Winter Storm Watches hoisted in anticipation of Thursday's storm

Winter Storm Watches have been extended further east this morning to cover northern Illinois and southern Wisconsin and will go into effect Wednesday evening.  It's important to remember that even though the watch has been extended further east it doesn't necessarily mean we'll get a lot of snow.  At this point it still looks like the heaviest snow band will fall just north and west of Rockford.  However, if the track of the low shifts a little further south then the heaviest snow band would be shifted further east and south.

Winter Storm Scenarios

If you saw today's forecast, you know a big storm is looming on the horizon, but what we see will depend almost solely on how the storm moves. Since the forecast can still change, let's talk about some of the scenarios we could see with this next system.

Possible Storm Tracks

Model runs are showing two general paths the storm could take. Some models, like the GFS and NAM, are tracking the storm right over Rockford or just to our north. The European model is breaking the trend, keeping the storm south. It's important to note here that the European model has been very consistent in forecasting the path of past storms. In my professional opinion, I'll side with the Euro over the other models almost every time.

Those two potential paths mean two very different things for the Stateline, especially Rockford. If the GFS and NAM hold, the forecast would look like this: A rain/snow mix for Wednesday night and a good chunk of Thursday, with a changeover to snow later in the day. The warmer air that would be pulled in with a northern track would mean less accumulating snow, although some snow on the ground by Friday morning is still a decent bet.

If the European model holds true, we'll be talking a blast of cold air much earlier on Thursday, meaning a lot more snow.

Watches for Thursday's Storm

But the question is how much snow? It's almost impossible to tell at this point, but the heaviest snow totals are always to the north and west of these storms. Knowing this, the National Weather Service has already issued WINTER STORM WATCHES for parts of Wisconsin and Iowa. That watch also includes Jo Daviess County. This is a good indicator of how close we'll be to some big time winter weather.

The storm doesn't need to move a lot to change our forecast. A difference of 50 miles could be the difference an inch of snow and half a foot of the white stuff. We'll have a much clearer picture if what we should see in the next 24-36 hours, and we'll definitely keep you updated as we go through the week. -BA

Could this next storm be the one?

11am Update:  The latest morning runs of the NAM and GFS are beginning to come in.  From last night to this morning the NAM has shifted the track of the low further south from its previous position (which had it moving through the Quad Cities to Dubuque with all rain falling).  If this track were to verify precip would begin as rain Wednesday night with a change over to snow Thursday.  The American GFS has maintained its track from Sunday evening but has had a slight shift further west.  This, too, would keep precip in the form of rain Wednesday night with a possible mix or change over by Thursday afternoon.  Bottom line, the highest snowfall totals will occur where snow falls during the whole duration of the storm and that might just be north and west of here.  It will interesting to see the morning run of the European model.  I wouldn't be surprised to see that shift further north as well.


Sunday tied the record for the longest stretch without measurable snowfall in Rockford...a whopping 287 days!  The previous record was set back in 1922.  Another snow less day is expected this afternoon so look for that old record to be surpassed, although, we may not remain snow less for long.

A few systems moving within the jet stream will traverse across the Midwest today and tomorrow but the one that has everyone asking "Will this be the one?" is now just moving onshore in the Pacific Northwest and is expected to be here by Wednesday night.  Even though Wednesday night doesn't seem that far away there remains a bit of uncertainty as to where exactly this storm system will track.  After all, a matter of 50-80 miles north or south would be the difference between a foot of snow or an inch of rain.  Before we get too excited about this next system I want to break down a few of the possible tracks and scenarios that may play out by Thursday night.  With this storm just beginning to move onshore there will be shifts in the track until it's sampled for about a day or so with the upper air network.  In fact, we've already seen a shift in the track within the past 24 hours.  The majority of the reliable weather models we look at have a general track from around Oklahoma to central Missouri by Wednesday night to central Illinois by Thursday morning and into Michigan by Thursday night.  Usually the band of heaviest snow will fall just north of where the surface low tracks and with this projected path it would place areas from Des Moines, IA to Freeport, IL to Madison, WI in a swath possible to receive nearly six inches of snow!  East and southeast of the track a rain/snow mix or just rain would fall leaving snowfall totals a little less near Chicago.



