Monday, March 05, 2012

From One Extreme To Another... Flooding Possible?

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1 PM Tuesday Update... As I said yesterday, there are still uncertainties as to how this next weather maker plays out.  The models are having a difficult time in the long range for sure.  Right now, the forecast for Thursday into Friday appears very clear with a round of rain and some of it could be heavy as a front slowly eases into the state.  After that, there's the American GFS vs. the rest of the world.  There may be a break in the action as we head through Saturday, but another round of wet weather could surge back into the state.  The GFS disagrees!  There's no doubt we need the rain, however too much isn't a good thing.  Several farmers have told me that an excessive amount will delay their work in the fields.  They tell me they can handle an inch or maybe even two.  That would be nice to get as that should diminish the wildfire threat for awhile.  However, most of the modeling says many locations could see in excess of 3'' and maybe 5-6'' over the course of a few days.

I'll have a full update hopefully later today.  It's my day off from work and I'm enjoying time with the kiddos!  Blake is a mess and I think Preston is realizing that now.  I say "mess" in a good way.  The things he says are hilarious.  "Yes" is "ya-hey".  He loves it when I change light bulbs around the house.   He goes and brags to mommy,  "Blake fix light bulb."  Loving every bit of it.
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11:45 AM Monday update... The latest run of the GFS and even the Canadian confirm my uncertainty as to where the axis of heaviest rain will set up.  That data shows a shift to the west.  It's all dependent upon the placement of a frontal boundary and the upper level low.  More shifting by the models will take place over the next day or so, then we should have a clearer picture.
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I think mother nature is using her script from 2008.  We are following in the foot steps of that year to some degree. 2008 and 2012 have La Nina in common and both years were marked by an early and active severe weather season.  For Arkansas however, it hasn't been to the extreme as 2008.  The tornado season at this point was far more deadly.  Also, in 2008, flooding became an issue in March.  I hope we can escape this La Nina with a much smaller version of 2008!

Yes, I said flooding.  There will be a period of rainy days and some of it could be heavy.  HOWEVER, THERE ARE STILL QUESTIONS THAT MUST BE ANSWERED!  We are dealing with an area of low pressure aloft that will be cut off from the main flow.  These can be very tricky to forecast.  I still have questions as to where the axis of highest moisture will set up due to the placement of the system aloft.  Also, how long will this last?  The movement of the low will not be handled well by the models.  The longer it sticks around, the higher the rainfall amounts will be.  I have also seen these things pick up forward speed and get out of the region much faster than the models predict.  With that said, I think there's the POTENTIAL for several rounds of rain beginning late Wednesday.  Depending on the intensity and duration, flooding could become an issue.  Some models have this exiting by Friday while others have it hanging around like a bad house guest until Sunday.  So as you see, there are uncertainties.  But it's amazing to see the similarities with March of 2008 when flooding was an issue then as well, but I don't think (I hope) it will be as extreme.

It seems like in Arkansas, we never get our weather in moderation.  It's always from one extreme to another.  Wildfire danger at the beginning of the week to heavy rain at the end.

One more thing I'll throw out there, the following week looks dry and warm.  That's long term so we'll see how that pans out.  Also, many are wondering about the potential for severe weather.  While I can't rule that out, I think this is more of a heavy rain event!

I'm going to post a few maps below including the past three runs of the GFS.  They will show rainfall totals through the end of the week.  This will demonstrate the uncertainties.

This is the 500mb pattern from the GFS showing the area of low pressure aloft over Texas and Oklahoma.   This is the low that becomes cut off.  There are questions as to the speed of the low and the duration of the event.
This is the midday run of the GFS on Sunday.  This shows a plume of moisture across the eastern half of the state totaling about 2-3 inches.
The next run of the GFS begins to indicate an axis of higher rainfall amounts through the state totaling about 3-5''
The overnight run of the GFS indicates a much larger area of heavy rainfall across much of Arkansas with more than 5'' possible.   So you can see over the course of 3 consecutive model runs, there's uncertainty to the placement of the heaviest rainfall and the duration.  This is due to the placement and location of the system aloft.

HPC manual forecast shows much of Arkansas could see more than 3'' over the course of the 5 day period.

3 comments:

Mitchell said...

A lot of times forecasters predict these heavy rain systems here days in advance and then when it gets here we get .20 inch. When I see it raining heavy I'll believe the forecast.

tboyce1979 said...

I'm so ready for a rainy weekend!s

Omarr Wilson said...

Although there are still some uncertainty on the Ammount and placement of the rain. One thing is For Certain. We will get some rain. Rain on a weekend that your off of work. That's Awesomely awesome. The Next 24 Hours will tell the Tail. Stay Tuned. Facebook, Twitter, Arkansas Weather Blog.