Thursday, April 3, 2014

Severe Weather Today & Tonight

The threat exists for severe weather in parts of the Midwest today through tonight.  The brunt of this post is going to be for southeast Missouri, southern Illinois and western Kentucky.

The Storm Prediction Center has already issued a Tornado Watch for parts of southeast Missouri, southern Illinois and western Kentucky.  The watch is in effect until 7pm CT Thursday.


Looking over morning computer model data, it appears there will be a decent amount of divergence in the atmospheric column over southeast Missouri, western Kentucky, northwest Tennessee and northeast Arkansas, especially in extreme northeast Arkansas and the Missouri bootheel.  What this basically means is that there will be a lifting mechanism in the atmosphere.  Lifting air allows for thunderstorm development, amongst other things.

Data also suggests instability will be in place over the area through late tonight (10pm-12am).

As of 1pm CT, there is ample "fuel" in the air over southeast Missouri, southern Illinois and western Kentucky.  The area is located in the "warm sector" of the storm.  Dew points have already climbed in to the 60°s.  The moisture, indicated by dew point temperature, acts as the gasoline for the storms.

All we need now is a trigger.  Oh wait, there is a trigger.  An area of low pressure is currently located over eastern Kansas and western Missouri.  This will move to the east and bring a cold front through the area overnight.

So here is my thinking as of now...

There could be two rounds of storms in southeast Missouri, southern Illinois and western Kentucky.

First round is this afternoon where scattered thunderstorms will be possible.  These storms will have the potential to drop large hail, tornadoes and gusty wind.

Second round comes through later tonight as a squall line develops over southwestern Missouri and western Arkansas.  The storms contained within the line will have the potential to produce damaging winds, hail and a couple of tornadoes.

Right now, I think the biggest threat for tornadoes will come during the first round this afternoon through early evening.  Any discreet cells that develop will need to be watched closely.  I'm not saying there couldn't be a tornado later tonight, but I think the better chance will be with the first round.

I used to play a little game where I would pick my target location for storm chasing.  If I were chasing today, my initial target would be Piggot, Arkansas.  Keep in mind, part of choosing a location is for the ability to re-position myself if things change.  Strategically, Piggot would be my spot.

FREAK-OUT-METER:

  • Southern Illinois: 6
  • Western Kentucky: 6
  • Southeast Missouri: 6
  • Missouri Bootheel: 7
Be sure to have a way of receiving severe weather alerts this afternoon/tonight.  If you have a NOAA weather radio, be sure the batteries work and the unit is turned on.

Do NOT rely on warnings from Facebook.  I've discussed this before, but due to Facebook algorithms only 3%-7% of status updates are available for viewing in news feeds.

Twitter is an ok option.  Be sure to follow me at @johndissauer where I send out watch and warning information along with other bits of information on a more real-time basis.

Friday, March 28, 2014

Around the Corner; Looking Long Range in to April

Have some extra time and looking at the experimental looooooooong range computer model projection from the European forecast agency.  I don't see any horrific cold snaps coming to the Midwest or Colorado anytime over the next month.  That isn't to say there won't be days below normal, as I think there likely will, but noting long-standing.

Here are a few observations from the data that goes out to April 27.
  • Pacific storm arrives to west coast April 1.
    • Cooler air arrives April 3.
    • Impacts Great Lakes April 4.
  • Upper-low develops over NW United States April 8.
    • Transitions to upper-Plains April 9-10.
    • Sends storms to Midwest April 11.
  • Warming up in Colorado April 14.
  • Warm-up in St. Louis and Indianapolis April 15.
  • Warm-up in Colorado and central Plains April 17.
  • Warm-up in Missouri, Illinois, Indiana, Kentucky, Arkansas, Tennessee April 18-19.
  • Upper-level ridge develops over western United States April 19-22.
    • Pacific storm arrives April 24 breaking down ridge.
  • Ridge re-develops over western United States April 27 until ?? (This is the outer edge of the computer model's projection.)
  • Cool and active weather in Midwest/Great Lakes/Northeast United States April 27 until ?? (This is the outer edge of the computer model's projection.)
Keep in mind, the model is just that.  A computer model.  The farther out the model looks, the higher the error rate.  The key to looking at this kind of data is to not look at specifics but instead trends and long wave patterns.

