Archive for the ‘Weather’ Category

In the wee hours of Monday morning when the admins posted the fog risk threat for this week, there was more than enough factors in play to put Thursday morning at HIGH risk:  calm winds, a warm day, cool night, and most importantly temperatures expected to be near the freezing point.  After one of the admins got off work early Thursday morning around 02:00 – the fears were confirmed and by 04:30 the live feed cameras were only confirming what could been happening:

As the morning lows dipped to 28 in Alton the admins made at least two posts on Facebook warning that river fog was present with the freezing temperatures and extreme caution was to be taken.  If that was not enough, Laura Hettiger was running her mouth at least two times during the 05:00 hour on Channel 4 to be aware of the fog threat.  One of the admins went to bed before 06:00 and the other was on the way to work after 05:30 there was not a lot of monitoring on either the Facebook or Twitter accounts.

At or around 06:50, the first of the multiple incidents that happened in a 20 to 25 minute time window happened westbound west of 367 and a second happened eastbound between Lilac and Riverview:

Within 10 minutes this was being reported:

By the way, even around 06:45 there was still river fog in the area of the river bridge by a TV reporter that was making a trip across while en route to an unrelated story:

It was clear that the freezing river fog caused a few slick spots during the AM crunch time and as soon one happened, all shit broke loose.

The river bridge one was in a bad spot too causing crews from Mitchell Fire Department to walk to the scene to get to the people. Luckily only minor injuries were reported in this ordeal.

There were some live videos as well

In the end, the westbound lanes at the bridge were closed for over an hour and it takes at least 90 minutes before things return to normal. The average delay was at least 60 to 90 minutes.  This morning should reinforce why river fog under certain circumstances can lead to the big incidents and all three incidents were consistent with people allegedly driving too fast for the conditions.  In fact, we are approaching the 40th anniversary of one of the first epic fails that happened on this section of 270 and it happened on a morning with freezing temperatures and conditions favorable for river fog.  What happened this morning was minor compared to what happened on the morning of November 12, 1977, and back in the late 1970s there was not much of a morning news scene, no internet, no social media, and everyone relied on the evening newspaper to get their gossip and CB radio for traffic conditions.

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We are approaching the winter months, which can mean “anything goes” with Mother Nature – and that includes the return of severe weather potential.  While 2017 has been a quiet year on the severe weather front, the concern is the cold front that is projected to move through the afternoon hours.  The NWS has labeled this area at an enhanced risk, but we are on the fringes of that threat.

Weather often leads to infamous events happening here, especially between the months of November through May.  The biggest epic fails often happen during this time of the year – and more often than not on mornings that there is very favorable conditions of river fog.  In fact, in a few days we are approaching the 40th anniversary of one of the first epic fails that ever happened – on a very cold morning where conditions for river fog was allegedly favorable.

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Fog risk forecast returning

Posted: 2017/09/11 in Weather
Tags:

As the colder weather months approaches, the fog risk forecast is returning as the prime time for river fog and eventually inversion type fog will return.  In recent weeks there have been posts on Facebook on nights where there were favorable conditions for such development, and almost every morning those posts were confirmed.

The reason why risk forecasts are posted from September through May starting last season was a good reason: river fog during the fall, winter, and spring months has the potential for a AM peak disaster.  The risk falls under a few categories and other weather conditions may play in a role in the risk.

Low – the conditions for fog to develop are not favorable

Medium – favorable conditions exist but not likely to cause the NWS to release Dense Fog Advisories

High – favorable conditions exist AND the NWS is likely to release Dense Fog Advisories

 

Fog risk forecasts are only posted via the Facebook page, likely on Sunday evenings.  The forecasts for early week are more likely going to be accurate than late in the week so there will be time that Thursday/Friday risk will be deferred.  Unless otherwise noted the risk will only be valid from 05:00 to 09:00.

Why is River Fog so dangerous?

Some of the biggest epic fails during the fall and winter months came on mornings that conditions for river fog to develop were favorable – which is warm days, cool nights, and a lack of a wind.  River fog only develops late at night or first thing in the morning around or near sunrise, and is much more likely to develop over or near a body of water.  It tends to dissipate late in the morning. From October through April, the temperatures in the morning can flirt with the freezing point and that can turn fog into ice.

What is Inversion Fog?

Inversion fog is more likely to occur during this time of the year and it can occur at any time of the day.  It is essentially warm air trapped over cold ground with a lack of wind.  The main difference is that it can last 24/7 and it is not limited to the river valleys.  It too can occur when the temperatures are at or below freezing.  Unlike River Fog that can happen on a sunny day, inversion fog usually occurs on a cloudy or rainy day, but there are times it can occur on a clear day when there is snow on the ground.

While the potential of the heavy traffic from this weather event has been ignored by the admins due to other more pressing reasons (thanks to IDOT that decides to load the entire month of August so far with a lot of lane closures on 270 including the weekend before the eclipse), the fact this is such a rare weather event people will be making the trip to this area.

While this section of 270 is essentially on the fringes of totality (it will not be at 100% path but it has to be very close to 99%), its clear that IDOT and MoDOT been posting stuff on social media.

