Sunday, February 28, 2010

Quiet Weather... For Now

Quiet weather continued through the weekend, with clear skies dominating the forecast. These clear skies allowed temperatures to moderate well over the weekend, with high temperatures into the 40s across the areas with little to no snow-pack and into the upper 20s and near 30 for those that do. The clear skies also gave way to cool overnight temperatures given ample variational cooling with the light winds. Conditions like this will continue for much of the week with a high pressure system centered over the Northern Plains.

A storm system will pass through the Southern Plains on Monday, and continue into the Gulf Coast on Tuesday. Behind this we will see a large scale ridge build into the Plains for midweek, allowing for another warm-up with temperatures likely reaching normal or perhaps even a few readings of above normal temperatures for Thursday/Friday! A quick wave will move across the Rockies on Friday and begin to flatten this ridge for the beginning of the weekend. This quick moving system will have enough energy that it may bring with it the chance of precipitation for areas of the Plains. At this time there is significant differences in the track and speed of the associated vorticity maximum and thus confidence is not very high to mention any areas or times for precipitation.

Behind this initial wave comes a system that has been well advertised by both the GFS and ECMWF for the past several days. A very strong upper level wave associated with great dynamics throughout its' lifetime as it crosses over the Plains and moves into the Great Lakes region. Details regarding position and exact timing are of course in question, given the near 60 hour difference in timing the GFS and ECMWF currently have. The track is a little more agreeable between the two models, given a low developing over the lee of the Rockies in Colorado and tracking eastward into KS/NE seems probable, with a quick ejection northwest into the Great Lakes region once reaching the Missouri River thanks to a strong jet maximum in the upper levels. This system has the potential to be one of the first severe weather producers given its' good dynamics and likely thermodynamics (50s for temperatures & dew points). Although the best bet would be a cold core situation close to the low pressure system. Other than the potential for severe weather, conditions to the northwest of the low center would likely endure blizzard conditions for at least a period of time. Moisture will be ample in addition to strong dynamics and deepening surface low, thus a strong deformation zone is likely. Given the tight pressure gradient, surface winds sustained above 30 mph would also appear likely with even higher gusts. Once again the exact location and timing are definite questions, but it does appear favorable for a significant storm system for the Plains in the March 8-11 time frame. Additional updates through the week will likely reference this storm for a majority of the discussion.

Wednesday, February 24, 2010

Cold Air...

Just a short update tonight as the weather is extremely quiet for a majority of the Plains through the remainder of the week. Cold temperatures was the story this morning, with a record low set at St. Joseph, MO (-2) and a record low tied at Kansas City International (2). Single digits were prominent over much of the Northern Plains, with teens over the Central Plains this morning. Below zero lows were common, with teens below zero for areas of Iowa, Minnesota, and the Dakotas. The lows tonight won't be too much warmer, with many single digits and below zero readings expected.

Feb. 24 Morning Low Temperatures

Looking ahead through the rest of the week, we'll slowly begin to warm-up through the weekend, although temperatures will remain below normal to well below normal for many areas of the Plains. A storm system will intensify on Thursday over the southern Plains, leading to areas of snow for southern Kansas and Oklahoma. The low pressure system associated with the snowfall will quickly move southeast on Thursday night and Friday, leaving areas of the southern Plains and perhaps even the lower Mississippi Valley under a blanket of snow.

With all of the precipitation remaining south, we'll continue to see fairly clear skies. The sun is beginning to feel pretty warm though, which is hopefully a sign that if we can begin to get rid of some of the snow that is currently covering the Plains that we can at least begin to see normal temperatures! Next update is expected on Saturday for a look at next week!

Monday, February 22, 2010

Feb. 21/22 Recap & A Look Ahead

The storm system this past weekend brought a mix of precipitation types to parts of the central Plains. Areas of flooding occurred and are ongoing due to substantial rainfall amounts across central Missouri this past weekend. An area from south-central Kansas into the Kansas City Metro saw ice accumulations of a few tenths to nearly a half-inch in a few isolated areas. Sleet was also a common precipitation type over the weekend, with several roadways in eastern Kansas and western Missouri becoming hazardous with slush accumulations of a half-inch or greater. And lastly there was snow, varying from around an inch on the south side of the Kansas City Metro and across I70 in Missouri to just an inch or so over parts of southern Iowa. In between however, a swath of 6-10 inches covered areas of northern Missouri with isolated amounts nearing 12 inches. Strong northwest winds allowed for blowing and drifting of the snow as well, creating large drifts in open areas and making travel impossible in some areas through the day on Sunday. To view all of the reports that came in from the region, check out the link posted below:

