Weather, Weather Recap, Winter Weather

Another brief update on the developing winter storm that will impact parts of the Northern and Central Plains on Thursday and Friday, and perhaps even into Saturday for parts of northern Minnesota and adjacent North Dakota. A surface low pressure system is currently located in eastern Colorado, and will push out of the shadows of the Rockies and onto the Plains overnight tonight. The low will likely be located south of Lincoln, NE along the Kansas/Nebraska borders by Noon tomorrow with areas of light rain possible across Iowa, then turning into the potential for freezing rain and finally snow by the time you reach central South Dakota and Nebraska. This initial low will continue northeast, dragging an areas of moderate to heavy snow across the Dakotas and Minnesota and perhaps even far northern Wisconsin through Thursday night. Other light precipitation will be possible over other parts of Nebraska and Iowa and even further south, with potential hazards for the northern areas where temperatures dropping below freezing may lead to some freezing of wet surfaces.

As this low pressure exits the U.S., another will develop and move onto the Plains by Friday morning and continue to progress northeast as well. This low looks to pass just north of Kansas City by Friday around Noon, and quickly move into Minnesota by Friday evening. Areas of thunderstorms and showers will be possible along the cold front that will move quickly east ahead of the low pressure system. Showers and thunderstorms may be possible across eastern Kansas and western Missouri early on Friday, and then across the rest of Missouri and perhaps even southern Iowa and other parts of the Southern Plains by Friday afternoon. There is even the potential for a few severe thunderstorms along the cold front over parts of Missouri, Arkansas and into the Southeast with the main threat likely being damaging winds and marginally severe hail. The tornado threat would appear to be rather low, however with such strong winds fields at least a couple tornadoes would not be out of the question. Otherwise, regarding the wintry precipitation, the heaviest snow with this second low pressure system is also likely to occur over the Dakotas and Minnesota, but at least moderate snow looks to occur over Nebraska and perhaps western Iowa and northern Kansas as well. Otherwise, the strong cold front will lead to much colder temperatures for the start of the new year across much of the Central and Northern Plains. Although the temperatures won’t be much below average for most areas, with temperatures expected to be well above average over areas to the east of the low pressure system on Thursday and Friday it will feel like a much more drastic change.

An interesting note for those watching the temperature today over areas of the Central Plains, the strong south winds that began today and will continue tonight and through tomorrow are leading to a unique temperature trend. Temperatures this morning began in the mid 30s, rose into the mid 40s by this afternoon and have actually continued to rise into the overnight tonight and are now approaching the mid 50s currently between 10-11pm! The temperature will continue to rise, perhaps steadying for a brief period late tonight and then rise even a little more tomorrow with a temperature in the lower 60s here in the Kansas City Metro. I’ll throw in an image of the modeled temperatures, and observations (black dots) for today and the next 7 days below:

New Years Eve Storm

// December 27th, 2010 // No Comments » // General Forecast, Severe Weather, Winter Weather

Will be hitting the road on a trek back to Iowa for the holidays, thus will get an update in before being away for a few days. Quiet weather is expected through midweek, with little in the way of expected weather. Strong southerly flow will return by Wednesday and begin to rapidly warm the area, high temperatures look to reach the 50s by Thursday and Friday with even 60s possible throughout southern portions of Kansas and Missouri. This warm and moist air mass may lead to a few light showers by late Wednesday or Thursday, but the main show looks to hold off until the next holiday.

A low pressure system looks to develop ahead of a very deep western trough on Thursday, and may quickly deepen into Friday. Where this occurs is still a large question with models varying by a few hundred miles on each run succession, this could mean a .5″ of rain for some, while nearly a half foot of snow for others dependent upon the track. For now it would appear the favored track will be from central Nebraska northeastward through parts of western Minnesota, leaving far western Nebraska and more likely areas for the Dakotas and northwest Minnesota reeling with more snowfall by this weekend. Areas east of this low pressure system are likely to ensure rain showers, perhaps even thunderstorms across parts of Kansas and Missouri. There have even been indications on the potential for severe weather in some areas of the Southern Plains with this system as a strong cold front is drug across the Plains. Just because you only see rain may not mean no problems, with such a strong cold front coming in behind the rainfall or with in some locations we may see a switch to wintry precipitation or see areas where wet surfaces freeze overnight.

