Potentially Serious Severe Weather Threat Tonight

Good Friday Morning WABBLES! I have got quite the blog post for you today with plenty to discuss. I wish I had better news, but a potentially serious severe weather threat will take place tonight.

Today

The SPC has most of WABBLES in an Enhanced Risk (Level 3/5) for severe weather tonight into tomorrow. This is a tornado and damaging wind-driven threat, so those will be the biggest concern.

Before I talk about how this will evolve, here is a graphic by the SPC to better understand their risk categories.

So, to start off this analysis of the severe weather threat, let’s first look at the moisture and highs that we could be experiencing today. Highs will likely break 70 for some across the area today, but it may take a good chunk of the day to reach it.

Thanks to southerly flow in the atmosphere, an abundance of moisture from the Gulf of Mexico will be pumped into the region. This flow will help build instability and temperatures to around 70 for some, even though models are suggesting slightly below 70.

Those 60+ degree dewpoints that we will be seeing are what we would experience in spring and even into summer, not the greatest sign when dealing with storms in December. This will be what we call a low cape high shear event, which means instability may be on the lower side, whereas the wind shear will likely be very strong.

Unfortunately, these wintertime events are so anomalous compared to what the models are used to computing, they will tend to struggle and disagree with each other on how things take place. That is exactly the case tonight, models are struggling with the timing of the actual event (how soon or how late do storms start to fire) and how much instability we will be dealing with. Right now, I will lean towards the more modest model in terms of instability that shows the best energy just off to our west. However, there is still enough energy over us to cause a concerning problem.

The overwhelmingly strong atmospheric characteristic at play will be the winds, this will help offset the potential lack of instability and keep a severe weather threat present. Circled below you can see a huge swath of wind shear with values of 50 knots up to about 65 knots that look to be present. This will help keep a severe weather threat alive in the winter.

Now, models are struggling like I said so take this with a grain of salt, but here is an idea of what future radar could look like tonight. Storms look to get going after 7 pm with pop up cells, these will need to be watched for tornado and damaging wind potential. Then, as the cold front comes closer, more messy linea-like storms will develop and advance towards us.

All in all, there is unfortunately some serious potential for severe weather tonight into tomorrow across the region. The main concerns will be damaging wind gusts within storms and a potential line of storms, followed by a threat for tornadoes. I would say the timeframe of concern at this moment would be 7 pm to 9 am.

Regardless of your risk categories tonight, the chances for severe weather are present and should be taken seriously. Below are a few tips for preparation and what to do in the event of severe weather and tornado warnings.

Other suggestions:

• Have at least 2 ways to recieve warnings at night (storm sirens do not count!)
• Have shoes ready in case you need to go to your tornado safe room, helmets, blankets, and winter coats are also a good idea.
• Have your phone fully charged or a battery powered radio ready to listen to updates if you lose power.

Saturday

Saturday Morning will feature the remnants of the severe weather threat from the night before. We should see an all-clear from severe weather by mid-late morning. The SPC does have another Marginal (Level 1-5) to Slight (Level 2/5) risk in place for WABBLES to account for that morning threat.

By the afternoon, we should see the passage of the cold front and rather uneventful rest of the day, actually. Temps will cool throughout the morning and afternoon into the mid-upper 30s.

Winds on the backside of the front in the afternoon will be mildly gusty as well, but will be in the process of dying down throughout the day. Gusts up to 20 mph are possible.

Sunday

Sunday will see the dominance of high pressure returning to the region, resulting in very calm and quiet conditions.

That high pressure should help us break out the sun by the afternoon, ultimately leading to a pretty nice day. Highs will also be in the mid 40s, so it’ll certainly be chilly, but not too bad out there.

Long Range

Looking at the long range pattern that the models are wanting to hint at is quite interesting. After this weekend, we will usher in a somewhat quiet period with warmer than average temperatures once again making a return. The CPC 6-10 day temperature outlook shows this nicely.

This warmer than the average pattern is being driven in a large part to the positive phase of the NAO (North Atlantic Oscillation) that we have been experiencing. Remember, the NAO is a teleconnection pattern that has been known to have strong influences on the eastern portion of the US. Especially during the wintertime. Thus, this and other teleconnections can be used to predict longer-range patterns for parts of the country.

In the models’ forecast of the NAO, we have another uptick in the positive phase expected as we go into quiet and warm period next week. However, once we start to get to the 19th to the 21st timeframe, we see the models wanting to flip into the negative phase of the NAO. During the negative phase, our region of the country typically experiences a better supply of cooler air.

Unfortunately, there is a caveat just like in any long-range forecast. Another teleconnection that I have discussed before, the PNA (Pacific North American Pattern) looks to exhibit little to no change from the negative phase throughout this timeframe. When in the negative phase of the PNA, our region typically experiences a better supply of warmer air.

One final teleconnection I will talk about today is the EPO (Eastern Pacific Oscillation). The majority of the models have the EPO flipping to a weak negative phase around the same timeframe as the NAO. The negative phase of the EPO also typically allows for a better supply of cooler air into our region.

So, what does all of this mean? Well, signs are there for a pattern shift around the 19th to 21st of December that should allow for cooler overall conditions, at least for a short while. We have at least 2 solid teleconnections pointing towards this, and 1 against this. So, the possibilities are certainly there for colder weather but it isn’t a slam dunk quite yet.

That will be all for this blog post folks! Please stay weather aware tonight and have multiple ways of receiving warnings. Linked below is our social media platforms which I highly encourage everyone to visit, as we provide more frequent updates there.

Have a blessed and safe day!