Monday, February 3, 2014

Monday Night Update: Mid-Week Winter Storm

New evening data is in the process of coming in and I've had a chance to look over it.  A slight southward jog in the track of the storm is evident from the computer models.  Last night I mentioned that the storm was taking a Monroe, LA to Nashville, TN track.  Tonight's runs are taking it on more of a Jackson, MS to Lexington, KY track.  This would favor more snow development for areas of Illinois and Indiana.
0z GFS - 6pm CT Tuesday
(Click image to see larger version.)
While there is a southward jog to the track of the low (not by much), this does not mean freezing rain/sleet will not be an issue, especially in southeast Missouri, extreme southern Illinois and western Kentucky.  In fact, freezing rain could cause issues for extreme southeast Missouri and western Kentucky.  As far as icing is concerned, I do think we are talking less than 1/3" of ice for places like New Madrid, MO, Caruthersville, MO, Kennett, MO, and Paducah, KY.

A little further north, in places like Poplar Bluff, MO, Cape Girardeau, MO, and Vienna, IL there could be a glazing of freezing rain mixed with sleet and followed up by snow.

Areas near Columbus, IN and south will be borderline.  Several computer models suggest it will be cold enough to keep things all snow.  A few other models suggest a period of freezing rain/sleet before changing over to snow.

As for amounts of snow... I have gone through an put together another snow matrix so you can get an idea of what several of the computer models are suggesting.
(Click image to see larger version.)
(Click image to see larger version.)
As for how much snow I think will accumulate.

ILLINOIS:
  • Mt. Vernon: 4"-6"
INDIANA:
  • Columbus: 4"-8"
  • Indianapolis: 6"-9"
  • Lafayette: 6"-10"
MISSOURI:
  • Cape Girardeau: Up to 2"
  • Poplar Bluff: 1"-3"
  • St. Louis: 4"-7"
FREAK-OUT-METER

For those that don't know what my Freak Out Meter is, it is a number I give out that attempts to quantify how big of a deal the upcoming weather event will be. It is based on a 0-10 scale. Zero being the lowest, "not a deal at all", and 10 being "get all the bread, milk and eggs and lock yourself in the basement". The score is 100% subjective and it's an attempt to have a little fun.

ILLINOIS:
  • Mt. Vernon: 4
INDIANA:
  • Columbus: 5
  • Indianapolis: 5
  • Lafayette: 5
MISSOURI:
  • Cape Girardeau: 4
  • New Madrid: 6
  • Poplar Bluff: 4
  • St. Louis: 4
As always, be sure to follow me on Twitter (@johndissauer) as I often have more frequent updates there as opposed to writing a new blog post.

I'm going to be dealing with my own round of snow in Colorado (where I now work/live) Tuesday so time permitting, I'll try to update my blog Tuesday night.

Sunday, February 2, 2014

Starting February with Snow & Ice

There has been a lot of talk in the one to two weeks about a colossal storm heading for the Midwest this week.  A lot of the talk and hype has been extremely irresponsible, but that is a discussion for a different day.  It does appear a storm will impact the Midwest Tuesday and Wednesday.

One of the reasons I have been relatively quiet about the storm and its potential is due to the many different solutions computer models were coming up with.  Some had it as a HUGE ice storm, others as a HUGE snow storm and most had it somewhere in between.

Patience is a virtue sometimes when it comes to weather forecasting.  Let the models battle it out for a while and then start to come up with a somewhat unified solution to what the storm could do.