To view other reports from the region, check your local NWS office homepage. The NWS in Kansas City has also provided a brief summary of the events that occurred in the metro area in regards to precipitation types. This includes a vertical cross-section image that shows the warm layer just above the surface that was responsible for the freezing rain over the southern metro area. The ongoing snow continues to make its' way into the record books, with a record daily snowfall at Kansas City International. With rounds of snowfall in Des Moines on Friday, they continued to increase their snow depth and continue to break records for the most consecutive and non-consecutive days with specific snow depth amounts. Plenty of other records are out there being broken as well, with plenty more likely to fall as the winter isn't about to give in to Spring.

Looking ahead for the remainder of the week, a cold front will sweep through the Plains tomorrow bringing with it the chance of flurries and some light snow mainly Iowa and eastern Missouri. Accumulations are expected to be little to none across the region due to limited moisture and meager lift along the boundary. The cold front passage will bring a reinforcement of cold air that will keep us well below normal for Wednesday and Thursday. Another storm system on Friday will bring the chance of precipitation to areas of the southern Plains, will have to watch and see how far north the precip chances can make it for Friday.

Wednesday, February 17, 2010

Potential Winter Storm(s)

I decided on one more update before I head back to Iowa for the remainder of the week, seeing as with such nice weather today there was only the upcoming two storm systems to look forward too. Models are beginning to show some agreement, or at least a few models are coming to the same agreement with this mornings' and afternoon model runs. Essentially the confidence is building that we will see a rain/snow event mainly over areas of Kansas and Missouri for both Friday and Sunday.

Friday: Both the 12z and 18z NAM showed consistency in their solution, which had been the outlier when compared to other model runs yesterday. However, this morning the runs of both the Canadian GEM and European ECMWF trended to a stronger solution. Still not as strong as the operational NAM, but is something to think about in regards to the strength of the upper level wave that will be moving across the area on Friday. For this reason, expect precipitation amounts to be higher than the GFS, but not as strong as the NAM. The other large question will be regarding temperatures, as with a stronger solution should come better warm air advection just ahead of the trough. This would likely lead to a rain/snow mix near/along I70, with snowfall likely just north and all rain further south. This is shown fairly well in the NAM, with a tight gradient of no snow to heavy snow essentially focused over Kansas City and other areas along I70. The most likely scenario will have a true mix of rain and snow for the Kansas City area, with ~1" of a heavy wet snow likely across the area. Areas just north of the KC Metro may see up to 2" of snow, while just south may only see a dusting. This will be a tricky forecast, thus even any subtle changes in the track/strength of the system could drastically change the snowfall forecast.

Sunday: Models are beginning to creep towards a consensus in allowing the pacific wave to come onshore and across the Rockies without much inhibition by the emerging blocking pattern. This would lead to a stronger system, and with ample moisture available may lead to some significant snowfall amounts over some portion of the central Plains. This is another system that will feature a tight gradient of no snow to heavy snow, as the thermal gradient along the surface and lower levels will be quite dramatic. The 18z GFS left this gradient nearly along I70 in Missouri and along I35 in Kansas, with areas north seeing mainly snow (perhaps heavy at times) and areas south seeing mainly rain. That does leave a small area that will be along the transition line that would see a mix of rain/snow and perhaps even some sleet or freezing rain dependent upon localized thermal profiles. The 12z Canadian has a similar solution in regards to strength and only slightly slower in timing, location-wise it is approximately 50-100 miles further south than the GFS. The ECMWF has been the outlier in regards to timing and strength with this system, and continues to be so. However, it has trended a little faster and stronger in the latest 12z run thus increasing the likelihood that a solution similar to the GFS/GEM can be expected. With this in mind, it does appear likely that some portions of Kansas/Missouri will have the potential of significant snowfall for Sunday. The band of heaviest snow would appear to have the potential for greater than 8" of snowfall, with this band being quite narrow it is going to be difficult to forecast for at this time. However, expect forecasts from local sources to begin more discussion on this event as the weekend nears.

Tuesday, February 16, 2010

Which System?!?

