More Severe Weather and Cooler Weather for Some

I’ve been absent from the Firsthand Weather website these last few days, but I’m hoping to start writing blogs a bit more consistently starting in May. This is usually the time of year that I begin to do a lot of my research on the upcoming hurricane season, summer/fall, and winter 2015-16. You won’t hear me saying anything about winter until later in the summer, but in the next few weeks, you will hear a lot more from me regarding the hurricane season. I’ll have an announcement on that soon.

April has been rather warm across much of the United States with a very active and wet pattern from the Southern Plains to the Gulf Coast states and extending into the Tennessee/Ohio Valley. For those of you in those mentioned regions, particularly if you’re in a place like Texas, I’m sure I just stated the obvious. This wetter pattern is going to continue for most of those regions, although a stronger trough in the eastern parts of the U.S. could begin suppressing moisture farther south next week.

In meteorology, you hear a lot about the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO), with both being particular important during the winter months. When there is blocking (warming) over the Arctic and Greenland, this can displace colder/cooler air farther south into the mid-latitutides, which includes parts of the U.S. The NAO is about to go into a negative phase and the AO into a neutral/slightly negative phase, which is something that didn’t occur much of last winter. Although this will be brief, this pattern will be bringing unseasonably cooler weather for much of the eastern third of the U.S. this week and particularly into next week.

GFS departures from average for early Monday morning:

departures from average

Ridging will be pretty persistent over the southern Gulf Coast states into Florida, which should keep those areas warmer, but the models do try to dig the trough pretty far south next week, which could bring a day or two of cooler weather. Although the southern-most regions could experience some of the cooler weather, the more noteworthy cooler temps will be farther north. The mid-section of the country will consistently stay warm with more volatile temps on the West Coast.

As far as heavy rainfall and severe weather, a heightened severe weather threat could set up across the Southern Plains towards the middle of this week, which I will discuss in detail in another article. A piece of energy from the Southwestern U.S. is going to eventually get absorbed into the eastern U.S. trough towards the weekend, and surface low pressure system will likely develop/strengthen as a response to the overall pattern. I expect more moisture to get pulled up from the Gulf this weekend as this low moves east, and the conditions could be favorable across portions of the Gulf Coast states for a severe weather threat. This would not be as far north as today’s severe weather, but it is something to keep an eye on for those a little farther south.

Wetter conditions are definitely possible again for many areas this weekend:

GFS wet

As you can see, there is a lot going on. Although this upcoming pattern will favor cooler temperatures for some, it’s important to understand that this pattern will likely not persist for most of those regions. A window will likely remain open for severe weather/tornadoes through at least much of May for the typical tornado-prone zones and even across portions of the Gulf Coast states, Tennessee Valley, and eastern U.S.

  • Jon Land

    It definitely felt like fall here in NW Ga. today. After all the rain and turmoil last week, it was nice to have a mild(cooler) day today.