This is a storm that is going to develop over far southern New Mexico, western Texas and northern Mexico.  As it matures, moisture will become plentiful as it taps in to the Gulf of Mexico Tuesday.

Here is a solution the latest run of NOAA's Global Forecast model has come up with.  The image depicts 6pm CT Tuesday.
0z GFS - 6pm CT Tuesday
(Click image to see larger version.)
This is a classic winter storm for the Midwest.  The surface center of low pressure is tracking from around Monroe, Louisiana to just south of Nashville, Tennessee by Tuesday evening.  We're talking snow along and north of I-44 in Missouri and roughly along I-70 in Illinois.  This also means the rain/snow line is at play for southeast Missouri, southern Illinois and western Kentucky.

At this time, I do think all forms of winter precipitation will be possible for southeast Missouri, extreme southern Illinois and western Kentucky.  The primary nuisance will be rain, freezing rain and sleet.  There will probably be a change over to a little snow towards the end of the event.  The exact location of the rain/snow line is a little difficult to pinpoint this far out.  As you often hear meteorologists say, "The track of the storm will be extremely important." and this will be the case this time.  A change in just 40-miles will have a huge impact on what type of precipitation falls.

Right now, for places like Cape Girardeau, Paducah, and Poplar Bluff, I think rain, freezing rain and sleet will be the primary types of precipitation.  Icing could potentially be a concern, but let me say right now... This is NOT anything like the ice storm of 2009.  NO WHERE CLOSE.

TALKING SNOW

Let's talk a little snow for the Midwest.  I have gone through and looked at several computer model runs and have come up with a snow matrix.  Looking at the matrix can give you an idea of the range computer models are suggesting could happen through Wednesday night.  The data includes tonight's runs of the NAM and GFS and also Sunday morning's run of the European forecast agency's computer model as well as the 23-member SREF ensemble.
Missouri/Illinois Snow Matrix
(Click image to see larger version.)

Indiana Snow Matrix
(Click image to see larger version.)

Colorado Snow Matrix
(Click image to see larger version.)
As you can see, there is some variation between the computer models, but I must say, they are coming in to line with each other.

For many, the storm is still out 36 to 48 hours but I'll go ahead and throw out some ball park numbers.  I hope to update my blog tomorrow evening (time permitting) with fine tuned numbers.  Although, if you have followed my blog for a while, you know that my initially numbers usually only get slightly tweaked.  Think of it as a very time course correction.  But do know, these numbers can adjust as we get closer to the event.

COLORADO: (Monday night through Wednesday afternoon)
  • Colorado Springs:  3"-5"
  • Lamar:  5"-9"
  • Pueblo:  2"-4"
  • Springfield:  4"-6"
ILLINOIS: (Tuesday through Wednesday night)
  • Mt. Vernon:  2"-5"
INDIANA: (Tuesday through Wednesday night)
  • Columbus:  4"-8"
  • Indianapolis:  6"-8"
  • Lafayette:  5"-9"
MISSOURI: (Tuesday through Wednesday night)
  • Cape Girardeau:  Up to 1"
  • Poplar Bluff:  Up to 2"
  • St. Louis:  3"-5"
FREAK-OUT-METER

COLORADO:
  • Colorado Springs: 2
  • Lamar: 5
  • Pueblo: 2
  • Springfield: 4
ILLINOIS:
  • Mt. Vernon: 5
INDIANA:
  • Columbus: 5
  • Indianapolis: 5
  • Lafayette: 5
MISSOURI:
  • Cape Girardeau: 4
  • Poplar Bluff: 4
  • St. Louis: 3
For those that don't know what my Freak Out Meter is, it is a number I give out that attempts to quantify how big of a deal the upcoming weather event will be. It is based on a 0-10 scale. Zero being the lowest, "not a deal at all", and 10 being "get all the bread, milk and eggs and lock yourself in the basement". The score is 100% subjective and it's an attempt to have a little fun.