I decided to get one more post in before I head away on a trip back to Iowa for the Iowa State High School Wrestling Tournament. The reason for the update is mainly as a initial thoughts on what could be an interesting weather weekend for the central Plains states. Two waves are likely to travel across portions of the Plains and may bring the chance of precipitation, in both liquid and solid form. The best part about the upcoming forecast is that there really has not been a forecast model to get a good grip on a solution to this point. With the NAM favoring the initial wave, the GFS favoring the second wave, the ECMWF favoring the second but also being even slower, and the SREF ensembles which range anywhere from 0.00" to 0.97" for Kansas City Intl into this weekend. These are just subtle changes either, the 12z & 18z NAM today put out nearly 1"/hour rates of snowfall for Friday and Friday night leading to what the NAM believes is a foot of snow by Saturday at dawn for the Kansas City area! The GFS on the other hand, does not send out as much energy with the first wave and hence gives the Kansas City area a solid 0.00" of precipitation through Saturday morning.

The reason for the discrepancies is due to a wave of energy that will drop down into the Rockies late Thursday, and another wave that will drop southward from our arctic low. These two waves of energy would likely incur some phasing as they entered the Plains states on Friday, but the question that the models are trying to answer is how much energy from the 'southern' wave will actually eject out onto the Plains. The NAM of course has a majority of the wave coming out onto the Plains and thus forecasting a large amount of precipitation with it. The GFS on the other hand will keep most of the energy in the Rockies, providing little to no precipitation for the late week.

What happens with the initial wave will likely have large impacts on our second wave for Sunday/Monday. Looking at the ensemble members, you can judge that those which have this stronger system on Friday do not have as much energy shown with Sun/Mon and thus do not expect much of an impact with this system. With the ensemble members that do not expect much on Friday, have a much larger and significant system for the Sunday/Monday time frame. Essentially if a majority of our first wave is held back in the Rockies, it will contribute to the second wave that will be pushed out onto the Plains with the storm system entering the West Coast late Friday.

Although a good amount of time was spent looking at things today, it is still very hard to tell which model may have a better handle of this that far out. It would appear that it may be best to hedge towards the second event being the largest of the two, leading to some significant precipitation for Sunday/Monday across the central Plains. However, as mentioned it is pretty hard to make much of a justification for this. For now I will keep an eye on it as it may disrupt my travel plans for a return from Des Moines, but I won't likely see time to post any updates on the blog. For now keep an eye on what the various forecasters have to say, as it will be interesting to see who throws their hat out into prediction of the big storm as either Friday or Sunday/Monday.

The next update will likely not come until early next week, perhaps even after both storm systems have exited and there is a little downtime to post a recap of what occurred, or what didn't! In the meantime, enjoy a few days of quiet weather before we at least have a chance at adding to some snow totals across the Plains.

Monday, February 15, 2010

Winter Storm: Feb. 14 Recap

Snowfall over the weekend held a few surprises, the biggest coming with a 'snow squall' in the Kansas City area that led to multiple pileups on interstates within the metro. These snow squalls were caused by strong lapse rates and elevated instability that was collocated with the best dendritic growth zone (-10 to -20C). This allowed for rapid snowfall associated with strong northwest winds, creating near-zero visibility for a short period (~15 minutes) across several areas near the Kansas City metro. For a little more background and a few graphics, check out the link below from Kansas City NWS and for a more meteorological review check out the blog post by Jon Davies:

Kansas City Valentine's Day Snow Squall

Jon Davies Snow Squall Blog Post

The heaviest bands of snowfall occurred across parts of eastern Nebraska, western/central Iowa and into northeast Missouri and other areas along the Mississippi River. The upper level low made its' turn east and allowed the heaviest snowfall to occur into parts of Illinois and Indiana. A few maps of the snowfall totals from this weekend are also posted below:

Omaha NWS Sunday Snowfall Image

St. Louis NWS Sunday-Monday Snowfall Image

Springfield NWS Regional Snowfall Map

Saturday, February 13, 2010

Winter Weather - Feb. 13/14

Snow ongoing over parts of northern Iowa, western Minnesota and the eastern Dakotas with some heavy snow reports even coming in at times. A few reports that have came in already include 4" in Sioux Falls, SD and 2.5" in Rock Rapids, IA. This snow will continue to expand through the overnight, and slowly make its' way southward as a surface low forms in association with the upper level low that has made its' way into the eastern Dakotas. No major changes in forecasted snow totals with a band of 3-5" and isolated 6" amounts still seeming likely from western/central Iowa south/southeast through central and eastern Missouri. The latest Kansas City NWS graphic shows a pretty good depiction of forecasted snow totals.