Find a safe spot to pull over and wait out the event.  Don’t forget the appropriate glasses.  Most of the influx of traffic the day before has been near the SIU campus for an unrelated reason.  Most of the traffic congestion is right before and shortly after the eclipse begins, as the majority of the people from out of state have opted to use campgrounds.  Still there will be heavier than normal traffic for the time of day, especially in South County where that section of 270 is in the path of 100%.

The NWS has set this area to Moderate Risk for severe weather as the main event is expected to roll through this area late this afternoon.  While this section of 270 is on the fringes of the Moderate Risk threat, the main threat of this outbreak being strong winds is a concern for the truckers that are using this road during the holiday weekend.

The admins think the worst will happen to the south and especially the southwest of here.  There is a preceding line forming that could affect the potency of the severe storms later this afternoon.

While a tornado watch is now out, it does not include this section of 270 at the time:

However, a severe storm watch was issued as the admins were writing this post:

Please stay weather aware this afternoon.

Today the NWS gave us bad news and confirmed that the Mississippi River at Alton will go past the 29 foot threshold as early as Monday.  The bad news when the river hits that point is that the southbound lanes of 367 just south of the Clark Bridge start to flood and that usually renders the southbound direction of the Clark Bridge off limits.alton-apr30at1700

The projected crest is on Wednesday at or around the 33 foot mark.

Based on an recent MoDOT press conference held this evening, the NB lanes of 367 will be converted into two-way traffic and that will help with the heavier than normal traffic on this section of 270. However, this also means that there will be delays in both the AM and PM peak starting Monday afternoon and lasting likely through the end of the week. Either way, traffic on 270 will be heavier than normal for a few days, the canal bridge area is a known choke point, and plan on delays on both the Clark Bridge and the Chain of Rocks.

While the NWS DOES NOT have Winter Weather Advisories in effect for this area (but they do have in effect in the counties along and north of I-72), snow is expected to come just before the Monday morning peak:

While the ground temperatures are above freezing, an recent cold snap and the fact nobody has seen the white stuff for two months may mean very slick roads. (There has been more severe weather outbreaks than inches of snow this season to put this in perspective.) With that in mind combined with a recent run of terrible form when it comes to the North County drive (with last week AM peak fatal MVA on WB 270 in consideration), the admins made the decision to put the AM peak at HIGH risk. (It is also a full moon out there as well so people may be driving much more crazier than normal.)

While not a lot of snow is expected (the worst is expected to remain to the north), the timing can cause big problems as it does not take a lot of snow to cause gridlock, given that 270 up in North County is hilly and the 1-3 inch range is where people often get complacent when it comes to snow.

Although some of the previous models have put this section of 270 on the fringes of the severe weather threat, some of the latest model runs this morning is pointing to an enhanced threat.  While the TORCON is set at 4, the biggest risk is an outbreak consistent with an derecho:


This is the second possible severe weather outbreak in a week, and the first one the threat just missed to the east with the hail while the worst was about 75 miles south.

The risk forecast for Tuesday morning has been upgraded to medium as is may affect the morning peak. Stay weather aware as conditions may change in an instant.

UPDATE 2/28/17 at 11:30 – the NWS has upgraded the risk to medium

While the winter has been a flop in one term (not even 2 inches of snow for the entire season and maybe a total of four winter weather events – and the last one was over six weeks ago), the anything goes mentality means that severe weather can be a threat.  The NWS has put this area in the enhanced risk for Tuesday evening/Wednesday morning time window, and while that threat is still subject to change it is the first major weather threat since mid January.  Fearing weather complacency and the recent run on very poor form when it comes to that Clark Bridge commute (three major incidents in the past two weeks), the admins are somewhat concerned and has hit the peak periods for Tuesday afternoon/Wednesday morning as HIGH RISK.

The bottom line is that people need to remain weather aware on Tuesday evening/Wednesday morning time window.  While the admins do not expect a direct hit during the peak periods there could be a isolated shower popping in time for the Tuesday evening peak and leftover rain for Wednesday morning.

For the first time in just over 10 years an ice storm warning has been put in effect.  The winter weather event that hit an month ago was just a dry run compared to what this storm is bringing and as such all the schools along 270 in North County and the Riverbend have called off classes for tomorrow.

To add to the misery, tomorrow is Friday the 13rh which is a day known to superstition as either good luck or bad luck.  With the past history with ice events along 270 we know it will likely bring bad luck out there so please stay off the roads.  A state of emergency has been issued for Missouri.  The worst will likely happen just to the southwest, but the storm could very well come in time for the morning peak.  The morning peak is going to be very questionable and the evening peak will likely be like this:

iced-earth-horror-show

The bottom line is stay home if possible because your kids are already home from school on what turned out to be a 4 day weekend for them.

If you must head out please note the crews will be out and treating the roads.  Earlier this afternoon they were out prepping the bridges:

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The NWS has issued the Ice Storm Warning for the area until Sunday, when the temperatures are expected to be warm enough to turn all the freezing rain into plain liquid rain and the conditions will slowly improve for the remainder of the event.

Remember, when there is ice, it takes very little to cause massive problems.