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Wednesday, November 25, 2015

Record Rain



While a few showers will be possible Thanksgiving, especially over western Arkansas, the rain will become likely Friday and Saturday.  This may even extend into Sunday.

The Razorback game weather in Fayetteville will be brutal.  Temperatures falling through the 40s with heavy rainfall.  Remember, it could always be worse.  The Oklahoma State v. Oklahoma game in Stillwater Saturday evening will be even colder with rain possibly changing to ice.  That should be interesting to watch on Channel 7.

Remember I said to follow the Euro with temperatures Saturday.  I just looked at the newest run of the GFS  this morning and it's backing way off those 60s.  It may be close to 60 at midnight, but those readings will fall during the rest of the day.

Now onto the rainfall.  Little Rock has had 5.25'' so far this month and we could double that by early next week.  This could propel us into the top 10 wettest November's on record.

In west Little Rock, the monthly total so far is 7.61''.

Here are the top 10 wettest November's in Little Rock weather history.
  1. 2011 - 14.57''
  2. 1988 - 13.14''
  3. 2000 - 10.99''
  4. 1987 - 10.96''
  5. 1889 - 10.20''
  6. 1982 - 9.72''
  7. 2004 - 9.66''
  8. 1957 - 9.54''
  9. 1977 - 9.34''
  10. 1973 - 9.03''
I find it interesting that 5 of the top 10 wettest November's have all occurred since 1987.  This helps answer the question why November is our wettest month on average.  Those are 30 year averages which determine that and all those are years are included in that calculation.

Here are the model projections which should launch us into that record territory.

EURO 5 DAY RAINFALL 
GFS 5 DAY RAINFALL

Tuesday, November 24, 2015

Thanksgiving Weekend Forecasting Headache

I think it's a given we're going to have rain and plenty of it.  Once again flooding will be a concern.  I think Thanksgiving will be mostly dry with a few light showers mainly over western Arkansas.

The forecasting headaches begin Friday and really push into Saturday.  The GFS and Euro disagree on frontal placement and that plays a huge role in forecasting temperatures.  One GFS model run had the front through central Arkansas and temperatures only in the 40s Saturday and now the newest run has us in the 60s.  What about the Euro?  I go over all that in this very detailed video.




Thursday, November 19, 2015

Thanksgiving Weather And Beyond



Lots going on over the next week or two weather wise and that's very important considering we have the busiest travel day of the year coming up, Thanksgiving, shopping, and trying to get into the Christmas spirit!

As we first told you, a freeze is expected this weekend, but there could be even colder air down the road, plus another warm up.  It's all in this video

Also, I address the upcoming winter weather contest.




Monday, November 16, 2015

Storm Timing and Going Cold Turkey



This blog is loaded with tons of information...


  • SPECIFIC TIMING FOR RAIN AND STORMS MONDAY AND TUESDAY
  • SPECIFIC THREATS 
  • THANKSGIVING WEEK TEMPERATURES


Sunday, November 15, 2015

Update... Super Soaker



It's Monday night into Tuesday we're watching very carefully for the heavy rain threat.  Flash flood watches are already up as well.  There's also the risk for some severe weather and this video goes over everything you need to know.


Friday, November 13, 2015

Super Soaker!



1:10PM Friday Update... I posted this on twitter this afternoon.


The question isn’t, “if it will rain?” , but “HOW MUCH?”  Euro a bit more realistic… hopefully 

Both the Euro and GFS show the rain, but differ greatly on how this plays out.  The GFS closes the low off west of the state and keeps it west of us for quite awhile and high rainfall amounts result.  The Euro is more progressive.  It brings rain, then shoots the low northeast.  The answer?  It's a wait and see thing.  The Euro has been known to handle these things better, but if the low does close off, typically they are slow moving.  I'm taking the middle of the road approach at this time.




Here's the Euro next Wednesday at 6AM at 500 mb (about 20K feet up) .  The low is opening up and shooting northwest.  It's located near the borders of Missouri, Iowa, and Illinois.

The GFS is vastly different at the same time and has the upper level low over western Kansas.   See that closed black circle near Goodland, KS?  It's well west of us with a strong fetch of moisture ahead of it and disturbances affecting the state.  Huge difference in placement of the storm system

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If you watched the video yesterday, I pointed out the differences between the GFS and the Euro.  The GFS closes the low off and keeps it west of the state while the Euro closes the low and moves it more rapidly to the east.  History tells us closed lows often do not move fast at all giving the GFS a bit more credibility.  Usually the answer is somewhere in the middle.

The end result is in rainfall amounts and timing differences at to when the system leaves.  If you believe the GFS, our rainfall amounts could be extreme.  The Euro is nothing to brush off though.  It shows heavy rain, but not nearly as much as the GFS.

The position and movement of the low is crucial.  The circulation around the low will entrain dry air from the southwest and shut down precip, but the question is where and when.  This entrainment of dry air is very typical in these systems and we refer to them as a "dry slot".  When that arrives and shuts down the rainfall is what needs to be answered.  That will be slower if you believe the GFS and faster if you believe the Euro.


This is the European rainfall amounts through Wednesday morning at 5AM.  Believe it or not, this is the lightest between the two main models.  It's very possible to have at least 3-4 inches of rainfall.