Beyond the snowfall, expect northwest winds to increase during the overnight and Sunday for the area. Leading to blowing and drifting snow and hazardous driving conditions for your Valentines' Day. Cold and breezy conditions will continue through Monday before we see the sun again and a slight warm-up through midweek.

Friday, February 12, 2010

Weekend Snowfall

The weekend rounds of winter weather continue to be fairly well handled by forecast models. No significant changes have occurred since my update yesterday, with two rounds of winter precipitation likely across the Central Plains. The first of which will occur Saturday with accumulations ranging from 1-3" across parts of Missouri and Iowa. A second more robust round of precipitation will occur as our low pressure system dives south along the NE/IA and KS/MO borders before sliding eastward across southern Missouri. The heaviest snowfall should occur in areas of northeast/central Missouri where a band of 3-6" is likely as the low pressure begins its' trek eastward. Winter Weather Advisories have already been issued for areas of Missouri that are expected to see the heaviest snow accumulations.

Expect temperatures to drop dramatically as the low pressure system passes by, with increasing winds as well. All of this will lead to increased likelihood of snow accumulations on roadways and blowing snow leading to hazardous driving conditions on Sunday. We'll stay cold and breezy on Monday, with a few flurries continuing to fly as moisture is ringed out of the arctic air mass. We'll finally see the sun again on Tuesday, but likely remain below freezing for a majority of areas that saw the snow over the weekend.

Although areas of Missouri may see upwards of 6" of snow totals this weekend, I don't expect to make any additional updates regarding our weekend snowfall due to the weekend. I will likely post a recap on Monday/Tuesday to summarize any events that occurred and provide snow total maps. Enjoy the Valentines weekend...

Thursday, February 11, 2010

A Few Disturbances...

A few different blobs of information today, the first of which will be about a weak disturbance that is making its' way through the Plains tonight and tomorrow. The next about a disturbance currently over the southern Plains, giving areas of northern Texas over a half-foot of snow and still going. And finally we'll get to the next large storm system for the Plains states that will come across on Valentine's weekend.

So for the first disturbance to discuss, an upper level wave associated with a weak surface low pressure system is colocated across the Iowa/Nebraska borders at this time. These two features will continue to rotate down into Missouri during the overnight hours, and push eastward during the day tomorrow. At this time the system is going to lack moisture and sufficient large scale lift to give areas anything more than an inch or so of snowfall. These areas of snow are going to be pretty small in terms of coverage as well. Portions of northern Missouri and southern Iowa may see ~1" of snow during the overnight tonight, with the typical flurries for many other adjacent areas including Kansas City. This 'snowfall' will continue into areas of central and eastern Missouri during the afternoon tomorrow before exiting into the midwest and Ohio Valley by tomorrow night. This may be able to create some slick conditions for a few areas overnight, but does not appear to be a widespread event.

Our next discussion wil be about the upper level disturbance over the Southern Plains today that will continue to push eastward along the Gulf Coast tomorrow, developing an area of low pressure just off shore later this evening. With cold air already entrenched well south, this low pressure system will aid in pulling the cold air even further along the Gulf Coast and resulting in snowfall for many areas of Louisiana, Mississippi, Alabama, Georgia, and even the Florida Panhandle! Accumulations along the shorelines are not expected to be significant, however areas not too far inland may see accumulations greater than 4". Winter Storm Warnings have been issued for many of these areas expecting to see snow through Friday.

Finally our discussion on the next significant storm for the Plains. As we head into the weekend, the next storm system to affect the northern and central Plains will begin to take shape. Diving nearly straight south out of Canada will come an upper level low and associated disturbances. Currently, models depict the upper level low traveling through eastern portions of the Dakotas and Nebraska before closing off at 500hPa and beginning its' turn eastward over Missouri. This is a path that would likely give areas of western/central Minnesota, western/central Iowa, and northeast Missouri the heaviest snows. Generally 3-6" will be a good estimate for these areas, with heavier amounts coming as the storm rotates eastward. Meaning areas of northeast Missouri and into central Illinois may see the heaviest amounts nearing ~8" as of current model runs. This system will enter/exit the Plains on the weekend, leaving us with cold and flurries by the start of next week. One thing to note for those watching the east coast get burried, this storm system also looks to take a track to give most of those areas at least a few more additional inches of snow for early next week!