For more frequent updates, be sure to follow me on Twitter at @johndissauer.

Thursday, January 9, 2014

Northern Lights Visible Tonight To Some

Strong coronal mass ejection, CME, from the Sun has arrived to Earth.

Space forecasters say that a strong CME arrived to earth around 1pm MT Thursday.  According to NOAA, a large Earth-facing solar event happened on the Sun January 7, 2014 sending the energy towards Earth.

Sunspots on Sun
(Click image to see larger version.)
Is this unusual?  Not at all.  CME's happen frequently through the year.  This CME comes from one of the largest sunspots in the current solar cycle. (see right image)  The sunspot area covers 124,000 miles.  The largest core within the region is three times larger than the Earth.

NOAA forecasters predict this event will be a G3-class.  That classifies it as "strong" with minor affects to power systems and could produce intermittent GPS navigation disruption along with high-frequency radio transmissions.  With a G3-class event, auroras can be seen as far south as Oregon, Wyoming and Illinois.

The aurora borealis, also known as the Northern Lights, will likely not be visible in southern Colorado.  However, they might be visible in northern parts of the state. If you want to give it a try, go out once the sky is dark.  If you are in southern Colorado look north along the horizon.

X-ray image of the Sun from
GOES satellite.
(Click image to see larger version.)
Daniel Barker, director of CSU-Boulder's Labratory for Atmospheric and Space Physics, describes the aurora borealis "They are brilliant dancing lights in the night sky caused by intense interactions of energetic electrons with the thin gases in Earth's upper atmosphere," said Baker. "The aurora are most commonly seen in Alaska, northern Canada and Scandinavia when the sun sends out powerful bursts of energy that can strike Earth's protective outer magnetic shield called the magnetosphere."

Additional Information:

Sunday, January 5, 2014

9:30am Weather Update

Things are still looking on track with winter storm moving through the Midwest today.  I have already seen reports of 3" to 5" of snow across the St. Louis area and 1" to 3" across central Indiana.

National radar composite from 10:23am CT.
I have been hearing several people complain about rain falling this morning in parts of Missouri and Indiana.  Keep in mind, all day yesterday I had said there would be rain in the morning and it would change over to snow in the afternoon.  That is still expected to happen in a couple of hours.  Patience.

I have been taking a quick glance at some of the data coming in this morning.  I'm feeling pretty good with most of my snow forecast but I am going to make a few minor tweaks.

SNOW FORECAST

ILLINOIS:
  • Mt. Vernon:  8"-11"
INDIANA:
  • Columbus:  4"-7"
  • Indianapolis:  8"-12" (Locally higher amounts possible.)
  • Lafayette:  9"-13"
MISSOURI:
  • Cape Girardeau:  4"-7"
  • Poplar Bluff:  4"-7"
  • St. Louis:  8"-11" (Locally higher amounts possible.)
FREAK-OUT-METER
Normally the Freak-Out-Meter is based off precipitation but this time the numbers are going to be a little higher because I'm combining snow with the dangerous cold air coming in.

Keep in mind, the Freak-Out-Meter is based on a 0-10 scale.

ILLINOIS:
  • Mt. Vernon: 7
INDIANA:
  • Columbus: 6
  • Indianapolis: 8
  • Lafayette: 8
MISSOURI:
  • Cape Girardeau: 6
  • Poplar Bluff: 6
  • St. Louis: 8
BOTTOM LINE
  • Snow will continue through Sunday afternoon/night.
  • For places like Poplar Bluff, Cape Girardeau, and Columbus (IN) there will likely be a period of rain during the morning.  It should change over to snow by late morning/early afternoon.
  • The snow could be heavy at times during the afternoon with snow rates in excess of 1" per hour.
  • Winds will increase and there will be drifting snow.
  • COLD air will arrive Sunday and linger through Tuesday.  Wind chills will drop to -30° to -40° in some areas.
  • Because of the cold air coming, be sure to not have your gas tank on empty.  Gas could freeze if your car is parked outside.
  • Travel is not advised Sunday night and Monday.  If you must go out, be sure to have blankets and other survival items in your vehicle in case you get stranded.
  • Be extremely careful when you go out to shovel snow Sunday evening and Monday morning.  I'm not talking about slick spots in the driveway, but be careful of the bitterly cold air.  Frostbite will be a serious concern.
As always, for more frequent updates follow me on Twitter: @johndissauer.