There really are still a lot of questions in store with this system, but for the last couple days of December may truly be very warm in some areas and perhaps get rid of some or all of the snow that fell this past holiday weekend! I may be able to provide an additional update before this storm system impacts the Plains to give a better idea of who will see what, but for now I’ll leave you waiting…

A White Christmas (For Some)

// December 26th, 2010 // No Comments » // Severe Winter Weather, Weather Recap, Winter Weather

Many areas which haven’t seen snow yet this year saw plenty of it during Christmas Eve and Christmas day, with areas of the Southeast US seeing their first white Christmas in many, many years!  The storm system featured two waves of energy, one that was very weak and traveled across Texas while the second moved south out of the Northern Plains on Christmas Eve.  This secondary wave, or in fact the main piece of energy, left a swath of snow across parts of the Northern and Central Plains with areas receiving a half-foot or more in parts of Iowa, Missouri and Illinois on Christmas Eve or the day before in Iowa.

This storm continued to dig south into the Tennessee Valley and Southeastern United States on Christmas day, and led to snowfall as far south as northern Alabama and Georgia!  This storm will now begin to deepen and travel along the East Coast, providing snow and winds to areas from the Carolinas’ northward to Maine by Monday. Snowfall amounts will be very impressive for some areas, with more than a foot possible to go along with strong winds and blizzard or near-blizzard conditions. This will setup to be an after-Christmas nor’easter and may affect travel plans for many as they begin their trip back home from the Christmas holiday.

Looking back on the storm and its’ effect on the Kansas City area, while precipitation was present on Thursday night and Friday it came in the form of not just snow, but sleet and drizzle/mist as well. Temperatures were also near 32 degrees during much of the precipitation, even rising above during the afternoon on Christmas Eve and melting any snowfall that did accumulate during the morning hours. The lack of snowfall for areas of western Missouri and eastern Kansas came with the lack of mid-level moisture. What does mid-level moisture have to do with snowfall? Well, snow crystals most readily form between -10 and -20 Celsius, which in this event occurred between 15,000 and 18,000 feet (~600 to 500 hPa).  Without moisture at this level, snow crystals cannot form and thus you see precipitation fall as a drizzle or freezing drizzle and in some instances where there is a slight warm layer in the lower levels you can also see sleet.  This is exactly what we saw here in Kansas City late Thursday night and Friday…  For a better understanding, check out the observed upper air sounding from Topeka, KS at 6pm Thursday.

Even as the surface cooled and most, if not all of the thermal profile (red line) was below freezing the lack of moisture aloft (separation between the green and red lines) providing this lack of snow crystals and thus the lack of snowfall. The mid-level moisture was improved off to the north and east, where the snowfall more readily occurred and in some instances came down heavily at times. I guess that will conclude this lesson of the day… Hope you enjoyed your Christmas holiday! I’ll provide another update tomorrow on the next storm system that may affect parts of the Central and Northern Plains by New Years Eve!

Pre-Christmas Winter Storm

// December 22nd, 2010 // No Comments » // General Forecast, Severe Winter Weather, Winter Weather

I had mentioned in my previous post about the potential for a Thursday/Friday winter storm for areas of the Northern and Central Plains.  A lot of adjusting has gone on since that time, when many people were considering the potential for a widespread freezing rain event as well as moderate to heavy snowfall.  The adjustments have came to a slower and colder solution to be general, with precipitation likely waiting until after Thursday evening and then continuing through Friday for areas of the Central Plains (eastern Kansas and Missouri).  The colder solution also is going to essentially rid the forecast of any freezing rain potential, with perhaps a slight chance of some sleet mixing in before becoming an all snow event for much of eastern Kansas and Missouri.  Warm air will still be in place over the southern third to half of Missouri, leaving some areas under rain showers for Thursday night before transitioning to snow on Friday…  Nonetheless it looks like a much ‘cleaner’ winter storm than it did a few days ago.

Not to much on the specifics yet, as a lot of details are still going to be hashed out as the event nears.  The southern storm system that may or may not be the big snow-maker for the Central Plains is just beginning to impact the California coast, so this morning’s 12z (6am) model runs which are just initializing will be the first to have a true sampling of this storm system.  Hopefully for forecasting purposes it doesn’t do anything silly, but in general it seems like models have an ‘okay’ agreement on what will play out for the end of the work week and the beginning of the Christmas traveling season.