Tuesday, February 9, 2010

Winter Storm: Feb. 7/8 Recap

Snowfall was heaviest over parts of eastern Minnesota and central/eastern Iowa where as much as 12" fell over the span of 48 hours. You can push back the span even further and see values increase to nearly 18" as the snow began over parts of the Plains well before the upper low became nearly stationary during the day yesterday. Currently only flurries and a few light snow showers are left across parts of the Plains, as the upper level low has begun its' trek into the Ohio Valley and eventually the east coast where it will once again dump several inches of snow. The upper low and its' associated features were an interesting sight to watch, as noted by the previous update that featured a surface plot of temperatures. What could be classified as a mesoscale high pressure system essentially formed along the upper level low and allowed clear skies and calm winds to drop temperatures dramatically over a short period of time last night and into this morning across parts of Iowa and Missouri. Strong northwest winds hampered travel conditions yesterday and much of today across the Plains, as blowing and drifting snow created slick road conditions. Even with areas simply receiving flurries and light snow the winds allowed for a drop in visibility and created some spotty areas of snow covered roads.

With the storm on its' decline for the Plains, several National Weather Service offices have issued their summaries of snowfall totals. They are listed below:

Minneapolis NWS Snowfall Map

Des Moines & Omaha may be added if available

Kansas City NWS Snowfall Map

St. Louis NWS Snowfall Map

Springfield NWS Snowfall Map

Winter Storm: Feb. 7/8 Update #5

Although the vast majority of moderate and heavy snowfall is out of the Plains region, lingering flurries and light snow are continuing across a large portion of the Plains due to the cold arctic air that is plunging in.  This cold air is featured in the layer of the atmosphere that is favorable for snow growth, thus flurries or light snow is being condensed out and falling over several areas. While this snow isn't expected to accumulate much, the strong northwest winds will continue to blow any loose snow around.  Some portions of Minnesota, Iowa and northern Missouri may be able to squeeze out another inch of snowfall with the persistent light snow that is featured next to the upper level low.  For this reason many of the local NWS offices have yet to issue any maps regarding snowfall totals.  If you would like to keep up with the totals in Iowa, the IEM has a automatically updating plot on snowfall totals available at the following link:

Some travel concerns continue where the snowfall was heavy enough and light enough to continue to blow and drift with the strong northwest winds.  The winds are expected to slowly decrease this evening and through the overnight, relieving any travel concerns by tomorrow morning. A final recap on this winter storm will be posted when summary maps are available...

Monday, February 8, 2010

Winter Storm: Feb. 7/8 Update #4

A quick update with a look at a surface chart with contoured and color-filled gradient of surface temperatures, as well as 10-meter wind speeds overlayed.  Can you tell me where the upper-low, cold front, and occlusion is occurring?  A pretty impressive surface map with temperatures dropping like a rock across parts of northwest Iowa and adjacent areas, Spencer recorded a temperatures of -19 back at 8PM.  These temperatures will slowly rise through the night as the low pressure overhead moves eastward and northwest winds actually advects warmer air into the area!

I'll post an additional update later on tonight or early tomorrow with some of the snow totals, currently it would look as if parts of eastern Iowa and Minnesota won the snow battle with 6-10" in that area. Portions of Missouri and Kansas were able to get into the 3-6" range with a few isolated higher amounts in southern Kansas. Parts of northern Arkansas also won the snow big with a few reports over 6" being received as well. This snow will continue over parts of eastern Iowa, Minnesota, Missouri and other adjacent areas. More details on snow totals later...  For now enjoy the fancy image below:

Winter Storm: Feb. 7/8 Update #3

Our winter storm continues across the Plains states, however, with decreasing forecasted snow totals for many regions. Nearly all locals have seen a decrease in their forecasted snow totals as the two systems are struggling to produce better than a light to moderate snowfall. While over time the light to moderate snow will still lead to heavy accumulations in some areas, mainly central and eastern Iowa, this will not lead to significant accumulations across most other areas due to the longevity of the storm.  A cold front sweeping down through areas of the central Plains this afternoon/evening will put an end to the snowfall in some areas, which will hinder the storm totals that could otherwise continue to increase through the overnight.

