Tropical moisture has been streaming northward the past few days across portions of the southern Plains. That is teaming up with a slow moving system out of the west, and will lead to the potential of heavy rain across the region over the next few days. Let’s break down how much rain may fall, who is under the flood threat, and how a tropical system in the Pacific may enhance the heavy rain potential.
Heavy Rain & Flooding Likely
With the slow moving nature of the system, along with plenty of Gulf moisture to work with, rainfall amounts are expected to be quite heavy over the next five days. A general area of 5″ or more is possible over much of Texas northward into Oklahoma as we work through the weekend, but some areas may receive up to ten inches by the time the weekend is over.
— D.J. Kayser | Praedictix (@dkayserwx) October 22, 2015
In fact, some of the models are showing a good 3-5″ of rain this evening and into the overnight hours alone in parts of Oklahoma. This is the 15z run of the HRRR model from this morning, showing approximately 3″ of rain for the Oklahoma City area this evening.
Flash Flood Watches are already in effect for parts of Texas and Oklahoma due to the amount of rain expected in a short amount of time. While the forecast may currently call for up to ten inches of rain in spots, it’s hard to tell where the best pockets of that may occur as it’ll be up to smaller scale features that set up, such as slow moving storms or storms that “train” (move over the same area over and over) each other.
Dallas is one of the expected to be hit hard with rain over the next few days. The best timing for rain in the Metroplex appears to be Friday into Saturday. The potential of six or more inches of rain is there across the region by Sunday.
What Role May Patricia Play?
You may be wondering what a system in the Pacific has to do with the heavy rain in Texas. Well, as Patricia makes landfall later this weekend in Mexico, some of the systems mid-layer moisture and energy will be streaming northward. This will help to give the overall system a boost, providing more lift and the potential for more heavy rain to fall in the Southern Plains.
Texas Back In Drought
You may also remember earlier this year another heavy rain event hit portions of the southern Plains, with some parts of Texas and Oklahoma receiving over 20″ of rain during the month of May. That ended the drought that had been occurring for a long time in most of these areas. However, since about mid-summer, many areas could not buy a drop of water out of the sky, and a drought has quickly reformed in this portion of the country. While they could use the rain, once again it looks to come all at one time, which really isn’t good news as it leads to the possibly of flash flooding.
(CHECK OUT YOUR FORECAST: wx.aerisweather.com)
– Meteorologist D.J. Kayser