Midweek Weather Briefing: Wednesday should remain generally dry, then transition to storms begin

Submitted by: Daniel Crawley (@SoApps1979)

 

Good Wednesday morning to everyone, we hope that your week has been a good one up to this point. So far in the weather world, I would categorize it as being pretty good across the Western Carolinas. Thunderstorm activity, at least on a widespread basis,  has taken a hiatus the past few days which for this forecaster has been greatly appreciated. Today should provide another break for the most part as storm chances are slight, however a gradual shift toward the return of active weather looks to be in the books as we round out the end of the work week.

 

First thing we’ll do is look at the early morning water vapor image and it shows what I would consider as a complex pattern, especially for the middle of August. Normally we are at the peak of the summer where the jet streak is furthest north, it’s usually a time in which not a lot is going on country-wide. But that can’t be said when looking at the water vapor as we have several upper level features, while detached from the main jet, is still playing a big role in what’s going on. There is one departing upper low over New England, the next feature is spinning around in the Central Plains states and is waiting for the New England feature to slide off so it can also eject east. The third upper feature of interest is located across Eastern Montana and slowly moving into the Dakotas.

 

 

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The New England upper low really pushed some drier air into the Western Carolinas on northwest winds aloft. That push of air really disrupted what had been a very unstable atmosphere for several days prior. Precipitable water values, which this time of the year is key player in storm development, have lowered significantly in the past 48 hours. You can see on the meso-analysis, PWAT values or 1.3 in or less pushed into North Carolina while the higher values (1.5+ PWAT’s) generally pushed south of Interstate 20. You will also notice back over the Mississippi River Valley how precipitable water values have recovered…those values will begin to push east over time.

 

 

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Today’s weather will continue to be dominated by down-sloping winds aloft and lower moisture content. A brief shower or storm cannot be ruled out late in the day but overall we continue to see ourselves in a quiet weather pattern. High’s today will top out in the mid/upper 80’s along Interstate 40 with a few low 90’s possible in our southern tier.

 

On Thursday we will begin to see a few changes as high pressure at the surface will begin to set up just off the east coast. Light and variable winds of Wednesday will begin to veer around to the south and southeast. That is going to accelerate the process of bringing deep low level moisture back into the Western Carolinas and with that expect a few extra showers and storms to develop with temps still in the upper 80’s to near 90.

 

 

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By the time we get to Friday an improved low level setup will start to receive assistance at the upper levels as well. The Central Plains upper low will have opened up into a trough axis by this point and will provide an extra trigger for afternoon and evening storms on Friday, just in time for the weekend! Friday evening is also the start of the high school football season in North Carolina, so I’m sure many people will be keeping an eye on the weather for the Week 1 Games across the region.

 

 

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Rain chances Friday/Fri Night will be generally in the 50 percent range and will also persist into the weekend ending this run of generally quiet weather. With the wind flow overall being quite light, we’ll need to keep an eye for areas of heavy rain potential where repeated storms might fire up. As you remember several parts of the coverage area racked up some hefty rainfall totals going back to last weekend. And even though its been dry as of recent, it won’t take many rounds of storms to saturate the ground again.

 

 

As we said this looks to be the pattern going into the weekend, as the feature moving east finally begins to exit on Sunday it will be replaced hot on its heels with the next upper trough. So overall we are getting back into a convective weather pattern with high precipitable water values. That should help keep daytime temperatures at or below seasonal norms going into early next week.

 

 

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Have a great day!