The two storm systems will begin to conjoin during the day today, with continued snow across parts of southern Kansas and northern Oklahoma spreading eastward. Ongoing light to moderate snow is expected over areas of Iowa as the northern stream upper level low continues to dig and spin without much movement. This is still expected to leave two bands of heavier snow, one over Iowa and another over southern Kansas into portions of Missouri. The latest Kansas City NWS graphic has a good interpretation of these two bands, although don't expect to see accumulations too much higher than 5" in the band across Missouri.


An additional update is expected tonight as the arctic air begins to enter the Plains and aid in stopping the snowfall, I'll try and update on accumulations thus far as well.

Sunday, February 7, 2010

Winter Storm: Feb. 7/8 Update #2

Several NWS offices have begun to issue their latest forecasted snow totals for portions of the Plains states.  The Topeka NWS office has decreased their amounts compared to their first forecast, with only 5-7" expected in their warning area with less amounts to the north. This 5-7" line has shifted slightly south as well, just south of the Kansas City Metro to align with the forecasted totals from the Kansas City NWS office as well.  The Des Moines NWS office on the other hand did actually increase the snow totals for parts of central and eastern Iowa where 10-13" is now forecasted.  This area is currently the favorite to see a prolonged period of moderate to heavy snow as the upper level low from the northern stream stalls for a moment during the day Monday before moving eastward during the evening and overnight.  It is important to note that any changes in the path of the northern stream upper level low could create a change in the forecasted snow totals.  I've posted the latest NWS maps regarding storm totals below, these are all as of 1:30 PM on Sunday.

Winter Storm: Feb. 7/8 Update #1

A truly complex situation has resulted in many questions regarding the amounts and placements of snowfall totals across the Plains states.  An initial shortwave that is rounding the northern low pressure system is creating some light snow across parts of the central Plains this morning, with accumulations staying rather light through the day today.  The more important feature will be a shortwave and associated trough that is currently making its' way into the four corners region this morning. This will continue to move eastward through the day and make its' way onto the Plains during the overnight, just ahead of this shortwave we will see a brief ridge develop in response to the digging trough which will allow a good return of moisture northward.  As this trough continues eastward it will begin to interact with the cutoff low pressure system that will be positioned over the northern Plains, and this is where the forecast truly becomes complicated.  These two features will eventually come together as one, with the southern stream shortwave allowing for the low pressure system to finally move eastward sometime on Monday. An interesting note found in the Kansas City NWS discussion shows just how unique this event is, as they were not able to find a good analog event for just such an instance.  In other words, they do not have record of a similar event occurring this far east over the Plains states.  All of this comes together to paint a very messy and snowy picture for the Plains, but a wide range of snowfall forecasts for this winter storm.

The morning models have really had a rough time this morning, with a variance of snowfall accumulations greater than 6 inches in some locations between the NAM and GFS.  Of course the Kansas City Metro is once again along the line of receiving anywhere from 6-9" of snowfall to only 2-5" of snowfall depending upon the track of the southern wave and its' precipitation.  We could also see a fluctuation in snowfall amounts depending upon where the two systems interact and begin to push eastward with a strong cold front.  This has essentially led to a hedging of snowfall amounts for the area, with 4-8" a decent forecast at this point with so many questions remaining still only ~24 hours out.  The hardest hit areas will likely be over southern Kansas and Missouri, and then eastern portions of Iowa/Minnesota ahead of the northern upper level low.  Both of these areas will likely see 8"+ snowfall amounts by Tuesday morning. Other portions of eastern Missouri will likely see a good 4-8" swath of snowfall, while areas of northwest Missouri (W of I35, N of KC Metro), Nebraska, and extreme western Iowa will miss out on the majority of heavy snows and see less than 4" of snowfall.  An additional update late tonight is expected, with any additional refining to snowfall totals based upon the location of the southern stream system.

Saturday, February 6, 2010

Winter Storm: Feb. 7/8

Another winter storm featuring two waves of energy will impact the Plains states beginning Sunday afternoon and continuing through the day on Monday into Monday night.  A trough coming onshore that has just came ashore in the Pacific coast will continue eastward overnight and begin to deepen, pulling additional moisture northward into the central Plains once again. This will begin our snowfall during the afternoon/evening hours for Kansas/Missouri and will combine with the stronger northern system during the overnight and continue to produce snowfall for the day on Monday and into Monday night for eastern portions of Missouri.  This northern system is a strong closed low that will rotate down into the Plains, pulling with it a strong push of arctic air.  As the system moves east it will once again setup portions of the east coast for another significant snowfall event.