Areas of the Dakotas will see snow develop Wednesday night, with this band of snow transitioning across Iowa and adjacent halves of Minnesota and Nebraska by Thursday evening.  This band of snowfall could lead to areas of a half-foot or more of snow over parts of Iowa, best potential along a line from Sioux Falls, SD to Davenport, IA.  While this snowfall is occurring, a second band of heavier precipitation seems probably over areas of Missouri, perhaps far eastern Kansas and extending into the Tennessee Valley by Friday.  While initially this band was thought of as a wintry mix and freezing rain, it now appears that the bulk of this will fall as snow and thus may lead to some accumulations nearing the half-foot mark (6″).  This swath still appears to be highly variable in its’ exact location, as models for the most part are still trying to pin-down the strength and location of upper level features with the southern storm system.

Either way, the potential for a white Christmas over many areas of the Central Plains is on the rise with this upcoming storm system.  Which personally will be a welcome sight down here in Kansas City…

I’ll try and provide another update either late Wednesday or early Thursday with more details on where the heaviest snow may fall, and exactly how much snow I may see here in Kansas City!

Personal Christmas Climatology

// December 20th, 2010 // No Comments » // General Information, Weather Recap, Winter Weather

The upcoming Christmas holiday will be my first outside of the state of Iowa since being born in 1987!  With the potential of above freezing conditions and perhaps no snow on the ground here in Kansas City, I thought it might be interesting taking a look at what kind of Christmas weather I’ve seen thus far.  Take a look below at the data:

A few notes from the table above,

~ Warmest was 1991 with a high temperature of 38 degrees.
~ Coldest was 2000 with a low temperature of -17 degrees.
~ The wettest/snowiest was just last year (2009) with .6″ of liquid resulting in 7″ of new snow.
~ The deepest snow-pack was also achieved just last year (2009) with 25″ on the ground.

~ Only 6 of 23 (26%) Christmas’s have been above freezing
~ Only 3 of 23 (13%) Christmas’s have featured precipitation (snowfall)
~ 2 Christmas’s featured temperatures not even rising above zero

How will my first Christmas outside of Iowa compare?  Well the initial forecast for the upcoming Saturday (Christmas Day) is calling for a high temperature of 32 degrees, a low temperature (likely occurring late day) in the mid 20s.  A more interesting note is the idea that we may see a few lingering flurries lasting into Christmas day, but precipitation for Christmas Eve is a near definite.  I’ll have another update tomorrow on this potentially significant winter storm coming for Thursday, as areas of rain, freezing rain, sleet and snow are all going to be possible across areas of Kansas and Missouri.

A Recap of the Past Week

// December 17th, 2010 // No Comments » // General Forecast, General Information, Severe Winter Weather, Weather Recap, Winter Weather

The last update that I had given was in preparation for the snowfall and windy conditions that were expected over the weekend. Well, needless to say that those predication became a reality with blizzard conditions over much of the Northern Plains where winds gusts over 60 mph for several hours and blew snowfall ranging from 6-10″ across northern Iowa to 16-20″ over parts of Minnesota and Wisconsin. This heavy snowfall over the Twin Cities has of course caused the well talked about collapse of the Metrodome roof. Here in Kansas City were received anywhere from a 1/2″ to nearly 2″ from southwest to northeast, much of which has already disappeared with only areas of drifting being left. The strong winds did make the snowfall appear much worse, but some areas of accumulating snow in downtown areas did cause slick conditions.

A few days of downright cold weather followed for the early portions of this week, low temperatures well below zero across the Northern Plains where fresh snow, light winds and clear skies allowed for strong radiational cooling. Well below normal temperatures also occurred across the Central Plains earlier this week before we slowly rose to just below normal temperatures. Then, a very interesting event occurred Wednesday night over areas of Kansas, Missouri, Illinois and other areas towards the Tennessee Valley. The quick return of warm air and moisture just above the surface allowed for very light precipitation over the Kansas City area, and a few rain showers near St. Louis. With air and road temperatures both below freezing when precipitation began Wednesday evening, wet surfaces were quickly transformed into icy surfaces. Numerous accidents were reported with motorists sliding off of the roads covered in black ice, even several major highways in eastern Missouri and western Illinois were closed as numerous accidents blocked the roadways.

The weather once again calmed down by yesterday afternoon, and this looks to continue into the weekend. A few weak disturbances will likely lead to increased cloud cover and perhaps a few areas of light snow across the Northern Plains by Saturday and Sunday. The next true weather producer looks like it will arrive on Monday and Tuesday next week as a stronger disturbances moves across Nebraska and Iowa. Snowfall is back into the forecast for areas of the Northern Plains, and some models are beginning to indicate the potential for another decent snow for areas of Minnesota and Wisconsin that already have nearly two feet of snow on the ground.