January 1996 Snowfall

It's important to look at what will occur at the surface but to gain a better understanding of the storm system we have to look at what's occurring above our heads.  A dip in the jet stream out west will allow for not only a surface low to develop in the central/southern Plains but also an upper level low in the southwest.  This low will become a closed circulation as it moves northeast into the Great Lakes.  When we see this happen in the flow aloft it means the low will strengthen as the jet stream develops a negative tilt and will usually slow down.  As is typical with systems that slow down we usually tend to see a slight shift of the surface low to the north and west; which was already observed from the American GFS model from Sunday morning to Sunday night as well as a slight shift north from the European model.  So I wouldn't be surprised if this general trend towards a more north and west track continues. 



January 1996 Snowfall

To also aid in trying to forecast potential significant storm systems we look back at previous events that have had a similar track as to the one we're expecting.  One such past storm occurred back on January 1996 which dumped a significant amount of snow from Iowa to southern Wisconsin while northern Illinois received only a few inches.  Should the track of this storm shift further north and west the heaviest snow band would shift as well and further away from the Stateline.


   


By Tuesday morning we should have a pretty good idea of just where this low will track and how much snow or rain we should receive.  Stay tuned!

It's Beginning to Look LIke a White Christmas

Sunday was a drab day across northern Illinois.  Weak weather systems dominate the weather picture, so the clouds are stubborn, and will continue to be overnight, and on through the day on Monday.  As of 10 pm CST the temperature has been stuck on 38 degrees for 8 hours in a row at the Rockford airport.  With that in mind I don't think it will get as cold tonight as I thought earlier.  Instead of the upper 20's for lows tonight, I think the temperature will have a difficult time falling below 32 degrees all night.  The wind will be light tonight and tomorrow, and the high on Monday will be in the upper 30's. Every day this month has been warmer than normal.   The weather has been mild so far in December with the temperature averaging  a little more than 12 degrees above normal.  That is a big differential.  It will not last because there is colder weather on the way for the end of the week through the weekend.  Little if any precipitation is expected through the daylight hours on Wednesday.  High temperatures will run from the upper 30's into the low 40's, and lows at night will be in the upper 20's to low 30's.  Things start to get interesting on Wednesday....  Low pressure starts to pull itself together over the panhandle of the southern plains.  A strong surface jet is in place from the southern plains northeast across southern Missouri, southeastern Illinois, into Michigan.  The low will have plenty of cold air to the north, and plenty of warm and humid air from the Gulf of Mexico to the south.  The intensifying winter storm is expected ride the thermal boundary to the northeast in an almost ideal path  (for producing heavy snow for the Stateline) across southern Illinois across east central Illinois into Michigan on Thursday.  It's a little early to call for snow fall totals while the makings for this storm are still off the Pacific NW coast, but the models have been pretty good lately on predicting major storm developments.   It is possible that this whole system may fizzle and never develop, but right now it looks like 4" to 8" of blowing and drifting snow is possible by late Thursday.  The precipitation will probably start as a rain and snow mix on Wednesday night, and change to all snow before daybreak on Thursday.  It will snow all day on Thursday, and gradually diminish to flurries on Thursday night.  The wind will gust to 35 mph, and possibly higher, blowing the snow around, reducing visibilities making driving difficult.  The high on Thursday will only be around 32 degrees, and the low Thursday night will be in the upper teens.  The rest of the week will be cold with below average temperatures.