With another complex system comes another complex snowfall forecast, with even a few NWS offices not tipping their hand as to what they are thinking.  It does appear that we will have a significant area of 6"+ snowfall over Kansas/Missouri/Iowa/Minnesota by Tuesday morning.  A few areas may be able to pull off an 8"+ snowfall amount, especially those further east.  Compared to the last system, this one will see snowfall become much drier, and therefore lighter allowing the wind to become a factor.  This is especially true as a cold front brings northwest winds gusting upwards of 25 mph which will provide blowing and drifting snow over a large area of the Plains. With this systems' start time late Sunday, we will start to see NWS offices upgrade their winter storm watches to various advisories and warnings. An additional update tomorrow morning will put a final rough estimate of expected snowfall for the Plains states...

Winter Storm: Feb. 5 Recap

A storm that featured two different waves of energy, the first of which was unorganized and allowed for very little snowfall across the central Plains states.  The second wave of energy provided a unique situation across parts of KS/MO where a mesoscale snow-band allowed for accumulations at rates upwards of 2" per hour.  This mesoscale band was the highlight of the event, as the system quickly became starved of both upper level support and continued moisture advection.  Further to the north, a deformation zone across the Omaha area allowed for 3-5" over the two day stretch of Feb. 4/5 with lesser amounts to the east/west of the Missouri River.

Haven't had much time to really look at things with this event, as another strong storm system is aiming for the Plains states and will be the focus for the next post.  Links to a few of the National Weather Service snowfall reports/maps are posted below:

Omaha NWS Snowfall Map

Kansas City NWS Snowfall Map

St. Louis NWS Snowfall Map

Friday, February 5, 2010

Winter Storm: Feb. 5 Update #1

Light to moderate snow has fallen over the Kansas City area this morning, with nearly an inch of accumulation thus far.  Snow is expected to continue here through the next couple of hours with at least another inch of accumulation likely.  All but the northeast portion of Kansas has seen the snow taper to just flurries with much of their accumulations falling overnight with this initial band.  Snowfall reports through central and eastern Kansas have varied from 0.5" to upwards of 2-4" in eastern Kansas where the snow has ended within the past few hours.

The band of snow that is currently over western Missouri and northeast Kansas will continue to move eastward through the afternoon, arriving along the Mississippi River during the late afternoon. Snowfall amounts of 2-4 inches are expected across much of the state with this band, with only the far southern portions of the state being too warm to see significant snow accumulations.  There may be a few isolated spots of 5 or 6 inch amounts across mainly central and east-central Missouri as models have indicated an area of enhanced snowfall growth. 

Further north across Nebraska and Iowa, snowfall has tapered across most areas, with some snowfall still possible over southeast NE and southwest IA with this second wave and band of snow. Total accumulations overnight were greatest in the Omaha metro area where 3-4 inches fell with a few isolated higher amounts.  Other areas of Iowa saw an inch or two last night, and a 1-3 inch swath was seen across parts of southern Nebraska.

A later update will include a recap of snowfall reports received over the central Plains region...

Winter Storm: Feb. 5

Conditions and forecast remain on track for a minor winter storm to occur across portions of Nebraska, Kansas, Missouri and other adjacent areas.  A band of snowfall will continue to work east through the overnight hours across central and eastern Kansas, and continuing through the state of Missouri tomorrow.  Total snow accumulations will likely range from 2-4 inches, however, some areas may see higher amounts where snow growth can be maximized for short periods of time.  The best chance for these areas will be over portions of central and east-central Missouri during the afternoon hours tomorrow.  These areas of enhanced snow growth may be able to see 3-6 inches of a heavy wet snow...

Expect some travel delays tomorrow morning across the Kansas City metro, with delays and concerns for the St. Louis metro during the commute back home tomorrow evening.  Other parts of the state of Missouri will also have travel problems over all but the far southern region due to snowfall.

Further north in areas of Nebraska and extreme western Iowa a light to moderate snow will continue through much of the night, producing widespread 2-4 inch amounts across eastern Nebraska and western Iowa.  These amounts are also expected to be of a wet and heavy snow, which won't create any additional blowing or drifting snow problems like many of the storms previous have.