Since the GFS is slower, it makes sense rainfall amounts are heavier with 4-6 inches possible.  I think the answer is somewhere in the middle.  Nevertheless, significant rainfall is likely.
This is 500mb from the GFS valid late Wednesday.  You see that closed line over southeast CO?  That's the upper level low. The GFS is much slower compared to the Euro.  That's why rainfall amounts are heavier with this particular model.
Here's the Euro during that same time period.  HUGE DIFFERENCE!!!  The upper low is on the Missouri/Iowa border.  This model is more progressive with the storm.  While it brings rain, it's not as heavy as the GFS.  As I said, the answer is probably somewhere in the middle.

Thursday, November 12, 2015

The Rain Faucet Stays On



What drought?  Once you get into a wet weather pattern, you stay in it for awhile.  We have yet another storm system next week to watch.  Both of the main computer models I look at have a strong area of low pressure affecting the state, but both have differences as to exactly how this will play out and that's very typical when you're talking about a forecast several days in advance.  Bottom line, both show the threat for heavy rainfall next Tuesday.

This video goes over everything you need to know.


Wednesday, November 11, 2015

BIG Rains Possible Next Week



It's a week away, but the main guidance we use both indicate a formidable storm system we must watch next Tuesday and Wednesday.  It's way too early for specifics, but at this time, it has the potential to be a big rain producer.

This video goes over everything you need to know!


Tuesday, November 10, 2015

BIG Storms Or No BIG deal?

As meteorologists, we always want to get it right, but the truth of the matter is only one person knows what will happen and it isn't me.  I can analyze the data all day long, but curve balls are always thrown.  I think once you accept that as a forecaster, the busts are easier to take.

As I look at the data today (Tuesday), I am cautiously optimistic we can escape with minimal severe weather, but remember, it only takes one.  With that said, I DO NOT WANT ANYONE TO LET THEIR GUARD DOWN!  I still think thunderstorms will develop, but the worst of this may be up into Missouri and Iowa.

At this time, it looks like wind shear is plentiful.  If storms were to get going, they would have the ability to develop rotation.

Now onto instability.  That's in question.  There will be some, but not a ton and the corridor of instability is very narrow as the front sweeps across the state.  Since this is a quick moving system, where rainfall (storms) do occur, flooding should not be an issue.

Once again, we MUST keep an eye to the sky Wednesday, but I think the worst of this will be well north of Arkansas.

Late afternoon instability is present, but not in huge amounts.  Notice how narrow the area is!
There will be large amounts of spin in the lower atmosphere along and ahead of the front.
While simulated radar is NOT perfect, this is valid late Wednesday afternoon and it shows a broken line of showers and thunderstorms from north central Arkansas into southwestern areas of the state.
Most of the state has a slight risk for severe weather.   There will be a 15% chance for severe weather (wind, hail, and an isolated tornado) within 25 miles of a given point.
The storm prediction center (SPC) has identified northern Missouri, western Illinois, and southern Iowa for a higher threat for severe weather.  Once again, we can't let our guard down.

Monday, November 9, 2015

Wednesday Weather Worries



Here we go with another round of fall thunderstorms as our secondary severe weather season is in high gear.  Thankfully, the last round of storms wasn't all that bad.  As we focus on this next round, there are a couple things that really stand out to me as I analyze the data.  First, the system Wednesday is a quick mover.  Second, the corridor for severe weather potential over Arkansas is quite narrow as instability will be in question.  Since this system will move quickly and the area of thunderstorm potential will be narrow, I don't expect flooding to be an issue.

There are other factors we need to consider.  This is a very strong area of low pressure moving into the central United States.  The air aloft is super cold.  This can help promote the development of severe weather.  All of the models agree the track of the low should be well north of the state.  I think it's closer to that track where you will find the worst weather.  So northern Arkansas up into Missouri will really need to watch this.   That does not mean other areas of the state are immune and things can't change since it's a couple days away.

Satellite imagery over the eastern Pacific shows the storm system quite well.  When you see this cloud pattern circled, it indicates very cold air aloft and the potential for deep convection (big storms).  I worked in western Montana for a couple of years straight out of college.  When these strong areas of low pressure aloft worked through (cold air aloft), we would get convective snow showers.  Lift from the mountains would also enhance their intensity.  I would be quite common to pick up several inches of snow in a very short amount of time in the higher elevations.  I was hiking once and got caught in one of these.  It came with a little thunder and lightning too.  Wild!!!!  At times, these convective snow bands would work into the valley areas of western Montana.  I remember quite well watching a wall of white moving towards me.  I picked up 2 inches of snow in 20 minutes from one of those snow squalls.  It was crazy.   I couldn't see my hand in front of my face.  Anyway, my point is this... the pocket of cold air aloft moving on top of relatively warmer surface temperatures will be conducive to promoting thunderstorms here.  NO SNOW though. LOL.  However, watch eastern Colorado and the Denver area.  They will have snow.
Here's the GFS valid late Wednesday at the surface.  The area of low pressure is well north of the state in Iowa.  The blue area is instability.  Notice it's in a narrow corridor from the Gulf up into the low.  Also instability values are not that high, however, there are times when the models underestimate this value.