A Potential Snow Storm Later This Week

Low pressure located near La Crosse, Wisconsin will move to Green Bay by Sunday evening and continue northeast into the UP of Michigan on Monday. It will be cloudy overnight with some light rain possible. No measurable rainfall is expected.   Temperatures will remain fairly steady with a low in the middle 40's. On Sunday the drab weather will continue with clouds and a chance of a little light rain in the morning. The high temperature will be in the middle 40's. It will be mostly cloudy and cooler on Sunday night as winds swing around to the northwest dropping overnight lows down into the upper 20's.  Cold surface high pressure will be in place over the central plains on Monday.  An upper level disturbance passing over central Illinois on Monday afternoon could scatter some light rain showers or sprinkles into the Stateline on Monday afternoon.  It will be cooler, but still above average with highs in the upper 30's.  Skies will be partly cloudy, and it will be a little colder on Monday night with lows in the middle 20's.  Another disturbance could cause some rain or snow showers on Tuesday afternoon, but any precipitation should be minimal.  On Wednesday the high pressure ridge will be well to the east of the Stateline.  A storm system looks like it will beginning to put itself together over the Texas/Oklahoma panhandle area on Wednesday morning.  It will be partly sunny across northern Illinois with a high around 40 degrees.  The low will track toward the east on Wednesday night.  It will become quite intense with strong winds, and rain or snow will develop on Wednesday night.  Right now it appears as if the low will track into central Illinois by 6 am on Thursday morning.  If it travels just a little bit further south, the Stateline looks like it could be in for a heavy snow storm.  With the track through central Illinois it looks like a rain/snow mix gradually changing to all snow as the storm pulls off to the northeast on Thursday afternoon and night.   Friday will be partly sunny, windy, and colder with a high in the middle 20's.  Saturday will be a cold day.  The low in the early morning will be around 12 degrees, and the afternoon high will be around 24.

Late Week Storm to Impact the Midwest/Great Lakes

While rain falls this morning and afternoon we're already eyeing another significant storm system that could impact the Midwest and Great Lakes by next Thursday and Thursday Night.



European Model Thursday Evening

Even though it's several days out, low pressure looks to develop near the panhandle of Oklahoma and lift north of Springfield Missouri by Wednesday evening and then north of St. Louis, MO to just south of Chicago by Thursday evening.  A swath of heavy snow will likely fall somewhere from Iowa, Illinois, Wisconsin to Michigan by Thurday night.  It's just a matter of where exactly that band will be.   The first image on the left is a snap shot of the European model for Thursday at 6pm.  If this were to hold true precipitation would initially begin as a mixture of rain and snow late Wednesday night into Thursday morning.  As the low passes near Chicago a possible change over to heavier snow would occur from northwest to southeast.

The second image is a snap shot of the American GFS model during the same time period.  It also has a strengthening low developing by Thursday evening but it's shifted a little further northeast.  A shift in either direction would mean a big difference in precipitation type and accumulation.  We'll continue to analyze each model run as they continue to come in this weekend and early next week and provide the latest updates right here as shifts in the track and intensity are to be expected. 

Snow or Not... Drought Relief On Its Way

Everyone hoping for a White Christmas will not be happy with this weekend's forecast, but local farmers will be ecstatic. We may not talk about it as much now that the harvest is over, but the Stateline's ongoing drought is still a big problem.

Dec. 11th Drought Monitor

Here's the latest drought monitor from Tuesday, Dec. 11th. As you can see, the Stateline is still classified under a severe drought. This is important because farmers still need moisture over the winter months to make sure the ground is ready to go when planting season arrives in the spring.

This weekend's storm system is now being forecast as an all rain event. Rain moves in after midnight on Friday, and continues throughout the day on Satuday with a few lingering showers possible Sunday morning.

Potential Rainfall This Weekend

Our in-house models are showing a good 0.50" of rain possible with this system, but that is quite possibly on the low end of what we'll actually see. The National Weather Service is predicting up to an inch of rain possible this weekend for parts of the Stateline!

This won't be enough to break our drought, but it's definitely a step in the right direction. And for everyone hoping for a snowy holiday... don't panic just yet. Some models are suggesting some accumulating snow sometime near the end of next week, which is continued great news for our drought. For farmers, precip is precip!