12:30am Weather Update

A quick update to show you what the evening run of the computer models are suggesting.  Generally speaking, they have come in a little "wetter", meaning they are suggesting there is more moisture to play with.

Here is a look at a matrix of snow amounts I have come up with for 26 various computer model runs.
(Click image to see larger version.)
You can compare the numbers to what the morning runs were suggesting by going to my earlier blog post.

When you compare Saturday morning's versus Saturday evening's runs this evening's runs are roughly 8%-15% higher.  That being said, the above numbers are numbers straight from forecast models.

My overall thinking hasn't changed much, although I am tweaking the numbers a little bit.  In some situations, there may be a little bit more rain during the morning in places like Cape Girardeau, Poplar Bluff, Carbondale, Bloomington, IN and Columbus, IN.  By afternoon, it should change back over to all snow.  In fact, the snow could be heavy at times during the afternoon along I-70 from St. Louis to Indianapolis and across areas north and south of I-70.

SNOW FORECAST

ILLINOIS:
  • Mt. Vernon:  8"-11"
INDIANA:
  • Columbus:  6"-9"
  • Indianapolis:  8"-12" (Locally higher amounts possible.)
  • Lafayette:  9"-13"
MISSOURI:
  • Cape Girardeau:  5"-8"
  • Poplar Bluff:  4"-7"
  • St. Louis:  8"-11" (Locally higher amounts possible.)
FREAK-OUT-METER
Normally the Freak-Out-Meter is based off precipitation but this time the numbers are going to be a little higher because I'm combining snow with the dangerous cold air coming in.

Keep in mind, the Freak-Out-Meter is based on a 0-10 scale.

ILLINOIS:
  • Mt. Vernon: 7
INDIANA:
  • Columbus: 7
  • Indianapolis: 8
  • Lafayette: 8
MISSOURI:
  • Cape Girardeau: 6
  • Poplar Bluff: 6
  • St. Louis: 8
BOTTOM LINE
  • Snow will start early Sunday morning.  It will continue through Sunday afternoon/night.
  • For places like Poplar Bluff, Cape Girardeau, and Columbus (IN) there will likely be a period of rain during the morning.  It should change over to snow by late morning/early afternoon.
  • The snow could be heavy at times during the afternoon with snow rates in excess of 1" per hour.
  • Winds will increase and there will be drifting snow.
  • COLD air will arrive Sunday and linger through Tuesday.  Wind chills will drop to -30° to -40° in some areas.
  • Because of the cold air coming, be sure to not have your gas tank on empty.  Gas could freeze if your car is parked outside.
  • Travel is not advised Sunday night and Monday.  If you must go out, be sure to have blankets and other survival items in your vehicle in case you get stranded.
  • Be extremely careful when you go out to shovel snow Sunday evening and Monday morning.  I'm not talking about slick spots in the driveway, but be careful of the bitterly cold air.  Frostbite will be a serious concern.
As always, for more frequent updates follow me on Twitter: @johndissauer.

Saturday, January 4, 2014

Major Winter Storm To Hit Midwest

You've likely heard about it for days.  A major winter storm is taking aim on the Midwest and now we are twenty-four hours from it's arrival.

First and foremost, in my opinion the BIGGEST impact from this storm is going to be the barbaric cold air coming down from the arctic for Monday and Tuesday.  Temperatures projected to be experienced early in the week haven't been felt in this part of the country for nearly 20 years (if not longer).