I will try and get another update done before we see our next snowfall across the Plains and we can see if there will be any additional areas that can look forward to a white Christmas!

Blizzard for some!!

// December 10th, 2010 // No Comments » // General Forecast, Severe Winter Weather, Winter Weather

Thought I had better at least get a brief update since it has been a while and we are looking at quite the winter storm for areas of the Northern Plains. To follow the snowfall, a very cold air mass, the coldest thus far this season for many areas of the Northern and Central Plains looks to arrive for the latter half of the weekend and into early next week.

A developing storm system currently entering the western Dakotas will continue to strengthen overnight tonight, with areas of showers over Kansas/Missouri and most of Nebraska and Iowa while snowfall may begin over parts of the Dakotas and Minnesota. A small portion of northern Iowa and southern Minnesota may also see a mixed precipitation type with some freezing rain, sleet and eventually snow by late tonight. As this storm system continues to develop and wraps up late tonight, much of Minnesota will become covered in freshly fallen snow with areas of northern Iowa also getting into the fun as well. Snowfall looks to continue through the day on Saturday, with some lingering into Sunday as well towards the Great Lakes. By and large, by the system finally moves out of the region a decently large swath of greater than 12″ of snow is likely from central Minnesota through northern and central Wisconsin.

Even though other areas may not see that much snow, with any snowfall amounts there will be considerable blowing with winds likely exceeding 30 mph in many areas; even approaching 50 mph in some areas of far northern Iowa and parts of Minnesota and Wisconsin. This blowing and drifting snow has prompted several Blizzard Warnings to be issued across parts of the Northern Plains already this afternoon. These strong winds combined with the dropping temperatures will mean wind chill values well below zero, -20 to -40 in some locations by Saturday night and Sunday. Temperatures are likely to fall to at least near zero on Saturday night even as a few snow showers and cloudy conditions hang over parts of the fresh snowpack. By Sunday night, clearing skies and this fresh snow pack will likely lead to even raw air temperatures falling into the teens and 20s below zero!

While my hometown enjoys 5-7 inches of snow and blizzard conditions, down here in Kansas City we will (hopefully) be seeing at least a few wind blown flurries and perhaps a light snow shower Saturday afternoon and evening. A dusting of accumulation is at most what is expected through much of Kansas and a good portion of Missouri (south of I70). We won’t escape the cold conditions either, with temperatures trying to near the single digits Saturday and Sunday night. I’ll try and provide a quick recap on the total snowfall and who saw the blizzard conditions early next week.

Precipitation?!?

// December 6th, 2010 // No Comments » // General Forecast, Weather Recap, Winter Weather

It has been a while since there has been measurable precipitation within Kansas City! In fact, the last time either Kansas City International Airport or the Kansas City Downtown Airport received anything greater than a Trace of precipitation was November 17. That means today starts the 19th day without measurable precipitation for Kansas City, with no measurable rain or snow expected through the rest of the work week it looks like we will be able to stretch the dry-spell out to at least 23 days. The past few days have been on the chilly side with temperatures below normal, the overnight tonight will be the same with lows dropping into the teens under clear skies and high pressure dropping in from the north.

Looking ahead through the rest of the week, temperatures will remain on the cool side through Tuesday as high pressure remains the dominant feature across the Central Plains. There are a few weak disturbances, the first which will pass by to the south and may be some light precipitation to areas of western Kansas and perhaps other areas of the Southern Plains. A strong disturbance will move across areas of the Dakotas, Minnesota and into the Great Lakes region from late Wednesday and through Thursday. This disturbance will bring another round of snowfall to these areas, and reinforce the cold air mass that will be in place.

That ends the work week with little to no chance of precipitation for areas of the Central Plains. But, the upcoming weekend looks like we may be able to break the streak of consecutive days without measurable precipitation. Many of the GFS ensemble members indicate signs of a developing/developed storm system across the Central Plains on Saturday with yesterdays 12z ECMWF also displaying a strong storm system over the weekend as well (see surface pressure plots below).

The 00z GFS also came on board with a stronger solution, potentially too strong depending on how the ensembles come out, but it makes for an interesting scenario for next weekend. Check out a portion of the 00z GFS below, surface winds, temperatures and pressure on the left image; with 12 hour precipitation on the right image, both valid at 7pm Saturday.

