An Active Pattern Ahead

Good Monday Morning my friends across WABBLES, I hope everyone had a great weekend and are ready for a great week ahead. In the weather world, there are lots of things to track and talk about, so let’s dive right into it with an active pattern ahead.

Time to sit by the window and look dramatically out in the rain (Giphy)


Today will be the first of many rain chances coming in the next week or so. Although better conditions for more widespread and heavier rain remains south of WABBLES in Tennessee, we will get in on some light and scattered rain starting as early as mid morning. Rain chances will continue throughout the afternoon and evening with an active pattern ahead.

WPC Frontal Chart

Aside from the dreary rain, temperatures also won’t escape the mid-40s leading to a cool and not so pleasant day around the area.

Model Highs for Tomorrow (Pivotal Weather)

Tuesday – Wednesday

Tuesday and Wednesday will feature more on again off again rain chances with the possibilities for some thunderstorms embedded within the rain. Rain showers will be scattered clusters providing occasional breaks before the next round arrives thanks to the active pattern ahead.

Model Future Radar Tuesday – Wednesday (Pivotal Weather)

Temps actually look to warm up a bit for Tuesday and Wednesday into the low – mid 60s. So, if you’re not the biggest fan of the cold, this would be good news if it weren’t for the rain.

Model Temps Tuesday – Wednesday (Pivotal Weather)

Thursday – Friday

Thursday and Friday is where things get complicated and dicey. All of these rain chances are leading up to a larger system passage that is expected Thursday Night into Friday. This has the potential to bring a swath of heavy rain and severe weather potential. Quite an active pattern ahead.

Model Radar Thursday into Friday (Tropical Tidbits)

Diving into the heavy rain threat first, there has been a notable northward trend in the GFS over the past few runs, putting the area of heaviest precip for the week over WABBLES. One thing to keep in mind, do not pay attention to rainfall totals, they will likely be inaccurate this far out. Rather, look at the overall pattern and where the larger totals are trending to set up.

GFS Trend Loop for Rainfall (Pivotal Weather)

So, keep in mind that heavy rainfall is very possible Thursday into Friday and rainfall totals in excess of 3-4″ is possible by the end of the week. This is currently nothing to panic over with an active pattern ahead.

Switching gears to severe weather, there is a low-end severe weather threat that looks to accompany this system. This is very conditional, however. I am confident that we will have strong upper-level winds in place (this is very common for this time of year).

Model 500mb level Winds (Pivotal Weather)

There will also be stronger winds in place at about 5,000 feet above the ground, this combined with the winds previously mentioned help produce what’s called wind shear. When we get into winter time, these strong winds are very common with storm systems. This is a crucial piece to the severe weather puzzle.

Model 850mb winds (Pivotal Weather)

Another crucial piece in the severe weather puzzle is moisture/instability, this is typically the wildcard that determines if we see severe weather at this time of year. Thanks to the warmer temperatures in place, the models are suggesting an area of dew points greater than 60 degrees will be in place for this system.

Model Surface Dew Points (Pivotal Weather)

Even though there looks to be enough moisture to help and allow instability to build, the models are suggesting that there won’t be much instability present at all. This is yet another crucial piece of the puzzle, and when you remove any of the pieces from the picture, the severe threat becomes very questionable, but not necessarily nonexistent.

Model Mixed-Layer CAPE (Pivotal Weather)

The bottom line is that:

  • A conditional threat for severe weather exists Thursday Night into Friday.
  • This is not a slam dunk forecast and questions still remain.
  • Do not panic or worry yet, stay tuned to weather outlets for future updates.

Long Range

Diving into the nitty gritty of the long range forecast, the -NAO pattern I discussed around Thanksgiving did in fact verify. However, we have largely been dealing with rather mild temperatures with only occasional cold shots not the overall cold pattern I suggested, why?

Model Blend NAO Forecast (Weather Models)

The other teleconnection I discussed around Thanksgiving was the PNA, the models suggested that it would trend closer to and end up going into its positive phase, allowing for the colder pattern with the -NAO. This somewhat happened, the PNA has ended up becoming rather close to neutral, but not quite as much as a few models suggested.

Model Blend PNA Forecast (Weather Models)

The models are wanting the PNA to slowly trend positive once again around the 17th or 19th of December, but given how close to the neutral line they all are, everything is still very questionable. So, until the PNA switches things up, you can expect normal to above average temperatures as suggested by the CPC 6-10 and 8-14 day outlook.

CPC Long Range Temperature Outlooks

That will be all for today my friends! I hope everyone enjoyed the discussion and are ready for an active pattern ahead. I encourage you all to visit our social media accounts linked below for the latest on the upcoming weather threats.

Have a blessed day.