Sorry for the short update, but a long evening of work due to this storm and it is time to call it a night.  A brief recap of the storm may be posted this weekend, otherwise an additional update on Saturday will likely be posted to let you know about the upcoming Super Bowl storm for parts of the Plains!!

Wednesday, February 3, 2010

Upcoming Winter Storms!!

A multitude of storm systems will impact the central and northern Plains states within the next week, providing ample snowfall to areas as far north of the Dakotas and as far south as northern Oklahoma and Arkansas. The first system will result from a trough in the southwest moving onto the Plains state tomorrow, and will be reinforced by a shortwave during the day on Friday. This is likely going to lead to a widespread swath of 2-5" of snow across much of the central Plains including Kansas, Missouri, Iowa, Nebraska and even points further north. This system will be able to cause widespread snowfall due to its' extensive moisture plume that is available just ahead of the system. You can already see this ample moisture with the warm-air advection precipitation sheild that is moving northward over much of the southern Plains. This will continue to move northward, perhaps causing a mix of rain/snow for some areas of the central Plains tomorrow morning. Otherwise we'll see a change to all snow for most areas by tomorrow afternoon, and accumulating snow continuing through the day on Thursday and into Friday for some of the eastern portions of the Central Plains. For more specific details regarding snowfall totals be sure to check with the latest NWS information. The next update will likely come as this system is ongoing, thus will provide just a brief update on the ongoing storm and expected accumulations.

The second storm system has become much more organized with the latest model runs, indicating the potential for another significant winter storm over areas of the central and southern Plains. The heaviest band of snow does once again appear to be centered over the KS/OK and MO/AR borders. With snowfall accumulations rivaling that of the prevoius system which brought widespread 5-8" with isolated higher amounts. The timing of this system would bring the snowfall through these areas beginning late Sunday and continuing through the day on Monday. Other areas of northern Kansas/Missouri and even adjacent areas just north into NE/IA will also see snowfall with this system, however amounts should remain below 6" given current model indications. More details regarding this second system will be available in later updates...

Tuesday, February 2, 2010

Two Upcoming Storm Systems...

The forecast remains dry for Tuesday and Wednesday, but a low pressure system coming off of the Gulf of Mexico will bring precipitation chances to much of the central Plains by Thursday and Friday. The low pressure system will come onshore and remain along the Gulf Coast through the end of the week, however, an elongated trowel region will bring precipitation well northwest of the lows' center along the Gulf Coast. Precipitation should begin across areas of central and southern Kansas by Thursday afternoon, likely in the form of rain. By Thursday evening the precipitation should continue to move northeast and enter areas of eastern Kansas and western Missouri overnight, with some areas seeing rain and others potentially a rain/snow mix through Friday morning. As the precipitation continues to move northeast, at least some cold air will likely push southward into KS/MO to aid in a change-over to snow as the main precip type. Dependent upon the precipitation intensity, this change-over may be able to occur sooner on Friday morning if intensities are at least moderate. Total snowfall amounts are hard to pinpoint at this time, not only with many questions regarding the extent of the trowal region, but also to when will we have the change-over to snow. Regardless, precipitation will be able to filter through much of Missouri through the day on Friday and leaving the state under sprinkles/flurries by Saturday afternoon. Areas further north, including Nebraska and Iowa, may also be able to see some precipitation from this system. The best chances will be over the southern regions of these states, where at least a few inches of snow are likely to fall by end of the week.

Total snow accumulations further south over areas of Kansas and Missouri are still in question, but would not be surprised to see some areas with 3-6 inches by the end of the week if some model indications are correct. Details regarding this system and its' snowfall potential will be assessed in a later update...

Beyond this system for Thursday/Friday, we are looking at a cold front to work its' way through the central Plains on Sunday/Monday. This will also bring snow potential for the entire central Plains region and behind its' passing will also be more cold air to deal with. Some flurries may remain possible on Saturday behind the first system, and increasing in intensity through the day on Sunday and into Sunday night. This system may not last long, but its' intensity with the push of cold air will quickly rid the atmosphere of moisture and likely allow for a 'quick' 1-3 inches across the area with locally higher amounts. More details on this system will be forthcoming over the weekend as our first system passes by...