A lot of questions still about the positioning and timing of the storm system, as there will undoubtedly be a zone of rain, an area of snow and perhaps some areas see rain transitioning to snow. Either way, it looks like we actually have a storm system to watch for that may bring some exciting weather to the Central Plains!!

A Week Review…

// November 30th, 2010 // No Comments » // General Forecast, General Information, Weather Recap, Winter Weather

Been a decent length of time since the last update, as my family and I were preparing for the 350 mile trip from Kansas to northwest Iowa late Tuesday night into Wednesday morning in order to beat the rapid moisture return northward. We did this successfully, leaving Kansas City shortly after 2am and arriving to our destination in northwest Iowa around 7:20am. Light freezing drizzle began after 10am and by Noon the roads were beginning to be covered with a thin film of ice, by evening roadway conditions on all but major highways were hazardous. A few days of very chilly conditions continued for our time back in Iowa, then a return back to Kansas City on Saturday brought us back into the 50s for temperatures.

The above normal temperatures continued on Sunday across the Central Plains, but an abundance of cirrus during the day indicated that a return of moisture was on its’ way. Areas of drizzle across Kansas City, along with showers and thunderstorms over parts of Missouri ensued on Monday. And yesterday (Monday) afternoon the cold front swept through with a swift change to breezy and chilly northwest winds. Temperatures in the mid 20s this morning and continued breezy conditions led to wind chills in the single digits across the Kansas City metro, with some snow over areas of eastern Nebraska, northeastward through parts of the Dakotas, Iowa and Minnesota. A few flakes for Kansas City were seen late overnight and again this morning, but no accumulations and obviously no problems with the few flakes that were seen. After a few chilly days this week we will return to rising temperatures for the latter half of the week. This weekend may bring a small chance of precipitation for the Central Plains, otherwise a better chance for those north of I-80. Another cold front will likely bring below normal temperatures back for early next week…

Outrunning the Moisture…

// November 24th, 2010 // No Comments » // General Forecast, General Information, Winter Weather

Just a quick update regarding the weather for the next few days, after a cold front drove through the Central Plains yesterday and pushed well into the Tennessee Valley and into areas of Arkansas and Oklahoma it is beginning to return north as a warm front with showers and thunderstorms already developing along and north of it. This is in response to a deepening low pressure in the lee of the Rockies tonight, with moisture surging back northward and over-running the frontal boundary will make for some interesting conditions for areas of Nebraska, Iowa and even the Dakotas and Minnesota tomorrow and through the Thanksgiving holiday.

Showers and thunderstorms will dominate the forecast for much of Missouri on Wednesday, as the warm front pushes well into the state and any freezing temperatures are pushed well north. The cold front will begin to push back through the state during the evening, leading to an end to the precipitation over the northwestern half of the state. An additional wave of energy combined with continued southerly flow aloft will allow for showers and perhaps a few thunderstorms to continue over the southeastern half of the state through the overnight. The true push of ‘arctic’ air is expected to be behind the front by a few hours for areas of Kansas City, however this air will quickly catch-up to the lingering cold front and likely bring a change-over from light rain to light freezing rain for areas near/along the I-44 corridor by Thursday (Thanksgiving) morning. Surface temperatures are not expected to drop below freezing, thus don’t expect any significant ice accumulations over these areas but it will bare watching.

Further north over areas of Nebraska and Iowa, the over-running moisture Wednesday morning will likely lead to areas of freezing drizzle and rain. With surface temperatures below freezing, there will likely be some accumulations and thus may cause some problems for travel through the morning hours on Wednesday. Thus, the reason of the title ‘Outrunning the Moisture…’, we are just about ready to take off into the darkness to beat the moisture back to northwest Iowa as to not get caught in any ice-glazed roads if we waited until after sunrise. Temperatures will continue to rise through the afternoon, with much of Iowa and Nebraska changing over to rain for a few hours before the cold air arrives and provides a brief change back over to frozen precipitation before ending. Portions of the Dakotas and Minnesota will be stuck with areas of snow throughout the day Wednesday, and with the low pressure tracking through these areas it would appear the snow will continue into the Thanksgiving holiday as well. Snowfall accumulations are not expected to be too significant, however with the amount of travelers it will most certainly cause problems.

Beyond the upcoming storm in the next 48 hours we look to dry off and warm up through the weekend. Then the next upper level trough and surface low look to develop Sunday afternoon across the Rockies, making its’ way onto the Plains by Monday with the next chance of both rain and snow for areas of the Northern and Central Plains!