Temperatures Monday morning are expected to drop well below zero.
12z ECMWF - Projected low temperatures Monday morning.
(Click the image to see larger version.)
Don't expect the air to warm much through the day Monday.  Many locations, especially in central Indiana will struggle to reach -5° during the afternoon.  We're talking temperatures in some locations of Indiana, Illinois and Missouri 40° to 50° below normal.
12z ECMWF - Temperature departure from normal Monday afternoon.
(Click the image to see larger version.)
The most asked question I have received in last three days is about snow.  Yes, there is going to be snow across much of the Midwest.  My concern is not so much with the snow, but instead when people go out to shovel the snow... Spending 30-45 minutes clearing their driveway and not being prepared for below zero temperatures and wind chills -20° to -35°.  Frost bite will be a BIG concern Monday morning along with exposure.

SAY IT AIN'T SNOW

Now to get on to what everyone wants to know.  "How much snow are we getting?"

I have been holding off on putting out numbers until close to the event because the storm still had a few wobbles in it and I didn't feel comfortable putting out numbers I didn't feel confident in.  Now that we are within 24-hours from the start of the storm, and now that all the morning computer model runs are in, I feel a bit more confident with the numbers.

I have gone over 26 computer models from this morning's runs and have come up with the snow matrix below.
(Click the image to see larger version.)
In the snow matrix you can see how much snow I think the computer model is suggesting.  It includes a blending of snow ratios I think we could be dealing with.  Due to the cold air coming in towards the tail end of the system, we could see snow ratios as high as 23:1 in some locations.  At the same time, some locations near the Ohio River, could see several hours of rain mixed in.

Keep in mind, the numbers on the snow matrix is not my forecast.  Here is what I am thinking as of this morning.

ILLINOIS:
  • Mt. Vernon: 8"-11"
INDIANA:
  • Columbus: 7"-10"
  • Indianapolis: 8"-11" (Wouldn't be surprised by a 12" amount somewhere.)
  • Lafayette: 8"-12"
MISSOURI:
  • Cape Girardeau: 4"-7"
  • Poplar Bluff: 4"-7"
  • St. Louis: 6"-10" (An 11" amount wouldn't surprise me.)
The majority of snow in Illinois, Indiana and Missouri will end by Sunday night and will start anywhere from Saturday evening through early morning Sunday.

I mentioned rain mixed in for some areas.  Some of the data is suggesting temperatures will be warm enough at the start to keep things rain until the cold air arrives.  Once it does so, rain should quickly change over.  Also, in southern Indiana (Columbus) it could start as snow early morning Sunday, change over to rain for a few hours, then change back to snow by Sunday afternoon.  For Columbus, if the changeover to rain does not happen, we could add another 2" to 3" of snow to the total I mentioned above.

FREAK-OUT-METER:
Normally the Freak-Out-Meter is based off precipitation but this time the numbers are going to be a little higher because I'm combining snow with the dangerous cold air coming in.

Keep in mind, the Freak-Out-Meter is based on a 0-10 scale.

ILLINOIS:
  • Mt. Vernon: 7
INDIANA:
  • Columbus: 7
  • Indianapolis: 8
  • Lafayette: 8
MISSOURI:
  • Cape Girardeau: 6
  • Poplar Bluff: 6
  • St. Louis: 8
BOTTOM LINE
  • Snow will being Saturday night through Sunday morning.  It will continue through Sunday afternoon/night.
  • Winds will increase and there will be drifting snow.
  • COLD air will arrive Sunday and linger through Tuesday.  Wind chills will drop to -30° to -40° in some areas.
  • Because of the cold air coming, be sure to not have your gas tank on empty.  Gas could freeze if your car is parked outside.
  • Be extremely careful when you go out to shovel snow Sunday evening and Monday morning.
As always, for more frequent updates follow me on Twitter: @johndissauer.

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